FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
ROTARY MACHINE CONTROL APPARATUS;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION
ORGANISED AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE
ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO
1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
2
DESCRIPTION
Field
[0001] The present disclosure relates to a rotary
machine control apparatus that obtains and controls rotor5
position information without using a position sensor that
detects a rotor position.
Background
[0002] In order to sufficiently bring out performance of10
a rotary machine in driving the rotary machine, position
information on a rotor is necessary. Therefore, position
information detected by a position sensor attached to a
rotary machine has been used to drive the rotary machine.
Meanwhile, in recent years, a technique of driving a rotary15
machine without a position sensor has been developed from
the viewpoints of further reducing the manufacturing cost
of the rotary machine, reducing the size of the rotary
machine, and improving the reliability of the rotary
machine.20
[0003] In the control of a rotary machine using no
position sensor, a method for estimating a rotor position
of the rotary machine from an induced voltage of the rotary
machine according to a speed region and a method for
estimating a rotor position of the rotary machine by using25
saliency are used in combination or selectively used
depending on the purpose. The former is used in a high-
speed area in which an induced voltage necessary for
position estimation can be sufficiently obtained, and the
latter is used in a low-speed area in which a sufficient30
induced voltage cannot be obtained.
[0004] As a conventional technique of estimating a rotor
position of a rotary machine by using saliency as in the
3
latter method, for example, Patent Literature 1 below
discloses a technique of estimating a rotor position of a
rotary machine by applying, to the rotary machine, a high-
frequency voltage having a frequency higher than a
fundamental frequency.5
[0005] A control system including this type of control
apparatus can be roughly divided into a rotor position
estimation system and a current control system. In the
rotor position estimation system, an alternating-current
component of a high-frequency current generated by10
application of a high-frequency voltage is calculated, and
a rotor position is estimated from rotor position
information included in the alternating-current component.
For this rotor position estimation system, fundamental wave
current for driving a rotary machine is a disturbance.15
Therefore, it is desirable to extract only the high-
frequency current component by removing a fundamental wave
current component from a detected current. For example, a
band-pass filter or a high-pass filter is used to extract a
high-frequency current component. These filters are20
designed such that a high-frequency current component can
be extracted on the premise that the frequency of high-
frequency voltage to be superimposed is widely different
from a fundamental wave frequency for driving a rotary
machine.25
Citation List
Patent Literature
[0006] Patent Literature 1: Japanese Patent Application
Laid-open No. 2004-34383330
Summary of Invention
Problem to be solved by the Invention
4
[0007] The filters described above are generally
installed on the premise that high-frequency current
includes only the same frequency component as a
superimposed frequency component. However, actual high-
frequency current includes not only the same frequency5
component as the superimposed frequency component but also
a sideband component of the superimposed frequency
component. There are two sideband components. One is an
upper sideband which is a sideband component to be
generated on a side on which the absolute value of10
frequency is higher than the absolute value of superimposed
frequency. The other is a lower sideband which is a
sideband component to be generated on a side on which the
absolute value of frequency is lower than the absolute
value of superimposed frequency. These sideband components15
are affected by the speed of the rotary machine, and when
the speed of the rotary machine increases, the two sideband
components are distributed over a wide area. Therefore,
there is a problem in that the sideband components
adversely affect processing to be performed in the current20
control system and the rotor position estimation system.
[0008] For example, there is a problem in that when the
lower sideband component of high-frequency current
approaches a response frequency of the current control
system due to an increase in the speed of a rotary machine25
and is distributed in the band of the current control
system, the response of the current control system is
deteriorated or becomes unstable.
[0009] Furthermore, when, for example, a high-pass
filter is used to extract a high-frequency current,30
attenuation characteristics and phase characteristics
differ between a frequency band lower than a cutoff
frequency and a frequency band higher than the cutoff
5
frequency. Therefore, there is a problem in that an S/N
ratio in the rotor position estimation system varies
between a case where the upper sideband is generated and a
case where the lower sideband is generated. This problem
is noticeable in applications in so-called four-quadrant5
driving, such as a driving device for a railroad car.
[0010] The present disclosure has been made in view of
the above, and an object of the present disclosure is to
provide a rotary machine control apparatus capable of
preventing an adverse effect on a current control system10
and a rotor position estimation system, possibly caused by
a sideband component of high-frequency current.
Means to Solve the Problem
[0011] In order to solve the above-described problems15
and achieve the object, a rotary machine control apparatus
according to the present disclosure includes a current
detection unit, a position estimation unit, a current
control unit, a position estimation voltage generation unit,
and a voltage application device. The current detection20
unit detects a rotary machine current flowing to a rotary
machine. The position estimation unit calculates an
estimate value of a rotor position based on the rotary
machine current, the rotor position being position
information on a rotor of the rotary machine. The current25
control unit generates a first voltage command based on a
detection value of the rotary machine current and the
estimate value of the rotor position, the first voltage
command being a command value of rotary machine voltage for
driving the rotary machine. The position estimation30
voltage generation unit generates a high-frequency voltage
based on rotation information regarding direction of
rotation of the rotor, the high-frequency voltage being a
6
position estimation voltage for estimating the rotor
position, the high-frequency voltage having a frequency
higher than a frequency of the first voltage command. The
voltage application device applies a driving voltage to the
rotary machine based on a second voltage command, the5
second voltage command being a voltage command obtained by
superimposition of the position estimation voltage on the
first voltage command.
Effects of the Invention10
[0012] The rotary machine control apparatus according to
the present disclosure has the effect of preventing an
adverse effect on a current control system and a rotor
position estimation system, possibly caused by a sideband
component of high-frequency current.15
Brief Description of Drawings
[0013] FIG. 1 is a diagram illustrating an exemplary
configuration of a rotary machine control apparatus
according to a first embodiment.20
FIG. 2 is a diagram illustrating an example of
waveforms of high-frequency voltages to be output from a
position estimation voltage generation unit in FIG. 1.
FIG. 3 is a flowchart for describing operation of a
high-frequency voltage generator illustrated in FIG. 1.25
FIG. 4 is a diagram illustrating an exemplary
configuration of a rotary machine control apparatus
according to a second embodiment.
FIG. 5 is a diagram illustrating an exemplary
configuration in which the control apparatus having the30
configuration illustrated in FIG. 4 is installed on a
railroad car.
FIG. 6 is a table illustrating details of internal
7
processing to be performed in a host control unit
illustrated in FIG. 4.
