JP7183827B2 - Multi-winding AC motor drive system - Google Patents

Description

The present invention is a multi-winding AC motor drive system in which power is supplied from the same number of single-phase inverters to the stator windings of a plurality of multi-winding AC motors having output shafts connected to each other. It is about.

A multi-winding AC motor (hereinafter also simply referred to as a motor) having m groups (m: natural number) of n-phase (n: an integer of 4 or more) stator windings insulated from each other is connected to the input side of a multi-winding AC motor from a DC power supply. A multi-winding AC motor drive system in which the AC sides of (m×n) single-phase two-level inverters to be fed are connected to each other, and each inverter is PWM (Pulse Width Modulation) controlled to feed power to the stator windings. are described in Patent Documents 1 and 2, for example.

In addition, in order to increase the output of the entire device and to enable continuous operation even if some multi-winding AC motor drive devices (hereinafter simply referred to as drive devices) fail, multiple drive devices are connected in parallel. In addition, there are cases where the output shafts of a plurality of electric motors driven by these drive devices are connected to each other. Furthermore, in such a system in which a plurality of drive devices are connected in parallel, when the required motor output is small, some of the drive devices and motors are stopped, and the remaining drive devices and motors are operated to operate at high power. Efficiency is also well known.

For example, FIG. 10 is a configuration diagram of a multi-winding AC motor drive system in which q (where q is an even number equal to or greater than 2) multi-winding AC motors M ₁ to M _q are driven by the same number of drive devices. The output shafts M ₁ ′ to M _{q-1 ′ of} M ₁ to M _q are connected to adjacent motors, and the motor M ₁ is provided with a position detector 3 for detecting the rotor position θ. It is
In the drive system of FIG. 10, (m×n) single-phase two-level inverters, for example, inverter groups 2 ₁₁ to 2 _1m , connected to a DC power supply 1 constitute one drive device. It drives a motor _M1 having (m×n) windings in groups and n phases. Similarly, inverter groups 2 _q1 to 2 _qm constitute one driving device, and this driving device similarly drives a motor M _q having (m×n) windings.
Here, each inverter is controlled by turning on/off a semiconductor switching element using a PWM pulse obtained by comparing a carrier wave such as a triangular wave and a signal wave.

More specifically, _the inverter group 2 ₁₁ includes _{n units (} Inverter group 2 1m is composed of inverters INV1 ₁₁ to INV1 _1n of n phases), and likewise, inverter group 2 _1m has a DC side connected in parallel and _an AC side connected to windings m ₁ to m _n of the m-th group, respectively. ~ INV1 _mn .
In addition, the inverter groups 2 _q1 to 2 _qm constituting the driving device of the electric motor M _q are basically configured in the same manner as the inverter groups 2 ₁₁ to 2 _1m described above.
In FIG. 10, V _d11 to V _d1m and V _dq1 to V _dqm are the DC input voltages of each inverter, and V _o111 to V _o1mn and V _oq11 to V _oqmn (V _o1mn and V _oqmn are not shown for convenience) are The single-phase output voltages, i _o111 to i _o1mn and i _oq11 to i _oqmn are the output currents.

In Patent Documents 1 and 2, which will be described later, for example, in the inverter group 2 ₁₁ , by shifting the phase of the carrier wave for PWM control of the n inverters INV1 ₁₁ to INV1 _1n between each inverter (between each phase), It is described that vibration of a predetermined frequency (carrier frequency or its integral multiple frequency) contained in the current or voltage of the DC power supply 1 can be suppressed. However, there is no particular description or suggestion regarding the mutual phase relationship between carriers among the inverter groups 2 ₁₁ , 2 ₁₂ , . . . , 2 _1m .

FIG. 11 is a block diagram showing a conventional control circuit for controlling the multi-winding AC motor drive system described above.
In FIG _{. 11} , 100 ₁ is an inverter control circuit for _electric motor M ₁ and consists of control units 100 ₁₁ , 100 ₁₂ , . ing. Although the illustration of the internal configuration is omitted, _100q is an inverter control circuit for the motor _Mq , which is configured in the same manner as the control circuit ₁₀₀₁ .

