DESCRIPTION

CONTROL DEVICE FOR AC ROTATING MACHINE

Technical Field

[0001]
This invention relates to a control device for an AC rotating machine having a current limiting function for protecting the AC rotating machine and its drive circuit from over-current.

Background Art

[0002]
The conventional control device for the AC rotating machine of this kind was disclosed in JP5-68398A (patent document 1) . The control device for the AC rotating machine as disclosed in this patent document 1 comprises a current arithmetic circuit for computing a detected current value from each phase current flowing through the AC rotating machine, s-a correction frequency arithmetic circuit for computing a frequency correction value from the current set value and the detected current value in accordance with a predetermined arithmetic operation, a subtracter for subtracting the frequency correction value from a frequency command value, a voltage command arithmetic circuit for computing a voltage command value in accordance with the subtraction output of the subtracter, and voltage application means for applying a drive voltage to the AC rotating machine based on the voltage command value.

[0003]
In the control device for the AC rotating machine as disclosed in the patent document 1, the detected current value is outputted by the current arithmetic circuit. If the detected current value exceeds a preset current set value, the correction frequency arithmetic circuit computes and outputs the frequency correction value by integrating at least a deviation between the detected current value and the current set value.

[0004]
The frequency correction value is subtracted from a frequency command value inputted from the outside by the subtracter, and inputted as an inverter frequency into the voltage command circuit. The voltage command circuit computes a voltage command value in accordance with a preset functional relation, in which the voltage command value is outputted to the voltage application means. In the voltage application means, a drive voltage applied to the AC rotating machine is controlled to follow the voltage command value.

[0005]
Herein, the correction frequency arithmetic circuit outputs the frequency correction value for correcting the frequency command value in accordance with a predetermined functional operation so that the detected current value may not exceed the current set value, irrespective of the power or regenerative state of the AC rotating machine. With such a configuration, the control device for the induction motor can protect an inverter circuit from over-current by conducting the current limiting operation which is stable not only during the normal operation but also during the hard acceleration or deceleration or the regeneration.

[0006]
Patent document 1: JP5-68398A

Disclosure of the Invention

Problems that the Invention is to Solve

[0007]
In the control device for the AC rotating machine, the current limiting performance greatly depends on the rating or kind of the AC rotating machine and the gain of the frequency correction value arithmetic means. For example, if the gain is too low for the AC rotating machine to be driven, a transient response of the current limiting performance is worse and an over-current occurs. Conversely, if the gain is too high for the AC rotating machine to be driven, the control system becomes unstable due to influence of the control period or the carrier frequency of a power inverter. For these reasons, it is required to appropriately set the gain for the AC rotating machine to be driven to obtain the desired current limiting performance. However, a method of setting the gain was not disclosed in the patent document 1.

Because of a difference in the operation area of the AC rotating machine, especially when the AC rotating machine operates in the constant output area, there is a problem that the desired current limiting performance can not be obtained even by using a method as described in the patent document 1.

[0008]
This invention has been achieved to solve the above-mentioned problem, and it is an object of the invention to obtain the reliable current limiting performance in driving the AC rotating machine with a known or unknown electrical constant, and provide the control device for the AC rotating machine in which the amplification gain in the frequency correction value arithmetic means is appropriately computed from the electrical constant of the AC rotating machine.

Means for Solving the Problems

[0009]
According to this invention, there is provided a control device for an AC rotating machine comprising current detection means for detecting a current supplied to the AC rotating machine as a detected current value, frequency correction value arithmetic means for outputting a frequency correction value, inverter frequency arithmetic means for outputting an inverter frequency based on a frequency command value and the frequency correction value, voltage command arithmetic means for computing a voltage command value in accordance with the inverter frequency, and voltage application means for applying a voltage to the AC rotating machine based on the voltage command value, wherein the frequency correction value arithmetic means comprises a current deviation computing element for outputting a current deviation based on the detected current value and a current limiting command value, a constant storage memory for storing an electrical constant of the AC rotating machine, an amplification gain computing element for computing an amplification gain by using the electrical constant of the AC rotating machine outputted from the constant storage memory and an arbitrary set value, an amplifier for amplifying the current deviation outputted by the current deviation computing element based on the amplification gain computed by the amplification gain computing element to compute a frequency correction arithmetic value, and an output selector for outputting the frequency correction arithmetic value as the frequency correction value in a predetermined running state of the AC rotating machine.

Advantage of the Invention

[0010]
With the control device for the AC rotating machine according to this invention, the amplitude of current of the AC rotating machine can be limited to the current limiting command value or less by correcting the inverter frequency if the detected current value exceeds the current limiting command value. Also, in driving the AC rotating machine with the electrical constant stored in the constant storage memory, the amplification gain can be appropriately designed, whereby the reliable current limiting performance can be obtained.

Brief Description of the Drawings

[0011]'
Fig. 1 is a block diagram showing an embodiment 1 of a control device for an AC rotating machine according to this invention.

Fig. 2 is a flowchart showing a current limiting operation of the embodiment 1.

Fig. 3 is a block diagram showing the transfer characteristic of a control system according to the embodiment 1.

Fig. 4 is an equivalent block diagram of rewriting Fig. J.

Fig. 5 is a characteristic diagram showing the transfer characteristic of the control system according to the embodiment 1.

Fig. 6 is an explanatory view for an operating range of the AC rotating machine.

Fig. 7 is a block diagram showing a modification 1A of the embodiment 1.

Fig. 8 is a block diagram showing an embodiment 2 of the control device for the AC rotating machine according to this invention.

Fig. 9 is a block diagram showing a modification 2A of the embodiment 2.

Fig. 10 is a block diagram showing an embodiment 3 of the control device for the AC rotating machine according to this invention.

Fig. 11 is a characteristic diagram showing the transfer characteristic of the control device according to the embodiment 3.

Fig. 12 is a block diagram showing a modification 3A of the embodiment 3.

Fig. 13 is a block diagram showing an embodiment 4 of the control device for the AC rotating machine according to this invention.

Fig. 14 is a block diagram showing a modification 4A of the embodiment 4.

Fig. 15 is a block diagram showing an embodiment 5 of the control device for the AC rotating machine according to this invention.

Fig. 16 is a block diagram showing a modification 5A of the embodiment 5.

Fig. 17 is a block diagram showing an embodiment 6 of the control device for the AC rotating machine according to this invention.

Fig. 18 is a block diagram showing a modification 6A of the embodiment 6.

Fig. 19 is a block diagram showing an embodiment 7 of the control device for the AC rotating machine according to this invention.

Fig. 20 is a block diagram showing a modification 7A of the embodiment 7.

Fig. 21 is a block diagram showing an embodiment 8 of the control device for the AC rotating machine according to this invention.

Fig. 22 is a block diagram showing a modification 8A of the embodiment 8.

Fig. 23 is a block diagram showing an embodiment 9 of the control device for the AC rotating machine according to this invention.

Fig. 24 is a block diagram showing a modification 9A of the embodiment 9.

Fig. 25 is a block diagram showing an embodiment 10 of the control device for the AC rotating machine according to this invention.

Fig. 26 is a block diagram showing a modification 10A of the embodiment 10.

Best Mode for Carrying Out the Invention

[0012]
The preferred embodiments of a. control device for an AC rotating machine according to the present invention will be described below in detail with reference to the drawings.

[0013]
Embodiment 1 (1) Explanation for the configuration of embodiment 1

Fig. 1 is a block diagram showing the configuration of an embodiment 1 of a control device for an AC rotating machine according to this invention. As shown in Fig. 1, the control device for the AC rotating machine according to this embodiment 1 comprises voltage application means 11 for driving an AC rotating machine 10, current detection means 13, voltage command means 15, inverter frequency arithmetic means 17, and frequency correction value arithmetic means 20. A three phase/dq-axis coordinate transformer 132. of the current detection means 13, the voltage command means 15, the inverter frequency arithmetic means 17 and the frequency correction value arithmetic means 20 are composed of a micro-computer, for example.

[0014]
The AC rotating machine 10 is an induction motor 101 in this embodiment 1. The voltage application means 11 is a drive circuit for the AC rotating machine 10, and specifically is composed of a three-phase inverter of VWF type, which generates a three-phase AC drive voltage Vuvw, based on a three-phase voltage command V* inputted from the voltage command means 15, and applies this three-phase AC drive voltage Vuvw to the AC rotating machine 10. The three-phase inverter of VWF type making up the voltage application means 11, which is variable in the drive voltage V of the three-phase AC drive voltage Vuvw for output and its drive frequency f, generates the three-phase AC drive voltage Vuvw having the drive voltage V designated by the three-phase voltage command V* and the drive frequency f, and supplies this three-phase AC drive voltage Vuvw to the induction motor 101.

[0015]
The current detection means 13 comprises a current detector 131 and the three-phase/dq-axis coordinate transformer 132. The current detector 131, which is made by using a current transformer, for example, detects each phase current iu, iv, iw of three phases flowing through the induction motor 101, based on the three-phase AC drive voltage Vuvw, and supplies each phase current iu, iv/ iw to the three-phase/dq-axis coordinate transformer 132. The three-phase/dq-axis coordinate transformer 132, which is a coordinate transformation unit for transforming the three phase coordinates into the rotation biaxial coordinates including the orthogonal d axis and q axis, inputs a phase signal 9 and generates the corresponding d-axis current value id and q-axis current value iq from each phase current iu, iv, iw, by using this phase signal 9. The three-phase/dq-axis coordinate transformer 132 generates a detected current value I, along with the d-axis current value id and the q-axis current value iq. The d-axis current value id and the q-axis current value iq are supplied to the voltage command means 15. The detected current value I is supplied to the frequency correction value arithmetic means 20. The detected current value I is made equal to the q-axis current value iq in this embodiment 1, and given in the following Numerical Expression 1.

[0016]

[Numerical expression 1]

[0017]
The voltage command means 15 is configured as a well-known induced voltage/drive frequency constant control system (hereinafter referred to as the (E/f) constant control system) or a well-known drive voltage/drive frequency constant control system (hereinafter referred to as the (V/f) constant control system). The (E/f) constant control system involves controlling a ratio (E/f) of the induced voltage E induced inside the AC rotating machine 10 based on the three-phase AC drive voltage Vuvw to the drive frequency f to be constant. The (V/f) constant control system involves controlling a ratio (V/f) of the drive voltage V of the three-phase AC drive voltage Vuvw to the drive frequency f to be constant. In this embodiment 1, the voltage command means 15 is configured as the (E/f) constant control system. The voltage command means 15 of this (E/f) constant control system has voltage command arithmetic means 153 of the (E/f) constant control method and a dq-axis/three-phase coordinate transformer 157.

[0018]
The inverter frequency arithmetic means 17 comprises a subtracter 171. This subtracter 171 is supplied with a frequency command value eo* from the outside, and also supplied with a frequency correction value Ao from the frequency correction value arithmetic means 20. The inverter frequency arithmetic means 17 subtracts the frequency correction value AGO from the frequency command value o* in accordance with the following Numerical Expression 2, and outputs an inverter frequency (a

[0019]
[Numerical Expression 2]

[0020]

The voltage command arithmetic means 153 of the (E/f) constant control system is supplied with a d-axis current value id and a q-axis current value iq from the three-phase/dq-axis coordinate transformer 132 of the current detection means 13, and also supplied with the inverter frequency (0± from the inverter frequency arithmetic means 17. This voltage command arithmetic means 153 computes a d-axis voltage command vd* and a q-axis voltage command vq* based on the d-axis current value id, the q-axis current value iq and the inverter frequency a± in accordance with the following Numerical Expressions 3 and 4, and supplies the d-axis voltage command vd* and the q-axis voltage command vq* to the dq-axis/three-phase coordinate transformer 157. The dq-axis/three-phase coordinate transformer 157, into which a phase signal 0 is inputted, transforms the d-axis voltage command vd* and the q-axis voltage command vq* into a three-phase voltage command V*, by using this phase signal 0, and supplies this three-phase voltage command V* to the voltage application means 11.

[0021]

[Numerical Expression 3]

[Numerical Expression 4]

In the Numerical Expressions 3 and 4, Rx is a stator resistance of the induction motor 101, and Li is a stator ' inductance of it.

[0022]
The frequency correction value arithmetic means 20 has six input ports 20-11 tc 20-16, and one output port 20-O, and internally comprises a current deviation computing element 201, a constant storage memory 203, an amplification gain computing element 210, an amplifier 230, a zero value output part 231, a state signal generator 233, and an output selector 235. The input port 20-11 is supplied with the detected current value I from the three-phase/dq-axis coordinate transformer 132 of the current detection means 13. The input port 20-12 is supplied with a current limiting command value Limit from the outside. The input port 2 0-13 is supplied with the inverter frequency ©j.. The input port 20-14 is supplied with the frequency command value co*. The input port 20-15 is supplied with at least one of the inverter frequency ®i, the frequency command value co* and the three-phase voltage command V*. The input port 20-16 is supplied with a d-axis current command id* for the AC rotating machine 10, or the induction motor 101 in this embodiment 1. This d-axis current command id*, which is an exciting current for the induction motor 101, is used in the voltage command arithmetic means 153, and supplied from this voltage command arithmetic means 153 . The output port 20-O outputs the frequency correction value Aco to the subtracter 171 of the inverter frequency arithmetic means 17.