FIG. 7 is a diagram illustrating another exemplary
configuration of the rotary machine control apparatus
according to the second embodiment.5
FIG. 8 is a diagram illustrating an exemplary
configuration in which the control apparatus having the
configuration illustrated in FIG. 7 is installed on a
railroad car.
FIG. 9 is a diagram illustrating an exemplary10
configuration of a rotary machine control apparatus
according to a third embodiment.
FIG. 10 is a diagram illustrating a first exemplary
configuration of hardware that implements each function of
the control apparatuses according to the first to third15
embodiments.
FIG. 11 is a diagram illustrating a second exemplary
configuration of hardware that implements each function of
the control apparatuses according to the first to third
embodiments.20
Description of Embodiments
[0014] Hereinafter, rotary machine control apparatuses
according to embodiments of the present disclosure will be
described in detail with reference to the accompanying25
drawings.
[0015] First Embodiment.
FIG. 1 is a diagram illustrating an exemplary
configuration of a rotary machine control apparatus
(hereinafter, appropriately abbreviated as “control30
apparatus”) 100 according to a first embodiment. The
control apparatus 100 according to the first embodiment
includes a current detection unit 2, a voltage application
8
device 3, a position estimation unit 4, a current control
unit 5, and a position estimation voltage generation unit
30. In FIG. 1, the current control unit 5 is a controller
of a current control system, and the position estimation
unit 4 and the position estimation voltage generation unit5
30 are controllers of a rotor position estimation system.
[0016] A rotary machine 1 is a device to be driven by
the control apparatus 100. The rotary machine 1 includes a
stator 1a and a rotor 1b disposed inside the stator 1a. In
the present specification, an interior permanent magnet10
synchronous machine is cited as an example of the rotary
machine 1. However, the rotary machine 1 of the present
disclosure is not limited thereto. The rotary machine 1
may be a synchronous machine other than interior permanent
magnet synchronous machines.15
[0017] The current detection unit 2 detects rotary
machine currents iu, iv, and iw flowing between the voltage
application device 3 and the rotary machine 1. The rotary
machine currents iu, iv, and iw are stator currents each
flowing to corresponding one of the phases of the stator 1a,20
that is, stator currents flowing to the u-phase, v-phase,
and w-phase of the stator 1a, respectively. A current
detector is disposed in each phase of the current detection
unit 2. An example of the current detector is a current
transformer. Note that the current detection unit 225
detects all the three-phase currents in FIG. 1, but the
configuration of the current detection unit 2 is not
limited thereto. The current detection unit 2 may detect
currents of any two of the three phases, and a current of
the remaining one phase may be obtained by calculation by30
use of the fact that the rotary machine currents iu, iv,
and iw are in three-phase equilibrium. Alternatively,
instead of using the current detection unit 2 in FIG. 1, a
9
bus current flowing through a direct-current bus (not
illustrated), which is an electric wire for supplying
direct-current power to the voltage application device 3,
may be detected, and a rotary machine current may be
obtained by calculation from the bus current.5
[0018] The position estimation unit 4 calculates an
estimate value θL of a rotor position, which is position
information on the rotor 1b, based on the rotary machine
currents iu, iv, and iw. The current control unit 5
generates first voltage commands Vu*, Vv*, and Vw*, which are10
command values of rotary machine voltage for driving the
rotary machine 1, based on detection values of the rotary
machine currents iu, iv, and iw and the estimate value θL of
the rotor position. The position estimation voltage
generation unit 30 generates high-frequency voltages Vuh,15
Vvh, and Vwh having frequencies higher than frequencies of
the first voltage commands Vu*, Vv*, and Vw*, based on
rotation information regarding the direction of rotation of
the rotor 1b. The high-frequency voltages Vuh, Vvh, and Vwh
are position estimation voltages for estimating the rotor20
position. The current control unit 5 superimposes the
high-frequency voltages Vuh, Vvh, and Vwh on the first
voltage commands Vu*, Vv*, and Vw*, and outputs the
superimposed voltages as second voltage commands Vup*, Vvp*,
and Vwp* to the voltage application device 3. The voltage25
application device 3 applies a driving voltage to the
rotary machine 1 based on the second voltage commands Vup*,
Vvp*, and Vwp*. Note that, in the present specification, a
two-level three-phase inverter is cited as an example of
the voltage application device 3, but the voltage30
application device 3 is not limited thereto. In the
present specification, the voltage application device 3 may
be a three-level three-phase inverter, or may be a multi-
10
phase two-level or three-level inverter.
[0019] The current control unit 5 includes subtracters
13d and 13q, a d-axis current controller 14d, a q-axis
current controller 14q, a first coordinate converter 15, a
two-phase to three-phase converter 16, a second coordinate5
converter 17, a three-phase to two-phase converter 18, and
adders 23u, 23v, and 23w.
[0020] The subtracter 13d calculates a deviation Δid
between a d-axis current command id* and a current id output
from the second coordinate converter 17. The d-axis10
current controller 14d provided at the next stage
calculates a d-axis voltage command Vd* by performing
proportional-integral control such that the deviation Δid
becomes zero. The subtracter 13q calculates a deviation
Δiq between a q-axis current command iq* and a current iq15
output from the second coordinate converter 17. The q-axis
current controller 14q provided at the next stage
calculates a q-axis voltage command Vq* by performing
proportional-integral control such that the deviation Δiq
becomes zero. The d-axis current command id* is a command20
value of d-axis current for driving the rotary machine 1,
and the q-axis current command iq* is a command value of q-
axis current for driving the rotary machine 1. Both the d-
axis current command id* and the q-axis current command iq*
are provided from the outside of the current control unit 5.25
[0021] The first coordinate converter 15 converts the d-
axis voltage command Vd* and the q-axis voltage command Vq*
output from the d-axis current controller 14d and the q-
axis current controller 14q into voltage commands Vα* and
Vβ* on stationary biaxial coordinates, respectively. The30
two-phase to three-phase converter 16 converts the voltage
commands Vα* and Vβ* output from the first coordinate
converter 15 into the first voltage commands Vu*, Vv*, and
11
Vw* which are driving voltage commands of three-phase
alternating-current coordinates. Note that the estimate
value θL of the rotor position output from the position
estimation unit 4 is used by the first coordinate converter
15 to perform the processing.5
[0022] The three-phase to two-phase converter 18
converts the rotary machine currents iu, iv, and iw detected
by the current detection unit 2 into currents iα and iβ on
the stationary biaxial coordinates. The second coordinate
converter 17 converts the currents iα and iβ output from10
the three-phase to two-phase converter 18 into the currents
id and iq on the rotating coordinates that rotate in
synchronization with the estimate value θL of the rotor
position output from the position estimation unit 4, and
outputs the currents id and iq to the subtracters 13d and15
13q, respectively.
