DESCRIPTION

Title of Invention: ELEVATOR CONTROL DEVICE

Technical Field

[0001] The present invention relates to an elevator control device, in particular, to position sensorless control without using a magnetic pole position detector for an elevator hoisting machine using a permanent magnet synchronous motor.

Background Art

[0002] For vector control of a permanent magnet synchronous motor which is controlled based on a variable-voltage variable-frequency voltage by a power converter, it is necessary to control an armature current to flow not only in accordance with the magnitude of the armature current but also in a phase in accordance with a magnetic pole position. Therefore, a magnetic pole position of the permanent magnet synchronous motor is required to be constantly obtained.

[0003] In general, a magnetic pole position detector is mounted to the permanent magnet synchronous motor to obtain the magnetic pole position. In recent years, however, a position sensorless driving technology without the magnetic pole position detector such as, for example, an encoder, has been widely studied.

[0004] For the estimation of the magnetic pole position of the permanent magnet synchronous motor, there exist a method using magnetic pole position dependence of an induced voltage generated by the rotation of a rotor and a method of estimating the magnetic pole position based on a current response by applying a high-frequency voltage using magnetic pole position dependence of an inductance of a motor having saliency. With the method using the induced voltage, the magnetic pole position can be estimated even for a motor without saliency. However, there is a disadvantage in that it is impossible or difficult to estimate the magnetic pole position at a zero speed and a low speed. The "low speed" as used hereinafter refers to a relative speed with respect to a rated speed in a motor to be used, in particular, a speed range in which, although the speed estimation is not impossible, control cannot be performed due to a large estimate error because an S/N ratio is lowered due to a small induced voltage generated by the inducted voltage method. Although the method using the saliency is excellent in startability, there is a disadvantage in that the magnetic pole position cannot be estimated if the motor does not have the saliency.

[0005] For a motor without saliency included in an elevator hoisting machine, there is a device which releases a brake, estimates the magnetic pole position based on the induced voltage by using position dependency of the inductance, and detects a change in magnetic pole position by using an encoder after the estimation (see Patent Literature 1 cited below, for example). Moreover, there is a method using the permanent magnet synchronous motor having the saliency to estimate the magnetic pole position by using the saliency of the inductance so as to control the motor without an encoder corresponding to the position sensor (see Patent Literature 2 cited below, for example). Further, as the method using the induced voltage, a method of performing control by torque control using synchronous pull-in at the time of start and stop has been studied (see Patent Literature 3 cited below, for example).
Citation List Patent Literature

[0006] Patent Literature 1: JP 2000-78878 A Patent Literature 2: JP 2004-514392 A Patent Literature 3: JP 2008-245411 A Patent Literature 4: JP 2004-32907 A Patent Literature 5: JP 2001-190099 A Patent Literature 6: JP 3735836 B

Non Patent Literature

[0007] Non Patent Literature 1: Yoshihiko Kanehara, "Position Sensorless Control for PM Motor", The journal of the Institute of Electrical Engineers of Japan, Transactions D (on Industry Applications), Vol. 123, No. 5, 2003

Summary of Invention Technical Problem

[0008] In the case of the conventional position sensorless driving for the permanent magnet synchronous motor using the induced voltage as described above, the S/N ratio is reduced at the zero speed and the low speed because of the small induced voltage. Therefore, although the speed estimation is not impossible, there is a risk in that the permanent magnet synchronous motor rotates in a direction reverse to that of a speed command to result in running of the elevator because the control cannot be performed due to the large estimation error.

[0009] In the permanent magnet synchronous motor having the saliency, a current response, which is obtained when the voltage is applied, differs depending on the position of the magnetic pole because of the position dependence of the inductance. The magnetic pole position can be estimated by applying a voltage at a higher frequency (an integer multiple of a half frequency of a triangular wave of an inverter carrier) than a driving frequency of a motor, which does not contribute to a motor operation, and then obtaining a current response thereto. The magnetic pole position estimation by the application of the high-frequency voltage does not have speed dependence. Therefore, the method enables the estimation of the magnetic pole position even at the zero speed and the low speed.

[0010] For a cylindrical permanent magnet synchronous motor without the saliency, however, the above-mentioned method cannot be used. Therefore, (as described in Patent Literature 3 cited above), a stationary state is held and low-speed control is performed by the synchronous pull-in at the time of start and stop in the cylindrical permanent magnet synchronous motor. However, (in Patent Literature 3 cited above), a motor current which increases in a ramping manner flows when a load is applied during a stop state. Therefore, it takes long time to obtain a torque current large enough to be stable. Thus, there is a possibility in that the permanent magnet synchronous motor temporarily rotates in a reverse direction to result in running of the elevator.