[0023]
The current deviation computing element 201 comprises a subtracter 202, and this subtracter 202 is connected to the input ports 20-11 and 20-12. The current deviation computing element 201 subtracts the current limiting command value Limit from the detected current value I in accordance with the following Numerical Expression 5, and outputs a current deviation Al.

[0024]
[Numerical Expression 5]

[0025]
The constant storage memory 2 03 stores various kinds of electrical constants regarding the AC rotating machine 10, or the induction motor 101 in this embodiment 1. The electrical constants stored in this constant storage memory 203 include at least a leakage constant a of the induction motor 101, its rotor resistance R2, its rotor inductance L2 and a set value cox of the current limiting response speed for the induction motor 101.

[0026]
The amplification gain computing element 210 comprises an amplification gain arithmetic part 213, a zero value output part 221, a switch signal generating part 223, and a switching part 225. The electrical constants a, R2, L2 and a>x stored in the constant storage memory 203 are supplied to the amplification gain arithmetic part 213. The amplification gain arithmetic part 213 is connected to the constant storage memory 203 and the input port 20-16. This amplification gain arithmetic part 213 computes the amplification gains Gl and G2 by using the electrical constants c, R2, L2 and cox supplied from the constant storage memory 2 03 and the d-axis current command id* supplied to the input port 2 0-16 in accordance with the following Numerical Expressions 6 and 7, and supplies these amplification gains Gl and G2 to an input a of the switching part 22 5.

[0027]

[Numerical Expression 6]

[Numerical Expression 7]

[0028]
The d-axis current command id* is given by the following Numerical Expression 8.

[0029]

[Numerical Expression 8]

In this Numerical Expression (8), V0 is the rated voltage of the AC rotating machine 10, or the induction motor 101 in the embodiment 1, f0 is the base frequency, and Kvf is what is called a V/F transformation gain. This V/f transformation gain Kvf is given by the following Numerical Expression 9.

[0030]

[Numerical Expression 9]

[0031]
The zero value output part 221 supplies a zero value output to an input b of the switching part 225. The switch signal generating part 223 is connected to the input port 20-15. The switch signal generating part 223 determines whether or not an operating range of the AC rotating machine 10, or the induction motor 101, is in the constant torque area, based on at least one of the inverter frequency coi, the frequency command value o* and the three-phase voltage command V* supplied to the input port 20-15, and generates a switch signal SS, based on this determination. The switching part 225 has the input a connected to the amplification gain arithmetic part 213, the input b connected to the zero value output part 221 and the output c. In the state where the AC rotating machine 10, or the induction motor 101 in the embodiment 1, is run in the constant torque area, the switch signal SS enables the switching part 225 to select the input a to be output to the output c and supply the amplification gains Gl and G2 as represented in the Numerical Expressions 6 and 7 from the output c to the amplifier 230. In the state where the AC rotating machine 10, or the induction motor 101, shifts from the constant torque area to the constant output area, the switch signal SS enables the switching part 225 to select the input b to be output to the output c and supply the zero value output from the zero value output part 221 from the output c to the amplifier 230.

[0032]
In the state where the AC rotating machine 10, or the induction motor 101, is run in the constant torque area, the amplifier 230 computes the frequency correction arithmetic value Acoa by using the amplification gains Gl and G2 supplied from the amplification gain arithmetic part 213 in accordance with the following Numerical Expression 10, and outputs this frequency correction arithmetic value A©a to an input a of the output selector 235.

[0033]

[Numerical Expression 10]

In this Numerical Expression (10), s is the Laplace operator.

[0034]

The zero value output part 231 outputs the zero value output to an input b of the output selector 235. The output selector 235 selects any one of the inputs a and b to be output to the output c. The output c of this output selector 235 is the frequency correction value Aeo, and supplied from the output port 20-O of the frequency correction value arithmetic means 20 to the subtracter 171 of the inverter frequency arithmetic means 17 . The frequency correction value Aco outputted from the output c of the output selector 235 is the frequency correction arithmetic value Acoa outputted from the amplifier 230 or the zero value output outputted from the zero value output part 231.

[0035]
The state signal generator 233 is connected to the input ports 20-11 to 20-14, in which the detected current value I is supplied from the input port 20-11, the current limiting command value Limit is supplied from the input port 2 0-12, the inverter frequency ©i is supplied from the input port 20-13, and the frequency command value a>* is supplied from the input port 20-14. This state signal generator 233 firstly compares the detected current value I with the current limiting command value Limit, in which as a result of comparison, if the detected current value I is greater than the current limiting command value Limit, or there is the relationship of I>Limit/ a state signal CS enables the output selector 235 to select the input a to output the frequency correction arithmetic value Acoa supplied to the input a as the frequency correction value A© to the output c. Also, if the detected current value I is smaller than the current limiting command value I unit and if the inverter frequency ©i is' greater than the frequency command value co*, or the relationship of also is negated, in the state where the output selector 235 selects the Input a, the state signal CS generated by the state signal generator 233 enables the output selector 235 to select the input b to output the zero value output supplied to the input b as the frequency correction value Aco.

[0036]
Herein, the phase signal 0 for use in the coordinate transformation can be obtained by integrating the inverter frequency (o± as represented in the following Numerical Expression 11.

[0037]

[Numerical Expression 11]

[0038]
For the three phase/dq-axis coordinate transformer 132, among the d-axis current value id and the q-axis current value iq on the rotational biaxial coordinates including the d-axis and the q-axis that are orthogonal, the d-axis current value id is a current component in phase with the phase signal 0 and the q-axis current value iq is a current component in phase orthogonal to the phase signal 0. Also, for the dq-axis/three phase coordinate transformer 157, among the d-axis voltage command vd* and the q-axis voltage command vq* on the rotational biaxial coordinates including the d-axis and the q-axis that are orthogonal, the d-axis voltage command vd* is a voltage command component in phase with the phase signal 0 and the q-axis voltage command vq* is a voltage command component in phase orthogonal to the phase signal 9.

[0039]

(2) Explanation for the operation of embodiment 1

Referring to Fig. 1, the operation of the frequency correction value arithmetic means 20 that limits the current flowing through the induction motor 101 to the current limiting command value limit will be described below. In the state where the AC rotating machine 10, or the induction motor 101 in this embodiment 1, is run in the constant torque area, the frequency correction value arithmetic means 20 has a function of suppressing the current flowing through the induction motor 101 to less than the current limiting command value Limit by correcting the inverter frequency ©i with the frequency correction value Aoo, when the induction motor 101 becomes in an running state where the current flowing through the induction motor 101 exceeds the current limiting command value Δω

[0040]
In the state where the induction motor 101 is run in the constant torque area, the running state where the current flowing through the induction motor 101 exceeds the current limiting command value Iimit may possibly occur when a hard acceleration command value or a hard deceleration command value in which the frequency command value co* suddenly changes temporarily is given, or there is a sudden load variation such as an impact load in the induction motor 101, for example. In such running state, the current flowing through the induction motor 101 is suppressed by adjusting the inverter frequency (into increase or decrease with the frequency correction value Δω.

[0041]
Herein, if the current flowing through the AC rotating machine 10 exceeds the current limiting command value I limit/ the operation of adjusting the inverter frequency ©i is called a stall operation SA, and if the current flowing through the AC rotating machine 10 is not more than the current limiting command value Iimit the operation of adjusting the inverter frequency coi to be coincident with the frequency command value co* is called a recovery operation RA. The frequency correction value arithmetic means 20 in the embodiment 1 has an action of automatically performing the operation of adjusting the inverter frequency Qi in the state where the induction motor 101 is run in the constant torque area, if the induction motor 101 becomes in the running state where the current flowing through the induction motor 101 exceeds the current limiting command value I Iimit.

[0042]
Specifically, first of all, the current deviation computing element 201 computes the current deviation AI in accordance with the Numerical Expression 5. The amplifier 230 computes the frequency correction arithmetic value A©a corresponding to a current excess amount of the induction motor 101 in accordance with the Numerical Expression 10 in the state where the AC rotating machine 10, or the induction motor 101, is run in the constant torque area, because the switching part 225 outputs the amplification gains Gl and G2 computed in the amplification gain arithmetic part 213. The state signal generator 233 firstly compares the detected current value I with the current limiting command value I limit/ then compares the inverter frequency ©i with the frequency command value oo*, and generates the state signal CS. Based on the state signal CS, the output selector 235 outputs the zero value output from the zero value output part 231 in the normal running state, or outputs the frequency correction arithmetic value Acoa in the running state where the current flowing through the induction motor 101 exceeds the current limiting command value I limit

[0043]
In this way, the state signal generator 233 controls the switching of the output of the output selector 235 between the zero value output and the frequency correction arithmetic value A(Oa, whereby the current limiting operation as shown in Fig. 2 is enabled. Fig. 2 is a flowchart showing the current limiting operation. The flowchart of Fig. 2 includes seven steps Sll to S17, following the start. Firstly at step Sll, the state signal generator 2 33 makes a determination whether

or not the detected current value I is greater than the current limiting command value I limit. If the determination result is yes , the operation goes to step S12 . At this step S12 , the output selector 235 selects the input a to output the frequency correction arithmetic value Acoa as the frequency correction value Aco. If the determination result at step Sll is no, the operation returns to step Sll again.

[0044]
Proceeding from step S12 to step S13, the state signal generator 233 makes a determination again at step S13 whether or not the detected current value I is greater than the current limiting command value I limit. If the determination result is yes, the operation goes to step S14, where the stall operation SA is executed. If the stall operation SA is ended at this step S14, the operation returns to step S13 again. If the determination result at step S13 is no, the operation goes to step S15, where the recovery operation RA is executed. If the recovery operation RA at this step S15 is ended, the operation advances to step S16.

[0045]
At step SI6, the state signal generator 233 makes a determination whether or not the inverter frequency eoi is smaller than the frequency command value GO*. If the inverter frequency ©i is greater than the frequency command value GO*, and so the determination result at step S16 is no, the operation goes to step S17, where the output selector 235 selects the zero value output of the input b, and the operation returns to step Sll. If the determination result at step S16 is yes, the operation returns to step S13.

[0046]
With this flowchart of Fig. 2, if the detected current value I is greater than the current limiting command value I limit/ the current flowing through the induction motor 101 is controlled to be less than or equal to the current limiting command value I limit by repeating the stall operation SA and the recovery operation RA by using the frequency correction arithmetic value Acoa computed by the amplifier 230 at steps S12 to S15. However, if the current flowing through the induction motor 101 maintains the current limiting command value I limit/ the induction motor 101 continues to accelerate at any time. Thereby, if the inverter frequency G>i is greater than the frequency command value ± and inputs its subtraction output into block 31.

[0054]
Fig. 3 is a block diagram expanded in which the frequency command value oo* is constant in Fig. 2. From Fig. 3, it can be understood that the feedback control is performed with the amplifier 230 so that the detected current value I=iq may coincide with the current limiting command value I limit in the embodiment 1. Fig. 4 is an equivalent block diagram of Fig. 3. In Fig. 4, as rewritten from Fig. 3, the subtracter 202 is positioned at the left end, and block 31 representing the transfer characteristic Gm is positioned at the right end, so that the detected current value I is outputted from the block 31 to the right side. In Fig. 4, block 35 represents the transfer characteristic GIMSYS- This block 35 is the transfer function from the frequency correction value Aco to the detected current value I=iq, including block 31 representing the transfer characteristic GIM, block 33 representing a mechanical system of the AC rotating machine 10, and the subtracters 171 and 34.

[0055]
The current limiting performance of the control system in the embodiment 1 is decided by the amplification gains Gl and G2 of the amplifier 230, and the appropriate values of the amplification gains Gl and G2 can be obtained from the characteristic of the transfer function GiMSYs from the frequency correction value Aco to the output current I=iq as shown in Fig. 4.

[0056]
Fig. 5 is a characteristic diagram showing, the transfer characteristic GiMSYs in the cases where the frequency correction value Aco =0, namely, the frequency command value co* = inverter frequency ©i, with co*=c0i=10 [Hz] , 20 [Hz], 30 [Hz] and 40 [Hz] in the embodiment 1. Fig. 5(A) shows an output magnitude characteristic and Fig. 5(B) shows an output phase characteristic. The output magnitude characteristic of Fig. 5(A) shows the result of supplying a signal in which co*=cOi is added to the input sinusoidal wave having a predetermined

T
magnitude and changing in the frequency to block 35 representing the transfer characteristic GIMSYS , and analyzing a change in the magnitude of the output signal outputted from the block 35, in which the horizontal axis represents the frequency of the input sinusoidal wave in (rad/sec) , and the vertical axis represents. the magnitude of the output signal in . (dB) . The characteristic ml of Fig. 5(A) is the characteristic where ©*=®i=10[Hz], the characteristic m2 is the characteristic where co*=a)i=20 [Hz], the characteristic m3 is the characteristic where a*=(Bi=30 [Hz] , and the characteristic m4 is the characteristic where a)*=(Di=4 0 [Hz] .