[0023] The first voltage commands Vu*, Vv*, and Vw* output
from the two-phase to three-phase converter 16 and the
high-frequency voltages Vuh, Vvh, and Vwh output from the
position estimation voltage generation unit 30 are added20
together by the adders 23u, 23v, and 23w, respectively.
Outputs of the adders 23u, 23v, and 23w are applied as the
second voltage commands Vup*, Vvp*, and Vwp* to the voltage
application device 3, respectively. Therefore, the second
voltage commands Vup*, Vvp*, and Vwp* to be applied to the25
voltage application device 3 include the first voltage
commands Vu*, Vv*, and Vw* and the high-frequency voltages
Vuh, Vvh, and Vwh which are position estimation voltage
commands superimposed on the first voltage commands Vu*, Vv*,
and Vw*, respectively. Note that details of the high-30
frequency voltages Vuh, Vvh, and Vwh will be described below.
[0024] The position estimation unit 4 includes current
extractors 6u, 6v, and 6w, a high-frequency current
12
amplitude calculation unit 7, and a position calculator 8.
As described above, the second voltage commands Vup*, Vvp*,
and Vwp* to be applied to the voltage application device 3
include the first voltage commands Vu*, Vv*, and Vw* output
from the two-phase to three-phase converter 16 and the5
high-frequency voltages Vuh, Vvh, and Vwh output from the
position estimation voltage generation unit 30 and
superimposed on the first voltage commands Vu*, Vv*, and Vw*,
respectively. As a result, the rotary machine currents iu,
iv, and iw detected by the current detection unit 2 include10
high-frequency currents iuh, ivh, and iwh having the same
frequency components as frequency components of the high-
frequency voltages Vuh, Vvh, and Vwh, respectively.
[0025] Therefore, the current extractors 6u, 6v, and 6w
extract the high-frequency currents iuh, ivh, and iwh having15
the same frequency components as the frequency components
of the high-frequency voltages Vuh, Vvh, and Vwh from the
rotary machine currents iu, iv, and iw detected by the
current detection unit 2, respectively. A band-pass filter
or a notch filter can be used to extract the high-frequency20
currents iuh, ivh, and iwh. Note that when a notch filter is
used, the rotary machine currents iu, iv, and iw are input
to the notch filter to attenuate the same frequency
components as the frequency components of the high-
frequency voltages Vuh, Vvh, and Vwh, respectively. Then,25
the respective currents having passed through the notch
filter are subtracted from the rotary machine currents iu,
iv, and iw. Thus, the high-frequency currents iuh, ivh, and
iwh can be extracted.
[0026] The high-frequency current amplitude calculation30
unit 7 includes multipliers 9u, 9v, and 9w, integrators 10u,
10v, and 10w, and square root calculators 22u, 22v, and 22w.
These constituent parts are each provided for a
13
corresponding phase.
[0027] In the multipliers 9u, 9v, and 9w, the high-
frequency currents iuh, ivh, and iwh are squared to obtain
autocorrelation values, respectively. In the integrators
10u, 10v, and 10w, integration processing is performed with5
respect to time Tn corresponding to one integration cycle,
and an obtained value of integral is multiplied by (2/Tn)
and output. The square root calculators 22u, 22v, and 22w
calculate the square root of outputs of the integrators 10u,
10v, and 10w to obtain position estimation current10
amplitudes Iuh, Ivh, and Iwh, respectively.
[0028] Note that the high-frequency current amplitude
calculation unit 7 in FIG. 1 obtains the position
estimation current amplitudes Iuh, Ivh, and Iwh by
integrating the autocorrelation values of the high-15
frequency currents iuh, ivh, and iwh, respectively, and
calculating the square roots thereof, but the way of
obtaining the position estimation current amplitudes Iuh,
Ivh, and Iwh is not limited thereto. The high-frequency
current amplitude calculation unit 7 may obtain the20
position estimation current amplitudes Iuh, Ivh, and Iwh by
passing the autocorrelation values of the high-frequency
currents iuh, ivh, and iwh through a low-pass filter,
respectively.
[0029] The position calculator 8 calculates the estimate25
value θL of the rotor position based on the position
estimation current amplitudes Iuh, Ivh, and Iwh calculated by
the high-frequency current amplitude calculation unit 7. A
known method is used to calculate the estimate value θL of
the rotor position. Thus, a detailed description of30
calculation of the estimate value θL will be omitted here.
Note that for more details, refer to, for example, Japanese
Patent No. 5324646 that discloses a specific calculation
14
procedure.
[0030] Next, the high-frequency voltages Vuh, Vvh, and Vwh
to be output from the position estimation voltage
generation unit 30 will be described. FIG. 2 is a diagram
illustrating an example of waveforms of the high-frequency5
voltages Vuh, Vvh, and Vwh to be output from the position
estimation voltage generation unit 30 in FIG. 1. Note that
FIG. 2 shows an example of waveforms to be observed when
the voltage application device 3 includes a pulse width
modulation (PWM) inverter for triangular wave comparison.10
[0031] The horizontal axis represents time in FIG. 2.
In addition, FIG. 2 illustrates waveforms of a triangular
wave carrier, the u-phase high-frequency voltage Vuh, the
v-phase high-frequency voltage Vvh, and the w-phase high-
frequency voltage Vwh in order from the top. Assuming that15
a half period Tc of the triangular wave carrier is defined
as one section, each of the high-frequency voltages Vuh, Vvh,
and Vwh is a signal having a period of Th corresponding to
six sections (=6·Tc). In the example of FIG. 2, the high-
frequency voltages Vuh, Vvh, and Vwh have been set such that20
the high-frequency voltages Vuh, Vvh, and Vwh are out of
phase with each other by two sections (=2·Tc) so as to
achieve three-phase equilibrium. Note that FIG. 2 merely
shows an example, and the waveforms of the high-frequency
voltages Vuh, Vvh, and Vwh are not limited to the waveforms25
of this example. Any waveforms may be acceptable as long
as the waveforms allow the high-frequency voltages Vuh, Vvh,
and Vwh to be in three-phase equilibrium.
[0032] Returning to FIG. 1, the position estimation
voltage generation unit 30 will be described. The position30
estimation voltage generation unit 30 includes a speed
calculator 31 and a high-frequency voltage generator 32.
