Control device and method for multiple winding motor

Abstract

To provide a multiplex winding motor control device capable of controlling regenerative power with a simple configuration, without involving an unstable operation or a system loss increase.SOLUTION: A multiplex winding motor control device includes a plurality of inverters 4-1, 4-2 that are respectively connected to winding groups 5-1, 5-2 of a permanent magnet synchronization motor 5, the winding groups being different in the numbers of turns, regenerative current blocking diodes 3P, 3N that are disposed on the DC side of the inverter 4-1 in which an induction voltage generated in the windings when the motor is rotating is expected to become higher than a DC voltage (Vdc) of an inverter DC part, and a current command generation unit 8 that divides a torque command Trq* for the motor 5 into divided torque commands (Trq1*, Trq2*) respectively for the inverters 4-1, 4-2, according to, for example, the ratio of the numbers of turns of windings of the winding groups 5-1, 5-2, generates current commands for the respective inverters on the basis of the divided torque commands and motor rotation speed detection information ω, and outputs the current commands for the inverters.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device and a control method for a multiplex winding PM motor. [Background technology]

[0002] Conventionally, devices that drive a multiple-winding motor having multiple winding groups with different numbers of turns by multiple inverters respectively connected to each winding group have been proposed, for example, as described in Patent Documents 1 to 4. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6160563 [Patent Document 2] Patent No. 5428445 [Patent Document 3] JP 2013-121222 A [Patent Document 4] JP 2019-140725 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes a technology in which each winding group of a three-phase multiplex winding motor having multiple winding groups is controlled and driven by an inverter. Since each winding is driven by a separate inverter, even if an abnormality occurs in one inverter, the motor can be driven by the other inverter alone, which has the advantage of improving redundancy.

[0005] Furthermore, Patent Document 2 proposes a method of switching between windings to be energized so as to minimize system loss depending on the operating conditions, without using all of the multiple winding groups.

[0006] If the motor is a permanent magnet synchronous motor (PM motor) with a permanent magnet in the rotor, the method of switching the current-carrying 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 will be regenerated in the de-energized inverter, causing problems such as unstable operation and increased system losses.

[0007] To address this problem, Patent Document 2 provides a mechanism that can cut off the current path of unused winding groups. Although not a multiple winding configuration, Patent Documents 3 and 4 also provide a mechanism for cutting off the current path in a similar manner to address the same problem. 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 using a semiconductor element, there are disadvantages in that a power supply and wiring are required to operate the contacts.

[0008] Furthermore, although Patent Document 2 describes how to determine which windings of a multiple winding motor are energized, it is silent about the distribution of torque among the windings when energizing multiple windings, such as when all of the windings are energized.

[0009] The present invention is devised to solve the above-mentioned problems, and its object is to provide a control device and control method for a multiple winding motor that has a simple configuration and is capable of suppressing an increase in system loss in the inverter and motor and expanding the range in which it can be driven with high efficiency. [Means for solving the problem]

[0010] The control device for a multiplex winding motor according to claim 1 for solving the above problem 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; The power supply circuit is characterized by comprising a PWM control unit that generates gate command signals for each inverter based on the voltage commands for each inverter calculated by the current control unit and carrier signals having different phases for each inverter, and outputs the gate command signals to each inverter.

[0011] The control device for a multiplex winding motor according to claim 2 includes 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.

[0012] The control device for a multiplex winding motor according to claim 3 includes 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.

[0013] The control device for a multiplex winding motor according to claim 4 includes 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.

[0014] 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.

[0015] The control device for a multiplex winding motor according to claim 6 includes 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.

[0016] A method for controlling a multiplex 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.

[0017] The method for controlling a multiplex 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 a DC section of the inverter; 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.

[0018] The 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.

[0019] The method for controlling a multiplex winding motor according to claim 10 further 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.

[0020] The 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.

[0021] The method for controlling a multiplex winding motor according to claim 12 further 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. Effect of the Invention

[0022] (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 the inverter that is expected to have an induced voltage generated in the windings during motor rotation 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 recited in 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.