[0011] The present invention provides an elevator control device in which vector control stable over the entire speed range including a zero speed and a low-speed range is realized through position sensorless driving control even for a cylindrical permanent magnet synchronous motor without saliency.

Solution to Problem

[0012] The present invention provides an elevator control device, including driving command output means for performing speed control on a cage of an elevator through torque feedforward control, and for generating a driving command based on a torque necessary to stationarily hold the cage to perform vector control on a permanent magnet synchronous motor for raising and lowering the cage.

For example, the elevator control device includes: speed-command determining means for determining a speed command; a model reference controller for converting the speed command into an ideal speed command; a magnetic pole speed estimator for estimating a speed estimate value of a magnetic pole of the permanent magnet synchronous motor for raising and lowering the cage; an estimated speed switching unit for outputting the ideal speed command from the model reference controller in a period in which the ideal speed command indicates a speed equal to or smaller than a predetermined speed that is set in advance, and for switching the output to the speed estimate value from the magnetic pole speed estimator and outputting the speed estimate value when the speed indicated by the ideal speed command exceeds the predetermined speed; and the driving command output means for performing the torque feedforward control in a period in which the estimated speed switching unit outputs the ideal speed command, and for performing speed feedback control in a period in which the estimated speed switching unit outputs the speed estimate value.

Advantageous Effects of Invention

[0013] According to the present invention, the vector control stable over the entire speed range including the zero speed and the low-speed range can be realized through the position sensorless driving control even for the cylindrical permanent magnet synchronous motor without saliency.

Brief Description of Drawings

[0014] [FIG. 1] A diagram illustrating an overview of a configuration of an elevator system including an elevator control device according to the present invention.

[FIG. 2] A diagram illustrating a configuration of a control system of the elevator system illustrated in FIG. 1, which includes an elevator control device according to Embodiment 1 of the present invention.

[FIG. 3] A diagram illustrating an example of an internal structure of a model reference controller of the elevator control device according to the present invention.

[FIG. 4] A diagram illustrating an example of an internal structure of a magnetic pole position estimator of the elevator control device according to the present invention.

[FIG. 5] A diagram illustrating a configuration of a control system of the elevator system illustrated in FIG. 1, which includes an elevator control device according to Embodiment 2 of the present invention.

Description of Embodiments

[0015] The present invention realizes vector control which is stable over the entire speed range including a zero speed and a low-speed range with position sensorless driving control even for a cylindrical permanent magnet synchronous motor without saliency.

In this manner, even in a state in which a load is applied, a stationary state can be held and control at a low speed can be performed stably. In the following description, as used generally in a permanent magnet synchronous motor, as a rotating coordinate system, a direction of a magnetic flux generated by a permanent magnet of a rotor (direction of a center axis of the permanent magnet) is set to a d-axis, whereas an axis electrically and magnetically perpendicular thereto is set to a q-axis. A positive d-axis current as used hereinafter is defined as having a current direction in which field strengthening is performed, whereas a negative d-axis current as used hereinafter is defined as having a current direction in which field weakening is performed.

[0016] An elevator control device according to the present invention has a configuration in which control at a zero speed and a low speed, at which a speed cannot be estimated due to a lowered S/N ratio because a generated induced voltage is small with an induced voltage method, is performed with torque feedforward control, feedback control is performed based on a magnetic pole position and a speed estimate value obtained from the induced voltage at a speed higher than the above-mentioned speed, and an acceleration torque required for the torque feedforward control is obtained by a model reference controller and a torque required for holding a stationary state is obtained by a load detecting device.

[0017] Hereinafter, an elevator control device according to each of embodiments of the present invention is described with the drawings. In the embodiments, the same or equivalent parts are denoted by the same reference numerals, and the overlapping description thereof is herein omitted.