The speed calculator 31 calculates an estimated rotational
15
speed ωL based on the estimate value θL of the rotor
position. The estimated rotational speed ωL is an estimate
value of rotational speed of the rotor 1b. The estimated
rotational speed ωL is obtained by differential processing
or pseudo differential processing of the estimate value θL5
of the rotor position. Note that the pseudo differential
processing mentioned herein can be implemented by use of a
differentiator and a low-pass filter.
[0033] The high-frequency voltage generator 32 generates
the high-frequency voltages Vuh, Vvh, and Vwh described above,10
based on the estimated rotational speed ωL. Operation of
the high-frequency voltage generator 32 will be described
with reference to several formulas and a flowchart
illustrated in FIG. 3. FIG. 3 is a flowchart for
describing operation of the high-frequency voltage15
generator 32 illustrated in FIG. 1.
[0034] In describing the operation of the high-frequency
voltage generator 32, a formula representing high-frequency
current is derived. First, a voltage equation of the
rotary machine 1 on an α-axis and a β-axis in a coordinate20
system at rest is expressed by formula (1) below. Note
that the following assumes that the rotary machine 1 is an
interior permanent magnet synchronous machine.
[0035] Formula 1:
16
[0036] In formula (1) above, Vα, Vβ, iα, and iβ denote α-
axis voltage, β-axis voltage, α-axis current, and β-axis
current, respectively. Furthermore, R and KE denote stator
resistance and an induced voltage coefficient, respectively.5
In addition, Lα, Lβ, Lαβ, Ld, and Lq denote α-axis inductance,
β-axis inductance, mutual inductance between the α-axis and
the β-axis, d-axis inductance, and q-axis inductance,
respectively. Moreover, L0 is defined by a fifth equation
of formula (1) above, and L1 is defined by a sixth equation10
of formula (1) above. In addition, p denotes a
differential operator.
[0037] Considering only high-frequency components in
formula (1) above, formula (2) below is obtained.
[0038] Formula 2:15
[0039] In formula (2) above, Vαh, Vβh, iαh, and iβh denote
high-frequency components of the α-axis voltage, the β-axis
voltage, the α-axis current, and the β-axis current,
respectively. Note that regarding transformation from20
formula (1) above to formula (2) above, a similar formula
can also be obtained for a synchronous reluctance motor
that uses no magnet. Therefore, it is needless to say that
17
formula (2) above is not limited to an interior permanent
magnet synchronous machine.
[0040] When formula (2) above is solved for a current
derivative term, formula (3) below is obtained.
[0041] Formula 3:5
[0042] In addition, the high-frequency voltages Vα and
Vβ on the α-axis and the β-axis, respectively, are defined
by formula (4) below.
[0043] Formula 4:10
[0044] In formula (4) above, Vhαβ denotes high-frequency
voltage amplitude on the α-axis and the β-axis, and ωh
denotes angular frequency on the α-axis and the β-axis.
Note that the angular frequency is also called “angular15
speed”.
[0045] Here, the high-frequency voltages Vα and Vβ are
vectors, and rotational direction changes depending on
whether the angular frequency ωh is a positive value or a
negative value. That is, the rotational direction is20
reversed when the angular frequency ωh changes from a
negative value to a positive value, and vice versa. Here,
rotational direction is defined as “reverse rotation” when
the angular frequency ωh is a negative value, and
rotational direction is defined as “forward rotation” when25
the angular frequency ωh is a positive value.
[0046] When formula (4) above is expressed on three-
phase coordinates, formula (5) below is obtained.
[0047] Formula 5:
18
[0048] In formula (5) above, Vhuvw denotes high-frequency
voltage amplitude on the three-phase coordinates. Note
that the relationship between the rotational direction of
the high-frequency voltages Vuh, Vvh, and Vwh on the three-5
phase coordinates and the sign (positive or negative) of
the angular frequency ωh is the same as the relationship
with the high-frequency voltage Vα on the α-axis and the
high-frequency voltage Vβ on the β-axis.
[0049] When formula (4) above is substituted into10
formula (3) above, formula (6) below is obtained.
[0050] Formula 6:
[0051] Assuming that the rotary machine 1 is not in
operation, formula (7) below is obtained by integration of15
formula (6) above.
[0052] Formula 7:
[0053] In formula (7) above, ω denotes the angular
frequency of the rotary machine 1. The angular frequency20
of the rotary machine 1 is synonymous with the rotational
speed of the rotary machine 1. As with the high-frequency
voltages Vuh, Vvh, and Vwh, rotational direction is defined
as “reverse rotation” when the angular frequency ω of the
rotary machine 1 is a negative value, and rotational25
direction is defined as “forward rotation” when the angular
frequency ω is a positive value.
19
[0054] As shown in a second equation of formula (7)
above, the high-frequency currents iα and iβ include a term
including only the angular frequency ωh and a term
including both the angular frequencies ωh and ω. The
former is a term including only a superimposed frequency5
component for rotor position estimation, and the latter is
a term including the above-described sideband component.
[0055] Here, as described above, a sideband component to
be generated on a side on which the absolute value of
frequency is higher than the absolute value of superimposed10
frequency is referred to as an “upper sideband”, and a
sideband component to be generated on a side on which the
absolute value of frequency is lower than the absolute
value of superimposed frequency is referred to as a “lower
sideband”. As can be understood from the second equation15
of formula (7) above, when the angular frequency ω of the
rotary machine 1 and the angular frequency ωh of the high-
frequency voltages Vuh, Vvh, and Vwh have the same sign, a
component “ωh-2ω” corresponds to a lower sideband.
Meanwhile, when the angular frequency ω of the rotary20
machine 1 and the angular frequency ωh of the high-
frequency voltages Vuh, Vvh, and Vwh have different signs,
the component “ωh-2ω” corresponds to an upper sideband.
[0056] As described above, the sideband component
adversely affects processing to be performed in the current25
control system and the rotor position estimation system.
This will be described in more detail here.
[0057] First, a description will be given of the
influence of the sideband distribution of high-frequency
current on the current control system. High-frequency30
current including a superimposed frequency component and a
sideband component is a disturbance for the current control
system. Therefore, it is desirable that the frequency of
20
high-frequency current be widely different from the
response frequency of the current control system. However,
when the number of revolutions of the rotary machine
increases, the sideband component is distributed over a
wide area. In particular, under conditions where a lower5
sideband is generated, a lower sideband component is
distributed in a current control band. This causes adverse
effects on the current control system, such as
deterioration and instability of response. Meanwhile,
under conditions where an upper sideband is generated, the10
upper sideband is generated in a direction away from the
current control band, that is, outside the current control
band, so that the above-described adverse effects are not
exerted on the current control system. Therefore, a
condition that an upper sideband is constantly generated is15
a desirable condition for the current control system.
