JP7613175B2 - Control device and method for multiple winding motor - Google Patents

Description

The present invention relates to a control device and a control method for a multiple winding PM motor.

Devices that drive a multiple-winding motor having multiple winding groups with different numbers of turns using multiple inverters connected to each winding group have been proposed in the past, for example as described in Patent Documents 1 to 4.

Patent No. 6160563 Patent No. 5428445 JP 2013-121222 A JP 2019-140725 A

Patent Document 1 describes a technology in which each winding group of a three-phase multiplex winding motor, which has multiple winding groups, is controlled and driven by an inverter. Since each winding is driven by a separate inverter, if an abnormality occurs in one inverter, the motor can be driven by the other inverter alone, which has the advantage of improving redundancy.

Furthermore, Patent Document 2 proposes a method of switching the windings to which current is applied so as to minimize system losses depending on the operating conditions, without using all of the multiple winding groups.

If the motor is a permanent magnet synchronous motor (PM motor) with a permanent magnet in the rotor, this method of switching the energized windings generates an induced voltage in the de-energized windings as the motor rotates. If the induced voltage becomes higher than the inverter's DC voltage, power is regenerated in the de-energized inverter, causing problems such as unstable operation and increased system losses.

To address this issue, Patent Document 2 provides a mechanism that can cut off the current path of unused winding groups. In addition, Patent Documents 3 and 4 also provide a mechanism for cutting off the current path in a similar manner to address the same issue, although they do not use a multiple winding configuration. However, because this current path cut-off mechanism requires ON/OFF switching, if a semiconductor element such as an IGBT is used for this cut-off mechanism, a driver circuit is required to operate the semiconductor element, and even if a mechanical device such as an electromagnetic contactor is used without a semiconductor element, there are disadvantages in that a power supply and wiring are required to operate the contacts.

In addition, Patent Document 2 describes how to determine which windings of a multiple winding motor are energized, but does not describe how torque is shared among the windings when current is applied to multiple windings, such as when all windings are energized.

The present invention aims to solve the above problems, and its purpose is to provide a control device and control method for a multiple winding motor that can suppress increases in system losses in the inverter and motor and expand the range in which it can be driven with high efficiency, with a simple configuration.

In order to solve the above problem, a control device for a multiplex winding motor according to claim 1 comprises:
A multiple winding motor has multiple winding groups with different numbers of turns, and multiple inverters are connected to each of the winding groups;
a current command generating unit which distributes a torque command for the motor to a distribution torque command that reduces losses in the motor and the plurality of inverters, the distribution torque command being distributed to each of the inverters, and generates a current command for each inverter based on each distribution torque command and rotation speed detection information of the motor;
a current control unit that calculates a voltage command for causing an output current of each of the inverters to follow the generated current command of each of the inverters;
and a PWM control unit which generates gate command signals for each inverter based on the voltage commands for each inverter calculated by the current control unit and a carrier signal having a different phase for each inverter, and outputs the gate command signals to each inverter.

The control device for a multiplex winding motor according to claim 2 comprises the steps of:
The current command generating unit is characterized in that it has: a limiter that limits a shared torque command to be shared by an inverter among the plurality of inverters, which is one in which an induced voltage generated in the winding during motor rotation is expected to exceed the DC voltage of the inverter DC section, to a positive value; and an adder that adds a deviation between the shared torque command limited by the limiter and the shared torque command before the limiter was imposed, to the shared torque command of an inverter other than the inverter on the side in which an induced voltage generated in the winding during motor rotation is expected to exceed the DC voltage of the inverter DC section.

The control device for a multiplex winding motor according to claim 3 includes the control device according to claim 1 or 2,
The present invention is characterized in that it comprises a regenerative current blocking diode for blocking the inflow of regenerative current, which is provided on the DC side of an inverter among the plurality of inverters in which the induced voltage generated in the winding during motor rotation is expected to exceed the DC voltage of the inverter DC section.

The control device for a multiplex winding motor according to claim 4 comprises the steps of:
The current command generating section is characterized in that it allocates to each of the torque commands in accordance with a turn ratio of each of the winding groups.