For example, in the control unit 100 ₁₁ for the inverter group 2 ₁₁ of the first group, a torque command obtained by multiplying the total torque to be generated by the q motors by 1/(m×q) is input to the current control unit 5 . When stopping some of the plurality of motors, the torque command is obtained by substituting the number of motors to be operated instead of q.
The current control unit 5 generates voltage commands 1 11 to ₁ 1n for the inverters INV 1 ₁₁ to INV 1 _{1n of} the inverter group 2 ₁₁ from the torque command, the current detection values i ₀₁₁₁ to i _011n and the position detection value θ.
The standardization unit 6 standardizes the voltage commands 1 ₁₁ to 1 1n using the DC input voltage V _d11 of the inverter group 2 ₁₁ to create the signal waves 1 ₁₁ to _{1 1n for} the inverters INV1 ₁₁ to INV1 _1n . are input to the comparators 10 in the PWM control units 11 ₁ to 11 _n of .

Further, the carrier wave phase reference signal generator 8 for the inverter group ₂₁₁ of the first group generates a phase reference signal of the carrier wave, and similarly, the carrier wave of each inverter is generated from the carrier wave phase setter 7 for the inverter group ₂₁₁ of the first group. to generate phases 1 ₁₁ to 1 _1n of .
The carrier wave generators 9 in the PWM control _units 11 ₁ to _{11 n} generate the _carrier waves 1 ₁₁ to _{1 1n (} These codes are not shown.The same applies hereinafter.) are created and input to the comparator 10 respectively. These comparators 10 compare the signal waves 1 ₁₁ to 1 _1n and the carrier waves 1 ₁₁ to 1 _1n respectively to generate on/off signals (PWM pulses) to be given to the switching elements of the inverters INV _{1 11} to INV 1 _1n . do.

Furthermore, the run/stop signal generator 20 outputs a run/stop command for each of the motors M ₁ to M _q based on stop motor information manually set by the operator according to the total torque required. . This run/stop command is defined, for example, as " ₁ " for run and " ₀ " for stop. 1” and OFF is defined as “0”.
If the logical product of the run/stop command and the output of the comparator 10 is calculated by the AND circuits 12 ₁ to 12 _n , all the switching elements of the inverter that drives the motor for which the stop command is set by the operator are turned off. , the operation of the motor can be stopped.

In the control circuit of FIG. 11, a carrier phase setter 7 and a carrier phase reference signal generator 8 are provided for each group. The carrier phases are determined by chance without affecting each other. The same applies to carrier wave phases between inverters that drive the motors.
In addition, Patent Document 1 discloses that by shifting the carrier wave phase of each phase in one group, it is possible to suppress the oscillation of the DC current and voltage, and also describes the following: It has also been pointed out that the interference between the coils increases the harmonic components of the winding current, resulting in an increase in the copper loss of the motor.

Japanese Patent Application Laid-Open No. 2009-268277 (claim 3, [0038], FIG. 5, etc.) JP 2012-257456 A (Claim 1, [0040], FIG. 5, etc.)

Next, in the drive system shown in FIG. 10, the motor (m=1, n=5) having only one group of five-phase windings is driven by five inverters, and the output shafts are connected to each other. Consider the case where 20 inverters drive 4 motors (q=4).
In this case, FIG. 12 and FIG. 13 show the results of frequency analysis of the total waveform of the output power of five inverters (for example, inverters INV1 ₁₁ to INV1 ₁₅ ) that drive each motor. The vertical and horizontal axes in these figures are on the same scale.
FIG. 12 shows the analysis result when the phase difference of the carrier wave when PWM-controlling the five inverters INV1 ₁₁ to INV1 ₁₅ is set to 180 deg/5 each as shown in FIG. 14, and FIG. This is the analysis result when all five units are in the same phase, and the operating conditions other than the phase are completely the same.