[0058] Next, a description will be given of the
influence of the sideband distribution of high-frequency
current on the rotor position estimation system. The
sideband component of high-frequency current includes rotor20
position information. Therefore, when the sideband
component of the high-frequency current is reduced by the
current control system, an S/N ratio deteriorates, so that
the estimate value of the rotor position vibrates and
becomes unstable. This problem occurs due to distribution25
of a lower sideband in the current control band when speed
increases in a case where the sideband component of high-
frequency current is the lower sideband. Meanwhile, under
conditions where an upper sideband is generated, the upper
sideband is generated in a direction away from the current30
control band, that is, outside the current control band, so
that the above-described adverse effects are not exerted on
the current control system.
21
[0059] Furthermore, a case is considered in which a
filter having different attenuation characteristics and
phase characteristics between frequency lower than a cutoff
frequency and frequency higher than the cutoff frequency,
such as a BPF or HPF, is used for extracting high-frequency5
current. When such a filter is used, there is a difference
between position estimation characteristics under
conditions where an upper sideband is generated and those
under conditions where a lower sideband is generated. For
example, in a case where a filter that attenuates a low10
frequency component, such as the HPF, is used under
conditions where a lower sideband is generated, the S/N
ratio deteriorates due to attenuation of the lower sideband
including position information. In addition, since phase
characteristics differ between frequency lower than the15
cutoff frequency and frequency higher than the cutoff
frequency, there is a difference between position
estimation response under conditions where an upper
sideband is generated and that under conditions where a
lower sideband is generated. Therefore, a condition that20
an upper sideband is constantly generated is a desirable
condition for the rotor position estimation system.
[0060] As described above, the high-frequency voltage
generator 32 generates the high-frequency voltages Vuh, Vvh,
and Vwh that allow an upper sideband to be constantly25
generated. Specifically, operation is performed according
to the flowchart of FIG. 3.
[0061] The high-frequency voltage generator 32 receives
the estimated rotational speed ωL, which is an estimate
value of the rotational speed of the rotor 1b, from the30
speed calculator 31 (step S11). The high-frequency voltage
generator 32 checks the sign of the value of the estimated
rotational speed ωL. Specifically, the high-frequency
22
voltage generator 32 checks whether the value of the
estimated rotational speed ωL is equal to or greater than
zero (step S12). When the value of the estimated
rotational speed ωL is equal to or greater than zero (step
S12, Yes), the value of the angular frequency ωh is5
inverted. Specifically, the absolute value of the angular
frequency ωh is multiplied by “-1”, and an obtained value
is set as the angular frequency ωh (step S13). Furthermore,
when the value of the estimated rotational speed ωL is less
than zero (step S12, No), the absolute value of the angular10
frequency ωh is set as the angular frequency ωh (step S14).
[0062] The high-frequency voltage generator 32
calculates a phase angle θh according to formula (8) below
by using the angular frequency ωh set in step S13 or step
S14 (step S15).15
[0063] Formula 8:
[0064] In addition, the high-frequency voltage generator
32 generates the high-frequency voltages Vuh, Vvh, and Vwh
according to formula (9) below by using the phase angle θh20
calculated in step S15 (step S16).
[0065] Formula 9:
[0066] As a result of the above processing, the high-
frequency voltages Vuh, Vvh, and Vwh are generated which25
allow an upper sideband to be constantly generated.
[0067] Note that, in steps S13 and S14, the sign of the
angular frequency ωh is changed depending on the sign of
the estimated rotational speed ωL, but this method is not a
limitation. The phase sequence of any two phases in30
23
formula (9) above may be changed without a change of the
sign of the angular frequency ωh. In this way, the
rotational direction of the high-frequency voltages Vuh, Vvh,
and Vwh can be changed.
[0068] Furthermore, in the first embodiment, the speed5
calculator 31 calculates the estimated rotational speed ωL
based on the estimate value θL of the rotor position.
However, the speed calculator 31 does not necessarily need
to calculate the estimated rotational speed ωL. The speed
calculator 31 may detect the direction of rotation of the10
rotor 1b and output detection information to the high-
frequency voltage generator.
[0069] As described above, according to the rotary
machine control apparatus of the first embodiment, the
current control unit generates a first voltage command that15
is a command value of rotary machine voltage for driving a
rotary machine, based on a detection value of rotary
machine current and an estimate value of a rotor position.
Then, the position estimation voltage generation unit
generates a high-frequency voltage based on rotation20
information regarding the direction of rotation of the
rotor, the high-frequency voltage being a position
estimation voltage for estimating the rotor position, the
high-frequency voltage having a frequency higher than a
frequency of the first voltage command. As a result, it is25
possible to prevent an adverse effect on a current control
system and a rotor position estimation system, possibly
caused by a sideband component of high-frequency current.
[0070] Note that, in the rotary machine control
apparatus according to the first embodiment, the position30
estimation voltage generation unit may include a speed
calculator that calculates, as speed information on the
rotor, an estimate value of rotational speed based on the
24
estimate value of the rotor position. According to this
configuration, it is possible to generate position
estimation voltage by using, as the rotation information,
the estimate value of rotational speed calculated by the
speed calculator.5
[0071] In addition, according to the rotary machine
control apparatus of the first embodiment, the position
estimation voltage generation unit operates in such a way
as to generate high-frequency voltage that allows an upper
sideband to be constantly generated. The upper sideband is10
generated in a direction away from the current control band,
that is, outside the current control band, so that it is
possible to prevent adverse effects on the current control
system, such as deterioration or instability of response.
In addition, since the high-frequency voltage generated by15
the position estimation voltage generation unit prevents
generation of a lower sideband, it is possible to prevent a
decrease in the S/N ratio in filter characteristics of a
filter to be used to extract the high-frequency current.
This makes it possible to stabilize response20
characteristics in the rotor position estimation system.
[0072] Second Embodiment.