[0018]

Embodiment 1

FIG. 1 is a diagram illustrating an overview of a configuration of an elevator system including an elevator control device according to the present invention. A cage 1 of an elevator and a counterweight 2 are connected to each other by a main rope 3 and are suspended by a sheave 4 in a traction fashion. The sheave 4 is also connected to a permanent magnet synchronous motor 5 for driving the elevator with the main rope 3. The cage 1 is raised and lowered by power of the permanent magnet synchronous motor 5. A brake 6 is mounted to the permanent magnet synchronous motor 5 so that the sheave 4 is braked by the brake 6. The brake 6 may be a car brake which directly brakes the cage 1 or may be a rope brake which brakes the rope (the details thereof not shown). A power converter for driving the permanent magnet synchronous motor 5 and a principal part of the elevator control device according to the present invention, which generates a control signal (three-phase voltage command) to the power converter, are stored in a control board 7.

[0019] FIG. 2 is a diagram illustrating a configuration of a control system of the elevator system illustrated in FIG. 1, which includes an elevator control device according to Embodiment 1 of the present invention. As illustrated in FIG. 2, a power converter 8 including, for example, an inverter, which is provided in the control board 7 (sometimes provided on the outer side thereof), outputs a variable-voltage variable-frequency (VWF) voltage in response to a voltage command (control signal) output from the elevator control device. Through the variable-voltage variable-frequency voltage, driving of the permanent magnet synchronous motor 5 is controlled. Current sensors 9a to 9c are provided for the respective phases between the power converter 8 and the permanent magnet synchronous motor 5 so as to detect phase currents flowing in the respective phases (u-phase, v-phase, and w-phase) of the permanent magnet synchronous motor 5. In general, a balanced three-phase current is used. Therefore, the current sensors are sometimes mounted to only two of the three phases (for example, the u-phase and the v-phase).

[0020] The elevator control device includes, for example, a model reference controller 10, a speed controller 11, a current controller 12, an estimated speed switching unit 13, a magnetic pole position estimator 14, coordinate converters 15a and 15b, a load detector 16, a magnetic pole speed estimator 17, and speed-command determining means 19. The above-mentioned components can be configured by, for example, a single computer constructed to have the above-mentioned functions.

[0021] The speed-command determining means 19 determines a speed command value in accordance with input conditions of a floor on which the cage 1 is currently present, a car-call command from inside of the cage 1, and further, a landing-call command from a landing of each floor (the inputs are denoted by a reference symbol C illustrated in FIG. 2). The elevator control device calculates a three-phase command (voltage command) to the power converter 8 in accordance with the speed command value.

[0022] Through the control of the elevator control device, the elevator is subjected to vector control. The coordinate converters 15a and 15b perform vector transformation on a magnetic pole angle corresponding to an output of the magnetic pole estimator 14. The coordinate converter 15a converts the phase current values detected by the current sensors 9a to 9c into d-q coordinates perpendicularly crossing each other, which are rotating coordinates, based on the magnetic pole angle output from the magnetic pole position estimator 14. The coordinate converter 15b performs vector transformation on voltage commands in the d-q coordinates, which are output from the current controller 12, into voltage commands for the three-phase voltage based on the magnetic pole angle of the magnetic pole position estimator 14.

[0023] FIG. 3 illustrates an example of an internal structure of the model reference controller 10 supposing that a reference model is a complete rigid body. The model reference controller 10 receives a speed command ooref corresponding to the output of the speed-command determining means 19 as an input to output an ideal speed command wideal and an ideal torque command Tideal. In FIG. 3, a subtractor 10c subtracts the ideal speed command toideal output from an ideal speed computing unit 10b from the speed command ooref. An ideal torque computing unit 10a computes an ideal torque by the upper formula of Formulae (1) described below so as to realize the speed command coref in accordance with the output from the subtractor 10c based on the reference model included therein, which is obtained by regarding the elevator as a rigid-body model, and outputs the ideal torque command Tideal. The ideal speed computing unit 10b computes an ideal speed by the lower formula of Formulae (1) described below in accordance with the output from the ideal torque computing unit 10a to output the ideal speed command wideal.

[0024] Supposing that the elevator ideally behaves as the reference model, the model reference controller 10 computes a torque, and in addition, a speed, which are required for the acceleration of the elevator, from the speed command and the reference model to output the ideal torque command and the ideal speed command.

[0025] The relation among the speed command toref, the ideal torque command Tideal, and the ideal speed command ooideal is expressed by Formulae (1).

[0026] Tideal=JmK(turef-tuideal)
u)ideal=Tideal/(Jm • s) (1)

[0027] In the formulae, K is a response speed, and Jm is a rigid-body model (inertia) of the elevator. In practice, the reference model is not necessarily a complete rigid-body model but can also be a spring-mass-damper model or a finite element model in some cases.