The control device for a multiplex winding motor according to claim 5 comprises the steps of:
The current command generating unit has a torque sharing table which lists the relationship between the motor rotation speed and each shared torque command for each magnitude of the torque command for the motor, and outputs a shared torque command which minimizes the sum of the motor loss and the inverter loss according to the torque command for the motor and the motor rotation speed.

The control device for a multiplex winding motor according to claim 6 includes the control device for a multiplex winding motor according to any one of claims 2 to 5,
The power supply control device further comprises an inverter stop request unit which, when the torque command allocated by the current command generation unit is zero, outputs a request to stop operation of the inverter on the side whose torque command is zero.

A method for controlling a multiple winding motor according to claim 7, comprising the steps of:
A method for controlling a multiple-winding motor having multiple winding groups with different numbers of turns, the multiple-winding motor having multiple inverters connected to each of the winding groups, comprising the steps of:
a torque sharing step in which a current command generating unit generates a torque command for the motor as a shared torque command that reduces losses in the motor and the inverters, and each of the inverters shares the shared torque command;
a current command generating step in which a current command generating unit generates a current command for each inverter based on each allocated torque command allocated in the torque allocation step and rotation speed detection information of the motor;
a current control step in which a current control unit calculates a voltage command for causing an output current of each of the inverters to follow the current command of each of the inverters generated in the current command generating step;
The method is characterized by comprising a step in which the PWM control unit generates a gate command signal for each inverter based on the voltage command for each inverter calculated by the current control step and a carrier signal having a different phase for each inverter, and outputs the gate command signal to each inverter.

The method for controlling a multiple winding motor according to claim 8 further comprises the steps of:
The current command generating step includes:
a limiting step of limiting, to a positive value, a torque command shared by an inverter of the plurality of inverters on a side where an induced voltage generated in the winding during motor rotation is expected to exceed a DC voltage of an inverter DC section;
a subtraction step of calculating a deviation between the shared torque command limited by the limiting step and the shared torque command before the limiting step;
an adding step of adding the deviation of the shared torque command obtained in the subtracting step to a shared torque command of an inverter other than the inverter on the side where an induced voltage generated in the winding during rotation of the motor is expected to exceed a DC voltage of an inverter DC section;
and generating a current command for each inverter based on the shared torque command limited in the limiting step, the shared torque command added in the adding step, and motor rotation speed detection information.

A method for controlling a multiplex winding motor according to claim 9 further comprises the steps of:
The present invention is characterized in that it comprises a regenerative current blocking diode for blocking the inflow of regenerative current, which is provided on the DC side of an inverter among the plurality of inverters in which the induced voltage generated in the winding during motor rotation is expected to exceed the DC voltage of the inverter DC section.

A method for controlling a multiplex winding motor according to claim 10 comprises the steps of:
The torque sharing step is characterized in that the torque sharing step shares each shared torque command in accordance with a turn ratio of each of the winding groups.

A method for controlling a multiplex winding motor according to claim 11 further comprises the steps of:
a torque sharing table which lists the relationship between the motor speed and each shared torque command for each magnitude of a torque command for the motor, and outputs a shared torque command which minimizes the sum of a motor loss and an inverter loss according to the torque command for the motor and the motor speed;
The torque sharing step is characterized in that a torque command to be shared by each inverter is output by referring to the torque sharing table based on a torque command for the motor and the rotation speed of the motor.

A method for controlling a multiplex winding motor according to claim 12 comprises the steps of:
The inverter stop request unit is characterized by comprising an inverter stop request step of outputting a request to stop operation of the inverter on the side whose shared torque command is zero when the shared torque command shared in the torque sharing step is zero.

(1) According to the invention as set forth in claims 1 to 12, in controlling a multiple winding motor, it is possible to efficiently share torque, suppress an increase in system loss in the motor and inverter, and expand the range in which the motor can be driven with high efficiency.
(2) According to the invention described in claims 2 and 8, the torque command shared by the inverter of one of the multiple inverters in which the induced voltage generated in the windings during motor rotation is expected to exceed the DC voltage of the inverter DC section is limited to a positive value, thereby preventing unnecessary regenerative torque from being generated.
(3) According to the inventions of claims 3 and 9, since a regenerative current blocking diode is provided, even if the voltage induced in the winding exceeds the DC voltage of the inverter DC section, it is possible to prevent power from being regenerated through the inverter connected to the winding with a simple configuration. This makes it possible to prevent the motor operation from becoming unstable and the system loss from increasing.