FIG. 4 is a diagram illustrating an exemplary
configuration of a rotary machine control apparatus 100A
according to a second embodiment. Comparing the control25
apparatus 100A according to the second embodiment with the
control apparatus 100 illustrated in FIG. 1, the position
estimation voltage generation unit 30 has been replaced
with a position estimation voltage generation unit 30A in
FIG. 4. In addition, the high-frequency voltage generator30
32 illustrated in FIG. 1 has been replaced with a high-
frequency voltage generator 32A in the position estimation
voltage generation unit 30A. Furthermore, FIG. 4
25
illustrates a host control unit 33 and an operation control
device 34 as components provided outside the control
apparatus 100A. Except for these points, the configuration
of the control apparatus 100A is the same as or equivalent
to the configuration of the control apparatus 100. Thus,5
the same or equivalent constituent parts are designated by
the same reference numerals, and redundant description will
be omitted.
[0073] FIG. 5 is a diagram illustrating an exemplary
configuration in which the control apparatus 100A having10
the configuration illustrated in FIG. 4 is installed on a
railroad car. As illustrated in FIG. 5, the control
apparatus 100A according to the second embodiment is
configured on the assumption that the control apparatus
100A is to be installed on a railroad car. Note that15
although FIG. 5 shows an example of a two-car train, the
number of cars is not limited to two, and the control
apparatus 100A may be installed on a single-car train or a
train with three or more cars. For example, in the case of
a two-car train, two operation control devices 34, a single20
host control unit 33, and two control apparatuses 100A are
provided as illustrated in FIG. 5.
[0074] The two operation control devices 34 (34a, 34b)
are installed as illustrated in FIG. 5. In this
configuration, a train car direction switching signal S is25
output from one of the devices, and the train car direction
switching signal S is transmitted to the host control unit
33. The train car direction switching signal S is a signal
to be output when the traveling direction of the train is
switched. The host control unit 33 can recognize whether30
the traveling direction of the train is “forward” or
“backward” by receiving this signal.
[0075] As described above, the train car direction
26
switching signal S is a signal for determining whether to
cause the train cars to move “forward” or “backward”. In
practice, a train driver who gets on either of the train
cars performs a required operation as to whether the train
travels as an up train or a down train (upbound or5
downbound) on a route. As a result of this operation, the
train car direction switching signal S of moving “forward”
or “backward” is output to the host control unit 33.
[0076] When receiving the transmitted train car
direction switching signal S, the host control unit 3310
converts the train car direction switching signal S into a
train car traveling direction signal Rev, and transmits the
train car traveling direction signal Rev to two control
apparatuses 100A1 and 100A2 in the train cars. Then, the
host control unit 33 causes the control apparatuses 100A115
and 100A2 to recognize whether the train is moving
“forward” or “backward”.
[0077] FIG. 6 is a table illustrating details of
internal processing to be performed in the host control
unit 33 illustrated in FIG. 4. More specifically, when the20
operation control device 34a in FIG. 5 outputs a signal of
moving “forward” as the train car direction switching
signal S, the host control unit 33 outputs a signal “F”
(forward) as the train car traveling direction signal Rev
to the control apparatuses 100A1 and 100A2, and when the25
operation control device 34a outputs a signal of moving
“backward” as the train car direction switching signal S,
the host control unit 33 outputs a signal “R” (reverse) as
the train car traveling direction signal Rev to the control
apparatuses 100A1 and 100A2.30
[0078] Meanwhile, when train car direction switching
signal S is output from the operation control device 34b,
the above relationship is reversed. That is, when the
27
operation control device 34b outputs a signal of moving
“forward” as the train car direction switching signal S,
the host control unit 33 outputs a signal “R” as the train
car traveling direction signal Rev to the control
apparatuses 100A1 and 100A2, and when the operation control5
device 34b outputs a signal of moving “backward” as the
train car direction switching signal S, the host control
unit 33 outputs a signal “F” as the train car traveling
direction signal Rev to the control apparatuses 100A1 and
100A2.10
[0079] Returning to description of FIG. 4, the host
control unit 33 receives the train car direction switching
signal S from the operation control device 34. The host
control unit 33 outputs the train car traveling direction
signal Rev to the high-frequency voltage generator 32A15
based on the train car direction switching signal S. The
high-frequency voltage generator 32A uses the train car
traveling direction signal Rev as rotation information.
Then, the high-frequency voltage generator 32A generates
the high-frequency voltages Vuh, Vvh, and Vwh by using the20
method of the first embodiment. As a result, the high-
frequency voltage generator 32A can generate the high-
frequency voltages Vuh, Vvh, and Vwh that allow an upper
sideband to be constantly generated.
[0080] Note that although FIG. 4 shows an example in25
which the train car traveling direction signal Rev
generated based on the train car direction switching signal
S is transmitted from the host control unit 33 to the two
control apparatuses 100A1 and 100A2 in the train cars, the
configuration of the control apparatus 100A according to30
the second embodiment is not limited to this example. The
rotary machine control apparatus 100A according to the
second embodiment may be configured as illustrated in FIGS.
28
7 and 8. FIG. 7 is a diagram illustrating another
exemplary configuration of the rotary machine control
apparatus 100A according to the second embodiment.
Furthermore, FIG. 8 is a diagram illustrating an exemplary
configuration in which the control apparatus 100A having5
the configuration illustrated in FIG. 7 is installed on a
railroad car.
[0081] In FIGS. 4 and 5, the train car traveling
direction signal Rev is input to the control apparatuses
100A1 and 100A2 via the host control unit 33 and the10
operation control device 34, but may be directly input from
an operation device 35 as illustrated in FIGS. 7 and 8.
The operation device 35 is a command device to be provided
in a cab of a railroad car.
[0082] When railroad cars are traveling in, for example,15
a left direction in the drawing, an operation device 35a
located in front in a train car traveling direction outputs
a signal “F” as the train car traveling direction signal
Rev to a signal line 36. The control apparatuses 100A1 and
100A2 can recognize the traveling direction of the railroad20
cars by receiving the train car traveling direction signal
Rev through the signal line 36.
[0083] In addition, when the railroad cars are traveling
in, for example, a right direction in the drawing, an
operation device 35b located in front in the train car25
traveling direction outputs a signal “F” as the train car
traveling direction signal Rev to a signal line 38. The
control apparatuses 100A1 and 100A2 can recognize the
traveling direction of the railroad cars by receiving the
train car traveling direction signal Rev through the signal30
line 38.