[0057]
The output phase characteristic of Fig. 5(B) shows the result of supplying a signal in which co*=0)i is added to the input sinusoidal wave having a predetermined magnitude and changing in the frequency to block 3.5 representing the transfer characteristic GIMSYS , and analyzing a change in the phase of the output signal outputted from the block 35, in which the horizontal axis represents the frequency of the input sinusoidal wave in (rad/sec) , and the vertical axis represents the phase of the output signal in (deg). The characteristic pi in Fig. 5(B) is the characteristic where ±=1Q [Hz], the characteristic p2 is the characteristic where a>*=ct>i=20 [Hz] , the characteristic p3 is the characteristic where i=10 [Hz]«60[rad/sec] , the characteristic m2 has a steep change in the characteristic near the frequency command value co*= & is the d-axis component of the rotor magnetic flux of the induction motor 101, Lx Is the stator inductance of the induction motor 101, vq is the q-axis voltage of the stator voltage of the induction motor 101, L2 is the rotor inductance of the induction motor 101, a is the leakage constant of the induction motor 101, M is the mutual inductance of the induction motor 101, ©r is the rotational frequency (electrical angle) of the induction motor 101, and ©i is the inverter frequency (electrical angle) of the induction motor 101.

[0062]

Herein, a steep characteristic change near the inverter frequency ©± in the transfer characteristic of the induction motor 101 is caused by an interference characteristic between d-axis and q-axis. In the Numerical " Expression 12 representing the q-axis current value iq, the second term contains the d-axis current value id, and the second term is the interference component between d-axis and q-axis. Accordingly, the transfer characteristic without consideration for the steep characteristic change near the inverter frequency ©i can be derived by making the second term of the Numerical Expression 12 zero. Herein, if by making the second term of the Numerical Expression 12 zero, and vq=vq* in additionally assuming an ideal power source, the following Numerical Expression 13 can be obtained.

[0063]
[Numerical Expression 13]

[0064]
Also, the voltage operation expression of the q-axis voltage command vq* is the Numerical Expression 4, and substituting the Numerical Expression 4 into the Numerical Expression 13 yields the following Numerical Expression 14.

[0065]
[Numerical Expression 14]

[0066]
From this Numerical Expression 14, the following

Numerical Expression 15 is obtained.

[0067]
[Numerical Expression 15]

[0068]
Accordingly, based on the Numerical Expression 15, the DC gain K of the transfer characteristic GiM from the inverter frequency a>i to the q-axis current value iq and the frequency 1/T at bended point are given in the following Numerical Expressions 16 and 17, respectively.

[0069]
[Numerical Expression 16]

[Numerical Expression 17]

[0070]
The DC gain K of the transfer characteristic GiM is illustrated by the dotted line parallel to the horizontal axis of Fig. 5(A), and the frequency 1/T at bended point is illustrated by the dotted line parallel to the vertical axis of Figs. 5(A) and 5(B).

[0071]
The relational expression between the frequency correction value ACQ and the inverter frequency ®± as shown in Figs. 3 and 4 is the Numerical Expression 2, in which if the input frequency command value ©* is fixed, the transfer characteristic from the frequency correction value Aco to the q-axis current value iq is the transfer characteristic GiM with a sign of minus, or -GiM.

[0072]
Next, the amplification gains Gl and G2 of the amplifier 230 are set so that the current limiting response speed at the time of limiting the current may be cox, by using the above transfer characteristic GiM. From the Numerical Expression 10, the transfer characteristic Gpi of the amplifier 230 is given by the following Numerical Expression 18. Herein, the current limiting response speed at the time of limiting the current becomes ± is increased with the ratio of (E/f) or (V/f) kept constant until the inverter frequency ©i reaches a base frequency, the drive voltage V can not be increased because of the constraints of the power source, so that the operation is out of the constant torque area CTA, and if the drive frequency f is raised with this drive voltage V kept constant, the input of the AC rotating machine 10 is constant and the torque is inversely proportional to the inverter frequency ©i, whereby the constant output operation in which the output is almost constant is enabled. The area where such constant output operation is performed is the constant output area COA.

[0083]
Though in the embodiment 1, the AC rotating machine 10 is the induction motor 101, the transfer characteristic GIM as described in this embodiment 1 is the characteristic for the constant torque area CTA, and the amplification gains Gl and G2 in the Numerical Expressions 6 and 7 and the Numerical Expressions 20 and 21 are also appropriate in the constant torque area CTA, but inappropriate values in the constant output area COA. Therefore, in the embodiment 1, the switching part 225 selects the zero value output from the zero value output part 221 in the state where the induction motor 101 is run in the constant output area COA by the switch signal SS of the switch signal generating part 223, thereby making the amplification gains Gl and G2 of"the amplifier 230 zero and making the frequency correction arithmetic value Acoa of the amplifier 230 zero. Consequently, it is effective that the current flowing through the induction motor 101 is limited to the set value ©x of the current limiting response speed in the state where the induction motor 101 is run in the constant torque area CTA in the embodiment 1.

[0084] Modification 1A of the embodiment 1

Though in the embodiment 1, the AC rotating machine 10 is the induction motor 101, the AC rotating machine 10 is not limited to it, but may be any other AC rotating machine, for example, the synchronous motor 10S, to achieve the same effects .

[0085]
Fig. 7 is a block diagram showing the control device for the AC rotating machine according to this modification 1A. This modification 1A is configured by modifying the embodiment 1 as shown in Fig. 1 such that the AC rotating machine 10 is configured by the synchronous motor 10S, the voltage command means 15 is replaced with voltage command means 15A, the inverter frequency arithmetic means 17 is replaced with inverter frequency arithmetic means 17A, and further a stabilization high pass filter 40 is added. In this modification 1A, the voltage application means 11, the current detection means 13 and the frequency correction value arithmetic means 20 are made in the same way as the embodiment 1. The voltage command means 15A, the inverter frequency arithmetic means 17A and the stabilization high pass filter 40 are composed of a micro-computer, for example.

[0086]
In the modification 1A as shown in Fig. 7, the stabilization high pass filter 40 receives the detected current value I=iq from the current detection means 13, and outputs a frequency stabilization high frequency component a>high. The inverter frequency arithmetic means 17A of this modification 1A, which comprises two subtracters 171 and 172, computes the inverter frequency ©j., based on the frequency command value a>*, the frequency correction value Aco from the frequency correction value arithmetic means 20 and the frequency stabilization high frequency component ©high from the stabilization high pass filter 40, and supplies the inverter frequency C0i to the voltage command means 15A. The subtracter 171 is supplied with the frequency command value co* and the frequency correction value Ao from the frequency correction value arithmetic means 20, subtracts the frequency correction value Aco from the frequency command value ©*, and supplies the subtraction output co*-Aco to the subtracter 172. The subtracter 172 is further supplied with the frequency stabilization high frequency component ©high from the stabilization high pass filter 40. This subtracter 172 subtracts the frequency stabilization high frequency component cohigh from the subtraction output co*-Aco, computes the inverter frequency (0± in accordance with the following Numerical Expression 23, and supplies the inverter frequency ©i to the voltage command means 15A.

[0087]
[Numerical Expression 23]

[0088]
The voltage command means 15A in the modification 1A, like the embodiment 1, relies on an (E/f) constant control system, and has voltage command arithmetic means 154 of the (E/f) constant control system and the dq-axis/three phase coordinate transformer 157. The voltage command arithmetic means 154 computes the d-axis voltage command vd* and the q-axis voltage command vq* based on the inverter frequency ©i from the inverter frequency arithmetic means 17A and the d-axis current value id and the q-axis current value iq from the three phase/dq-axis coordinate transformer 132 of the current detection means 13' in accordance with the following Numerical Expressions 24 and 25, and outputs them.

[0089]
[Numerical Expression 24]

[Numerical Expression 25]

In the Numerical Expressions 24 and 25, R is the armature resistance [Q] of the synchronous motor 10S, and f is the magnetic flux of magnet [Wb] of the synchronous motor 10S.

[0090]
In the modification 1A, the amplification gain arithmetic part 213 of the frequency correction value arithmetic means 20 computes the amplification gains Gl and G2 in accordance with the following Numerical Expressions 26 and 27.

[0091]

[Numerical Expression 26]

[Numerical Expression 27]

In these Numerical Expressions 26 and 27, Lq is the q-axis inductance [H] of the synchronous motor 10S, Kh is the gain of the stabilization high pass filter 40, and cox is the set value of the current limiting response speed. The electrical constants regarding the synchronous motor 10S, specifically, the q-axis inductance Lq of the synchronous motor 10S, the magnetic flux of magnet # f, the gain Kh of the stabilization high pass filter 40 and the set value ©x of the current limiting response speed, are stored in the constant storage memory 203, and supplied to the amplification gain arithmetic part 213.

[0092]

The principle of deriving the Numerical Expressions 26 and 27 in the modification 1A will be described below. In this modification 1A, the following Numerical Expressions 28 to 32 are substituted for the Numerical Expressions 13 to 17. First of all, in the modification 1A, the q-axis current value iq of the synchronous motor 10S is given by the following Numerical Expression 28. This Numerical Expression 28 is the substitute for the Numerical Expression 13 in the embodiment 1.

[0093]

[Numerical Expression 28]

[0094]
Substituting the Numerical Expression 25 into the q-axis voltage command vq* of the Numerical Expression 28 yields the following Numerical Expression 29. This Numerical Expression 29 is the substitute for the Numerical Expression 14 in the embodiment 1.

[0095]
[Numerical Expression 29]

[0096]
From this Numerical Expression 29, the following Numerical Expression 30 is obtained. This Numerical Expression 30 is the substitute for the Numerical Expression 15 in the embodiment 1.

[Numerical Expression 30]

[0097]
From this Numerical Expression 30, the DC gain K of the transfer characteristic and the frequency 1/T at bended point are represented as in the following Numerical Expressions 31 and 32, respectively. These Numerical Expressions 31 and 32 are the substitute for the Numerical Expressions 16 and 17 in the embodiment 1.

[0098]
[Numerical Expression 31]

[Numerical Expression 32]

Based on the Numerical Expressions 31 and 32, in the modification 1A, the amplification gains Gl and G2 are given by the following Numerical Expressions 33 and 34. These Numerical Expressions 33 and 34 are the numerical expressions corresponding to the Numerical Expressions 20 and 21 in the embodiment 1, and the Numerical Expressions 26 and 27 are obtained from these Numerical Expressions 33 and 34.

[0099]
[Numerical Expression 33]

[Numerical Expression 34]


[0100]
In this modification 1A, like the embodiment 1, using the frequency correction value arithmetic means 20, the amplification gains Gl and G2 of the amplifier 230 can be appropriately designed and automatically set for the synchronous motor 10S to be driven, when the synchronous motor 10S with the known electrical constants is driven in the state where the synchronous motor 10S is run in the constant torque area CTA, and the current flowing through the synchronous motor 10S can be securely suppressed with the arbitrary set value cox of current limiting response speed, whereby the problem that the excess current may flow through the synchronous motor 10S or the problem that the entire control system becomes unstable is solved.

[0101] Embodiment 2
Fig. 8 is a block diagram showing an embodiment 2 of the control device for the AC rotating machine according to this invention. This embodiment 2 is configured by modifying the embodiment 1 such that the voltage command means 15 is replaced with voltage command means 15B. This voltage command means 15B is voltage command means of the (V/f) constant control system, and specifically has voltage command arithmetic means 155 of the (V/f) constant control system, and the dq-axis/three phase coordinate transformer 157. In others, the embodiment 2 is configured in the same way as the embodiment 1, in which the AC rotating machine 10 is the induction motor 101. The voltage command means 15B is composed of a micro-computer, for example.

[0102]
In the embodiment 2, the voltage command arithmetic means 155 outputs the d-axis voltage command. vd*=0 based on the following Numerical* Expression 35, computes the q-axis voltage command vq*, based on the q-axis current value iq from the current detection means 13 and the inverter frequency e>i from the inverter frequency arithmetic means 17 in accordance with the following Numerical Expression 36, and supplies the d-axis voltage command vd* and the q-axis voltage command vq to the dq-axis/three phase coordinate transformer 157.

[0103]
[Numerical Expression 35]

[Numerical Expression 36]

[0104]
In the Numerical Expression 36, id* is the d-axis current command, or the command value of exciting current for the induction motor 101. This d-axis current command id* is changed corresponding to. the specifications of the induction motor 101 if they are different, but if the specifications of the induction motor 101 are fixed, it is the constant value. In this embodiment 2, the d-axis voltage command vd* is 0 as shown in the Numerical Expression 35, and additionally if the specifications of the induction motor 101 are decided, the d-axis current command id* is also the constant value. As will be clear from the Numerical Expression 36, the q-axis voltage command vq* is changed in proportion to the inverter frequency ©i, and consequently .controlled so that the ratio of the drive voltage V to the drive frequency f from the voltage application means 11 may be kept constant, whereby the control is made by the (V/f) constant control system.

[0105]
In this embodiment 2, the amplification gain arithmetic part 213 of the amplification gain computing element 210 in the frequency correction value arithmetic means 20 computes the amplification gains Gl and G2 in accordance with the following Numerical Expressions 37 and 38, and supplies these amplification gains Gl and G2 to the amplifier 230 as the gains for amplifier in the state where the induction motor 101 is run in the constant torque area.

[0106]
[Numerical Expression 37]

[Numerical Expression 38]

[0107]

In this embodiment 2, the leakage constant from the frequency correction value arithmetic means 20 and the frequency stabilization high frequency component ©high from the stabilization high pass filter 40, and supplies this inverter frequency ©i to the voltage command means 15C. The subtracter 171 is supplied with the frequency command value © and the frequency correction value AGO, subtracts the frequency correction value A© from the frequency command value ©*, and supplies the subtraction output ©*-A© to the subtracter 172. The subtracter 172 is further supplied with the frequency stabilization high frequency component ©high from the stabilization high pass filter 40. This subtracter 172 subtracts the frequency stabilization high frequency component ©high from the subtraction output ©*-A©, computes the inverter frequency ©i in accordance with the Numerical Expression 23, and supplies the inverter frequency ©i to the voltage command means 15C.