[0023] 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 the 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. [Brief description of the drawings]

[0024] [Figure 1] 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; [Diagram 2] FIG. 2 is a configuration diagram of a current command generating unit according to the first embodiment of the present invention. [Diagram 3] FIG. 11 is a configuration diagram of a current command generating unit according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a configuration diagram of a torque sharing table according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiment. Fig. 1 shows the overall configuration of a control device for a multiple winding motor according to this embodiment.

[0026] In Fig. 1, 1 denotes a DC power supply unit, which may be a power supply obtained by rectifying a three-phase AC power supply. A capacitor 2 for smoothing 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.

[0027] An inverter 4-1 in which semiconductor switching elements U1, V1, W1, X1, Y1, and Z1 are connected in a three-phase bridge configuration is connected between the cathode of regenerative current blocking diode 3P and the anode of 3N.

[0028] An inverter 4-2, in which semiconductor switching elements U2, V2, W2, X2, Y2, and Z2 are connected in a three-phase bridge configuration, 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.

[0029] Reference numeral 5 denotes a permanent magnet synchronous motor having first and second winding groups 5-1 and 5-2, each of which is composed of a three-phase winding having a different neutral point.

[0030] The number of turns n1 of each of the windings constituting the first winding group 5-1 is set to be larger than the number of turns n2 of each of the windings constituting the second winding group 5-2 (n1>n2).

[0031] The AC output side of the inverter 4-1 is connected to a first winding group 5-1, and the AC output side of the inverter 4-2 is connected to a second winding group 5-2.

[0032] 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 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 DC side of the inverter.

[0033] Reference numeral 6 denotes a position detector that detects the rotor position of the permanent magnet synchronous motor 5 and outputs position information θ, and reference numeral 7 denotes a differentiator that differentiates the position information θ and outputs speed ω (motor rotational speed detection information).

[0034] 8 is a torque command Trq for the motor 5 to be set * From the current command id1 of the dq axis of each inverter 4-1, 4-2 * ,iq1 * ,id2 * ,iq2 *The torque command Trq * is a torque command that reduces the loss of the motor 5 and the inverters 4-1 and 4-2, and the torque command Trq1 of each inverter is * , Trq2 * and a mechanism for converting a torque command into a current command in accordance with the torque command and the motor speed ω.

[0035] A current sensor 9 measures the three-phase output currents iu1, iv1, and iw1 of the inverter 4-1, and may detect only two of the three phases. A current sensor 10 measures the three-phase output currents iu2, iv2, and iw2 of the inverter 4-2, and may detect only two of the three phases.

[0036] Reference numeral 11 denotes a uvw / dq converter that performs dq conversion on the three-phase output currents iu1, iv1, iw1 measured by the current sensor 9 based on position information θ detected by the position detector 6, and outputs a d-axis current id1 and a q-axis current iq1.

[0037] Reference numeral 12 denotes a uvw / dq converter that performs dq conversion on the three-phase output currents iu2, iv2, iw2 measured by the current sensor 10 based on position information θ detected by the position detector 6, and outputs a d-axis current id2 and a q-axis current iq2.

[0038] 13 calculates the d-axis current id1 and the q-axis current iq1 based on the speed ω output from the differentiator 7, and outputs the current command id1 generated by the current command generator 8. * ,iq1 * The d-axis voltage command vd1 that follows * ,q-axis voltage command vq1 * Based on the speed ω output from the differentiator 7, the d-axis current id2 and the q-axis current iq2 are calculated based on the current command id2 generated by the current command generator 8. * ,iq2 * The d-axis voltage command vd2 that follows * ,q-axis voltage command vq2 * This is a current control unit that calculates and outputs the above.

[0039] A PI controller or the like is used to calculate the voltage command.

[0040] 14 is a voltage command vd1 of the dq axis on the inverter 4-1 side calculated by the current control unit 13. * ,vq1 * This is a dq / uvw converter that converts the above into three-phase axes (u, v, w phases) based on position information θ detected by a position detector 6 and outputs three-phase voltage commands Vu1, Vv1, Vw1.

[0041] 15 is a voltage command vd2 of the dq axis on the inverter 4-2 side calculated by the current control unit 13 * ,vq2 * This is a dq / uvw converter that converts the above into three-phase axes (u, v, w phases) based on position information θ detected by a position detector 6 and outputs three-phase voltage commands Vu2, Vv2, Vw2.