[0084] As described above, the rotary machine control
apparatus according to the second embodiment is installed
29
on a railroad car, and rotation information regarding the
direction of rotation of a rotary machine is generated by
use of a train car traveling direction signal indicating
the traveling direction of the railroad car. As a result,
the rotary machine control apparatus according to the5
second embodiment can generate high-frequency voltage by
using the train car traveling direction signal as the
rotation information. Furthermore, according to the rotary
machine control apparatus of the second embodiment, the
speed calculator described in the first embodiment is10
unnecessary. As a result, it is possible to achieve the
effect of simplifying the configuration of the apparatus as
compared with the first embodiment in addition to the
effect of the first embodiment.
[0085] Note that, in the rotary machine control15
apparatus according to the second embodiment, the train car
traveling direction signal may be generated by use of a
train car direction switching signal generated when the
traveling direction of the train car is switched.
Alternatively, the train car traveling direction signal may20
be generated by use of upbound and downbound information on
train car operation, output from the operation control
device installed on the railroad car. Alternatively, the
train car traveling direction signal may be directly input
to the control apparatus from the operation device provided25
in the cab of the railroad car. With any of these
configurations, it is possible to achieve the effect of
simplifying the configuration of the apparatus in addition
to the effect of the first embodiment.
[0086] Third Embodiment.30
FIG. 9 is a diagram illustrating an exemplary
configuration of a rotary machine control apparatus 100B
according to a third embodiment. Comparing the control
30
apparatus 100B according to the third embodiment with the
control apparatus 100 illustrated in FIG. 1, the current
control unit 5 has been replaced with a current control
unit 5B in FIG. 9. Furthermore, a fundamental wave current
extractor 11 has been added to the configuration of the5
current control unit 5 illustrated in FIG. 1 to obtain the
current control unit 5B. Except for these points, the
configuration of the control apparatus 100B is the same as
or equivalent to the configuration of the control apparatus
100. Thus, the same or equivalent constituent parts are10
designated by the same reference numerals, and redundant
description will be omitted.
[0087] As described above, high-frequency current
including a superimposed frequency component and a sideband
component is a disturbance for a current control system.15
Therefore, it is desirable that the frequency of high-
frequency current be widely different from the response
frequency of the current control system. Meanwhile, for
the purpose of ensuring calculation time and reducing noise,
superimposed frequency is set to a lower frequency in some20
cases. Thus, the response frequency of the current control
system and superimposed frequency may be set closer to each
other. This adversely affects processing to be performed
in the current control system. In addition, as described
above, a sideband component is distributed over a wide area25
in an application in which the number of revolutions of a
rotary machine is high. This adversely affects processing
to be performed in the current control system.
[0088] Therefore, in the third embodiment, the
fundamental wave current extractor 11 is provided so as to30
remove or reduce the effect of high-frequency current
generated as a result of application of the high-frequency
voltages Vuh, Vvh, and Vwh. As illustrated in FIG. 9, the
31
fundamental wave current extractor 11 is disposed between
the current detection unit 2 and the three-phase to two-
phase converter 18, that is, at a stage preceding the
three-phase to two-phase converter 18.
[0089] The fundamental wave current extractor 115
extracts fundamental wave currents iuf, ivf, and iwf obtained
by removal or attenuation of the same frequency components
as frequency components of the high-frequency voltages Vuh,
Vvh, and Vwh, from the rotary machine currents iu, iv, and iw
detected by the current detection unit 2, respectively. A10
low-pass filter or a notch filter can be used to extract
the fundamental wave currents iuf, ivf, and iwf. The three-
phase to two-phase converter 18 performs the processing
described in the first embodiment by using the fundamental
wave currents iuf, ivf, and iwf as input signals. The15
subsequent processing is the same as that described in the
first embodiment.
[0090] According to the control apparatus 100B of the
third embodiment, a superimposed frequency component and a
sideband component thereof in the high-frequency currents20
iuh, ivh, and iwh are sufficiently removed from the rotary
machine currents iu, iv, and iw detected by the current
detection unit 2, respectively, in the processing to be
performed in the current control unit 5B which is a current
control system. As a result, it is possible to prevent25
adverse effects on the current control system, such as
deterioration or instability of response.
[0091] As described above, according to the rotary
machine control apparatus of the third embodiment, a
fundamental wave component extractor extracts a fundamental30
wave component by removing a harmonic superimposed
component included in a detection value of rotary machine
current. Then, the current control unit generates a first
32
voltage command based on an output from the fundamental
wave component extractor and an estimate value of a rotor
position. As a result, it is possible to reliably prevent
adverse effects on the current control system, such as
deterioration or instability of response.5
[0092] Note that, in the third embodiment, the
configuration in which the fundamental wave current
extractor 11 is provided between the current detection unit
2 and the three-phase to two-phase converter 18 has been
applied to the configuration of the first embodiment10
illustrated in FIG. 1, but the configuration of the third
embodiment is not limited to this configuration. Needless
to say, the configuration in which the fundamental wave
current extractor 11 is provided between the current
detection unit 2 and the three-phase to two-phase converter15
18 may be applied to the configuration of the second
embodiment illustrated in FIG. 4.
[0093] Furthermore, examples of superimposing high-
frequency voltage on the three-phase coordinates that are
fixed coordinates have been described in the first to third20
embodiments. However, superimposition of high-frequency
voltage is not limited thereto. The current control units
5 and 5B may be configured such that high-frequency voltage
is superimposed on rotating coordinates. Even when high-
frequency voltage is superimposed on the rotating25
coordinates, a similar sideband is generated. Therefore,
even in a case where rotating voltage is superimposed on
the rotating coordinates, it is possible to achieve the
effects of the first to third embodiments described above
by generating high-frequency voltage such that an upper30
sideband is constantly generated.
[0094] Next, hardware configurations of the control
apparatuses 100, 100A, and 100B according to the first to
33
third embodiments described above will be described with
reference to FIGS. 10 and 11. FIG. 10 is a diagram
illustrating a first exemplary configuration of hardware
that implements each function of the control apparatuses
100, 100A, and 100B according to the first to third5
embodiments. FIG. 11 is a diagram illustrating a second
exemplary configuration of hardware that implements each
function of the control apparatuses 100, 100A, and 100B
according to the first to third embodiments. Note that
each function of the control apparatuses 100, 100A, and10
100B refers to each of the functions of the position
estimation unit 4, the current control units 5 and 5B, and
the position estimation voltage generation units 30 and 30A
included in the control apparatuses 100, 100A, and 100B.