[0123]
The voltage command means 15C in the modification 2A is configured as the voltage command means of the (V/f) constant control system, and has voltage command arithmetic means 156 of the (V/f) constant control system and the dq-axis/three phase coordinate transformer 157 as shown in Fig. 9. The voltage command arithmetic means 156 computes the d-axis voltage command vd* and the q-axis voltage command vq based on the inverter frequency ©t from the inverter frequency arithmetic means 17A in accordance with the following Numerical Expressions 45 and 4 6, and outputs them to the
dq-axis/three phase coordinate transformer 157.

[0124]

[Numerical Expression. 45]

[Numerical Expression 4 6]

In the Numerical Expression 46, 4>t is the magnetic flux of magnet [Wb] of the synchronous motor 10S.

[0125]
In the modification 2A of the embodiment 2, the amplification gain arithmetic part 213 of the frequency correction value arithmetic means 20 computes the amplification gains Gl and G2 in accordance with the following Numerical Expressions 47 and 48.

[0126]
[Numerical Expression 47]

[Numerical Expression 48]

[0127]
In these Numerical Expressions 47 and 48, Lq is the q-axis inductance [H] of the synchronous motor 10S, R is the armature resistance [Q], Kh is the gain of the stabilization high pass filter 40, and cox is the same set value of the current limiting response speed as used in the embodiment 2. The electrical constants regarding the synchronous motor 10S, specifically, the q-axis inductance Lq of the synchronous motor 10S, the magnetic flux of magnet .f, the armature resistance R, the gain Kh of the stabilization high pass filter 40 and the set value cox of the current limiting response speed, are stored in the constant storage memory 203, and supplied to the amplification gain arithmetic part 213.

[0128]
The Numerical Expressions 47 and 48 in the modification 2A are derived in the same way as the Numerical Expressions 33 and 38 in the modification 1A of the embodiment 1, though the explanation for the principle of deriving them is omitted. In this modification 2A, by using the frequency correction value arithmetic means 20, the amplification gains Gl and G2 of the amplifier 230 can be appropriately designed and automatically set for the synchronous motor 10S to be driven, when the synchronous motor 10S with the known electrical constants is driven in the state where the synchronous motor 10S is run in the constant torque area, and the current flowing through the synchronous motor 10S can be securely suppressed with the arbitrary set value cox of current limiting response speed, whereby the problem that the excess current may flow through the synchronous motor 10S or the problem that the entire control system becomes unstable is solved.

[0129]
Though in the embodiment 1 and its modification 1A, as well as the embodiment 2 and its modification 2A, the current detection means 13 detects all the three phase currents iu, iv and iw flowing through the AC rotating machine 10, two phase currents of these three phase currents may be detected, for example, or bus currents of the voltage application means 11 may be detected, and the three phase currents flowing through the AC rotating machine 10 may be detected based on the detected value of the bus currents. Furthermore, for the detected current value I that is outputted to the frequency correction value arithmetic means 20, I=iq, but the effective values of the three phase currents flowing through the AC rotating machine 10 may be outputted by computing the detected current value I in accordance with the following Numerical Expression 49, or the bus currents of the voltage application mean 11 may be detected and outputted.

[0130]

[Numerical Expression 49]

[0131]

Embodiment 3

(1) Explanation for the configuration of embodiment 3 Fig. 10 is a block diagram showing the configuration of an embodiment 3 of the control device for the AC rotating machine according to this invention. The control device for the AC rotating machine according to this embodiment 3 is configured by modifying the embodiment 1 such that the frequency correction value arithmetic means 20 is replaced with the frequency correction value arithmetic means 20A . The AC rotating machine 10 in the embodiment 3 is the induction motor 101, as in the embodiment 1, and has the voltage application means 11, the current detection means 13, the voltage command means 15 and the inverter frequency arithmetic means 17 in the same way as the embodiment 1. The frequency correction value arithmetic means 20A is also composed of a micro-computer, for example.

[0132]
The frequency correction value arithmetic means 20A in the embodiment 3 has five input ports 20-11 to 20-15, and one output port 20-O. In this frequency correction value arithmetic means 20A, the input port 20-16 in the frequency correction value arithmetic means 20 of the embodiment 1 is deleted. In the same way as the embodiment 1, the input port 20-11 is supplied with the detected current value I from the three-phase/dq-axis coordinate transformer 132 of the current detection means 13, the input port 20-12 is supplied with the current limiting command value In„u from the outside, the input port 20-13 is supplied with the inverter frequency a>t, the input port 20-13 is supplied with the inverter frequency (dit the input port 20-14 is supplied with the frequency command value 0*, and the input port 20-15 is supplied with at least one of the inverter frequency ©i, the frequency command value co* and the three-phase voltage command V*. Also, the output port 20-O supplies the frequency correction value ACQ to the subtracter 171 of the inverter frequency arithmetic means 17.

[0133]
The frequency correction value arithmetic means 20A in the embodiment 3.internally comprises the current deviation computing element 201, the constant storage memory 203, an amplification gain computing element 210A, the amplifier 230, the zero value output part 231, the state signal generator 233, and the output selector 235. The current deviation computing element 201, the constant storage memory 203, the amplifier 230, the zero value output part 231, the state signal generator 233, and the output selector 235 in the embodiment 3 are configured in the same way as the embodiment 1. The amplification gain computing element 210A is substituted for the amplification gain computing element 210 of the embodiment 1. The amplification gain computing element 210A in the embodiment 3 has an amplification gain arithmetic part 214, the zero value output part 221, the switch signal generating part 223, and the switching part 225. The amplification gain arithmetic part 214 is connected to the input b of the switching part 225, and the zero value output part 221 is connected to the input port a of the switching part 225.

[0134]
The amplification gain arithmetic part 214 in the embodiment 3 is supplied with the inverter frequency (a± from the input port 20-13, and the electrical constants of the induction motor 101 from the constant storage memory 203. This amplification gain arithmetic part 214 computes the amplification gains Gl and G2 of the amplifier 230 based on the inverter frequency ®i and the electrical constants of the induction motor 101 in accordance with the following Numerical Expressions 50 and 51, and supplies the amplification gains Gl and G2 to the amplifier 230.

[0135]
[Numerical Expression 50]

[Numerical Expression 51]

[0136]
In the Numerical Expressions 50 and 51, a is the leakage constant of the induction motor 101, Ri is the stator resistance, R2 is the rotor resistance, Li is the stator inductance, V0 is the rated voltage of the induction motor 101, and GH is the inverter frequency. The leakage constant CT of the induction motor 101, the stator resistance Rlf the rotor resistance R2, stator inductance Li, and the rated voltage V0 are stored in the constant storage memory 203, and supplied to the amplification gain arithmetic part 214. The inverter frequency coi is supplied from the input port 20-13 to the amplification gain arithmetic part 214.

[0137]
(2) Explanation for the operating area of the induction motor 101 in the embodiment 3 When the AC rotating machine 10 is driven by the voltage application means 11 made up using the inverter, the operating area of the AC rotating machine 10 includes the constant torque area CTA and the constant output area COA, as shown in Fig. 6. The transfer characteristic GiM as used in the embodiment 1 and the modification 1A of the embodiment 1, as well as the embodiment 2 and the modification 2A of the embodiment 2 is the transfer characteristic in consideration of the constant torque area, and the amplifier gain designed based on this can not attain the desired current limiting performance in the constant output area where the drive voltage value V of the three-phase AC drive voltage Vuvw is constant, whereby the zero value output is supplied from the switching part 225 to the amplifier 230 to make the amplification gains Gl and G2 zero in the state where the AC rotating machine 10 is run in the constant output

area COA. In this embodiment 3, it is possible to attain the desired current limiting performance in the state where the AC rotating machine 10 is run in the constant output area COA.

[0138]
(3) Explanation for. the operation of the embodiment 3 In the state where the induction motor 101 is run in the constant output area COA, the amplification gain computing element 210A computes the gains Gl and G2 of the amplifier 230 in accordance with the Numerical Expressions 50 and 51.

[0139]
With the frequency correction value arithmetic means 20A configured in this way, when the induction motor 101 with the known electrical constants is driven, the amplification gains Gl and G2 of the amplifier 230 can be appropriately designed and set online for the induction motor 101 to be driven in the constant output area COA, whereby the current flowing through the induction motor 101 can be suppressed to the set value cox of the current limiting response speed. Thereby, the desired current limiting performance can be attained in the state where the induction motor 101 is run in the constant output area COA. In the embodiment 3, the switching part 225 of the amplification gain arithmetic means 210A outputs the zero value' from the zero value output part 221 to the amplifier 230 in the state where the AC rotating machine, or the induction motor 101, is run in the constant torque area CTA.

[0140]
In this embodiment 3, the set value ©x of the current limiting response speed is given by the following Numerical Expression 52.

[0141]
[Numerical Expression 52]

[0142]
The set value cox of this current limiting response speed may be stored as the set value of cox in the constant storage memory 203, or computed by the amplification gain arithmetic part 214 from the stator resistance Ri, the stator inductance Li and the leakage constant i=150 [Hz], and the characteristic m8 is the characteristic where co*=c0i=200 [Hz] .

[0145]
The output phase characteristic of Fig. 11(B) shows the result of supplying a signal in which co*=©i is added to the input sinusoidal wave having a predetermined magnitude and changing in the frequency to block 35 representing the transfer function GiMSYs, and analyzing a change in the phase of the output signal outputted from the block 35, in which the horizontal axis represents the frequency of the input sinusoidal wave in (rad/sec) , and the vertical axis represents the phase of the output signal in (deg). The characteristic p4 in Fig. 11(B) is the characteristic where ©*=(Oi=40 [Hz], the characteristic p5 is the characteristic where ©*=(0i=50 [Hz] , the characteristic p6 is the characteristic where ©*=©i=100 [Hz], the characteristic p7 is the characteristic where ffl*=©i=150 [Hz] , and the characteristic p8 is the characteristic where ©*=©i=200 [Hz] .

[0146]
In Figs. 11(A) and 11(B), the chain lines f5, f6, f7 and f8 parallel to the vertical axis show the plotting at the frequency 50 [Hz], 100[Hz], 150[Hz] and 200 [Hz], respectively.

[0147]
From Fig. 11 (A) , it can be understood that the transfer characteristic in the constant output area COA is greatly different from the first-order lag characteristic that is the transfer characteristic in the constant torque area CTA. Also, there is a sudden change in the characteristic near the frequency band over the inverter frequency first and the output magnitude of Fig. 11(A) suddenly falls at an inclination of 20dB/decade or less. It can be understood that the transfer characteristic is complex as a whole, but the first-order lag characteristic in the band of the inverter frequency ©i or less. Also, it can be understood that as the inverter frequency co± increases, the DC gain of the transfer characteristic falls.

[0148]
The transfer characteristic GIH in the constant output area COA can be described as in the following Numerical Expression 53 by linearizing a voltage equation of the induction motor 101 as vq*=V"o.

[0149]
[Numerical Expression 53]

In the Numerical Expression 53, all the constants are values decided from the electrical constants of the induction motor 101.

[0150]
Though in the embodiment 1, the high response current limiting can be realized by setting the current limiting response speed ©x at the time of limiting the current in a frequency range higher than the inverter frequency ©i, the transfer characteristic GIM in the constant output area COA is not the first-order lag characteristic because the output magnitude suddenly falls at an inclination of -20dB/decade or less as shown in Fig. 11(A). Also, since the phase becomes -180° or less as indicated by the straight line <£ -180 parallel to the horizontal axis in Fig. 11 (B) , the control system becomes unstable in designing the gains Gl and G2 of the amplifier 230 as shown in the embodiment 1. These phenomena may cause the problem that the desired current limiting performance can not be obtained even using the voltage command means 15, 15A of the (E/f) constant control system when the AC rotating machine 10 is run in the constant output area COA.

[0151]
In the embodiment 3, the gains of the amplifier 230 are designed in a frequency band below the inverter frequency ©i indicating the first-order lag characteristic in Fig. 11(A). Specifically," the transfer characteristic indicating the first-order lag characteristic coincident in the frequency band below the inverter frequency ©± is derived from the Numerical Expression 53, and the amplification gains of the : amplifier 230 are designed from the transfer characteristic as derived herein.

[0152]
The Numerical Expression 53, like the Numerical Expression 15, is approximated by K/(1+Txs). In this case, first of all, the Laplace operator s in the Numerical Expression 53 is made zero, whereby the following Numerical Expression 54 is obtained to give the DC gain K.

[0153]

[Numerical Expression 54]

[0154]
Also, if the first-order lag characteristic contained in the Numerical Expression 53 is extracted, this first-order lag characteristic is represented in the following Numerical Expression 55.

[0155]

[Numerical Expression 5.5]

The transfer characteristic GiM approximated by the first-order lag characteristic is a combination of the Numerical Expressions 54 and 55, and the reciprocal of axLi/Ri included in the denominator of the Numerical Expression 55 becomes the frequency 1/T at bended point. That is, the frequency 1/T at bended point is given by the following Numerical Expression 56.