According to FIGS. 12 and 13, among the harmonic components, the harmonic components near the second harmonic (harmonic having a frequency _{of 2f c when} the carrier frequency is fc) which is the most problematic with the lowest frequency As a result, the components (1) and (2) are generated in FIG. 12, and the component (3) is generated in FIG.
Comparing FIG. 12 and FIG. 13, (1) and (2) in FIG. 12, in which the carrier wave of each inverter is provided with a phase difference of 180 deg/5, is better in (3) in FIG. However, the most problematic harmonic component near the second harmonic cannot be completely eliminated. For this reason, there is a problem that vibrations such as DC current having the same frequency as the harmonic component are generated, and mechanical vibration and noise having the same frequency are also generated in the electric motor.

12 and 13 show frequency analysis results for five inverters that drive one electric motor. When some of the motors are stopped and the remaining motors are driven, vibration and noise are generated due to harmonic components near the second harmonic.
For this reason, there is a problem that the cost of the entire system is increased due to the large amount of cost required for anti-vibration measures such as anti-vibration rubbers for suppressing vibration and anti-sound measures.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to appropriately adjust the carrier wave phase of each inverter even when a plurality of motors are connected and operated, or when only a part of them is operated, so that the second harmonic or It is an object of the present invention to provide a multi-winding AC motor drive system capable of reducing costs by suppressing vibration and noise due to harmonic components such as fourth and sixth harmonics.

In order to achieve the above object, the invention according to claim 1 provides q units (q: 2 or more) having m groups (m: natural number) of mutually insulated n-phase (n: an integer of 4 or more) stator windings. The output shafts of the multi-winding AC motors are connected to each other, and the AC output sides of (m×n) single-phase inverters fed from a DC power supply are connected to the stator windings, respectively, A multi-winding AC motor drive system that generates ON/OFF signals for semiconductor switching elements of the single-phase inverter by PWM control that compares a carrier wave and a signal wave,
In a multi-winding AC motor drive system having a function of driving only some of all the multi-winding AC motors,
One set is composed of q groups obtained by selecting one group from each of the m groups of stator windings of each motor, and m sets are obtained from (m x q) groups for all the motors. and the carrier phase for n single-phase inverters respectively feeding the n-phase stator windings forming one group of one motor in each set and one of the other motors in the same set. A carrier wave phase for n single-phase inverters that respectively feed n-phase stator windings that constitute two groups, and an integer multiple of 180 deg / (q × m × p) (p: natural number) for each group and different values from each other.

The invention according to claim 2 is characterized in that, in the multi-winding AC motor drive system according to claim 1, said p is 1 or 2.

The invention according to claim 3 is characterized in that in the multi-winding AC motor drive system according to claim 1 or 2, the operation of (q/2) motors out of all the motors is stopped.

The invention according to claim 4 is the multi-winding AC motor drive system according to claim 3, wherein when the q is 4 or more, the carrier wave phase difference of each group in one set is 360 deg/(q*m* p) is selected, and (q/2) motors having stator windings of these groups are stopped.

The invention according to claim 5 is the multi-winding AC motor drive system according to any one of claims 1 to 4, wherein when the m is 2 or more, the stator windings of one group of each motor The difference between the carrier wave phases for the n single-phase inverters feeding the motor and the carrier wave phases for the n single-phase inverters feeding the stator windings of the other groups of the same motor is 360deg/(q×m ×p).

According to the present invention, regardless of whether a plurality of motors are connected and operated or only a part of them is operated, by appropriately shifting the carrier wave phase of each inverter among a plurality of groups, Suppresses harmonic components such as the 2nd, 4th, and 6th harmonic components contained in the combined output power of multiple inverters to reduce current vibration, machine vibration, and noise, and provide anti-vibration Vibration countermeasures such as rubber and noise countermeasures can be simplified, and the cost required for these can be reduced.
In addition, there is no need to reset the carrier wave phase difference between the inverters when stopping the running motor or restarting the stopped motor. It is possible to change the number of motors in operation while continuing operation by simple control without taking measures to generate abnormal on/off signals to the switching elements.

