Control device for AC rotating electrical machine

Abstract

Provided is a control device for an AC rotating electrical machine capable of suppressing a low-frequency component such as a current generated in a specific number of carrier signals. A control device for an AC rotating electrical machine changes one or both of a carrier cycle and an update cycle. The evaluation value calculated on the basis of the number of carrier signals and the update cycle, which are values obtained by dividing the AC cycle of the AC voltage command value by the carrier cycle, does not coincide with a specific value in which a component having a frequency lower than the AC cycle increases for at least one of the current, voltage, and power supplied to the plurality of windings.

Description

Technical Field

[0001] The present application relates to a control device for an AC rotating electric machine. Background Art

[0002] The control device of the AC rotating electric machine turns the switching element of the inverter on and off through PWM control (Pulse Width Modulation). It is a control method that is expected to reduce the loss of the inverter. The loss generated by the inverter includes switching loss and conduction loss. Switching loss is the loss generated by the on-off action of the switching element, and conduction loss is the loss generated when the current in the switching element is turned on. If the carrier frequency of the PWM control is reduced and the number of times the switching element is turned on and off is reduced, the switching loss can be reduced. However, if the carrier frequency is reduced too much, the control becomes unstable.

[0003] In order to reduce switching loss and ensure control stability, for example, in Patent Document 1, when the carrier signal number, which is the oscillation frequency of the carrier signal in the AC cycle, decreases, a synchronous PWM mode is switched to set the carrier frequency to a natural multiple of the AC frequency.

[0004] In Patent Document 2, control is performed to prevent a frequency that becomes extremely large depending on the power supply angular frequency, among electromagnetic noises caused by a switching frequency, from becoming equal to or greater than a predetermined value. Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent No. 4205157 Patent Document 2: Japanese Patent Application Publication No. 2013-198342 Summary of the invention Technical problem to be solved by the invention

[0006] In order to improve the output of the inverter and reduce the switching loss, the inventors controlled the AC voltage command value to an overmodulation state in which the vibration range exceeds the vibration range of the carrier signal. When the control was performed with a low number of carrier signals, when the number of carrier signals was a specific number, the low-frequency component in one or more of the current, voltage, and power increased. However, Patent Documents 1 and 2 do not disclose a solution to this phenomenon.

[0007] Therefore, an object of the present application is to provide a control device for an AC rotating electric machine that can suppress low-frequency components of current or the like generated at a specific carrier signal number. Technical solutions to technical problems

[0008] The control device of an AC rotating electric machine involved in the present application controls an AC rotating electric machine having a multi-phase winding via an inverter, and the control device of the AC rotating electric machine includes: a voltage command calculation unit, which calculates and updates the multi-phase AC voltage command value applied to the multi-phase winding in an update cycle; a PWM control unit that generates a carrier signal having an amplitude corresponding to the DC voltage supplied to the inverter and vibrating at a carrier period, and performs on-off control of a plurality of switching elements of the inverter based on a comparison result between the multi-phase AC voltage command values ​​and the carrier signal; and a period changing unit, the period changing unit changing one or both of the carrier period and the update period, The period changing unit changes one or both of the carrier period and the update period so that an evaluation value calculated based on a value obtained by dividing the AC period of the AC voltage command value by the carrier period, i.e., the number of carrier signals, and the update period does not coincide with a specific value that increases a component with a frequency lower than the AC period for one or more of the current, voltage and power supplied to the multiple windings. Effects of the Invention

[0009] According to the control device of the AC rotating motor of the present application, when the evaluation value calculated based on the number of carrier signals and the update period is consistent with a specific value, the low-frequency component increases. Therefore, by changing one or both of the carrier period and the update period so that the evaluation value is inconsistent with the specific value, the increase of low-frequency components such as current can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic configuration diagram of an AC rotating electric machine and a control device for the AC rotating electric machine according to the first embodiment. Figure 2 This is a schematic block diagram of a control device for an AC rotating electric machine according to the first embodiment. Figure 3 This is a hardware configuration diagram of the control device for the AC rotating electric machine according to the first embodiment. Figure 4 This is a timing chart for explaining a control behavior according to a comparative example of the first embodiment. Figure 5 This is a timing chart for explaining the control behavior when P=11 and n=1 according to the comparative example of the first embodiment. Figure 6 This is a timing chart for explaining the control behavior when P=11 and n=2 according to the comparative example of the first embodiment. Figure 7This is a diagram for explaining the magnitude of the offset component of the phase current corresponding to the change in the number P of carrier signals when n=1 and n=2 according to the comparative example of the first embodiment. Figure 8 This is a timing chart for explaining the control behavior when N=5 and n=1 according to the comparative example of the first embodiment. Fig. 9 This is a timing chart for explaining the control behavior when N=10 and n=2 according to the comparative example of the first embodiment. Fig.10 This is a diagram for explaining the magnitude of 1 / N corresponding to a change in the number of carrier signals P when n=1 according to the comparative example of the first embodiment. Fig.11 This is a timing chart for explaining the control behavior when N=7 and n=1 in the overmodulation state according to the comparative example of the first embodiment. Fig.12 This is a timing chart for explaining the control behavior when N=7 and n=1 in the normal modulation state according to the comparative example of the first embodiment. Fig.13 This is a diagram for explaining the region of the overmodulation state and the region of the normal modulation state according to the first embodiment. Fig.14 This is a diagram for explaining the setting of the carrier cycle based on the AC cycle involved in the first embodiment. Fig.15 This is a diagram for explaining the setting of the carrier cycle based on the AC cycle involved in the first embodiment. Fig.16 This is a diagram for explaining the random setting of the carrier period involved in Implementation Example 1. Fig.17 This is a diagram for explaining the setting of the update cycle based on the AC cycle according to the first embodiment. Fig.18 This is a diagram for explaining the setting of the update cycle based on the AC cycle according to the first embodiment. Fig.19 This is a diagram for explaining the setting of the carrier cycle when the synchronous PWM mode according to the first embodiment is executed. DETAILED DESCRIPTION