[0156]

[Numerical Expression 56]

[0157]

From the Numerical Expressions 55 and 56, the amplification gains Gl and G2 in the embodiment 3 are given by the following Numerical Expressions 57 and 58 in the same way as the Numerical Expressions 20 and 21.

[0158]

[Numerical Expression 57]

[0159]

Herein, considering the characteristic of the transfer function GXM in the constant output area COA, the set value cox of the current limiting response speed at the time of limiting the current is set to a smaller frequency than the inverter frequency COJ. in the Numerical Expressions 57 and 58, whereby the stability can be secured. A rough estimate of setting the set value a>x of the current limiting response speed may be about one-fifth of the inverter frequency wi. Further, in the characteristic of the transfer characteristic GIM in the constant output area COA as shown in Fig. 11(A), there is a tendency that as the inverter frequency a>i increases, the peak of the output magnitude in the frequency band of the inverter frequency coi is higher. At this peak value in the characteristic of the transfer characteristic GiM; the magnitude of the first-order lag characteristic is equal to or less than the magnitude corresponding to the frequency 1/T at bended point. That is, the set value co* of the current limiting response speed is equaled to the frequency (l/T)=Ri/(oxLi) at bended point in the first-order lag characteristic, as shown in the Numerical Expression 52, whereby the control system at the time of limiting the current can be always contained in the stable area. In this case, a gain margin of the control system may be secured to be 3dB or more.

[0160]
Accordingly, if the gains Gl and G2 of the amplifier 230 are designed in consideration of the transfer characteristic GIM in the constant output area COA, substituting the Numerical Expression 52 into the Numerical Expressions 57 and 58 yields the Numerical Expressions 50 and 51.

[0161]
If the frequency (l/T)=Ri/(oxLx) at bended point in first-order lag characteristic does not remote from the inverter frequency 0>i with a distance which is equal to or more than one-fifth of the inverter frequency coi, the set value (a* of the current limiting response speed is designed as ci)x=a)i/5, whereby the stabilization can be made. At this time, substituting (0x=(0i/5 into the Numerical Expressions 50 and 51 for designing the gains Gl and G2 of the amplifier 230 yields the following Numerical Expressions 59 and 60.

[0162]
[Numerical Expression 59]

[Numerical Expression 60]

[0163]
In this way, if the current of the induction motor 101 driven in the constant output area COA is limited to the current limiting command value I limit, the reliable current limiting performance can be attained by using the above-mentioned amplifier gains according to the inverter frequency to drive the induction motor 101. Though in the embodiment 3, the inverter frequency ©i is used to compute the gains Gl and G2, the frequency command value (0* may be used, instead of the inverter frequency ©i, to achieve the same effects.

[0164]
Modification 3A of the embodiment 3

Though in the embodiment 3, the AC rotating machine 10 is the induction motor 101, in this modification 3A, the AC rotating machine 10 in the embodiment 3 is replaced with any other AC rotating machine, for example, the synchronous motor 10S.

[0165]
Fig. 12 is a block diagram showing the control device for the AC rotating machine according to this modification 3A, in which the AC rotating machine 10 is the synchronous motor 10S. In this modification 3A, the stabilization high pass filter 40 is further added to the embodiment 3 as shown in Fig. 10, the voltage command means 15 in the embodiment 3 is replaced with the voltage command means 15A, and the inverter frequency arithmetic means 17 is replaced with the inverter frequency arithmetic means 17A. The stabilization high pass filter 40, the voltage command means 15A and the inverter frequency arithmetic means 17A are the same as the modification 1A of the embodiment 1 as shown in Fig. 7 . In others, the modification 3A is configured in the same way as the embodiment 3.

[0166]

In the modification 3A of the embodiment 3, the Numerical Expressions 50 and 51 as well as the Numerical Expressions 59 and 60 in the embodiment 3 are changed corresponding to the synchronous motor 10S, to compute the amplification gains Gl and G2, and the amplification gains Gl and G2 are supplied to the amplifier 230 in the state where the synchronous motor 10S is run in the constant output area COA. In the modification 3A of the embodiment 3, the frequency command value (0* may be used, instead of the inverter frequency a>i, in computing the gains Gl and G2, thereby achieving the same effects.

[0167] Embodiment 4

Fig. 13 is a block diagram showing an embodiment 4 of the control device for the AC rotating machine according to this invention. This embodiment 4 is configured by modifying the embodiment 3 as shown in Fig. 10 such that the voltage command means 15 is replaced with voltage command means 15B . In others, the embodiment 4 is configured in the same way as the embodiment 3, in which the AC rotating machine 10 is the induction motor 101. In this embodiment 4, the same frequency correction value arithmetic means 20A as in the embodiment 3 is also used.

[0168]
The voltage command means 15B in the embodiment 4 is the same as the embodiment 2 as shown in Fig. .8. This voltage command means 15B is the voltage command means of the (V/f) constant control system. This voltage command means 15B has the voltage command arithmetic means 155 of the (V/f) constant control system, and the dq-axis/three phase coordinate transformer 157. The voltage command arithmetic means 155 is supplied with the inverter frequency ©i from the inverter frequency arithmetic means 17. The voltage command arithmetic means 155 computes the d-axis voltage command vd* and the q-axis voltage command vq* based on the inverter frequency (0± in accordance with the Numerical Expressions 35 and 36, and supplies them to the dq-axis/three phase coordinate transformer 157.

[0169]
In the embodiment 4, like the embodiment 3, the amplification gain arithmetic part 214 of the frequency correction value arithmetic means 20A computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60, and supplies these amplification gains Gl and G2 to the amplifier 230 in the state where the induction motor 101 is run in the constant output area COA, thereby achieving the same effects as the embodiment 3. In the embodiment 4, in computing the gains Gl and G2, the frequency command value co* may be used, instead of the inverter frequency coi, thereby achieving the same effects.

[0170]

Modification 4A of the embodiment 4

Though in the embodiment 4, the AC rotating machine 10 is the induction motor 101, in this modification 4A the AC rotating machine 10 in the embodiment 4 is any other AC rotating machine, for example, the synchronous motor 10S.

[0171]
Fig. 14 is a block diagram showing the control device for the AC rotating machine in the modification 4A, in which the AC rotating machine 10 is the synchronous motor 10S. In the modification 4A, the stabilization high pass filter 40 is further added to the embodiment 4 as shown in Fig. 13 , the voltage command means 15B in the embodiment 4 is replaced with the voltage command means 15C, and the inverter frequency arithmetic means 17 is replaced with the inverter frequency arithmetic means 17A. In others, the modification 4A is configured in the same way as the embodiment 4.

[0172]
The stabilization high pass filter 40 in this modification 4A is the same as the stabilization high pass filter 40 in the modification 2A as shown in Fig. 9, and the inverter frequency arithmetic means 17A in the modification 4A is the same as the inverter frequency arithmetic means 17A as shown in Fig. 9.

[0173]

In the modification 4A of this embodiment 4, . the Numerical Expressions 50 and 51 as well as the Numerical Expressions 59 and 60 in the embodiment 3 are changed corresponding to the synchronous motor 10S, to compute the amplification gains Gl and G2, whereby the amplification gains Gl and G2 are supplied to the amplifier 230 in the state where the synchronous motor 10S is run in the constant output area COA. In the modification 4A of the embodiment 4, the frequency command value co* may be used, instead of the inverter frequency ©i, in computing the gains Gl and G2, thereby achieving the same effects.

[0174] Embodiment 5
Fig. 15 is a block diagram showing an embodiment 5 of the control device for the AC rotating machine according to this invention. This embodiment 5 is configured by modifying the embodiment 1 as shown in Fig.l such that the frequency correction value arithmetic means 20 is replaced with frequency correction value arithmetic means 20B . In others, the embodiment 5 is configured in the same way as the embodiment 1. The AC rotating machine 10 is the same induction motor 101' as the embodiment 1, and the voltage command means 15, which is configured as the same voltage command means of the (E/f) constant control system as the embodiment 1, has the voltage command arithmetic means 153 of the (E/f) constant control system and the dq-axis/three phase coordinate transformer 157. The frequency correction value arithmetic means 20B is also composed of a micro-computer, for example.

[0175]
The frequency correction value arithmetic means 20B for use in the embodiment 5 has amplification gain computing element 210B which is substituted for the amplification gain computing element 210. in the frequency correction value arithmetic means 20 in the embodiment 1 as shown in Fig. 1. In the frequency correction value arithmetic means 20B, the ' input port 20-16 in the frequency correction value arithmetic means 20 of the embodiment 1 is deleted. In others, the frequency correction value arithmetic means 20B is configured in the same way as the frequency correction value arithmetic means 20 as shown in Fig. 1.

[0176]

The amplification gain computing element 210B for use in the embodiment 5 has a first amplification gain arithmetic part 211, a second amplification gain arithmetic part 212, the switch signal generating part 223, and the switching part 225. The switch signal generating part 223 and the switching part 225 are the same as used in the embodiment 1 as shown in Fig. 1. The first amplification gain arithmetic part 211 is configured using the same amplification gain arithmetic part 213 as used in the frequency correction value computing element 20 as shown in Fig. 1. This amplification gain arithmetic part 213 computes the amplification gains Gl and G2-based on the electrical constants regarding the induction motor 101 stored in the constant storage memory 203 in accordance with the Numerical Expressions 6 and 7 or the Numerical Expressions 6 and 22, and supplies them to the input a of the switching part 225.

[0177]
The second amplification gain arithmetic part 212 is configured by using the same amplification gain arithmetic part 214 as used in the frequency correction value arithmetic means 20A as shown in Fig. 10. This amplification gain arithmetic part 214 computes the amplification gains Gl and G2 based on the electrical constants regarding the induction motor 101 stored in the constant storage memory 203 and the inverter frequency OH supplied to the input end 20-13 in accordance with the Numerical Expressions 50 and 51 or the Numerical Expressions 5 9 and 60, and supplies them to the input b of the switching part 225.

[0178]
In the embodiment 5 as shown in Fig. 15, the switch signal SS of the switch signal generating part 223 enables the switching part 225 to select the amplification gains Gl and G2 from the amplification gain arithmetic part 213 supplied to the- input a, and supply them from the output c of the switching part 235 to the amplifier 230 in the state where the induction motor 101 is run in the constant torque area CTA. The amplifier 230 computes the frequency correction arithmetic value A(0a in accordance with the Numerical Expression 10, by using the amplification gains Gl and G2 that the amplification gain arithmetic part 213 computes in accordance with the Numerical Expressions 6 and 7 or the Numerical Expressions 6 and 22 as in the embodiment 1, and supplies this frequency correction arithmetic value Acoa to the input a of the output selector 235 in the state where the induction motor 101 is run in the constant torque area CTA.

[0179]
In the embodiment 5 as shown in Fig. 15, the switch signal S.S of the switch signal generating part 223 enables the switching part 225 to select the amplification gains Gl and G2 from amplification gain arithmetic part 214 supplied to the input b, and supply them from the output c of the switching part 235 to the amplifier 230 in the state where the induction motor 101 is run in the constant output area COA. The amplifier 230 computes the frequency correction arithmetic value Acoa in accordance with the Numerical Expression 10, by using the amplification gains Gl and G2 that the amplification gain arithmetic part 214 computes in accordance with the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60 as in the embodiment 3, and supplies this frequency correction switching part 225 to the amplifier 230 in the state where the induction motor 101 is run in the constant torque area CTA. The amplifier 230 computes the frequency correction arithmetic value Acaa in accordance with the Numerical Expression 10, by using the amplification gains Gl and G2 that the amplification gain arithmetic part 213 computes in accordance with the Numerical Expressions 6 and 7 or the Numerical Expressions 6 and 22 as in the embodiment 1, and supplies this frequency correction arithmetic value Acoa to the input a of the output selector 235 in the state where the induction motor 101 is run in the constant torque area CTA.

[0180]
Consequently, the frequency correction value arithmetic means 2OB in the embodiment 5 performs the same operation as the amplifier 230 in the embodiment 1 amplifies the current deviation Al by using the amplification gains Gl and G2 with the amplification gain arithmetic part 213 in the state where the induction motor 101 is run in the constant torque area CTA, and performs the same operation as the amplifier 230 in the embodiment 3 amplifies the current deviation Al using the amplification gains Gl and G2 with the amplification gain arithmetic part 214 in the state where the induction motor 101 is run in the constant output area COA. Accordingly, the current flowing through the induction motor 101 can be limited to the current limiting command value I limit or less, irrespective of whether the induction motor 101 is run in the constant torque area CTA or the constant output area COA.

[0181]
In this way, with the embodiment 5, when the induction motor 101 is driven at variable speed in a wide speed range from the constant torque area CTA to the constant output area COA, the current limiting can be securely performed. Also, the gains Gl and G2 of the amplifier 230 are switched while the components of the control system are unchanged, whereby the program for installing the control system can be simplified. In the embodiment 5, the frequency command value co* may be used, instead of the inverter frequency ©i, in computing the gains Gl and G2 with the amplification gain arithmetic part 214, thereby achieving the same effects.

[0182] Modification 5A of the embodiment 5
Fig. 16 is a modification in which for the AC rotating machine 10, the inductionmotor 101 is replaced with any other AC rotating machine, for example, the synchronous motor 10S. This modification 5A is configured by modifying the embodiment 5 as shown in Fig.15 such that the AC rotating machine 10 is configured by the synchronous motor 10S, the voltage command means 15 is replaced with the voltage command means 15A, the inverter frequency arithmetic unit 17 is replaced with the inverter frequency arithmetic means 17A, and further the stabilization high pass filter 40 is added. In others, the modification 5A is configured in the same way as the embodiment 5 as shown in Fig. 15.