1 is a block diagram showing a control circuit of a multi-winding AC motor drive system according to an embodiment of the present invention; FIG. Fig. 2 shows the carrier phase of each inverter driving four motors each having only a first group of windings, where the carrier of each inverter in the group has a predetermined phase difference; FIG. 4 is a diagram showing the carrier wave phase of each inverter driving four electric motors each having only a first group of windings, where the carrier waves of each inverter in the group are in phase; FIG. 3 is a diagram showing a frequency analysis result of total output power of each inverter corresponding to FIG. 2; FIG. 4 is a diagram showing a frequency analysis result of total output power of each inverter corresponding to FIG. 3; 3 is a diagram showing carrier wave phases of respective inverters showing a modification of FIG. 2; FIG. It is a figure which shows the carrier wave phase of each inverter which shows the modification of FIG. FIG. 4 is a diagram showing the carrier wave phase of each inverter driving two electric motors having first and second groups of windings, in the case where the carrier waves of each inverter in the group have a predetermined phase difference. FIG. 4 is a diagram showing carrier wave phases of inverters for driving two electric motors having first and second groups of windings, in the case where carrier waves of inverters in the group are in phase. 1 is a configuration diagram of a multi-winding AC motor drive system; FIG. FIG. 11 is a block diagram showing a prior art control circuit for the multi-winding AC motor drive system of FIG. 10; FIG. 5 is a diagram showing the result of frequency analysis of the total waveform of the output power of five inverters in the prior art. FIG. 5 is a diagram showing the result of frequency analysis of the total waveform of the output power of five inverters in the prior art. FIG. 4 is a waveform diagram when carrier waves of five inverters for driving one electric motor have a predetermined phase difference; FIG. 4 is a waveform diagram when carrier waves of five inverters for driving one electric motor are in phase;

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a control circuit of a multi-winding AC motor drive system according to an embodiment of the present invention.
Here, the overall configuration of the multi-winding AC motor drive system is the same as in FIG. That is, a driving device comprising inverter groups 2 ₁₁ to 2 _1m drives a motor M ₁ having (m×n) stator windings of m groups and n phases, and in the same way, inverter group 2 _q1. ∼ 2 _qm drives a motor M _q having (m×n) windings, and the output shafts M ₁ ' to M _q-1 ' are connected by these q driving devices. Each of the q motors M ₁ to M _q is driven.

Returning to FIG. 1, reference numeral 200 ₁ denotes an inverter control circuit for the electric motor M ₁ , and a control unit having the same configuration for controlling the inverter group (first group to m-th group) 2 ₁₁ to 2 _1m in FIG. 200 ₁₁ , 200 ₁₂ , . . . , 200 _{1 m} . 200 _q is an inverter control circuit for the motor _Mq , which is configured in the same manner as the inverter control circuit 200 ₁ for the motor _M1 .

1 differs from the control circuit of FIG. 11 as follows.
In FIG. 11, each group has a carrier phase setter 7 and carrier phase reference signal generator 8, whereas in FIG. 1, a single carrier phase setter 7A and carrier phase reference signal generator 8A are provided. ing. Then, from _the carrier wave phase _{setter 7A} , phases 1 ₁₁ to 1 _1n , . _, q _m1 to q _mn for the inverter group ₍ first group to m-th group) for driving the motor M _q . Further, the carrier wave phase reference signal generator 8A outputs a common phase reference signal for synchronizing the carrier wave phases for each inverter group (first group to m-th group) that drive the motors M ₁ to M _q . .
Other parts in FIG. 1 are the same as in FIG.

In the present invention, the motor has only a first group of windings consisting of five phases (n=5, m=1), each winding is fed from five single-phase two-level inverters, and the motor is The first embodiment is a case where four motors are connected and operated (q=4), and each motor has a first group and a second group of windings each having five phases (n=5, m=2), A second embodiment is a case where each winding is fed with power from five single-phase two-level inverters and two of the above motors are connected and operated (q=2).
In addition, in each embodiment, not only the mode in which all the motors are operated, but also the mode in which some of the motors are operated and the remaining motors are stopped will be considered.