Moreover, the generated regenerative power can be regenerated via the inverter on the side where the regenerative current blocking diode is not provided.
(4) According to the invention as set forth in claims 5 and 11, the torque command is set so as to minimize system loss, so that operation can be performed with higher efficiency.
(5) According to the invention as set forth in claims 6 and 12, unnecessary operation of the inverter can be prevented, and efficiency is improved.

1 is a diagram showing the overall configuration of a control device for a multiplex winding motor according to an embodiment of the present invention; FIG. 2 is a configuration diagram of a current command generating unit according to the first embodiment of the present invention. FIG. 11 is a configuration diagram of a current command generating unit according to a second embodiment of the present invention. FIG. 11 is a diagram showing the configuration of a torque sharing table according to the second embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings, but the present invention is not limited to the following embodiment. Figure 1 shows the overall configuration of a control device for a multiple winding motor according to this embodiment.

In FIG. 1, 1 is a DC power supply unit, which may be a power supply obtained by rectifying a three-phase AC power supply. A capacitor 2 that smoothes the DC voltage is connected in parallel to the DC power supply unit 1. The anode of a regenerative current blocking diode 3P for preventing unintended regeneration is connected to the positive terminal of the DC power supply unit 1, and the cathode of a regenerative current blocking diode 3N for preventing unintended regeneration is connected to the negative terminal of the DC power supply unit 1.

An inverter 4-1, which is made up of semiconductor switching elements U1, V1, W1, X1, Y1, and Z1 connected in a three-phase bridge, is connected between the cathode of regenerative current blocking diode 3P and the anode of 3N.

An inverter 4-2, which has semiconductor switching elements U2, V2, W2, X2, Y2, and Z2 connected in a three-phase bridge, is connected between the common connection point of the positive terminal of the DC power supply unit 1 and the regenerative current blocking diode 3P, and the common connection point of the negative terminal of the DC power supply unit 1 and the regenerative current blocking diode 3N.

5 is a permanent magnet synchronous motor equipped with first and second winding groups 5-1 and 5-2, each of which is composed of a three-phase winding with a different neutral point.

The number of turns n1 of each winding that constitutes the first winding group 5-1 is set to be greater than the number of turns n2 of each winding that constitutes the second winding group 5-2 (n1>n2).

The AC output side of the inverter 4-1 is connected to the first winding group 5-1, and the AC output side of the inverter 4-2 is connected to the second winding group 5-2.

The regenerative current blocking diodes 3P, 3N prevent current from flowing into the inverter due to the induced voltage of the permanent magnet synchronous motor 5, and are provided on the DC side of an inverter, such as inverter 4-1, where the induced voltage in the winding group (5-1, 5-2) is expected to be higher than the DC voltage of the DC power supply unit 1 on the DC side of the inverter.

6 is a position detector that detects the rotor position of the permanent magnet synchronous motor 5 and outputs position information θ, and 7 is a differentiator that differentiates the position information θ and outputs speed ω (motor rotation speed detection information).

Reference numeral 8 denotes a current command generating unit which generates and outputs current commands id1 ^* , iq1 ^* , id2 ^* , iq2 ^* for the dq axes of each of the inverters 4-1, 4-2 from ^{a torque command Trq* that} is set for the motor 5, and which incorporates a torque sharing mechanism which shares the torque commands Trq1 ^* , Trq2 ^* of each inverter, and a mechanism which converts from a torque command to a current command in accordance with the shared torque command and the speed ω of the motor.

9 is a current sensor that measures the three-phase output currents iu1, iv1, and iw1 of inverter 4-1, and may detect only two of the three phases. 10 is a current sensor that measures the three-phase output currents iu2, iv2, and iw2 of inverter 4-2, and may detect only two of the three phases.

11 is a uvw/dq converter that performs dq conversion on the three-phase output currents iu1, iv1, and iw1 measured by the current sensor 9 based on the position information θ detected by the position detector 6, and outputs the d-axis current id1 and the q-axis current iq1.