[0028] The estimated speed switching unit 13 receives the ideal speed command coideal corresponding to the output of the model reference controller 10 and a speed estimate value coest output from the magnetic pole speed estimator 17 as inputs to output any one thereof as an estimated speed. The switching of the output of the estimated speed switching unit 13 is performed so that the ideal speed command wideal from the model reference controller 10 is output when the ideal speed command wideal corresponding to the output of the model reference controller 10 is equal to or smaller than a preset predetermined speed and the output is switched from the ideal speed command to the speed estimate value west output from the magnetic pole speed estimator 17 when a value of the speed command exceeds the predetermined speed. Then, when the ideal speed command wideal becomes equal to or smaller than the predetermined speed, the output is switched from the speed estimate value west output from the magnetic pole speed estimator 17 to the ideal speed command wideal output from the model reference controller 10.

[0029] Alternatively, the switching of the output of the estimated speed switching unit 13 is performed so that the ideal speed command coideal is output until the speed estimate value west from the magnetic pole speed estimator 17 converges ("convergence" refers to a state in which the estimation is completed without divergence of the estimate value) and the output is switched from the ideal speed command from the model reference controller 10 to the speed estimate value west from the magnetic pole speed estimator 17 after the speed estimate value west from the magnetic pole speed estimator 17 converges.

[0030] The speed controller 11 receives the ideal speed command wideal from the model reference controller 10, and the ideal speed command wideal or the speed estimate value west corresponding to the output of the estimated speed switching unit 13 as inputs to obtain a difference therebetween so as to output a current command in accordance with the obtained difference.

[0031] The load detector 16 detects a sum of a weight Wear of the cage 1 and a weight Wpeople of a passenger(s) by, for example, a weighing device (not shown) mounted to the cage 1 or inside a hoistway or detects a difference between the sum of the weight of the cage 1 and the weight of the passenger(s) (Wcar+Wpeople) and a weight Wweight of the counterweight 2 (rotation moment of the permanent magnet synchronous motor 5) (the weight Wweight of the counterweight 2 may be prestored in a memory (not shown)) so as to compute and output a torque (hereinafter, referred to as "stationary state holding torque") Thold required to stationarily hold the car 1 without falling, or output the result of conversion of Thold into a current. The computation may be performed in the load detector 16 or may be performed in the current controller 12. Given that a radius of the sheave 4 is Rs, the stationary state holding torque Thold is expressed by Formula (2).

[0032] Thold=(Wcar+Wpeople-Wweight)Rs (2)

[0033] The current controller 12 outputs a voltage command. A sum of the ideal torque command Tideal corresponding to the output of the model reference controller 10 and the result of conversion of the current command corresponding to the output of the speed controller 11 into a torque is obtained as a torque (hereinafter, referred to as "acceleration torque") Tacc required for the acceleration of the cage 1. For q-axis current corresponding to a torque current, a sum of the result of conversion of Tacc into a current and the result of conversion of the stationary state holding torque Thold corresponding to the output of the load detector 16 into a current is obtained as a current command value of the q-axis. A q-axis voltage command Vq output from the current controller 12 is output so that a difference between a current value Iq of the q-axis, corresponding to the output from the coordinate converter 15a, and the current command value of the q-axis becomes zero. Here, the q-axis current command value is a value obtained by converting (Tacc+Thold) into a current. Then, a voltage command Vd of the d-axis, which is output from the current controller 12, is output so that a difference between a preset predetermined d-axis current command value, and a current value Id of the d-axis, corresponding to the output of the coordinate converter 15a, becomes zero. The voltage command and the current command are converted by using a motor model.

[0034] The voltage commands Vd and Vq corresponding to the outputs of the current controller 12 are subjected to the vector transformation by the coordinate converter 15b to be voltage commands Vu, Vv, and Vw. The voltage commands Vu, Vv, and Vw become outputs of the elevator control device and are input to the power converter 8.

[0035] The magnetic pole speed estimator 17 is, for example, a magnetic flux observer described in Non Patent Literature 1 cited above. A magnetic pole speed estimator which uses the voltage commands output from the current controller 12 and current values obtained by coordinate conversion of the phase currents obtained by the current sensors 9a to 9c into the d-q axes by the coordinate converter 15a to estimate the position (angle) of the magnetic pole and the speed of the magnetic pole is given as an example.