[0183]
The voltage command means 15A in the modification 5A is configured as the voltage command means of the (E/f) constant control system as in the modification 1A of the embodiment 1 as shown in Fig. 7, and has the voltage command arithmetic means 154 of the (E/f) constant control system and the dq-axis/three phase coordinate transformer 157. The inverter frequency arithmetic means 17A and the stabilization high pass filter 40 in the modification 5A are the same as the modification 1A of the embodiment 1 as shown in Fig. 7.

[0184]
In this modification 5A, the same frequency correction value arithmetic means 20B as shown in Fig. 15 is also used. In this modification 5A, in the state where the synchronous motor 10S is run in the constant' torque' area CTA, the amplification gain arithmetic part 213 in the frequency correction value arithmetic means 20B computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 26 and 27 as in the modification 1A. Also, in the state where the synchronous motor 10S is run in the constant output area COA, the amplification gain arithmetic part 214 computes the amplification gains Gl and G2 in accordance with the expressions changed corresponding to the synchronous motor 10S from the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60.

[0185]
Consequently, the frequency correction value arithmetic means 20B in the modification 5A of the embodiment 5 performs the same operation as the amplifier 230 in the modification 1A of the embodiment 1 amplifies the current deviation AI by using the amplification gains Gl and G2 with the amplification gain arithmetic part 213 in the state where the synchronous motor 10S is run in the constant torque area CTA, and performs the same operation as the amplifier 230 in the modification 3A of the embodiment 3 amplifies the current deviation AI by using the amplification gains Gl and G2 with the amplification gain arithmetic part 214 in the state where the synchronous motor 10S is run in the constant output area COA. Accordingly, the current flowing through the synchronous motor 10S can be limited to the current limiting command value I limit or less, irrespective of whether the synchronous motor 10S is run in the constant torque area CTA or the constant output area COA.

[0186]
In this way, with the modification 5A of the embodiment 5, when the synchronous motor 10S is driven at variable speed in a wide speed range from the constant torque area CTA to the constant output area COA, the current limiting can be securely performed. Also, the gains Gl and G2 of the amplifier 230 are switched with the components of the control system' unchanged, whereby the program for installing the control system can be simplified. In the modification 5A of the embodiment 5, the frequency command value co* may be used, instead of the inverter frequency a>±, in computing the gains Gl and G2 with the amplification gain arithmetic part 214, thereby achieving the same effects.

[0187] Embodiment 6

Fig. 17 is a block diagram showing an embodiment 6 of the control device for the AC rotating machine according to this invention. This embodiment 6 is configured by modifying the embodiment 2 as shown in Fig.8 such that the frequency correction value arithmetic means 20 is replaced with the frequency correction value arithmetic means 20B . In others, the embodiment 6 is configured in the same way as the embodiment 2. In this embodiment 6, the AC rotating machine 10 is the' induction motor 101, and the voltage command means 15B of the (V/f) constant control system is used as in the embodiment 2 shown in Fig. 8.

[0188]
In this embodiment 6, the same frequency correction value arithmetic means 20B as shown in Fig. 15 is also used. In this embodiment 6, the amplification gain arithmetic part .213 in the frequency correction value arithmetic means 20B computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 37 and 38 in the same way as the embodiment 2 in the state where the induction motor 10S is run in the constant torque area CTA. Also, the amplification gain arithmetic part 214 computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60 in the state where the induction motor 101 is run in the constant output area COA.

[0189]
Consequently, the frequency correction value arithmetic means 2OB in the embodiment 6 performs the same operation as the amplifier 230 in the embodiment 2 amplifies the current deviation Al by using the amplification gains Gl and G2 with the amplification gain arithmetic part 213 in the state where the induction motor 101 is run in the constant torque area CTA, and performs the same operation as the amplifier 230 in the embodiment 4 amplifies the current deviation Al by using the amplification gains Gl and G2 with the amplification gain arithmetic part 214 in the state where the induction motor 101 is run in the constant output area COA. Accordingly, the current flowing through the induction motor 101 can be limited to the current limiting command value I limit or less, irrespective of whether the induction motor 101 is run in the constant torque area CTA or the constant output area COA.

[0190]
In this way, with the embodiment 6, when the induction motor 101 is driven at variable speed in a wide speed range from the constant torque area CTA to the constant output area COA, the current limiting can be securely performed. Also, the gains Gl and G2 of the amplifier 230 are switched with the components of the control system unchanged, whereby the program for installing the control system can be simplified.

In the embodiment 6, the frequency command value co* may be used, instead of the inverter frequency (0±, in computing the gains Gl and G2 with the amplification gain arithmetic part 214, thereby achieving the same effects.

[0191] Modification 6A of the embodiment 6 Fig. 18 is a modification of the embodiment 6 in which for the AC rotating machine 10, the induction motor 101 is replaced with any other AC rotating machine, for example, the synchronous motor 10S. This modification 6A is configured by modifying the embodiment 6 as shown in Fig. 17 such that the AC rotating machine 10 is the synchronous motor 10S, the voltage command means 15B is replaced with the voltage command means 15C, the inverter frequency arithmetic unit 17 is replaced with the inverter frequency arithmetic means 17A, and further the stabilization high pass filter 40 is added. In others, the modification 6A is configured in the same way as the embodiment 6 as shown in Fig. 17.

[0192]
The voltage command means 15C in the modification 6A is configured as the voltage command means of the (V/f) constant control system as in the modification 2A of the embodiment 2 as shown iri~Fig. 9, and has the voltage command arithmetic means 156 of the (V/f) constant control system and the dq-axis/three phase coordinate transformer 157. The inverter frequency arithmetic means 17A and the stabilization high pass filter 4 0 in the modification 6A are the same as the modification 2A of the embodiment 2 as shown in Fig. 9.

[0193]
In this modification 6A, the same frequency correction value arithmetic means 20B as shown in Fig. 15 is also used. In this modification 6A, in the state where the synchronous motor 10S is run in the constant torque area CTA, the amplification gain arithmetic part 213 in the frequency correction value arithmetic means 2 OB computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 47 and 48 in the same way as the modification 2A. Also, in the state where the synchronous motor 10S is run in the constant output area COA, the amplification gain arithmetic part 214 computes the amplification gains Gl and G2 in accordance with the expressions changed corresponding to the synchronous motor 10S from the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60.

[0194]
Consequently, the frequency correction value arithmetic means 20B in the modification 6A of the embodiment 6 performs the same operation as the amplifier 230 in the modification 2A of the embodiment 2 amplifies the current deviation AI by using the amplification gains Gl and G2 with the amplification gain arithmetic part 213 in the state where the synchronous motor 10S is run in the constant torque area CTA, and performs the same operation as the amplifier 230 in the modification 4A of the embodiment 4 amplifies the current deviation Al by using the amplification gains Gl and G2 with the amplification gain arithmetic part 214 in the state where the synchronous motor 10S is run in the constant output area COA. Accordingly, the current flowing through the synchronous motor 10S can be limited to the current limiting command value I limit or less, irrespective of whether the synchronous motor 10S is run in the constant torque area CTA or the constant output area COA.

[0195]
In this way, with the modification 6A of the embodiment 6, when the synchronous motor 10S is driven at variable speed in a wide speed range from the constant torque area CTA to the constant output area COA, the current limiting can be securely performed. Also, the gains Gl and G2 of the amplifier 230 are switched with the components of the control system unchanged, whereby the program for installing the control system can be simplified. In the modification 6A of the embodiment 6, the frequency command value GO* may be used, instead of the inverter frequency o>i, in computing the gains Gl and G2 with the amplification gain arithmetic part 214, thereby achieving the same effects.

[0196] Embodiment 7

Fig. 19 is a block diagram showing an embodiment 7 of the control device for the AC rotating machine according to this invention. This embodiment 7 is configured by modifying the embodiment 5 as shown in Fig.15 such that the frequency correction value arithmetic means 20B is replaced with frequency correction value arithmetic means 20C . In others, the embodiment 7 is configured in the same way as the embodiment 5. In this embodiment 7, the AC rotating machine 10 is the induction motor 101, and the voltage command means 15 of the (E/f) constant control method is used. ' The frequency correction value arithmetic means 20C is also composed of a micro-computer, for example.

[0197]
The frequency correction value arithmetic means 20C for use in the embodiment 7 has the amplification gain computing element 210C which is substituted for the amplification gain computing element 210B in the frequency correction value arithmetic means 20B in the embodiment 5 as shown in Fig. 15. In others, the frequency correction value arithmetic means 2 0C is configured in the same way as the frequency correction value arithmetic means 2QB. The amplification gain computing element 210C has a first amplification gain adjustment part 215 in addition to the first amplification gain arithmetic part 211, and a second amplification gain adjustment part 216 in addition to the second amplification gain arithmetic part 212 in the amplification gain computing element 210B of the embodiment 5 as shown in Fig. 15. In others, the amplification gain computing element 210C is configured in the same way as the amplification gain computing element 210B.

[0198]
The first amplification gain adjustment part 215 receives the amplification gain Gl, G2 computed by the amplification gain arithmetic part 213, adjusts its magnitude, and supplies the amplification gain Gl, G2 with the magnitude adjusted to the input a of the switching part 225. The second amplification gain adjustment part 216 receives the amplification gain Gl, G2 computed by the amplification gain arithmetic part 214, adjusts its magnitude, and supplies the amplification gain Gl, G2 with the magnitude adjusted to the input b of the switching part 225.

[0199]
The first and second amplification gain adjustment parts 215 and 216 adjust the magnitude of the amplification gains Gl and G2 computed by the amplification gain arithmetic parts 213 and 214 to adjust the natural vibration in a mechanical system into which the AC rotating machine 10 is built. Specifically, when the mechanical system into which the AC rotating machine 10 is built has the natural vibration based on an unknown large moment of inertia, if the current limiting operation is performed for the AC rotating machine 10 built into this mechanical system, the natural vibration of the mechanical system appears in the current limiting response. The first and second amplification gain adjustment parts 215 and 216 adjust the natural vibration appearing in the current limiting response, by adjusting the magnitude of the amplification gains Gl and G2 computed by the amplification gain arithmetic parts 213 and 214, whereby it is possible to attain the reliable current limiting performance, and to adjust' the natural vibration of the mechanical system based ■ on this current limiting performance.

[0200] Modification 7A of the embodiment 7

Fig. 20 is a block diagram showing a modification 7A of the embodiment 7. This modification 7A is configured by modifying the embodiment 7 such that the AC rotating machine 101 is replaced with the synchronous motor 10S, and the voltage command means 15A and the inverter frequency arithmetic means 17A are used, as in the modification 1A as shown in Fig. 7, and further the stabilization high pass filter 40 is used. In others, the modification 7A is the same as the embodiment 7 as shown in Fig. 19.

[0201]
In this modification 7A, the same frequency correction value arithmetic means 20C as in the embodiment 7 as shown in Fig. 19 is also used. In this frequency correction value arithmetic means 20C, the same amplification gain computing element 210C as shown in Fig. 19 is used, and the amplification gain computing element 210C has' the first and second amplification gain adjustment parts 215 and 216 as in the embodiment 7. These first and second amplification gain adjustment parts 215 and 216 adjust the natural vibration appearing in the current limiting response from the mechanical system built into the synchronous motor 10S, by adjusting the magnitude of the' amplification gains Gl and G2 computed by the amplification gain arithmetic parts 213 and 214, whereby it is possible to attain the reliable current limiting performance, and adjust the natural vibration of the mechanical system based on this current limiting performance.
[0202] Embodiment 8

Fig. 21 is a block diagram showing an embodiment 8 of the control device for the AC rotating machine according to this invention. This embodiment 8 is configured by modifying the embodiment 7 such that the voltage command means 15 is replaced with the same voltage command means 15B as the embodiment 2 as shown in Fig.8. In others, the embodiment 8 is configured in the same way as the embodiment 7 as shown in Fig. 1'9. ' The AC rotating machine 10 is the induction motor 101.

[0203]

In this embodiment 8, the same frequency correction value arithmetic means 20C as in the embodiment 7 as shown in Fig. 19 is also used. In this frequency correction value arithmetic means 20C, the same amplification gain computing element 2IOC as shown in Fig. 19 is used, and the amplification gain computing element 2IOC has the first amplification gain adjustment parts 215 and 216 in the same way as in the embodiment 7. These first and second amplification gain adjustment parts 215 and 216 adjust the natural vibration appearing in the current limiting response from the mechanical system into which the induction motor 101 is built, by adjusting the magnitude of the amplification gains Gl and G2 computed by the amplification gain arithmetic parts 213 and 214, whereby it is possible to attain the reliable current limiting performance and adjust the natural vibration of the mechanical system based on this current limiting performance.

[0204] Modification 8A of the embodiment 8

Fig. 22 is a block diagram showing the control device for the AC rotating machine according to the modification 8A of the embodiment 8. This modification 8A is configured by modifying the embodiment 8 such that the AC rotating machine 101 is replaced with the synchronous motor 10S, the voltage command means 15C and the inverter frequency arithmetic means 17A are used, as in the modification 2A as shown in Fig. 9, and further the stabilization high pass filter 40 is used. In others, the modification 8A is the same as the embodiment 8 as shown in Fig. 21.