12 is a uvw/dq converter that performs dq conversion on the three-phase output currents iu2, iv2, and iw2 measured by the current sensor 10 based on the position information θ detected by the position detector 6 to output the d-axis current id2 and the q-axis current iq2.

Reference numeral 13 denotes a current control unit which calculates a d-axis voltage command vd1* and a q-axis voltage command vq1 ^* based on the speed ω output from the differentiator 7 so as to cause the d-axis current id1 and the q-axis current iq1 to follow the current commands id1 ^* and iq1 ^* generated by the current command generating unit 8, and calculates and outputs a d-axis voltage command vd2 ^{* and} a q-axis voltage command vq2* based on the speed ω output from the differentiator 7 so as to cause the d-axis current id2 and the q-axis current iq2 to follow the current commands id2 ^* and iq2 ^* generated by the current command generating unit ⁸ .

A PI controller or the like is used to calculate the voltage command.

Reference numeral 14 denotes a dq/uvw converter which converts the dq axis voltage commands vd1 ^* , vq1 ^* on the inverter 4-1 side calculated by the current control unit 13 into three-phase axis (u, v, w phases) based on the position information θ detected by the position detector 6, and outputs three-phase voltage commands Vu1, Vv1, Vw1.

Reference numeral 15 denotes a dq/uvw converter which converts the dq axis voltage commands vd2 ^* , vq2 ^* on the inverter 4-2 side calculated by the current control unit 13 into three-phase axis (u, v, w phases) based on the position information θ detected by the position detector 6, and outputs three-phase voltage commands Vu2, Vv2, Vw2.

16 is a PWM control unit that normalizes the voltage commands Vu1, Vv1, and Vw1 converted by the dq/uvw converter 14 with the DC voltage Vdc detected by the voltage detector 18 of the capacitor 2, and outputs a gate command signal for the inverter 4-1 (INV1) by comparing the magnitude with the triangular wave carrier.

17 is a PWM control unit that normalizes the voltage commands Vu2, Vv2, and Vw2 converted by the dq/uvw converter 15 with the DC voltage Vdc detected by the voltage detector 18 of the capacitor 2 voltage, and outputs a gate command signal for the inverter 4-2 (INV2) by comparing the magnitude with the triangular wave carrier.

The phases of the triangular wave carriers of PWM control units 16 and 17 are shifted by 180° from each other.

In FIG. 1, the regenerative current blocking diodes 3P and 3N are provided on the DC side of the inverter 4-1, for example, where it is assumed that the induced voltage generated in the winding group (5-1, 5-2) will be higher than the DC voltage of the DC power supply unit 1 on the inverter DC side. However, the present invention is not limited to this, and can also be applied to a configuration in FIG. 1 in which the regenerative current blocking diodes 3P and 3N are not provided.

A current command generating unit 8 which distributes the torque command Trq ^* for the permanent magnet synchronous motor 5 among the distributed torque commands distributed by each of the inverters 4-1, 4-2 and generates current commands id1 ^* , iq1 ^* , id2 ^* , iq2 ^* for each of the inverters is configured as shown in the following examples 1 and 2.

Fig. 2 shows the configuration of the current command generating unit 8 of Fig. 1 according to the embodiment 1. In Fig. 2, reference numeral 21 denotes a gain multiplier that multiplies the torque command Trq ^* for the motor 5 by a conversion gain n1/(n1+n2) to obtain a torque command Trq1 ^* on the inverter 4-1 side, and reference numeral 22 denotes a gain multiplier that multiplies the torque command Trq* for the motor 5 by a conversion gain n2/(n1+n2 ⁾ to obtain a torque command Trq2 ^* on the inverter 4-2 side, and these gain multipliers 21 and 22 divide Trq ^* between Trq1 ^* and Trq2 ^* .

This torque sharing ratio is calculated from the following equations (1) and (2) using the number of turns n1 of each winding that constitutes the first winding group 5-1 and the number of turns n2 of each winding that constitutes the second winding group 5-2.

A limiter 23 limits the torque command Trq1 ^* (shared torque command) of the inverter 4-1 output from the gain multiplier 21 to a positive value, and outputs zero when Trq1 ^* is a negative value. This limiter 23 is provided on the torque command Trq1 ^* side of the inverter 4-1 to which regenerative current blocking diodes 3P, 3N are connected to the DC section of the inverter.