[0036] FIG. 4 illustrates an example of an internal structure of the magnetic pole position estimator 14. The magnetic pole position estimator 14 includes a stationary magnetic-pole position estimator 14a, an integrator 14b, and an adder 14c, and receives the estimated speed corresponding to an output of the estimated speed switching unit 13 as an input to estimate a magnetic pole angle. The magnetic pole angle indicates an angle formed by an a-axis (in general, aligned with the u-phase) in an o>(3 coordinate system corresponding to two static orthogonal axes of the N-pole of the permanent magnet corresponding to the rotor of the permanent magnet synchronous motor 5. The magnetic pole angle corresponding to an output of the magnetic pole position estimator 14 is obtained by adding, by the adder 14c, the result of integrating the output (estimated speed) of the estimated speed switching unit 13 by the integrator 14b to 60 which is the magnetic pole position in a stationary state, corresponding to the output of the stationary magnetic-pole position estimator 14a, as an initial value.

[0037] As the stationary magnetic-pole position estimator 14a, there is one described in, for example, Patent Literature 4 cited above, which allows the magnitude of current causing magnetic saturation to flow as a rotating current in a stationary coordinate system to estimate the magnetic pole position in the stationary state in accordance with a voltage response thereto.

[0038] Embodiment 2

FIG. 5 is a diagram illustrating a configuration of a control system for the elevator system illustrated in FIG. 1, which includes an elevator control device according to Embodiment 2 of the present invention. In FIG. 5, a d-axis current command generator 18 is added to the configuration illustrated in FIG. 1. A d-axis current command value corresponding to an output of the d-axis current command generator 18 is used as a current command of the d-axis. The current controller 12 receives a difference between the current value Id of the d-axis, corresponding to the output of the coordinate converter 15a, and the d-axis current command value as an input, and outputs a voltage command Vd of the d-axis. Specifically, the current controller 12 uses the d-axis current command value output from the d-axis current command generator 18 in place of the preset predetermined d-axis current command value. The d-axis current command generator 18 obtains the d-axis current command value in accordance with the stationary state holding torque (Thold) from the load detector 16.

[0039] Next, the reason why d-axis current control is performed is described. In the feedforward control, an operation is performed as commanded if a parameter does not contain any error or is not subjected to a disturbance. However, the feedforward control has a disadvantage in that the current speed and position cannot be obtained. Therefore, if an estimated angle has an error, an effective torque component of the q-axis current is reduced at the time of the coordinate conversion. Thus, the torque necessary for stationarily holding the cage cannot be demonstrated, resulting in the rotation of the motor in a direction reverse to that of the speed command to cause the elevator to run. If the estimated angle further shifts to result in zero demonstrated torque, the cage freely falls at last. In order to prevent the free fall, the feedforward control with a positive current flowing on the d-axis is considered.

[0040] When a positive d-axis current described in Patent Literatures 5 and 6 cited above flows, the d-axis current has a torque component in case of a magnetic pole shift. The torque current has a direction in which the magnetic pole shift is prevented. The magnitude of the torque component of the d-axis current is proportional to the magnitude of the d-axis current and a sine of a magnetic pole shift angle. Specifically, when the positive d-axis current flows, a larger correction torque is applied in the case where the angle shift is large within the range of ±90 degrees from a correct magnetic pole position and a smaller correction torque is applied in the case where the angle shift is small within the above-mentioned range. Through the flow of the d-axis current as described above, speed control can be performed even in the case where the magnetic pole shift occurs during the feedforward control in which the magnetic pole position cannot be obtained.

[0041] The current controller 12 includes a brake control section (not shown) for controlling the brake 6. After outputting the voltage command Vd of the d-axis based on the d-axis current command value determined by the d-axis current command generator 18 and then outputting the voltage command Vq of the q-axis based on the stationary state holding torque Thold necessary for holding the stationary state, which is obtained by the load detector 16, the brake control section outputs a release command to the brake 6 to enable the elevator to start.

[0042] The d-axis current command generator 18 has a feature that the d-axis current command generator 18 generates the magnitude of the d-axis current command value, which does not allow the cage to fall even if a maximum allowable load for the elevator is applied. As an example, the d-axis current command generator (18) generates the d-axis current command value based on a maximum torque of the stationary state holding torque (Thold) of the load detector 16 during running. Alternatively, as an example, as the d-axis current command value corresponding to the output of the d-axis current command generator 18, the d-axis current command value for the same magnitude of the current of the d-axis as that of the q-axis current under a maximum expected load is output.