[0205]
The voltage command means 15C in this modification 8A is configured as the voltage command means of the (V/f) constant control system as in the modification 2A of the embodiment 2 as shown in Fig. 9, and has the voltage command arithmetic means 156 of the (V/f) constant control system, and the dq-axis/three phase coordinate transformer 157.' The inverter frequency arithmetic means 17A and the stabilization high pass filter 40 in the modification 8A are the same as the modification 2A of the embodiment 2.

[0206]
In this modification 8A, the same frequency correction value arithmetic means 20C as in the embodiment 7 as shown in Fig. 19 is also used. In this frequency correction value arithmetic means 20C, the same amplification gain computing element 210C as shown in Fig. 19 is used, and the amplification gain computing element 210C has the first and second amplification gain adjustment parts 215 and 216 as in the embodiment 7. These first and second amplification gain adjustment parts 215 and 216~adjust the natural vibration appearing in the current limiting response from the mechanical system into which the synchronous motor 10S is built, by adjusting the magnitude of the amplification gains Gl and G2 computed by the amplification gain- arithmetic parts 213 and 214,. whereby it is possible to attain the reliable current limiting performance, and adjust the natural vibration of the mechanical system based on this current limiting performance.

[0207] Embodiment 9
Fig. 23 is a block diagram showing an embodiment 9 of the control device for the AC rotating machine according to this invention. This embodiment 9 is configured by modifying the embodiment 5 as shown in Fig.15 such, that the voltage command means 15 is replaced with the voltage command means 15a and the frequency correction value arithmetic means 20B is replaced with frequency correction value arithmetic means 20Ba. In others, the embodiment 9 is configured in the same way as the embodiment 5. In this embodiment 9, the AC rotating machine 10 is the induction motor 101. The voltage command means 15a and the frequency correction value arithmetic means 20Ba are also composed of a micro-computer, for example.

[0208]
The voltage command means 15a used in this embodiment 9 has first voltage command arithmetic means 151, second voltage command arithmetic means 152, the dq-axis/three phase coordinate transformer 157, and voltage command selection means 159. The first voltage command arithmetic means 151 used in this embodiment 9 has two of first and second functions. The first function is to supply a measurement voltage command vm* for measuring the electrical constants of the induction motor 101 to the voltage application means 11 and supply a measurement single phase AC voltage vm for measuring the electrical constants of the induction motor 101 from the voltage application means 11 to the induction motor 10. The second function is to compute the electrical constants of the induction motor 101 by receiving a measurement current im of single phase AC outputted from the current detection means 13 based on the current flowing from the voltage application means ll to the induction motor 101 at the measurement single phase AC voltage Vj,.

[0209]
The second voltage command arithmetic means 152 is the voltage command means of the (E/f) constant control system, and is configured by using the same voltage command arithmetic means 153 as shown in Fig. 15, to compute the d-axis voltage command vd* and the q-axis voltage command vq* in accordance with the Numerical Expressions 3 and 4, and supply them to the dq-axis/three phase coordinate transformer 157. The voltage command selection means 159 has an input port a for receiving the measurement voltage command vm* from the first voltage command arithmetic means 151, an input port b for receiving a three phase voltage command V* from the dq-axis/three phase coordinate transformer 157, and an output port c connected to the voltage application means 11. The voltage command selection means 159 selects the input port a to connect to the output port c to supply the measurement voltage command vm* from the first voltage command arithmetic means 151 to the voltage application means 11 in measuring the electrical constants of the induction motor 101, and selects the input port b to connect to the output port c to supply the three phase voltage command V* to the voltage application means 11 in driving the induction motor 101.

[0210]
The frequency correction value arithmetic means 20Ba for use in the embodiment 9 has an input port 20-17 added to the frequency correction value arithmetic means 2 0B in the embodiment 5 as shown in Fig. 15. In others, this frequency correction value arithmetic means 2 0Ba is configured in the same way as the frequency correction value arithmetic means 20B as shown in Fig. 15. The frequency correction value arithmetic means 20Ba internally comprises the current deviation arithmetic element 201, the constant storage memory 203, the amplification gain computing element 210B, the amplifier 230, the zero value output part 231, the state signal generator 233, and the output selector 235 as in the embodiment 5. In this frequency correction value arithmetic means 20Ba, the newly added input port 20-17 is connected to the first voltage command arithmetic means 151, and also connected to the constant storage memory 203 inside the frequency correction value arithmetic means 20Ba.

[0211]
A constant measuring device for measuring the electrical constants of the AC rotating machine 10 such as the induction motor was described in the international publication official gazette WO2006/008846 by the same applicant as for this application, and the detailed description is omitted. When ' the voltage command selection means 159 in the embodiment 9 selects the measurement voltage command vm* with the first voltage command arithmetic means 151, the measurement single phase AC voltage vm for measuring the electrical constants is supplied from the voltage application means 11 to the induction motor 101, and the current detection means 13 detects the measurement current im of single phase AC flowing through the induction motor 101 at this measurement single phase AC voltage vm. The first voltage command arithmetic means 151 computes the electrical constants of the induction motor 101 based on and the measurement current im and any one of the measurement voltage command vm* and the measurement single phase AC voltage vm, and supplies them to the constant storage memory 203.

[0212]
In the embodiment 9, the. AC rotating machine 10 is the induction motor 101, and the amplification gain arithmetic part 213 computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 6 and 7 or the Numerical Expressions 6 and 22, and the amplification gain arithmetic part 214 computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60, whereby the electrical constants of the induction motor 101 required for these arithmetic operations . are computed by the first voltage command arithmetic means 151 and stored in the constant storage memory 203. The set value ©x of the current limiting response speed is not measured by the first voltage command arithmetic means 151 but stored in the constant storage memory 203. In the embodiment 9, in computing the gains Gl and G2 with the amplification gain arithmetic part 214, the frequency command value ©* may be used, instead of the inverter frequency coi, thereby achieving the same effects.

[0213]
With this embodiment 9, even when the electrical constants of the induction motor 101 is unknown, the electrical constants of the induction motor 101 can be firstly measured by using the first voltage command arithmetic means 151, and stored in the constant storage memory 203. Thereafter, when the voltage command selection means 159 selects again the three phase voltage command V* with the d-axis voltage command vd* and the q-axis voltage command vq* outputted by the second voltage command arithmetic means 152 to drive the induction motor 10, the frequency correction value arithmetic value Acoa can be computed with the amplification gains Gl and G2 of the amplifier 230 appropriately designed, whereby the current can be securely limited to the current limiting command value I limit with the desired current limiting performance.

[0214]
In the embodiment 9, the frequency correction value arithmetic means 20Ba may be' replaced with the frequency correction value arithmetic means 20a in which the input port 20-17 is added to the frequency correction value arithmetic means 20 as shown in Fig. 1, the frequency correction value arithmetic means 20Aa in which the input port 20-17 is added to the frequency correction value arithmetic means 20A as shown in Fig. 10, or the frequency correction value arithmetic means 20Ca in which the input port 20-17 is added to the frequency correction value arithmetic means 20C as shown in Fig. 19. The frequency correction value arithmetic means 20a, 20A or 20Ca is also composed of a micro-computer, for example, in which the added input port 20-17 is connected to the first voltage command arithmetic means 151 and the constant storage memory 203, and the electrical constants of the induction motor 101 computed by the first voltage command arithmetic means 151 are stored in the constant storage memory 203.

[0215]

Modification 9A of the embodiment 9

Fig. 24 is a block diagram showing the control device for the AC rotating machine according to a modification 9A of the embodiment 9. This modification 9A is configured by-modifying the modification 5A of the embodiment 5 as shown in Fig. 16 such that the voltage command means 15A is replaced with the voltage command means 15Aa and the frequency correction value arithmetic means 2OB is replaced with frequency correction value arithmetic means 20Ba. In others, the modification 9A of the embodiment 9 is configured in the same way as the modification 5A of the embodiment 5. In the modification 9A of this embodiment 9, the AC rotating machine 10 is the synchronous motor 10S . The voltage command means 15Aa is also composed of a micro-computer, for example.

[0216]
The voltage command means 15Aa used in this modification 9A has the first voltage command arithmetic means 151, the second voltage command arithmetic means 152, the dq-axis/three phase coordinate transformer 157, and the voltage command selection means 159 in the same way as in the embodiment 9. The first voltage command arithmetic means 151 used in the modification 9A is configured in the same way as the first voltage arithmetic command means 151 as shown in Fig. 23, and has the first function of supplying the measurement voltage command vm* for measuring the electrical constants of the synchronous motor 10S to the voltage application means 11 and supplying the measurement single phase AC voltage vm for measuring the electrical constants of the synchronous motor 10S from the voltage application means 11 to the synchronous motor 10S, and a second function of computing the electrical constants of the synchronous motor 10S by receiving the measurement current im of single phase AC outputted from the current detection means 13 based on the current flowing from the voltage application means 11 to the synchronous motor 10S at the measurement single phase AC voltage vm. The first voltage command arithmetic means 151 computes the electrical constants of the synchronous motor 10S based on the measurement current im and any one of the measurement voltage command vm* and the measurement single phase AC voltage vm and supplies them to the constant storage memory 203.

[0217]
The second voltage command arithmetic means 152 is the voltage command means of the (E/f) constant control system, and is configured by using the same voltage command arithmetic means 154 as the modification 5A of the embodiment 5 as shown in Fig. 16, to compute the d-axis voltage command vd* and the q-axis voltage command vq* in accordance with the Numerical Expressions 24 and 25, and supply them to the dq-axis/three phase coordinate transformer 157. The voltage command selection means 159 is the same as shown in Fig. 23. This voltage command selection means 159 selects the input port a to connect to the output port c to supply the measurement voltage command vm* from the first voltage command arithmetic, means 151 to the voltage application means 11 in measuring the electrical constants of the synchronous motor 10S, and selects the input port b to connect to the output port c to supply the three phase voltage command V* to the voltage application means 11 in driving the synchronous motor 10S.

[0218]
The frequency correction value arithmetic means 20Ba for use in the modification 9A is configured in the same way as the embodiment 9. In this frequency correction value arithmetic means 20Ba, the newly added input port 20-17 is connected to the first voltage command arithmetic means 151, and also connected to the constant storage memory 203 inside the frequency correction value arithmetic means .20Ba.

[0219]
In this modification 9A, the AC rotating machine 10 is the synchronous motor 10S, and the amplification gain arithmetic part 213 computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 26 and 27, and the amplification gain arithmetic part 214 computes the amplification gains Gl and G2 in accordance with the expressions changed corresponding to the synchronous motor 10S from the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60, whereby the electrical constants of the synchronous motor 10S required for these arithmetic operations are computed by the first voltage command arithmetic means 151 and stored in the constant storage memory 203. The set value cox of the current limiting response speed is not measured by the first voltage command arithmetic means 151 but stored in the constant storage memory 203. In the modification 9A of the embodiment 9, in computing the gains Gl and G2 by the amplification gain arithmetic part 214, the frequency command value co* may be used, instead of the inverter frequency coi, thereby achieving the same effects.

[0220]
With this modification 9A, even when the electrical constants of the synchronous motor 10S are unknown, the electrical constants of the synchronous motor 10S can be firstly measured by using the first voltage command arithmetic means 151, and stored in the constant storage memory 203. Thereafter, when the voltage command selection means 159 selects again the three phase voltage command V* with the d-axis voltage command vd* and the q-axis voltage command vq* outputted by the second voltage command arithmetic means 152 to drive the synchronous motor 10S, the frequency correction value arithmetic value Acoa can be computed with the amplification gains Gl and G2 of the amplifier 230 appropriately designed, whereby the current can be securely limited to the current limiting command value Iumit with the desired current limiting performance.

[0221]
In the modification 9A, the frequency correction value arithmetic means 20Ba may be replaced with the frequency correction value arithmetic means 20a in which the input port 20-17 is added to the frequency correction value arithmetic means 20 as shown in Fig. 7, the frequency correction value arithmetic means 2 0Aa in which the input port 20-17 is added to the frequency correction value arithmetic means 20A as shown in Fig. 12, or the frequency correction value arithmetic means 20Ca in which the input port 20-17 is added to the frequency correction value arithmetic means 20C as shown in Fig. 20. The frequency correction value arithmetic means 20a, 20Aa or 20Ca is also composed of a micro-computer, for example, in which the added input port 20-17 is connected to the first voltage command arithmetic means 151 and the constant storage memory 203, and the electrical constants of the induction motor 101 computed by the first voltage command arithmetic means 151 are stored in the constant storage memory 203.

[0222] Embodiment 10
Fig. 25 is a block diagram showing an embodiment 10 of the control device for the AC rotating machine according to this invention. This embodiment 10 is configured by modifying the embodiment 6 as shown in. Fig. 17 such that the voltage command means 15B is replaced with the voltage command means 15Ba, and the frequency correction value arithmetic means 20B is replaced with the frequency correction value arithmetic means 20Ba. In others, the embodiment 10 is configured in the same way as the embodiment 6. In this embodiment 10, the AC rotating machine 10 is the induction motor 101. The voltage command means 15Ba is also composed of a micro-computer, for example.