[0011] 1. Implementation Method 1 A control device 1 for an AC rotating electric machine according to Embodiment 1 (hereinafter simply referred to as a control device 1 ) will be described with reference to the drawings. Figure 1 It is a schematic configuration diagram of the AC rotating electric machine 5 and the control device 1 according to the present embodiment.

[0012] 1-1. AC rotating motor The AC rotating motor 5 has a multi-phase winding. The AC rotating motor 5 has a stator and a rotor, and the multi-phase winding is arranged on the stator. In the present embodiment, three-phase windings Cu, Cv, and Cw of U phase, V phase, and W phase are arranged. The three-phase windings Cu, Cv, and Cw are connected in star shape. In addition, the three-phase windings can also be connected in delta shape. The AC rotating motor 5 is configured as a permanent magnet type synchronous rotating motor with a permanent magnet provided on the rotor. For example, the permanent magnet can use rare earth magnets such as neodymium and samarium cobalt, but various permanent magnets such as cheap ferrite magnets can also be used. In addition, the AC rotating motor 5 can also be configured as an excitation winding type synchronous rotating machine with an excitation winding provided on the rotor. Alternatively, the AC rotating motor 5 can also be an induction rotating machine with a box-shaped conductor provided on the rotor.

[0013] The AC rotating electric machine 5 includes a rotation sensor 6 that outputs an electric signal corresponding to the rotation angle of the rotor. The rotation sensor 6 is a Hall element, an encoder, a resolver, etc. The output signal of the rotation sensor 6 is input to the control device 1.

[0014] 1-2. Inverter The inverter 20 is a power converter for performing power conversion between the DC power supply 10 and the three-phase winding, and has a plurality of switching elements. The inverter 20 is provided with three sets of series circuits (branches) corresponding to the windings of each phase of the three phases, and the series circuit is connected in series with a high potential side switching element 23H (upper arm) connected to the high potential side of the DC power supply 10, and a low potential side switching element 23L (lower arm) connected to the low potential side of the DC power supply 10. The inverter 20 has a total of six switching elements, namely three high potential side switching elements 23H and three low potential side switching elements 23L. Then, the connection point where the high potential side switching element 23H and the low potential side switching element 23L are connected in series is connected to the winding of the corresponding phase.

[0015] Specifically, in the series circuit of each phase, the collector terminal of the high potential side switch element 23H is connected to the high potential side wire 24, the emitter terminal of the high potential side switch element 23H is connected to the collector terminal of the low potential side switch element 23L, and the emitter terminal of the low potential side switch element 23L is connected to the low potential side wire 25. The connection point between the high potential side switch element 23H and the low potential side switch element 23L is connected to the winding of the corresponding phase.

[0016] The switching element uses an IGBT (Insulated Gate Bipolar Transistor) with a diode 22 connected in reverse parallel, or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) having the function of a diode connected in reverse parallel, etc. The gate terminal of each switching element is connected to the control device 1. Each switching element is turned on or off by a control signal output from the control device 1.

[0017] The smoothing capacitor 26 is connected between the high potential side wire 24 and the low potential side wire 25. A voltage sensor 27 is provided for detecting the DC voltage VDC supplied from the DC power supply 10 to the inverter 20. The voltage sensor 27 is connected between the high potential side wire 24 and the low potential side wire 25. The output signal of the voltage sensor 27 is input to the control device 1.

[0018] The current sensor 28 outputs an electrical signal corresponding to the current flowing through each phase winding. The current sensor 28 is provided on the wires connecting the series circuit of the switching element and each phase of the winding. The output signal of the current sensor 28 is input to the control device 1. In addition, the current sensor 28 can also be provided in the series circuit of each phase.

[0019] The DC power source 10 outputs a DC voltage VDC to the inverter 20. The DC power source 10 may be any device that outputs a DC voltage VDC, such as a battery, a DC-DC converter, a diode rectifier, or a PWM rectifier.

[0020] 1-3. Control device The control device 1 controls the AC rotating electric machine 5 via the inverter 20. Figure 2 As shown in FIG. 1 , the control device 1 includes a rotation detection unit 31, a voltage command calculation unit 32, a PWM control unit 33, and a period change unit 34. Each function of the control device 1 is implemented by a processing circuit provided in the control device 1. Specifically, the control device 1 is as follows. Figure 3 As shown, as a processing circuit, it includes an operation processing device 90 (computer) such as a CPU (Central Processing Unit), a storage device 91 for exchanging data with the operation processing device 90, an input circuit 92 for inputting external signals to the operation processing device 90, and an output circuit 93 for outputting signals from the operation processing device 90 to the outside.