[0095] Each of the functions of the position estimation15
unit 4, the current control units 5 and 5B, and the
position estimation voltage generation units 30 and 30A can
be implemented by use of processing circuitry. In FIG. 10,
the position estimation unit 4, the current control units 5
and 5B, and the position estimation voltage generation20
units 30 and 30A in the first to third embodiments have
been replaced with dedicated processing circuitry 40. In a
case where dedicated hardware is used, the dedicated
processing circuitry 40 corresponds to a single circuit, a
composite circuit, an application specific integrated25
circuit (ASIC), a field-programmable gate array (FPGA), or
a combination thereof. The functions of the position
estimation unit 4, the current control units 5 and 5B, and
the position estimation voltage generation units 30 and 30A
may each be implemented by processing circuitry, or may be30
collectively implemented by processing circuitry.
[0096] Furthermore, in FIG. 11, the position estimation
unit 4, the current control units 5 and 5B, and the
34
position estimation voltage generation units 30 and 30A in
the configurations of the first to third embodiments have
been replaced with a processor 41 and a storage device 42.
The processor 41 may be an arithmetic means such as an
arithmetic unit, a microprocessor, a microcomputer, a5
central processing unit (CPU), or a digital signal
processor (DSP). In addition, examples of the storage
device 42 include nonvolatile or volatile semiconductor
memories such as a random access memory (RAM), a read only
memory (ROM), a flash memory, an erasable programmable ROM10
(EPROM), and an electrically EPROM (EEPROM (registered
trademark)).
[0097] In a case where the processor 41 and the storage
device 42 are used, each of the functions of the position
estimation unit 4, the current control units 5 and 5B, and15
the position estimation voltage generation units 30 and 30A
is implemented by software, firmware, or a combination
thereof. The software or firmware is described as a
program, and stored in the storage device 42. The
processor 41 reads and executes such programs stored in the20
storage device 42. Furthermore, it can also be said that
these programs cause a computer to execute procedures and
methods for the respective functions of the position
estimation unit 4, the current control units 5 and 5B, and
the position estimation voltage generation units 30 and 30A.25
For example, a nonvolatile or volatile semiconductor memory
such as a ROM, EPROM, or EEPROM, a flexible disk, an
optical disk, a compact disk, or a DVD can be used as the
storage device 42.
[0098] Some of the functions of the position estimation30
unit 4, the current control units 5 and 5B, and the
position estimation voltage generation units 30 and 30A may
be implemented by hardware, and other functions thereof may
35
be implemented by software or firmware. For example, the
functions of the position estimation voltage generation
units 30 and 30A may be implemented by use of dedicated
hardware, and the functions of the position estimation unit
4 and the current control units 5 and 5B may be implemented5
by use of the processor 41 and the storage device 42.
[0099] The configurations set forth in the above
embodiments show examples, and it is possible to combine
the configurations with another known technique or combine
the embodiments with each other, and is also possible to10
partially omit or change the configurations without
departing from the scope of the present disclosure.
Reference Signs List
[0100] 1 rotary machine; 1a stator; 1b rotor; 215
current detection unit; 3 voltage application device; 4
position estimation unit; 5, 5B current control unit; 6u,
6v, 6w current extractor; 7 high-frequency current
amplitude calculation unit; 8 position calculator; 9u, 9v,
9w multiplier; 10u, 10v, 10w integrator; 11 fundamental20
wave current extractor; 13d, 13q subtracter; 14d d-axis
current controller; 14q q-axis current controller; 15
first coordinate converter; 16 two-phase to three-phase
converter; 17 second coordinate converter; 18 three-phase
to two-phase converter; 22u, 22v, 22w square root25
calculator; 23u, 23v, 23w adder; 30, 30A position
estimation voltage generation unit; 31 speed calculator;
32, 32A high-frequency voltage generator; 33 host control
unit; 34, 34a, 34b operation control device; 35, 35a, 35b
operation device; 36, 38 signal line; 40 dedicated30
processing circuitry; 41 processor; 42 storage device;
100, 100A, 100A1, 100A2, 100B control apparatus.
36
We Claim:
[Claim 1] A rotary machine control apparatus comprising:
a current detection unit to detect a rotary machine5
current flowing to a rotary machine;
a position estimation unit to calculate an estimate
value of a rotor position based on the rotary machine
current, the rotor position being position information on a
rotor of the rotary machine;10
a current control unit to generate a first voltage
command based on a detection value of the rotary machine
current and the estimate value of the rotor position, the
first voltage command being a command value of rotary
machine voltage for driving the rotary machine;15
a position estimation voltage generation unit to
generate a high-frequency voltage based on rotation
information regarding direction of rotation of the rotor,
the high-frequency voltage being a position estimation
voltage for estimating the rotor position, the high-20
frequency voltage having a frequency higher than a
frequency of the first voltage command; and
a voltage application device to apply a driving
voltage to the rotary machine based on a second voltage
command, the second voltage command being a voltage command25
obtained by superimposition of the position estimation
voltage on the first voltage command.
[Claim 2] The rotary machine control apparatus according to
claim 1, wherein30
the position estimation voltage generation unit
includes a speed calculator to calculate an estimate value
of rotational speed based on the estimate value of the
37
rotor position, the estimate value of rotational speed
being speed information on the rotor, and
the position estimation voltage generation unit
generates the position estimation voltage by using the
estimate value of rotational speed as the rotation5
information.
[Claim 3] The rotary machine control apparatus according to
claim 1, wherein
the rotation information is input to the position10
estimation voltage generation unit from outside the control
apparatus.
[Claim 4] The rotary machine control apparatus according to
claim 2 or 3, wherein15
the position estimation voltage generation unit
generates a high-frequency voltage that allows an upper
sideband to be constantly generated.
[Claim 5] The rotary machine control apparatus according to20
claim 4, wherein
the control apparatus is installed on a railroad car,
and
the rotation information is generated by use of a
train car traveling direction signal indicating a traveling25
direction of the railroad car.
[Claim 6] The rotary machine control apparatus according to
claim 5, wherein
the train car traveling direction signal is generated30
by use of a train car direction switching signal, the train
car direction switching signal being generated when the
traveling direction of the railroad car is switched.
38
[Claim 7] The rotary machine control apparatus according to
claim 5, wherein
the train car traveling direction signal is output
from an operation device provided in a cab of the railroad5
car.
[Claim 8] The rotary machine control apparatus according to
any one of claims 1 to 7, wherein
the current control unit includes a fundamental wave10
component extractor to extract a fundamental wave component
by removing a harmonic superimposed component included in
the detection value of the rotary machine current, and
the current control unit generates the first voltage
command based on an output from the fundamental wave15
component extractor and the estimate value of the rotor
position.