[0223]
The voltage command means 15Ba for use in this embodiment 10 has the first voltage command arithmetic means 151, the •second voltage command arithmetic means 152, the dq-axis/three phase coordinate transformer 157, and the- voltage command selection means 159. The first voltage command arithmetic means 151 for use in this embodiment 10 is configured in the same way as shown in Fig. 23, and has the first function of supplying the measurement voltage command vm* for measuring the electrical constants of the induction motor 101 to the voltage application means 11 and supplying the measurement single phase AC voltage vm for measuring the electrical constants of the induction motor 101 from the voltage application means 11 to the induction motor 101, and the second function of computing the electrical constants of the induction motor 101 by receiving the measurement current im of single phase AC outputted from the current detection means 13 based on the current flowing through the induction motor 101 at the measurement single phase AC voltage vm. The first voltage command arithmetic means 151 computes the electrical constants of the synchronous motor 101 based on the measurement current im and any one of the measurement voltage command vm* and the measurement single phase AC voltage vm and supplies them to the constant storage memory 203.

[0224]
The second voltage command arithmetic means 152 is the voltage command means of the (V/f) constant control system, and is configured using the same voltage command arithmetic means 155 as shown in Fig. 17, to compute the d-axis voltage command vd* and the q-axis voltage command vq* in accordance with the Numerical Expressions 35 and 36, and supply them to the dq-axis/three phase coordinate transformer 157. The voltage command selection means 159 is configured in the same way as shown in Fig. 23. This voltage command selection means 159 selects the input port a to connect to the output port c to supply the measurement voltage command vm* from the first voltage command arithmetic means 151 to the voltage application means 11 in measuring the electrical constants of the induction motor 101, and selects the input port b to connect to the output port c to supply the three phase voltage command V* to the voltage application means 11 in driving the induction motor 101.

[0225]
The frequency correction value arithmetic means 20Ba for use in the embodiment 10 is configured in the same way as the embodiment 9. In this frequency correction value arithmetic means 20Ba, the newly added input port 20-17 is connected to the first voltage command arithmetic means 151, and also connected to the constant storage memory 203 inside the frequency correction value arithmetic means 20Ba.

[0226]
In this embodiment 10, the AC rotating machine 10 is the induction motor 10S, and the amplification gain arithmetic part 213 computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 37 and 38, and the amplification gain arithmetic part 214 computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 50 and 51 or the Numerical Expressions 59 and 60, whereby the electrical constants of the induction motor 101 required for these arithmetic operations are computed by the first voltage command arithmetic means 151 and stored in the constant storage memory 203. The set value cox of the current limiting response speed is not measured by the first voltage command arithmetic means 151 but stored in the constant storage memory 203. In the embodiment 10, in computing the gains Gl and G2 by the amplification gain arithmetic part 214, the frequency command value co* may be used, instead of the inverter frequency ©i, thereby achieving the same, effects.

[0227]
With this embodiment 10, even when the electrical constants of the induction motor 101 is unknown, the electrical constants of the induction motor 101 can be firstly measured using the first voltage command arithmetic means 151, and stored in the constant storage memory 203. Thereafter, when the voltage command selection means 159 selects again the three phase voltage command V* with the d-axis voltage command vd* and the q-axis voltage command vq* outputted by the second voltage command arithmetic means 152 to drive the induction motor 101, the frequency correction value arithmetic value Aoa can be computed with the amplification gains Gl and G2 of the amplifier 230 appropriately designed, whereby the current can be securely limited to the current limiting command value I limit with the desired current limiting performance.

[0228]
In the embodiment 10, the frequency correction value arithmetic means 20Ba may be replaced with the frequency correction value arithmetic means 20a in which the input port 20-17 is added to the frequency correction value arithmetic means 20 as shown in Fig. 8, the frequency correction value arithmetic means 20Aa in which the input port 20-17 is added to the frequency correction value arithmetic means 20A as shown in Fig. 13, or the frequency correction value arithmetic means 20Ca in which the input port 20-17 is added to the frequency correction value arithmetic means 20C as shown in Fig. 21. The frequency correction value arithmetic means 20a, 20Aa or 20Ca is also composed of a micro-computer, for example, in which the added input port 20-17 is connected to the first voltage command arithmetic means 151 and the constant storage memory 203, and the electrical constants of the induction motor 101 computed by the first voltage command arithmetic means 151 are stored in the constant storage memory 203.

[0229] Modification 10A of the embodiment 10 Fig. 2 6 is a block diagram showing the control device for the AC rotating machine according to the modification 10A of the embodiment 10. This modification 10A is configured by modifying the modification 6A of the embodiment 6 as shown in Fig. 18 such that the voltage command means 15C is replaced with the voltage command means 15Ca, and the frequency correction value arithmetic means 20B is replaced with the frequency correction value arithmetic means 20Ba. In others, the modification 10A is configured in the same way as the modification 6A of the embodiment 6. In this modification 10A, the AC rotating machine 10 is the synchronous motor 10S. The voltage command means 15Ca is also composed of a micro-computer, for example.

[0230]
The voltage command means 15Ca for use in this modification 10A has the first voltage command arithmetic means 151, the second voltage command arithmetic means 152, the dq-axis/three phase coordinate transformer 157, and the voltage command selection means 159. The first voltage command arithmetic means 151 for use in this modification 10A is configured in the same way as shown in Fig. 23, and has the first function of supplying the measurement voltage command vm* for measuring the electrical constants of the synchronous motor 10S to the voltage application means 11 and supplying the measurement single phase AC voltage vm for measuring the electrical constants of the synchronous motor 10S from the voltage application means 11 to the synchronous motor 10S, and the second function of computing the electrical constants of the AC rotating machine 10 by receiving the measurement current im of single phase AC outputted from the current detection means 13 based on the current flowing through the synchronous motor 10S at the measurement single phase AC voltage vm. The first voltage command arithmetic means 151 computes the electrical constants of the synchronous motor 10S based on the measurement current im and any one of the measurement voltage command vm and the measurement single phase AC voltage vm and supplies them to the constant storage memory 203.

[0231]
The second voltage command arithmetic means 152 is the voltage command means of the (V/f) constant control system, and is configured by using the same voltage command arithmetic means 15 6 as shown in Fig. 18, to compute the d-axis voltage command vd and the q-axis voltage command vq* in accordance with the Numeri cal Expressions 44 and 45, and supply them to the dq-axis/three phase . coordinate transformer 157. The voltage command selection means 159 is configured in the same way as shown in Fig. 23. This voltage command selection means 159 selects the input port a to connect to the output port c to supply the measurement voltage command vm* from the first voltage command arithmetic means 151 to the voltage application means 11 in measuring the electrical constants of the synchronous motor 10S, and selects the input port b to connect to the output port c to supply the three phase voltage command V* to the voltage application means 11 in driving the synchronous motor 10S.

[0232]
The frequency correction value arithmetic means 20Ba for use in the modification 10A is configured in the same way as the embodiment 9. In this frequency correction value -arithmetic means 20Ba, the newly added input port 20-17 is connected to the first voltage command arithmetic means 151, and also connected to the constant storage memory 203 inside the frequency correction value arithmetic means 20Ba.

[0233]
In this modification 10A, the AC rotating machine 10 is the synchronous motor 10S, and the amplification gain arithmetic part 213 computes the amplification gains Gl and G2 in accordance with the Numerical Expressions 41 and 48, and the amplification gain arithmetic part 214 computes the amplification gains Gl and G2 in accordance with the expressions changed corresponding to the synchronous motor 10S from the Numerical Expressions - 50 and 51 or the Numerical Expressions 59 and 60, whereby the electrical constants of the synchronous motor 10S required for these arithmetic operations are computed by the first voltage command arithmetic means 151 and stored in the constant storage memory 203. The set value 0)x of the current limiting response speed is not measured by the first voltage command arithmetic means 151 but stored in the constant storage memory 203. In the modification 10A of the embodiment 10, in computing the gains Gl and G2 by the amplification gain arithmetic part 214, the frequency command value co* may be used, instead of the inverter frequency (0±, thereby achieving the same effects.

[0234]
With this modification 10A, even when the electrical constants of the synchronous motor 10S are unknown, the electrical constants of the synchronous motor 10S can be firstly measured by using the first voltage command arithmetic means 151, and stored in the constant storage memory 203. Thereafter, when the voltage command selection means 159 selects again the three phase voltage command V* with the d-axis voltage command vd* and the q-axis voltage command vq* outputted by the second voltage command arithmetic means 152 to drive the synchronous motor 10S, the frequency correction value arithmetic value Acoa can be computed with the amplification gains Gl and G2 of the amplifier 230 appropriately designed, whereby the current can be securely limited to the current limiting command value I limit with the desired current limiting performance

[0235]
In the modification 10A, the frequency correction value arithmetic means 20Ba may be replaced with the frequency correction value arithmetic means 20a in which the input port 20-17 is added to the frequency correction value arithmetic means 20 as shown in Fig. 9, the frequency correction value arithmetic means 20Aa in which the input port 20-17 is added to the frequency correction value arithmetic means 20A as shown in Fig. 14, or the frequency correction value arithmetic means 20Ca in which the input port 20-17 is added to the frequency correction value arithmetic means 20C as shown in Fig. 22. The frequency correction value arithmetic means 20a, 20Aa or 20Ca is also composed of a micro-computer, for example, in which the added input port 20-17 is connected to the first voltage command arithmetic means 151 and the constant storage memory 203, and the electrical constants of the synchronous motor 10S computed by the first voltage command arithmetic means 151 are stored in the constant storage memory 203.

Industrial Applicability

[0236]
The control device for the AC rotating machine according to this invention is used to control the AC rotating machine, for example, the induction motor and the synchronous motor. Description of Reference Numerals and Signs

[0237]
10: AC rotating machine

11: voltage application means

13: current detection means

15, 15A, 15B, 15C, 15a, 15Aa, 15Ba, 15Ca: voltage command means

159: voltage command selector

17, 17A: inverter frequency arithmetic means

20, 20A, 20B, 20C, 20a, 20Aa, 20Ba, 20Ca: frequency correction value arithmetic means

201: current deviation computing element

203: constant storage memory

210, 210A, 210B, 210C: amplification gain computing element

211, 212, 213, 214: amplification gain arithmetic part 223: switch signal generating part .

225: switching part

215, 216: gain adjustment part

230: amplifier 233: state signal generator'

235: output selector

Amendment to Claims and Specification

: amended portion

A. Amendment to Claims

We wish to amend Claims as below.

CLAIMS

1. A control device for an AC rotating machine comprising:

current detection means for detecting a current supplied to the AC rotating machine as a detected current value;

frequency correction value arithmetic means for outputting a frequency correction value;

inverter frequency arithmetic means for outputting an inverter frequency based on a frequency command value and the frequency correction value;

voltage command means for computing a voltage command value in accordance with the inverter frequency; and

voltage application means for applying a voltage to the AC rotating machine based on the voltage command value;

wherein the frequency correction value arithmetic means comprises:

current deviation computing element for outputting a current deviation based on the detected current value and a current limiting command value;

a constant storage memory for storing an electrical

constant of the AC rotating machine;

an amplification gain computing element for computing an amplification gain by using the electrical constant of the AC rotating machine outputted from the constant storage memory and an arbitrary response set value;

an amplifier for amplifying the current deviation outputted by the current deviation computing element based on the amplification gain computed by the amplification gain computing element to compute a frequency correction arithmetic value; and

an output selector for outputting the frequency correction arithmetic value as the frequency correction value in a predetermined running state of the AC rotating machine.

2. The control device for the AC rotating machine according to claim 1,

wherein the amplification gain computing element computes the amplifier gain, by using any one of the inverter frequency and the frequency command value, in addition to the electrical constant of the AC rotating machine outputted from the constant storage memory and the arbitrary response set value, and outputs thereof.

3. The control device for the AC rotating machine according to claim 2,

wherein the amplification gain computing element has a first amplification gain computing element for computing a first amplification gain by using the electrical constant of the AC rotating machine outputted from the constant storage memory and the arbitrary response set value, a second amplification gain computing element for computing a second, amplification gain by using any one of the inverter frequency and the frequency command value, in addition to the electrical constant of the AC rotating machine outputted from the constant storage memory and the arbitrary response set value/ a switch signal generating part for generating a switch signal based on at least one of the inverter frequency, the frequency command value and the voltage command value, and a switching part for selectively outputting one of the first amplification gain from the first amplification gain computing element and the second amplification gain from the second amplification gain computing element, based on the switch signal, and

wherein the amplifier amplifies the current deviation outputted by the current deviation computing element, based on either one of the first amplification gain and the second amplification gain outputted by the switching part, to compute the frequency correction arithmetic value.

4. The control device for the AC rotating machine according to claim 3,

wherein the first amplification gain computing element is provided with a first amplification gain adjustment part for adjusting the first amplification gain, and the second

amplification gain computing element is provided with a second amplification gain adjustment part for adjusting the second amplification gain.

5. The control device for the AC rotating machine according to claim 1,

wherein the voltage command means has first voltage command arithmetic means and second voltage command arithmetic means, and

wherein the first voltage command arithmetic means generates a measurement voltage command for measuring the electrical constant of the AC rotating machine and applies a measured voltage to the AC rotating machine, and computes the electrical constant of the AC rotating machine based on a measured current flowing at the measured voltage and one of the measurement voltage command and the measured voltage and stores thereof in the constant storage memory, and the second voltage command arithmetic means computes the voltage command value in accordance with the inverter frequency.