[0021] The operation processing device 90 may include an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. In addition, the operation processing device 90 may include a plurality of operation processing devices of the same type or different types to share the execution of various processes. The storage device 91 may include a RAM (Random Access Memory) configured to read and write data from the operation processing device 90, a ROM (Read Only Memory) configured to read data from the operation processing device 90, and the like. The input circuit 92 is connected to various sensors and switches such as the voltage sensor 27, the current sensor 28, and the rotation sensor 6, and includes an A / D converter, etc., which inputs the output signals of these sensors and switches to the operation processing device 90. The output circuit 93 is connected to an electric load such as a gate drive circuit that drives the switching element to be turned on and off, and includes a drive circuit that outputs a control signal from the arithmetic processing device 90 to the electric load.

[0022] Furthermore, the control device 1 has Figure 2 The functions of the control units 31 to 34 are realized by the operation processing unit 90 executing the software (program) stored in the storage device 91 such as ROM, and cooperating with other hardware of the control device 1 such as the storage device 91, the input circuit 92, and the output circuit 93. In addition, the setting data such as the carrier period Tca and the update period Tup used by the control units 31 to 34 are stored in the storage device 91 such as ROM. The functions of the control device 1 are described in detail below.

[0023] <Rotation Detection Unit 31> The rotation detection unit 31 detects the magnetic pole position θ (rotation angle θ of the rotor) and the rotation angular velocity ω of the rotor under the electrical angle. In the present embodiment, the rotation detection unit 31 detects the magnetic pole position θ (rotation angle θ) and the rotation angular velocity ω of the rotor based on the output signal of the rotation sensor 6. In the present embodiment, the magnetic pole position is set in the direction of the N pole of the rotor. In addition, the rotation detection unit 31 can be configured to estimate the rotation angle (magnetic pole position) without using a rotation sensor based on current information obtained by superimposing harmonic components on the current command value (so-called sensorless method).

[0024] <Voltage Command Calculation Unit 32> The voltage command calculation unit 32 calculates and updates three-phase AC voltage command values ​​Vuo, Vvo, and Vwo applied to the three-phase winding at an update cycle Tup. The three-phase AC voltage command values ​​Vuo, Vvo, and Vwo vibrate at an AC cycle TAC. Each process of the voltage command calculation unit 32 is executed at each update cycle Tup.

[0025] Although the details will be described later, the update period Tup is set to a value obtained by dividing the carrier period Tca by n (n is a natural number) (Tup=Tca / n). In addition, the natural number is an integer greater than or equal to 1.

[0026] The voltage command calculation unit 32 calculates the three-phase AC voltage command value using the known vector control. The voltage command calculation unit 32 calculates the current command values ​​Ido and Iqo of the d-axis and the q-axis based on the torque command value To, the rotational angular velocity ω, and the DC voltage VDC detected by the voltage sensor 27. The voltage command calculation unit 32 converts the current detection values ​​Iur, Ivr, and Iwr of the three-phase winding detected by the current sensor 28 into the current detection values ​​Idr and Iqr of the d-axis and the q-axis based on the magnetic pole position θ. Then, the voltage command calculation unit 32 changes the voltage command values ​​Vdo and Vqo of the d-axis and the q-axis by PI control or the like so that the current detection values ​​Idr and Iqr of the d-axis and the q-axis are close to the current command values ​​Ido and Iqo of the d-axis and the q-axis, respectively. The voltage command calculation unit 32 converts the voltage command values ​​Vdo and Vqo of the d-axis and the q-axis based on the magnetic pole position θ into the three-phase AC voltage command values ​​Vuo, Vvo, and Vwo. In addition, the three-phase AC voltage command values ​​Vuo, Vvo, and Vwo may be subjected to known modulation for reducing the amplitude, such as two-phase modulation and third harmonic superposition. In this embodiment, a case where no modulation is applied will be described.

[0027] <PWM control unit 33> The PWM control unit 33 generates a carrier signal CA having an amplitude corresponding to the DC voltage VDC provided to the inverter 20 and vibrating at a carrier period Tca, and controls the on and off of multiple switching elements of the inverter 20 based on the comparison results between the three-phase AC voltage command values ​​Vuo, Vvo, and Vwo and the carrier signal CA.

[0028] like Figure 5 As shown, in this embodiment, the PWM control unit 33 generates a carrier signal CA having an amplitude of half the DC voltage VDC / 2 and vibrating at a carrier period Tca, with the vibration center value of the three-phase AC voltage command value (0 in this example) as the center. The carrier signal CA is set to a triangular wave.

[0029] For each phase, the voltage command calculation unit 32 turns on the switch signal when the AC voltage command value exceeds the carrier signal CA, and turns off the switch signal when the AC voltage command value is lower than the carrier signal. The switch signal is directly transmitted to the high-potential side switch element, and the switch signal obtained by inverting the switch signal is transmitted to the low-potential side switch element. Each switch signal is input to the gate terminal of each switch element of the inverter 20 via the gate drive circuit to turn each switch element on or off.

[0030] <Periodic Variation Section 34> The period changing unit 34 changes one or both of the carrier period Tca and the update period Tup. The changed carrier period Tca is transmitted to the PWM control unit 33 and reflected in the generation of the carrier signal CA. The changed update period Tup is transmitted to the voltage command calculation unit 32 and reflected in the calculation of the AC voltage command value.