[0042] Reference numeral 16 denotes a PWM control unit which normalizes the voltage commands Vu1, Vv1, and Vw1 converted by the dq / uvw converter 14 with the DC voltage Vdc detected by a voltage detector 18 which detects the voltage 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.

[0043] Reference numeral 17 denotes a PWM control unit which normalizes the voltage commands Vu2, Vv2, and Vw2 converted by the dq / uvw converter 15 with a DC voltage Vdc detected by a voltage detector 18 which detects the voltage of the capacitor 2, and outputs a gate command signal for the inverter 4-2 (INV2) by comparing the magnitude with the triangular wave carrier.

[0044] The phases of the triangular wave carriers of the PWM control units 16 and 17 are shifted from each other by 180°.

[0045] In addition, in FIG. 1, the regenerative current blocking diodes 3P, 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 is also applicable to a configuration in which the regenerative current blocking diodes 3P, 3N in FIG. 1 are not provided.

[0046] Torque command Trq for the permanent magnet synchronous motor 5 * The inverters 4-1 and 4-2 are assigned the torque command, and the current command id1 of each inverter is * ,iq1 * ,id2 * ,iq2 * The current command generating unit 8 that generates the current command is configured as in the following embodiment 1 and embodiment 2. EXAMPLES

[0047] 2 shows the configuration of the current command generating unit 8 of FIG. 1 according to the first embodiment. In FIG. 2, 21 denotes a torque command Trq for the motor 5. * This is multiplied by the conversion gain n1 / (n1+n2) to obtain the torque command Trq1 on the inverter 4-1 side. * 22 is a gain multiplier for obtaining a torque command Trq * is multiplied by the conversion gain n2 / (n1+n2) to obtain the torque command Trq2 on the inverter 4-2 side. * These gain multipliers 21 and 22 are gain multipliers for obtaining Trq * Trq1 * and Trq2 * The responsibilities are shared among:

[0048] 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.

[0049]

number

[0050]

number

[0051] 23 is a torque command Trq1 of the inverter 4-1 output from the gain multiplier 21 * This is a limiter that limits the shared torque command to a positive value. * When the value of Trq1 is negative, zero is output. This limiter 23 is connected to the DC section of the inverter 4-1, which has regenerative current blocking diodes 3P and 3N connected to the DC section of the inverter. * It is provided on the side.

[0052] In addition, in the case where the regenerative current blocking diodes 3P and 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, the torque command Trq1 of the inverter 4-1 * A limiter 23 is provided on the side.

[0053] 24 is the torque command value before passing through the limiter 23 (Trq1 * ) is a subtractor that subtracts the torque command value after passing through the limiter 23.

[0054] 25 is a torque command Trq2 of the inverter 4-2 outputted from the gain multiplier 22 in response to the deviation output of the subtractor 24. * This is an adder that adds to the (shared torque command).

[0055] This adder 25 causes Trq1 * The torque command limited by limiter 23 is Trq2. * will be added to.

[0056] 26 is a current command id1 of the dq axis of the inverter 4-1 based on the torque command after passing through the limiter 23 and the motor speed ω output from the differentiator 7 in FIG. * ,iq1 *is a current command conversion table that outputs

[0057] 27 calculates the current command id2 of the dq axis 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. * ,iq2 * is a current command conversion table that outputs

[0058] These current command conversion tables 26 and 27 are generally two-dimensional tables of motor torque and speed, and output a current command that allows the motor to be driven most efficiently.

[0059] In the configurations of 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 the larger number of turns, it can output large torque with a small current, but since the voltage will be higher, it is necessary to flow a large field-weakening current during high-speed rotation, etc. so as not to exceed the inverter output voltage.

[0060] 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, etc. 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 motor's operating conditions (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.

[0061] 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 of 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.

[0062] 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 regeneration 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 by inverter 4-2.

[0063] Specifically, the torque command Trq for the permanent magnet synchronous motor 5 is calculated using the gain multipliers 21 and 22 in FIG. * The torque command Trq1 of inverter 4-1 and inverter 4-2 is set according to the ratio of the number of turns of the motor windings. * , Trq2 * The ratio of the shares can be calculated using the following formulas (1) and (2) using the number of turns n1 and n2.