First, in the first embodiment, power is supplied to the windings of each group (first group) of the four electric motors M ₁ to M ₄ with respect to the carrier wave phase for PWM-controlling the single-phase two-level inverters of each group. The phases of the carrier waves for the inverters are set so that each group has a difference of integral multiples of 180 deg/(q×m×p) (p: natural number) and has different values. For example, when p = 1, the phases of the carrier waves for the inverters feeding the windings of the first group of the four electric motors M ₁ to M ₄ have a difference of 180deg/4 = an integer multiple of 45deg. , and set to different values.
When each group is composed of a plurality of single-phase two-level inverters, the most problematic harmonic component is the second harmonic component as shown in FIGS. However, if the electrical or mechanical resonance point is near 4f _c (where f _c is the carrier frequency), it is possible to suppress harmonic components near the fourth harmonic by setting p=2. .

As a modification, for example, p. 177-p. 179, when single-phase three-level inverters are used as inverters in each group and these inverters are dipolar-modulated to make the carrier wave phases of the inverters in each group the same, a plurality of A frequency analysis of the total output power of the inverter shows that no component near the second harmonic is generated, and the component near the fourth harmonic becomes prominent.
In this case also, by setting p=2, it is possible to suppress components near the fourth harmonic and higher-order harmonic components.

Next, FIG. 2 shows the phases of the carrier waves for the inverters feeding the windings of the first group of the motors M ₁ to M ₄ , each having a difference of integral multiples of 180deg/4=45deg and different values from each other. 5 inverters INV1 ₁₁ to INV1 ₁₅ , INV2 ₁₁ to INV2 ₁₅ , and INV3 ₁₁ to INV3 ₁₅ feeding the windings of the first group of the motors M ₁ to M ₄ under the conditions set such that , INV4 ₁₁ to INV4 ₁₅ , the phase difference between the carriers is 180deg/5=36deg as shown in FIG. 4 shows the carrier phase of each inverter in the case of .
Here, one set is composed of four (q=4) groups consisting of the first group (m=1) of the stator windings of the four electric motors M ₁ to M ₄ . and

These carrier phases are generated by the operations of the carrier phase reference signal generator 8A and the carrier phase setter 7A in FIG.
For example, in the first group control unit 200 ₁₁ for the motor M ₁ , the phase reference signal output from the carrier wave phase reference signal generator 8A is used as a common reference signal, and in the example of FIG. ₁₁ to INV1 ₁₅ , the carrier wave phase setter 7A outputs phases 1 ₁₁ to _{1 15} having a phase difference of 36 degrees from each other, and in the _example of FIG. In addition, in the first group control unit 200 ₁₂ for the electric motor M ₂ , the phase reference signal is used as a common reference signal in _the same way as the control unit 200 ₁₁ , and in the example of FIG. ₁₅ , the carrier wave phase setter 7A outputs phases 2 ₁₁ to 2 ₁₅ having a phase difference of 36 degrees from each other, and in the example of FIG. 3, the phases 2 ₁₁ to 2 ₁₅ are all 0 degrees. Subsequently, for the motors _M3 and _M4 , similar processing is performed to set the carrier wave phase for each inverter.

FIG. 4 is the result of frequency analysis of the total waveform of the output power of each inverter when the carrier wave phase difference for each of the five inverters for driving one electric motor is 36 degrees, corresponding to FIG. , (a) shows the case in which all four motors are operated, and (b) shows the case in which two motors are operated (two motors are stopped).
Also, FIG. 5 shows the result of frequency analysis of the total waveform of the output power of each inverter when the carrier waves for each of the five inverters for driving one electric motor are in phase, corresponding to FIG. (a) shows the case where all four motors are operated, and (b) shows the case where two motors are operated (two motors are stopped).

4(a), 4(b), 5(a), and 5(b) according to this embodiment are compared with FIGS. 12 and 13 of the prior art, respectively. For example, some components near the 8th harmonic are included, but no components near the 2nd to 6th harmonics are included. In addition, in FIGS. 4(b) and 5(b), there are some components near the 4th harmonic and components near the 8th harmonic, but no components near the 2nd harmonic are included. do not have.
4 ₍ b) and 5(b), two motors are operated (two motors are stopped) _{. M 2} and M ₄ are stopped), or the motors M ₂ and M ₄ are operated (motors M ₁ and M ₃ are stopped). ₃ or between the first group for motors M ₂ and M ₄ is 360 deg/(q×m×p)=90 deg.