[0031] <Increase in low-frequency components at a specific carrier signal number P> Next, the principle of periodic change is explained. Figure 4 Indicates the control behavior of a comparative example without periodic changes. The carrier period Tca is set to a constant value, and the update period Tup is set to the carrier period Tca (n=1). The rotational angular velocity ω is swept from low speed to high speed. At each rotational angular velocity ω, the vibration range of the AC voltage command value exceeds the vibration range of the carrier signal CA. In this case, the change in the value obtained by dividing the AC period TAC of the AC voltage command value by the carrier period Tca, that is, the change in the number of carrier signals P (=TAC / Tca), is shown. The AC period TAC is 2π / ω, which is inversely proportional to the rotational angular velocity ω, so as the rotational angular velocity ω increases, the number of carrier signals P decreases. In addition, the phase current flowing through each phase winding and the DC current IDC flowing between the DC power supply 10 and the inverter 20 are shown.

[0032] When the carrier signal number P is 13 and 11, pulsation is generated in the phase current and the DC current IDC.

[0033] Then, in Figure 5 In the case where the number of carrier signals P is 11, it indicates an amplified control behavior. Figure 5 In, with Figure 4 Similarly, the update period Tup is set to the carrier period Tca (n=1).

[0034] Figure 5The U-phase AC voltage command value Vuo is shown. The U-phase AC voltage command value Vuo is calculated and updated at each carrier cycle Tca. In addition, the figure shows the U-phase AC voltage command value Vuo when it is calculated continuously for easy understanding. The vibration range of the U-phase AC voltage command value Vuo exceeds the vibration range of the carrier signal CA, and becomes an overmodulation state.

[0035] As described above, the switching signal is generated based on the comparison result between the U-phase AC voltage command value Vuo updated for each update period Tup (carrier period Tca) and the carrier signal CA. Since it is in the overmodulation state, the number of on and off of the switching signal decreases.

[0036] The phase currents Iu, Iv, and Iw of each phase are offset, and thus the variation of the DC current IDC also increases.

[0037] Figure 6 Shown with Figure 5 The same operating conditions control actions. Figure 6 In, with Figure 4 and Figure 5 The update period Tup is set to half the carrier period Tca / 2 (n=2). Therefore, the update period Tup of the U-phase AC voltage command value Vuo is Figure 5 On the other hand, Figure 5 Likewise, since the overmodulation state is achieved, the number of on and off times of the switching signal decreases.

[0038] However, with Figure 5 There is no difference between the phase currents Iu, Iv, and Iw of each phase, and the variation of the DC current IDC does not increase.

[0039] Therefore, it can be seen that even if the number of carrier signals P is the same, the presence or absence of the offset variation of the phase current changes depending on the setting value of the update cycle Tup.

[0040] exist Figure 7 The upper part shows the magnitude of the offset component of the phase current in each carrier signal number P (=TAC / Tca) set by changing the AC period TAC (rotational angular velocity ω) when the carrier period Tca is set to a constant value, the update period Tup is set to the carrier period Tca (n=1), and the overmodulation state is in progress. Figure 7 The lower part indicates that the carrier period Tca is set to Figure 7 When the same value as the upper section is set, the update period Tup is set to half the carrier period Tca / 2 (n=2), and when the AC period TAC (rotational angular velocity ω) is changed, the size of the offset component of the phase current in each carrier signal number P (=TAC / Tca) is set.

[0041] exist Figure 7 In the upper section, the carrier signal number P is 13, 11.5, 11, 9.5, 8.5, 7, 6.5, 5.5, 5, 3.5, etc., and the offset component of the phase current increases. The carrier signal number P of 11 and 13 is Figure 4 The results when the rotation angular velocity ω is scanned are consistent.

[0042] exist Figure 7 In the lower section, the number of carrier signals P is 11.5, 9.5, 8.5, 6.5, 5.5, 3.5, etc., and the offset component of the phase current increases. Figure 7 Compared with the upper section, the offset component does not increase in P = 13, 11, 7, and 5, and the same tendency exists in other cases. For the voltage and power supplied to the three-phase winding other than the phase current, the amplitude of the low-frequency component increases relative to the AC frequency. Not limited to the offset component, the amplitude of the low-frequency component increases relative to the AC frequency for current, voltage, and power.

[0043] Here, assuming that the AC voltage command value of each phase is an ideal sine wave, the AC voltage command value Vo of each phase updated at the update period Tup is expressed by the following equation. [Mathematical formula 1]

[0044] Here, j is the number of the update cycle Tup, which increases one by one. δ is the phase difference between the phase of the trough of the carrier signal and the phase of the ideal triangle wave, Δ is the phase of each phase, Δ=0 for the U phase, Δ=2π / 3 for the V phase, and Δ=4π / 3 for the W phase. A is the amplitude of the AC voltage command value. K is an evaluation coefficient set to the minimum natural number that makes n×P×K a natural number.

[0045] From the first equation of equation (1), it can be seen that the natural number of the AC cycle TAC, that is, the K-fold value (2π×K), is divided by the smallest natural number, that is, n×P×K, and the sin value and the AC voltage command value Vo are calculated and updated during each division. In the overmodulation state, due to voltage saturation, the average value of the applied voltage in each division period after carrier comparison is at most +VDC / 2 or -VDC / 2. Therefore, when the number of divisions n×P×K is an odd number, the balance between the +VDC / 2 period and the -VDC / 2 period becomes unbalanced by the amount of one division period. Therefore, the total value of the applied voltage of each phase during the TAC×K period deviates from 0 by a maximum of ±VDC / 2×(TAC×K / (n×P×K)). Therefore, in the overmodulation state, as shown in the following equation, the average value Vave of the applied voltage of each phase deviates by a maximum of ±VDC / 2 / (n×P×K). Therefore, in the overmodulation state, when n×P×K is an odd number, the average value Vave of the applied voltage of each phase deviates from 0, and the amount of deviation of the average value Vave of the applied voltage of each phase is inversely proportional to n×P×K. [Mathematical formula 2]