[0064]

number

[0065]

number

[0066] As shown in FIG. 2, the inverter 4-1 in which the regenerative current blocking diodes 3P and 3N are inserted (or the inverter in which the regenerative current blocking diodes 3P and 3N are not inserted but the induced voltage generated in the winding during motor rotation is assumed to be higher than the DC voltage of the DC power supply unit 1 on the inverter DC side) has Trq1 * After that, Trq1 * A limiter 23 is provided to limit the value to a positive value.

[0067] This prevents the inverter on the side where the limiter 23 is provided from performing a regenerative operation. * When the limiter is reached, the torque command Trq that you want to output is * Since the output of the subtractor 24 is no longer output, the amount limited by the limiter 23 is added to the torque command Trq2 of the inverter 4-2 in the adder 25. * By adding to the torque command Trq * However, since the winding group 5-2 alone cannot output the regenerative torque equivalent to two windings, regeneration is limited to the range of torque that can be output by the winding group 5-2.

[0068] In addition, in the case of two or more multiplexing, the torque distribution is as shown in the following equation (3).

[0069]

number

[0070] As described above, according to the first embodiment, 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 where it is assumed that the induced voltage generated in the winding during motor rotation will 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, thereby preventing unnecessary generation of regenerative torque.

[0071] 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 via the inverter connected to the winding. This makes it possible to prevent the operation of permanent magnet synchronous motor 5 from becoming unstable and to prevent an increase in system loss.

[0072] In addition, the generated regenerative power can be regenerated via an 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, 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. EXAMPLES

[0073] 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 by shifting the phase of the inverter carrier, but since the number of turns of 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 second embodiment, the torque (current) is shared by each winding so that the 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.

[0074] That is, a torque command for permanent magnet synchronous motor 5 in FIG. 1 is divided into torque commands to be shared by each inverter, and current command generating unit 8 that generates a current command for each inverter is configured as shown in FIG.

[0075] 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, the torque command Trq * The motor rotation speed ω and each shared torque command Trq1 for each size * , Trq2 *The relationship between the torque command Trq and the motor is tabulated. * The shared torque command Trq1 that minimizes the sum of the motor loss and the inverter loss according to the motor speed ω. * , Trq2 * Further, the torque command Trq1 of the inverter 4-1 is output from the torque distribution table 30. * , Torque command Trq2 of inverter 4-2 * However, Trq1 * =0, Trq2 * 2. The difference is that comparators 31 and 32 are provided which output 1 when .DELTA..times ...

[0076] 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 unit.

[0077] The torque sharing table 30 is prepared by determining, for each rotation speed, 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, through experiments, simulations, analyses, etc., and then tabulating the torque sharing table 30 as shown in, for example, FIG. 4.

[0078] For example, although the iron loss of the motor cannot be taken into consideration, 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.

[0079] Objective function (to be minimized):

[0080]

number

[0081] Constraints:

[0082]

number

[0083] 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).

[0084] When taking into account the iron loss of the permanent magnet synchronous motor 5, the minimum-loss operating conditions cannot be calculated using the above calculations, 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.

[0085] In addition, Trq1 outputted from this torque distribution table 30 * or Trq2 * When the torque command is zero, comparators 31 and 32 issue a request to stop operation to the inverters (4-1 and 4-2) whose torque command is zero. The inverters that receive the request to stop operation stop operation according to the operation mode switching sequence.

[0086] Incidentally, 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.

[0087] As described above, according to the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

[0088] In other words, the torque command is set so as to minimize the system loss, thereby enabling more efficient operation.

[0089] Moreover, unnecessary operation of the inverter can be prevented, improving efficiency. [Explanation of symbols]

[0090] 1…DC power supply section 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 generation section 9,10...Current sensor 11,12...uvw / dq converter 13...Current control section 14,15...dq / uvw converter 16, 17…PWM control section 18…Voltage detector 21,22…Gain multiplier 23...Limiter 24…Subtractor 25…Adder 26, 27…Current command conversion table 30...Torque distribution table 31,32...Comparator U1, V1, W1, X1, Y1, Z1, U2, V2, W2, X2, Y2, Z2...semiconductor switching elements

Claims

1. 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 the 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. 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. 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.

4. 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. 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.

6. 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 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; 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 regenerative current flow is provided on the DC side of only one of the multiple 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.

7. 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. 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.

9. 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. 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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