[0043] Further alternatively, as an example, the d-axis current command generator 18 generates the d-axis current command so that the magnitude of an actual current of the q-axis and the magnitude of the d-axis current to be generated have a predetermined relation. For example, the d-axis current command generator 18 outputs the d-axis current command so that a d-axis current command value ld_ref output from the d-axis current command generator 18 and a q-axis current command value lq_ref corresponding to a current command output from the speed controller 11 have a relation expressed by Formula (3) described below.

[0044] tan_1(lq_ref/ld_ref)=C(constant) (3)

[0045] In this manner, by holding a state in which the magnetic pole of the motor is shifted by a constant angle, an electric angle of the allowable magnetic pole shift can be kept constant.

[0046] Alternatively, as an example, the d-axis current command generator 18 outputs the result of current conversion of a sum of the stationary state holding torque (Thold) obtained by the load detector 16 and the acceleration torque (Tacc) described above, that is, a value constantly larger than the q-axis current command, as the d-axis current command.

[0047] In the elevator control device, the torque feedforward control is performed while the estimated speed switching unit 13 outputs the ideal speed command (coideal) from the model reference controller 10 and the speed feedback control is performed while the speed estimate value coest from the magnetic pole speed estimator 17 is output.

[0048] In the torque feedforward control, the d-axis current command generator 18 inputs the result of converting the sum of the stationary state holding torque (Thold) from the load detector 16 and the ideal torque command (Tideal) from the reference controller 10 into a current to the current controller 12 as the d-axis current command value ld_ref to output the voltage command. At this time, the input to the speed controller 11 becomes always zero. Therefore, the current command output from the speed controller 11 also becomes zero.

[0049] On the other hand, in the speed feedback control using the speed estimate value west from the magnetic pole speed estimator 17, the d-axis current command generator 18 inputs a sum of the q-axis current command value Iq (lq_ref) from the speed controller 11 and the result of converting the sum of the stationary state holding torque (Thold) from the load detector 16 and the ideal torque command (Tideal) from the model reference controller 10 into a current to the current controller 12 as the d-axis current command value ld_ref to output the voltage command.

[0050] To the d-axis current command generator 18, the outputs necessary for processing may be directly input from the respective devices or may be collectively supplied from, for example, the current controller 12 to which the outputs are input, as illustrated in FIG. 5.

[0051] Embodiments

An elevator control device according to Embodiment 3 of the present invention has a feature that the d-axis current command generator 18 switches the d-axis current command value to be generated for the torque feedforward control and for the speed feedback control using the estimated speed in the elevator control device illustrated in FIG. 5.

[0052] When the speed feedback control using the estimated speed is performed, the d-axis current is not required to flow for the stabilization of the magnetic pole position because the magnetic pole position is estimated. Therefore, the d-axis current command generator 18 switches a command value at the time of switching of control. Specifically, when the control is the torque feedforward control, as described in Embodiment 2, the d-axis current command generator 18 generates the positive d-axis current command for the stabilization of the magnetic pole position. After the control is switched to the speed feedback control, the d-axis current command is set to zero or switched to a predetermined command value. As the predetermined command value, the d-axis current command.is a predetermined constant or is determined so that the voltage command value does not exceed a predetermined value by performing the field weakening.

[0053] As described above, by switching the d-axis current command, power consumption of the elevator control device is reduced. Through the field weakening, the induced voltage is reduced to improve an rpm under the limit of a power supply voltage.

[0054] For example, the speed controller 11, the current controller (brake control section 12a) 12, the magnetic pole position estimator 14, and the coordinate converters 15a and 15b constitute driving command output means.

[0055] The present invention is not limited to each of the embodiments described above and therefore, it is apparent that the present invention encompasses all the possible combinations thereof.

Reference Signs List

[0056] 1 cage, 2 counterweight, 3 main rope, 4 sheave, 5 permanent magnet synchronous motor, 6 brake, 7 control board, 8 power converter, 9a to 9c current sensor, 10 model reference controller, 10a ideal torque computing unit, 10b ideal speed computing unit, 10c subtractor, 11 speed controller, 12 current controller, 13 estimated speed switching unit, 14 magnetic pole position estimator, 14a stationary magnetic-position estimator, 14b integrator, 14c adder, 15a, 15b coordinate converter, 16 load detector, 17 magnetic pole speed estimator, 18 d-axis current command generator, 19 speed-command determining means.