[0046] On the other hand, even if n×P×K is an odd number, when it is a multiple of 3, the offsets of the applied voltages of the U phase, V phase, and W phase have a phase difference of 2π / 3, and are mutually cancelled by the three-phase balance, and the phase currents of the phases are not offset. Therefore, in the overmodulation state, when n×P×K is an odd number and is not a multiple of 3, an offset of the phase current and an increase in low-frequency components occur. In addition, the offset of the average value Vave of the applied voltage of each phase is inversely proportional to n×P×K. Therefore, when n×P×K becomes larger, the offset of the average value Vave of the applied voltage of each phase becomes smaller, and the offset of the phase current becomes smaller.

[0047] That is, in the overmodulation state, when the evaluation value N calculated according to n×P×K shown in the following formula is an odd number and is other than a multiple of 3, for one or more of the current, voltage and power supplied to the three-phase winding, the component with a frequency lower than the AC cycle TAC increases. [Mathematical formula 3] N=n×P×K…(3)

[0048] Here, as described above, the evaluation coefficient K is set to the minimum natural number that makes the evaluation value N (=n×P×K) a natural number. The larger n×P×K is, the smaller the increase in the low-frequency component is.

[0049] exist Figure 7In the case of the upper stage, since n=1, the offset component of the phase current increases relatively greatly for P=13, 11.5, 11, 9.5, 8.5, 7, 6.5, 5.5, 5, 3.5, respectively, K=1, 2, 1, 1, 2, 2, 1, 2, 2, 1, and N=13, 23, 11, 19, 17, 7, 13, 11, 5, 7. Therefore, no matter which evaluation value N is an odd number and a multiple of 3. Among them, K=1, N is small, and the increase in the offset component of P=13, 11, 7, 5 is relatively large. On the other hand, K=2, N is large, and the increase in the offset component of P=11.5, 9.5, 8.5, 6.5, 5.5, 3.5 becomes smaller. In addition to the carrier signal number P described here, there is also a carrier signal number P where the evaluation value N is an odd number and is a multiple of 3. However, since the increase in the offset component decreases as the evaluation value N increases, the description is omitted.

[0050] exist Figure 7 In the case of the lower section, since n=2, the offset component of the phase current increases relatively greatly at P=9.5, 8.5, 6.5, 5.5, and 3.5, respectively, K=1, 1, 1, 1, and N=19, 17, 13, 11, and 7. Therefore, all evaluation values ​​N are odd numbers and are other than multiples of 3. On the other hand, in the upper section of n=1, the increase in the offset component is large at P=13, 11, 7, and 5, which become even numbers such as N=26, 22, 14, and 10 in the lower section of n=2, so the offset component does not increase. In addition to the carrier signal number P described here, there is also a carrier signal number P whose evaluation value N is an odd number and is other than a multiple of 3, but since the increase in the offset component decreases as the evaluation value N increases, the description is omitted.

[0051] Figure 8 The control behavior is shown when the system is in a state of overmodulation close to the maximum, the number of carrier signals P is 5, the update period Tup is set to the carrier period Tca (n=1), the evaluation coefficient K is 1, and the evaluation value N (=n×P×K) is 5. The evaluation value N=5 is an odd number and is a multiple of 3. As described using formula (1), the AC period TAC×1 is divided by the evaluation value N=5, and the sin value and the AC voltage command value Vo are calculated for each period after the division. However, since the system is in a state of overmodulation close to the maximum, the average value of the applied voltage in each divided period is +VDC / 2 or -VDC / 2. Since the number of divisions is an odd number of 5, the balance between the +VDC / 2 period and the -VDC / 2 period becomes unbalanced by the amount of one divided period. Figure 8 In the example, the on period of the switching signal of the U phase is longer than the off period by one division period. As a result, the average value Vave of the applied voltage of the U phase is shifted to VDC / 2 / 5, and the average value of the phase current of the U phase winding is shifted to the positive side.

[0052] Fig. 9 The control behavior is shown when the overmodulation state is close to the maximum, the number of carrier signals P is 5, the update period Tup is set to half the period of the carrier period Tca / 2 (n=2), the evaluation coefficient K is 1, and the evaluation value N (=n×P×K) is 10. The evaluation value N=10 is an even number. As described using formula (1), the AC period TAC×1 is divided by the evaluation value N=10, and the sin value and the AC voltage command value Vo are calculated for each period after the division. However, since it is a state of overmodulation close to the maximum, the average value of the applied voltage in each divided period is +VDC / 2 or -VDC / 2. Since the number of divisions is an even number of 10, the period of +VDC / 2 is equal to the period of -VDC / 2. Fig. 9 In the embodiment, the on-period and off-period of the switching signal of the U phase are equal. As a result, the average value Vave of the applied voltage of the U phase does not deviate from 0, and the average value of the phase current of the U phase winding does not deviate.