In addition, in the case of a configuration in which the regenerative current blocking diodes 3P, 3N are not provided, it is assumed that the induced voltage generated in the winding group (5-1, 5-2) during motor rotation will be higher than the DC voltage of the DC power supply unit 1 on the inverter DC side. For example, a limiter 23 is provided on the torque command Trq1 ^* side of the inverter 4-1.

A subtractor 24 subtracts the torque command value after passing through the limiter 23 from the torque command value (Trq1 ^* ) before passing through the limiter 23 .

An adder 25 adds the deviation output of the subtractor 24 to a torque command Trq2 ^* (shared torque command) of the inverter 4-2 output from the gain multiplier 22.

This adder 25 adds the torque command resulting from limiting Trq1 ^* by the limiter 23 to Trq2 ^* .

Reference numeral 26 denotes a current command conversion table which outputs current commands id1 ^* , iq1 ^* of the dq axes of the inverter 4-1 from the torque command after passing through the limiter 23 and the motor speed ω output from the differentiator 7 in FIG.

Reference numeral 27 denotes a current command conversion table which outputs current commands id2 ^* , iq2 ^* of the dq axes of the inverter 4-2 from the torque command output from the adder 25 and the motor speed ω output from the differentiator 7 in FIG.

These current command conversion tables 26 and 27 are generally two-dimensional tables of motor torque and speed, and output a current command that will drive the motor with the highest efficiency.

In the configurations shown in Figures 1 and 2, the number of turns n1 of each winding in winding group 5-1 of permanent magnet synchronous motor 5 and the number of turns n2 of each winding in winding group 5-2 are set so that n1 > n2. Since winding group 5-1 has a larger number of turns, it can output a large torque with a small current, but since the voltage is higher, it is necessary to pass a large field-weakening current during high-speed rotation so as not to exceed the inverter's output voltage.

On the other hand, the windings of winding group 5-2 cannot output torque unless a large current flows through them, but because the voltage is low, a small flux-weakening current is sufficient during high-speed rotation. Therefore, by switching between mode 1, which drives using only winding group 5-1, mode 2, which drives using only winding group 5-2, and mode 3, which drives using both windings, depending on the operating conditions of the motor (speed and torque), it is possible to operate in an operating mode with less system loss in the inverter and motor, making it possible to expand the range in which it can be driven with high efficiency.

However, when operating in mode 2, as the motor rotates, an induced voltage is generated in the windings of winding group 5-1 due to the interlinked magnetic flux from the rotor magnet. If the induced voltage generated in this unused winding group 5-1 becomes higher than the voltage (Vdc) of the DC section of the inverter, current flows into the inverter 4-1, causing regeneration. When this happens, unnecessary regenerative torque is generated in winding group 5-1, causing the motor to become unstable and increasing system losses.

Therefore, regenerative current blocking diodes 3P and 3N are added to the DC section of inverter 4-1. This makes it possible to prevent regeneration due to induced voltage. Since only diodes are added, no drive circuit or control wiring is required. However, with this method, when driving in mode 1 or mode 3, regenerative current cannot be passed if regenerative operation is desired. Therefore, a control configuration such as that shown in Figure 1 is used to regenerate the portion that cannot be regenerated by inverter 4-1 in inverter 4-2.

2, torque command Trq ^* for permanent magnet synchronous motor 5 is distributed to torque commands Trq1* and Trq2 ^* of inverters 4-1 and 4-2 in accordance with the ratio of the number of turns of the motor windings. The distribution ratio can be calculated from the following equations (1) and (2 ⁾ using the numbers of turns n1 and n2.

In the inverter 4-1 in which the regenerative current blocking diodes 3P, 3N are inserted (or in the inverter in which the regenerative current blocking diodes 3P, 3N are not inserted but in which the induced voltage generated in the winding during motor rotation is expected to be higher than the DC voltage of the DC power supply unit 1 on the inverter DC side), a limiter 23 is provided after Trq1 ^* to limit Trq1 ^* to a positive value, as shown in FIG. 2.