Claims

[Claim 1 ] An elevator control device, comprising:

a magnetic pole speed estimator for estimating a speed estimate value of a magnetic pole of a permanent magnet synchronous motor for raising and lowering a cage of an elevator;

a load detector for outputting a stationary state holding torque;

speed-command determining means for determining a speed command;

a model reference controller for converting the speed command into an ideal torque command and an ideal speed command;

an estimated speed switching unit for outputting the ideal speed command from the model reference controller in a period in which the ideal speed command indicates a speed equal to or smaller than a predetermined speed that is set in advance, and for switching the output to the speed estimate value from the magnetic pole speed estimator and outputting the speed estimate value when the speed indicated by the ideal speed command exceeds the predetermined speed;

stationary magnetic pole position estimating means for estimating a magnetic pole position in a stationary state;

a magnetic pole position estimator for estimating the magnetic pole position based on an output from the magnetic pole speed estimator; and

driving command output means for performing vector control on the permanent magnet synchronous motor based on the magnetic pole position estimated by the magnetic pole position estimator to perform torque feedforward control by a driving command based on a sum of the ideal torque command and the stationary state holding torque, the driving command output means performing the torque feedforward control in a period in which the estimated speed switching unit outputs the ideal speed command, and performing speed feedback control in a period in which the estimated speed switching unit outputs the speed estimate value.

[Claim 2] An elevator control device, comprising:

a magnetic pole speed estimator for estimating a speed estimate value of a magnetic pole of a permanent magnet synchronous motor for raising and lowering a cage of an elevator;

a load detector for outputting a stationary state holding torque;

speed-command determining means for determining a speed command;

a model reference controller for converting the speed command into an ideal torque command and an ideal speed command;

an estimated speed switching unit for outputting the ideal speed command until the speed estimate value output from the magnetic pole speed estimator converges, and for switching the output to the speed estimate value and outputting the speed estimate value after the speed estimate value converges;

stationary magnetic pole position estimating means for estimating a magnetic pole position in a stationary state;

a magnetic pole position estimator for estimating the magnetic pole position based on an output from the magnetic pole speed estimator; and

driving command output means for performing vector control on the permanent magnet synchronous motor based on the magnetic pole position estimated by the magnetic pole position estimator to perform torque feedforward control by a driving command based on a sum of the ideal torque command and the stationary state holding torque, the driving command output means performing the torque feedforward control in a period in which the estimated speed switching unit outputs the ideal speed command, and performing speed feedback control in a period in which the estimated speed switching unit outputs the speed estimate value.

[Claim 3] The elevator control device according to claim 1 or 2,

wherein the driving command output means outputs, as the driving command, a d-axis voltage command, a q-axis voltage command, and a magnetic pole angle estimate value for the vector control of the permanent magnet synchronous motor for raising and lowering the cage, and

wherein the elevator control device further comprises a d-axis current command generator for outputting a d-axis current command in accordance with the stationary state holding torque so as to obtain the d-axis voltage command.

[Claim 4] The elevator control device according to claim 1 or 2,

wherein the driving command output means outputs, as the driving command, a d-axis voltage command, a q-axis voltage command, and a magnetic pole angle estimate value for the vector control of the permanent magnet synchronous motor for raising and lowering the cage, and

wherein the elevator control device further comprises a d-axis current command generator for outputting a d-axis current command based on a maximum stationary state holding torque during running so as to obtain the d-axis voltage command.

[Claim 5] The elevator control device according to claim 1 or 2,

wherein the driving command output means outputs, as the driving command, a d-axis voltage command based on a d-axis current command, a q-axis voltage command based on a q-axis current command, and a magnetic pole angle estimate value for the vector control of the permanent magnet synchronous motor for raising and lowering the cage, and

wherein the elevator control device further comprises a d-axis current command generator for outputting the d-axis current command so that a ratio of the q-axis current command and the d-axis current command becomes constant, to thereby obtain the d-axis voltage command.

[Claim 6] The elevator control device according to any one of claims 3 to 5, further comprising a brake control section which prevents a brake of the elevator from being released until the driving command output means outputs the d-axis voltage command and the q-axis voltage command which enable a stationary state to be held.

[Claim 7] The elevator control device according to any one of claims 3 to 5, wherein the d-axis current command generator switches a command value so as to prevent a positive d-axis current for stabilization of a magnetic pole position from flowing during the speed feedback control using an estimated speed.