[0053] Fig.10 Representation and Figure 7 However, the vertical axis is changed to 1 / N, which is related to the increase in the low-frequency component. Even if the evaluation value N is an odd number other than a multiple of 3, 1 / N becomes smaller when the evaluation value N is larger. 1 / N is roughly the same as Figure 7 The increase in the offset component of the upper segment is related to Fig.10 In , a threshold line of 1 / N equals 1 / B is drawn, but in order to effectively suppress the increase of low-frequency components, n and Tca can be set so that 1 / N does not become an evaluation value N larger than 1 / B. Fig.10 In the examples, when P = 13, 11, 7, 6.5, 5.5, 5, 3.5, etc., 1 / N is greater than 1 / B.

[0054] <Periodic Variation Section 34> Therefore, the period changing unit 34 changes one or both of the carrier period Tca and the update period Tup so that the evaluation value N calculated based on the carrier signal number P and the update period Tup does not coincide with a specific value that increases a component with a frequency lower than the AC period TAC for one or more of the current, voltage and power supplied to the three-phase winding. The above-mentioned carrier signal number P is a value obtained by dividing the AC period TAC of the AC voltage command value by the carrier period Tca.

[0055] According to this configuration, if the evaluation value N matches the specific value, the low-frequency component increases. Therefore, by changing one or both of the carrier period Tca and the update period Tup so that the evaluation value N does not match the specific value, the increase of the low-frequency component can be suppressed.

[0056] In this embodiment, the evaluation value N is a value calculated by the above formula (2), and the evaluation coefficient K is set to the minimum natural number that makes the evaluation value N a natural number. In addition, the specific value is set to the evaluation value N that is an odd number and a value other than a multiple of 3. One or more specific values ​​are set.

[0057] According to this structure, as described using equations (1) and (2), the K-fold value (2π×K) of the AC cycle TAC is divided by the evaluation value N (=n×P×K) which is the smallest natural number, and the AC voltage command value Vo of each phase is calculated and updated in each divided period. In the overmodulation state, due to voltage saturation, the average value of the applied voltage in each divided period after carrier comparison is at most +VDC / 2 or -VDC / 2. Therefore, when the evaluation value N is an odd number, the balance between the period of +VDC / 2 and the period of -VDC / 2 becomes unbalanced by the amount of one divided period. Therefore, the total value of the applied voltage of each phase during the TAC×K period deviates from 0 by a maximum of ±VDC / 2×(TAC×K / (n×P×K)). Therefore, the average value Vave of the applied voltage of each phase deviates by a maximum of ±VDC / 2 / (n×P×K). On the other hand, even if the evaluation value N is an odd number, when it is a multiple of 3, the offsets of the U phase, V phase, and W phase have a phase difference of 2π / 3, and the three-phase balance cancels each other, and the phase current of each phase does not shift. Therefore, when the evaluation value N is an odd number and is other than a multiple of 3, an increase in low-frequency components occurs. Therefore, by setting the specific value to the evaluation value N that is an odd number and a value other than a multiple of 3, one or both of the carrier period Tca and the update period Tup are changed so that the evaluation value N does not coincide with the specific value, thereby suppressing the increase in low-frequency components.

[0058] In the present embodiment, the specific value is set to an evaluation value N that is an odd number, a value other than a multiple of 3, and is equal to or smaller than the threshold value B.

[0059] According to this structure, if you use Figure 7 and Fig.10 As described above, if 1 / N is related to the increase in the low-frequency component, and 1 / N becomes greater than 1 / B, that is, the specific value is set to the evaluation value N where N is less than B, then the specific value is set to the evaluation value N that needs to suppress the increase in the low-frequency component, which can effectively suppress the increase in the low-frequency component. For example, B is set to 17.

[0060] For example, in Fig.10 In the example, among P=13, 11, 7, 6.5, 5.5, 5, 3.5, the specific values ​​are set to the corresponding N=13, 11, 7, 13, 11, 5, 7 respectively, that is, any one or more of N=13, 11, 7, 5.

[0061] The specific value may be set to an evaluation value N at which the increase in the low-frequency component becomes equal to or greater than a threshold value. The specific value may be set to an evaluation value N at which the increase in the low-frequency component becomes problematic.

[0062] In this embodiment, when the vibration range of the AC voltage command value Vo exceeds the vibration range of the carrier signal CA, the period changing unit 34 changes one or both of the carrier period Tca and the update period Tup so that the evaluation value N does not coincide with the specific value.

[0063] Fig.11 The control behavior in the overmodulation state under n=1, P=7 and N=7 is shown. In the overmodulation state, due to voltage saturation, the number of on-off times of the switch signal is less than the number of carrier signals, the continuous on period and the continuous off period become longer, and the on period and the off period of the switch signal are likely to be unbalanced. As a result, the phase current of each phase is likely to be offset.

[0064] on the other hand, Fig.12 The control behavior when n=1, P=7 and N=7 is not in an overmodulation state is shown. When it is not in an overmodulation state, the number of on-off times of the switch signal is not less than the number of carrier signals, the continuous on period and the continuous off period do not become longer, and it is difficult to produce an imbalance between the on period and the off period of the switch signal. As a result, it is difficult to produce an offset in the phase current of each phase. Therefore, in the case of an overmodulation state, by performing periodic changes, the increase of low-frequency components can be effectively suppressed. In addition, even in the case of not being in an overmodulation state, the periodic change unit 34 can change one or both of the carrier period Tca and the update period Tup so that the evaluation value N does not coincide with a specific value.