This prevents the inverter on the side where the limiter 23 is provided from performing a regenerative operation. When the torque command Trq1 ^* of the inverter 4-1 hits the limiter, the torque command Trq ^* that is originally intended to be output is not output, so the torque command Trq ^* can be output by adding the amount limited by the limiter 23 (the subtraction output of the subtractor 24) to the torque command Trq2 ^* of the inverter 4-2 in the adder 25. However, since the winding group 5-2 alone cannot output regenerative torque for two windings, regeneration is performed within the range of torque that can be output by the winding group 5-2.

In the case of two or more overlapping, the torque distribution is as shown in the following formula (3).

As described above, according to the present embodiment 1, the torque command shared by the inverter on the side where the regenerative current blocking diodes 3P, 3N are provided, or on the side where the regenerative current blocking diodes 3P, 3N are not inserted but the induced voltage generated in the winding during motor rotation is expected to be higher than the DC voltage of the DC power supply unit 1 on the inverter DC side, is limited to a positive value by the limiter 23, so that unnecessary generation of regenerative torque is avoided.

In addition, with the simple configuration of FIG. 2 or the configuration of FIG. 2 and regenerative current blocking diodes 3P, 3N, even if the induced voltage in the winding exceeds the DC voltage of the inverter DC section, it is possible to prevent power from being regenerated through the inverter connected to the winding. This makes it possible to prevent the operation of the permanent magnet synchronous motor 5 from becoming unstable and to prevent an increase in system loss.

The generated regenerative power can be regenerated through the inverter (4-2) on the side where the regenerative current blocking diodes 3P, 3N are not provided, or, if the regenerative current blocking diodes 3P, 3N are not provided, through an inverter other than the inverter on the side where the induced voltage generated in the winding during motor rotation is expected to be higher than the DC voltage of the DC power supply unit 1 on the inverter DC side.

By shifting the phase of the inverter carrier in a multiple winding motor, it is expected that the carrier ripple of the motor current can be cancelled out and iron loss can be reduced, but because the number of turns in each winding is different, even if the same current is passed through each winding, the effect of reducing the carrier ripple may not be very great. Therefore, in this embodiment 2, the torque (current) is shared by each winding so that system loss is minimized, including the proportion of the iron loss reduction effect due to the cancellation of this carrier ripple, the copper loss of the motor, and the loss of the inverter.

That is, the torque command for the permanent magnet synchronous motor 5 in FIG. 1 is divided into torque commands shared by each inverter, and the current command generation unit 8 that generates a current command for each inverter is configured as shown in FIG. 3.

In Fig. 3, the same parts as in Fig. 2 are denoted by the same reference numerals. The difference between Fig. 3 and Fig. 2 is that instead of the gain multipliers 21 and 22, a torque sharing table ³⁰ is provided which is a table showing the relationship between the motor speed ω and each shared torque command Trq1 ^* , Trq2 ^* for each magnitude of the torque command Trq ^* for the motor 5, and outputs shared torque commands Trq1 ^* , Trq2 ^* that minimize the sum of the motor loss and the inverter loss according to the torque command Trq* for the motor and the motor speed ω, and further includes comparators 31, 32 which output 1 when the torque command Trq1 ^* for the inverter 4-1 and the torque command Trq2 ^* for the inverter 4-2 output from the torque sharing table 30 are Trq1 ^* =0 and Trq2 ^* =0, and output 0 otherwise. The other parts are configured in the same way as in Fig. 2.

The "0" output by the comparator 31 indicates a request to operate the inverter 4-1, and the "1" indicates a request to stop the inverter 4-1. The "0" output by the comparator 32 indicates a request to operate the inverter 4-2, and the "1" indicates a request to stop the inverter 4-2. These comparators 31 and 32 constitute an inverter stop request section.

The torque sharing table 30 uses experiments, simulations, analysis, etc. to determine the torque sharing that minimizes the sum of the motor's copper loss, iron loss, and power converter loss for each torque, and the dq-axis current at that time for each rotation speed, and then creates a table, for example, as shown in Figure 4.

For example, although the iron loss of the motor cannot be taken into account, the torque and dq-axis currents that minimize the copper loss can be derived by solving the following optimization problem according to the operating conditions of each torque command and rotation speed.