In general, when (q/2) motors are operated (stopped) in a system in which q motors are coupled, the carrier wave phase difference between groups is 360 deg/(q×m×p). Inverters for (q/2) motors should be selected. As described above, in FIG. 2 or FIG. 3, the mutual carrier wave phase difference in the first group is 360 deg/(q×m×p)=90 deg in the pair for the motors M ₁ and M ₃ and the motor A set for M ₂ and M ₄ . Therefore, by selecting one of the pairs and operating (stopping) the two motors, the second harmonic component can be removed, and the oscillation of the DC current having the same frequency as that of the harmonic component can be eliminated. mechanical vibration and noise can be reduced.

Next, FIGS. 6 and 7 show modifications of the first embodiment. That is, FIG. 6 corresponds to the case in which the carrier wave phase of each inverter for motor _M2 and the carrier wave phase of each inverter for motor _M4 in FIG. 2 are exchanged, and _FIG . and the carrier phase of each inverter for motor _M4 are exchanged.
In any case, the phases of the carrier waves for the inverters feeding the windings of the first group of the four electric motors M ₁ to M ₄ have an integral multiple difference of 180 deg/4=45 deg for each group. , and are set to have mutually different values.
In the example of FIG. 6, as in FIG. 2, each of the five inverters INV1 ₁₁ to INV1 ₁₅ , INV2 ₁₁ to INV2 ₁₅ , and INV3 ₁₁ to feed the first group windings of the motors M ₁ to M ₄ . The phase difference between the carriers of INV3 ₁₅ and INV4 ₁₁ to INV4 ₁₅ is set to 180 deg/5=36 deg, and in the example of FIG. 7, they are all set to the same phase as in FIG.

When four motors M ₁ to M ₄ are operated with the carrier wave phase of each inverter set as shown in Fig. 6, the result of frequency analysis of the total waveform of the output power of all inverters is the same as Fig. 4 (a). When two motors, for example, motors M ₁ and M ₃ or motors M ₂ and M ₄ are operated, the result of frequency analysis of the total waveform of the output power of all inverters is the same as in FIG. 4(b). Become.
Furthermore, when the carrier wave phase of each inverter is set as shown in FIG. 7 and four electric motors M ₁ to M ₄ are operated, the result of frequency analysis of the total waveform of the output power of all inverters is shown in FIG. When two motors, for example, motors _M1 and _M3 or motors _M2 and _M4 are operated, the results of frequency analysis of the total waveform of the output power of all inverters are shown in FIG. 5(b). become identical.

Next, a second embodiment of the invention will be described. In this second embodiment, the motor has first and second groups of stator windings each consisting of five phases (n=5, m=2), and each winding has five single-phase two-level inverters. , and the two motors are connected and operated (q=2).
8 and 9 show that the carrier wave phase difference of each inverter in the first group for the two motors M ₁ and M ₂ is 45 degrees, and the carrier wave phase difference of each inverter in the second group is 45 degrees. ₄₅ degrees, and the carrier wave phase difference of each inverter between the first _group and the second group for the motors M ₁ and M ₂ is 90 degrees. A set composed of two (q = 2) groups consisting of the first group of stator windings of the motors M ₁ and M ₂ is defined as the first group. A set composed of two (q=2) groups is referred to as a second set.

More specifically, FIG. 8 shows the carrier wave phase differences of five inverters INV1 ₁₁ to INV1 ₁₅ and INV2 ₁₁ to INV2 ₁₅ in the first and second groups for the motors M ₁ and M ₂ as shown in FIG. shows the carrier wave phase when 180 deg/5=36 deg, and FIG. 9 shows the carrier wave phase when all are in phase as in FIG.
These carrier phases are also generated by the operations of the carrier phase reference signal generator 8A and the carrier phase setter 7A in FIG.