[0065] In the present embodiment, the period changing unit 34 determines whether the overmodulation state is present based on the ratio of the line voltage of the three-phase AC voltage command value to the DC voltage VDC, that is, the modulation rate M. The period changing unit 34 calculates the modulation rate M based on the d-axis and q-axis voltage command values ​​Vdo and Vqo and the DC voltage VDC using the following formula. [Formula 4]

[0066] In this embodiment, the period changing unit 34 determines that it is an overmodulation state when the modulation rate M is greater than 1, and determines that it is not an overmodulation state (normal modulation) when the modulation rate M is less than 1. In addition, the threshold value may be increased or decreased from 1 in consideration of the increase in the low-frequency component.

[0067] In addition, when the three-phase AC voltage command values ​​Vuo, Vvo, and Vwo are subjected to known modulation for reducing the amplitude, such as two-phase modulation and third harmonic superposition, the period changing unit 34 determines that it is in an overmodulation state when the modulation rate M is greater than 1.15, and determines that it is not in an overmodulation state when the modulation rate M is less than 1.15. In this case, the threshold value may also be increased or decreased from 1.15.

[0068] For example, the area of ​​overmodulation state and the area of ​​normal modulation state are as follows Fig.13 The overmodulation state exists in the region of high rotation angular velocity and high torque.

[0069] <Cycle variation based on AC cycle TAC> The period varying unit 34 varies one or both of the carrier period Tca and the update period Tup based on the AC period TAC so that the evaluation value N does not match the specific value. The AC frequency 1 / TAC or the rotational angular velocity ω may be used instead of the AC period TAC.

[0070] As shown in formula (3), the number of carrier signals P related to the evaluation value N changes with the AC cycle TAC. Therefore, based on the AC cycle TAC, it is possible to determine whether the evaluation value N is consistent with a specific value without changing one or both of the carrier cycle Tca and the update cycle Tup. Then, based on the AC cycle TAC, it is possible to change one or both of the carrier cycle Tca and the update cycle Tup with high accuracy so that the evaluation value N does not coincide with the specific value.

[0071] For example, the period changing unit 34 calculates and sets one or both of the set value of the carrier period Tca and the set value of the update period Tup corresponding to the current AC cycle TAC with reference to the mapping data in which the relationship between the AC cycle TAC and the set value of the carrier period Tca and the set value of the update period Tup when the evaluation value N does not coincide with the specific value is preset. The carrier frequency 1 / Tca may be set instead of the carrier period Tca.

[0072] <Case of Changing Carrier Cycle Tca> For example, if you use Fig.10 As described above, when the update period Tup is set to the carrier period Tca (n=1), for example, the evaluation values ​​N=13, 11, 7 corresponding to the number of carrier signals P=13, 11, 7 may be set as specific values. Fig.14 The horizontal axis is the AC frequency 1 / TAC, the vertical axis is the carrier frequency 1 / Tca, and an example of lines where the number of carrier signals P coincides with 13, 11, and 7 and the setting value of the carrier frequency 1 / Tca is shown.

[0073] like Fig.14As shown in FIG. 1 , the carrier frequency 1 / Tca changes based on the AC frequency 1 / TAC to avoid the carrier signal numbers P=13, 11, 7 corresponding to the specific values ​​13, 11, 7. Fig.14 The mapping data of the relationship between the setting value of the AC frequency 1 / TAC and the carrier frequency 1 / Tca is shown. Fig.14 In the example, the avoided carrier signal number P is set to 13, 11, and 7, but the value of the avoided carrier signal number P may also change according to the operating range of the AC frequency 1 / TAC, the setting range of the carrier frequency 1 / Tca, and the setting value of the update period Tup. The mapping data can be set so that the carrier frequency 1 / Tca avoids one or more carrier signal numbers P corresponding to one or more specific values, and can be set to Fig.14 Any value that is different.

[0074] In addition, if Fig.15 As shown, the period changing unit 34 may also set the carrier period Tca to a preset second carrier period Tca2 so that the evaluation value N does not coincide with the specific value when the evaluation value N is close to the specific value when the carrier period Tca is set to the preset first carrier period Tca1, and set the carrier period Tca to the first carrier period Tca1 outside the specific condition. Fig.15 In the case of , the update period Tup is set to the carrier period Tca (n=1), and the evaluation values ​​N=13, 11, 7 corresponding to the number of carrier signals P=13, 11, 7 are set as specific values. Fig.15 In the example, when the first carrier frequency 1 / Tca1 is set, in a specific region of the AC frequency 1 / TAC where the evaluation value N is close to the specific value 13, 11, the carrier frequency 1 / Tca is set to the second carrier frequency 1 / Tca2. Fig.15 In the example of FIG. 1 , the second carrier frequency 1 / Tca2 is set to a frequency lower than the first carrier frequency 1 / Tca1, but may be set to a frequency higher than the first carrier frequency 1 / Tca1.

[0075] Or, if Fig.16 As shown, the period changing unit 34 may randomly change the carrier period Tca under a specific condition that the evaluation value N is close to a specific value when the carrier period Tca is set to the preset first carrier period Tca1, and set the carrier period Tca to the first carrier period Tca1 except under the specific condition. Fig.16 In the example of , when the first carrier frequency 1 / Tca1 is set, the carrier frequency 1 / Tca changes randomly in a specific region of the AC frequency 1 / TAC where the evaluation value N is close to specific values ​​13 and 11. Fig.16In the example of , the carrier frequency 1 / Tca is randomly changed within a predetermined range with the first carrier frequency 1 / Tca1 as the center. By randomly changing, the period during which the evaluation value N coincides with the specific value can be greatly shortened.