Objective function (minimization):

Constraints:

Where:
Trq1 ^* =Pn{(Ld1-Lq1)×id1 ^* ×iq1+φd1×iq1 ^* +Md×iq1 ^* ×id2 ^* −Mq×id1 ^* ×iq2 ^* }
Trq2 ^* =Pn{(Ld2-Lq2)×id2 ^* ×iq2+φd2×iq2 ^* +Md×iq2 ^* ×id1 ^* −Mq×id2 ^* ×iq1 ^* }
vd1=R1×id1 ^* -ω×Lq1×iq1 ^* -ω×Mq×iq2 ^*
vq1=R1×iq1 ^* +ω×Ld1×id1 ^* +ω×Md×id2 ^* +ω×φd1
vd2=R2×id2 ^* -ω×Lq2×iq2 ^* -ω×Mq×iq1 ^*
vq2=R2×iq2 ^* +ω×Ld2×id2 ^* +ω×Md×id1 ^* +ω×φd2
Pn: number of pole pairs of the motor, R1: winding resistance of winding group 5-1, R2: winding resistance of winding group 5-2, Ld1, Lq1: dq-axis inductance of winding group 5-1, Ld2, Lq2: dq-axis inductance of winding group 5-2, φd1, φd2: flux linkage due to permanent magnets of winding groups 5-1, 5-2, Md, Mq: dq-axis mutual inductance of winding groups 5-1, 5-2, i1max, i2max: current limit value of winding groups 5-1, 5-2 (e.g., maximum motor current value), v1max, v2max: voltage limit value of winding groups 5-1, 5-2 (e.g., maximum inverter output voltage value).

When considering the iron loss of the permanent magnet synchronous motor 5, the above calculations cannot be used to calculate the minimum loss operating conditions, so analysis software such as JMAG (electromagnetic field analysis software) is used to find the operating conditions that minimize loss for each torque and rotation speed.

Furthermore, when Trq1 ^* or Trq2 ^* output from the torque sharing table 30 is zero, a request to stop operation is issued from comparators 31 and 32 to the inverters (4-1 and 4-2) whose torque commands are zero. The inverters that receive the request to stop operation stop operation according to the operation mode switching sequence.

The comparators 31 and 32 constituting the inverter stop request unit of the present invention may be provided on the output side of the gain multipliers 21 and 22 in FIG. 2 in the same manner as in FIG. 3.

As described above, according to this embodiment 2, in addition to the effects of the first embodiment, the following effects can be obtained.

In other words, the torque command is set to minimize system losses, allowing for more efficient operation.

It also prevents unnecessary operation of the inverter, improving efficiency.

1...DC power supply unit 2...Capacitor 3P, 3N...Regenerative current blocking diode 4-1, 4-2...Inverter 5...Permanent magnet synchronous motor 5-1...First winding group 5-2...Second winding group 6...Position detector 7...Differentiator 8...Current command generating unit 9, 10...Current sensor 11, 12...UVW/dq converter 13...Current control unit 14, 15...dq/UVW converter 16, 17...PWM control unit 18...Voltage detector 21, 22...Gain multiplier 23...Limiter 24...Subtractor 25...Adder 26, 27...Current command conversion table 30...Torque sharing table 31, 32...Comparator U1, V1, W1, X1, Y1, Z1, U2, V2, W2, X2, Y2, Z2...Semiconductor switching element

Claims (10)