Even when the windings of each motor have a plurality of groups as in the second embodiment (when m is a plurality of groups), the carrier wave phase difference for the inverter feeding each group of windings in the motor is set to 360 deg/ If two motors M ₁ and M ₂ are operated with (q×m×p)=90 deg, the second to sixth harmonic components can be removed in the same manner as in FIGS. 4(a) and 5(a). can be done. Therefore, it is possible to eliminate the vibration of the DC current having the same frequency as these harmonic components, thereby reducing the mechanical vibration and noise of the motor.

Here, not only when the two electric motors M ₁ and M ₂ are operated as described above, but also when one of the two electric motors is stopped and only one is operated, FIG. , similar to FIG. 5(b), the components near the second and sixth harmonics can be removed. At this time, the carrier wave phase of each inverter is left as it is, and the inverters that should be stopped are stopped by gate-off. By simply performing a simple control process, it is possible to realize operation by a part of the motors while suppressing vibrations. It is possible.
In addition, if the carrier wave phases for all inverters in each group are the same as shown in FIG. can be prevented.

In addition, the present invention is provided with a plurality of DC power sources, as in the case where power is supplied not only from the common DC power source 1 as shown in FIG. It can also be applied to drive devices.

1: DC power supply 2 ₁₁ to 2 _1m , 2 _q1 to 2 _qm : Inverter group 3: Position detector 5: Current control unit 6: Reference unit 7A: Carrier wave phase setter 8A: Carrier wave phase reference signal generator 9: Carrier wave Generator 10: Comparator 11 ₁ to 11 _n : PWM control section 12 ₁ to 12 _n : AND circuit 20: Run/stop signal generator 200 ₁ to 200 _q : Control circuit 200 ₁₁ to 200 _1m : Control section M ₁ to M _q : Multi-winding AC motor M ₁ ' to M _q-1 ': Output shaft INV1 ₁₁ to INV1 _1n , INV1 _m1 to INV1 _mn , INVq ₁₁ to INVq _1n , INVq _m1 to INVq _mn : Single-phase two-level inverter

Claims (5)

The output shafts of q (q: an even number of 2 or more) multi-winding AC motors having m groups (m: a natural number) of mutually insulated n-phase (n: an integer of 4 or more) stator windings are connected to each other. The stator winding is connected to the AC output sides of (m×n) single-phase inverters supplied with power from a DC power supply, and the single-phase inverters are controlled by PWM control that compares carrier waves and signal waves. A multi-winding AC motor drive system that generates on/off signals for the semiconductor switching elements of
In a multi-winding AC motor drive system having a function of driving only some of all the multi-winding AC motors,
One set is composed of q groups obtained by selecting one group from each of the m groups of stator windings of each motor, and m sets are obtained from (m x q) groups for all the motors. and the carrier phase for n single-phase inverters respectively feeding the n-phase stator windings forming one group of one motor in each set and one of the other motors in the same set. A carrier wave phase for n single-phase inverters that respectively feed n-phase stator windings that constitute two groups, and an integer multiple of 180 deg / (q × m × p) (p: natural number) for each group and different values from each other. In the multi-winding AC motor drive system according to claim 1,
A multi-winding AC motor drive system, wherein said p is 1 or 2. 3. In the multi-winding AC motor drive system according to claim 1 or 2,
A multi-winding AC motor drive system characterized by stopping operation of (q/2) motors out of all motors. In the multi-winding AC motor drive system according to claim 3,
When the q is 4 or more, select groups in which the carrier wave phase difference of each group in one set is 360 deg/(q×m×p), and have the stator windings of these groups (q/2 ) multi-winding AC motor drive system characterized by stopping the operation of the motors of the stage. In the multi-winding AC motor drive system according to any one of claims 1 to 4,
When m is 2 or more, the carrier wave phase for n single-phase inverters feeding one group of stator windings of each motor and n feeding the other group of stator windings of the same motor A multi-winding AC motor drive system characterized in that a difference from a carrier wave phase for a single-phase inverter is set to 360 deg/(qxmxp).

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