A multiple winding motor has multiple winding groups with different numbers of turns, and multiple inverters are connected to each of the winding groups;
a current command generating unit which distributes a torque command for the motor to a distribution torque command that reduces losses in the motor and the plurality of inverters, the distribution torque command being distributed to each of the inverters, and generates a current command for each inverter based on each distribution torque command and rotation speed detection information of the motor;
a current control unit that calculates a voltage command for causing an output current of each of the inverters to follow the generated current command of each of the inverters;
a PWM control unit that generates a gate command signal for each inverter based on a voltage command for each inverter calculated by the current control unit and a carrier signal having a different phase for each inverter, and outputs the gate command signal to each inverter ;
A control device for a multiple-winding motor, characterized in that a regenerative current blocking diode for blocking the flow of regenerative current is provided on the DC side of only one of the multiple inverters in which an induced voltage generated in the winding during motor rotation is expected to exceed the DC voltage of the inverter DC section . 2. The control device for a multiple winding motor according to claim 1, wherein the current command generating unit includes: a limiter that limits a shared torque command to be shared by one of the plurality of inverters, the inverter being one on which an induced voltage generated in the windings during motor rotation is expected to exceed a DC voltage of the inverter DC section, to zero or a positive value; and an adder that adds a deviation between the shared torque command limited by the limiter and the shared torque command before the limiter was imposed, to a shared torque command of an inverter other than the inverter being one on which an induced voltage generated in the windings during motor rotation is expected to exceed a DC voltage of the inverter DC section. 3. The control device for a multiplex winding motor according to claim 1, wherein the current command generating section allocates a torque command to each of the plurality of winding groups in accordance with a turn ratio of each of the plurality of winding groups. 3. The control device for a multiple winding motor according to claim 1 or 2, wherein the current command generating unit has a torque sharing table which lists the relationship between the motor rotation speed and each shared torque command for each magnitude of a torque command for the motor, and outputs a shared torque command which minimizes the sum of a motor loss and an inverter loss in accordance with the torque command for the motor and the motor rotation speed. 5. The control device for a multiple winding motor according to claim 2, further comprising an inverter stop request unit which, when a torque command shared by the current command generation unit is zero, outputs a request to stop operation of an inverter on a side whose torque command is zero . A method for controlling a multiple-winding motor having multiple winding groups with different numbers of turns, the multiple-winding motor having multiple inverters respectively connected to each of the winding groups, comprising:
a torque sharing step in which a current command generating unit generates a torque command for the motor as a shared torque command that reduces losses in the motor and the plurality of inverters, and each inverter shares the shared torque command;
a current command generating step in which a current command generating unit generates a current command for each inverter based on each allocated torque command allocated in the torque allocation step and rotation speed detection information of the motor;
a current control step in which a current control unit calculates a voltage command for causing an output current of each of the inverters to follow the current command of each of the inverters generated in the current command generating step;
a step of a PWM control unit generating a gate command signal for each inverter based on the voltage command for each inverter calculated in the current control step and a carrier signal having a different phase for each inverter, and outputting the gate command signal to each inverter ;
A method for controlling a multiple-winding motor, characterized in that a regenerative current blocking diode for blocking the flow of regenerative current is provided on the DC side of only one of the multiple inverters in which the induced voltage generated in the windings during motor rotation is expected to exceed the DC voltage of the inverter DC section . The current command generating step includes:
a limiting step of limiting, to a zero or positive value, a torque command shared by an inverter of the plurality of inverters on a side where an induced voltage generated in the winding during motor rotation is expected to exceed a DC voltage of an inverter DC section;
a subtraction step of calculating a deviation between the shared torque command limited by the limiting step and the shared torque command before the limiting step;
an adding step of adding the deviation of the shared torque command obtained in the subtracting step to a shared torque command of an inverter other than the inverter on the side where an induced voltage generated in the winding during rotation of the motor is expected to exceed a DC voltage of a DC section of the inverter;
7. The method for controlling a multiple winding motor according to claim 6, further comprising a step of generating a current command for each inverter based on the shared torque command limited in said limiting step, the shared torque command added in said adding step , and detection information on the rotational speed of the motor. 8. The method for controlling a multiplex winding motor according to claim 6 , wherein the torque sharing step shares the torque commands with each other in accordance with a turn ratio of each of the winding groups. a torque sharing table which lists the relationship between the motor speed and each shared torque command for each magnitude of a torque command for the motor, and outputs a shared torque command which minimizes the sum of a motor loss and an inverter loss according to the torque command for the motor and the motor speed;
8. The method for controlling a multiple winding motor according to claim 6, wherein the torque sharing step outputs a torque command to be shared by each inverter, based on a torque command for the motor and a rotation speed of the motor, by referring to the torque sharing table. 10. The method for controlling a multiple winding motor according to claim 7, further comprising an inverter stop request step of outputting a request to stop operation of an inverter on a side whose shared torque command is zero when the shared torque command shared in the torque sharing step is zero.

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