[0076] exist Fig.16 In the example, specific values ​​13 and 11 are combined to set a specific area of ​​AC frequency 1 / TAC so that it changes randomly, but a specific area for specific value 13 and a specific area for specific value 11 can also be set separately so that it changes randomly in each specific area.

[0077] <Case of changing the update cycle Tup> For example, when the update period Tup is set to the carrier period Tca (n=1), the evaluation values ​​N=13, 11, 7 corresponding to the number of carrier signals P=13, 11, 7 are set to specific values, but when the update period Tup is set to the half period Tca / 2 of the carrier period (n=2), there is no specific value set. That is, the specific value changes according to the update period Tup. Fig.17 The horizontal axis is the AC frequency 1 / TAC, the vertical axis is the carrier frequency 1 / Tca, and an example of lines where the number of carrier signals P coincides with 13, 11, and 7 and the setting value of the carrier frequency 1 / Tca is shown.

[0078] like Fig.17 As shown in FIG. 1 , the carrier frequency 1 / Tca is set to a constant value. On the other hand, the update period Tup varies based on the carrier period Tca to avoid the specific values ​​13, 11, and 7 when n=1. Fig.17 As shown in FIG. 1 , the mapping data of the relationship between the AC frequency 1 / TAC and the setting value of the update cycle Tup(n) is preset. Fig.17 In the example, when n=1, the number of carrier signals P to be avoided is set to 13, 11, and 7, but the value of the number of carrier signals P to be avoided may also change according to the operating range of the AC frequency 1 / TAC, the setting range of the carrier frequency 1 / Tca, and the setting value of the update period Tup.

[0079] In addition, if Fig.18 As shown, the period changing unit 34 may also set the update period Tup to a preset second update period Tup2 so that the evaluation value N does not coincide with the specific value when the update period Tup is set to the preset first update period Tup1 under a specific condition that the evaluation value N is close to the specific value, and set the update period Tup to the first update period Tup1 except for the specific condition. Fig.18In the case of , the first update period Tup1 is set to the carrier period Tca (n=1), and the second update period Tup2 is set to the half period Tca / 2 of the carrier period (n=2). The specific values ​​of the first update period Tup1 are 13, 11, and 7, and there is no specific value of the second update period Tup2. In the case of the same specific value as the first update period Tup1, the specific value can be avoided by changing to the second update period Tup2. Fig.18 In the example of FIG. 1 , when the first update cycle Tup1 is set, in a specific region of the AC frequency 1 / TAC where the evaluation value N is close to specific values ​​13 and 11, the update cycle Tup is set to the second update cycle Tup2 .

[0080] Alternatively, the period changing unit 34 may simultaneously change the carrier period Tca and the update period Tup based on the AC period TAC so that the evaluation value N does not coincide with a specific value.

[0081] 2. Implementation Method 2 Next, the AC rotating electric machine 5 and the control device 1 according to Embodiment 2 are described. The description of the same components as those in Embodiment 1 is omitted. The basic structure of the AC rotating electric machine 5 and the control device 1 according to this embodiment is the same as that of Embodiment 1, but the PWM control unit 33 is configured to execute the synchronous PWM mode, and accordingly, the processing of the period changing unit 34 is different.

[0082] In the present embodiment, the PWM control unit 33 executes a synchronous PWM mode in which the carrier period Tca is changed in proportion to the AC period TAC. In the synchronous PWM mode, the carrier frequency 1 / Tca is set to a value obtained by multiplying the AC frequency 1 / TAC by a natural number proportionality coefficient Kp. In addition, the PWM control unit 33 can also execute an asynchronous PWM mode in which the carrier period Tca is changed in a non-proportional manner to the AC period TAC. For example, the PWM control unit 33 executes the asynchronous PWM mode when the rotation angular velocity ω is less than the switching value, and executes the synchronous PWM mode when the rotation angular velocity ω is greater than the switching value.

[0083] When executing the synchronous PWM mode, the period changing unit 34 sets the proportionality coefficient Kp so that the evaluation value N does not coincide with a specific value, and changes the carrier period Tca in proportion to the AC period TAC using the set proportionality coefficient Kp.

[0084] For example, Fig.19 As shown, when the update period Tup is set to the carrier period Tca (n=1), for example, the evaluation values ​​N=13, 11, 7 corresponding to the number of carrier signals P=13, 11, 7 may be set as specific values. Fig.19In the example, in the area of ​​AC frequency 1 / TAC (rotational angular velocity ω) executing the synchronous PWM mode, the evaluation value N is not close to the specific values ​​13, 11, 7, and in the area of ​​AC frequency 1 / TAC executing the asynchronous PWM mode, the evaluation value N is close to the specific values ​​13, 11, 7.

[0085] The proportionality coefficient Kp changes based on the AC frequency 1 / TAC so as to avoid the number of carrier signals P=13, 11, 7 corresponding to the specific values ​​13, 11, 7. That is, the proportionality coefficient Kp is set to a natural number other than the specific values ​​13, 11, 7. Fig.19 In the example, the proportional coefficient Kp is set to 12.9. Fig.19 As shown in FIG. 1 , map data of the relationship between the AC frequency 1 / TAC and the set value of the proportionality coefficient Kp is set in advance. In this way, by setting the proportionality coefficient Kp so that the evaluation value N does not coincide with a specific value, it is possible to suppress the increase of low-frequency components.

[0086] Furthermore, in the execution region of the synchronous PWM mode, when the evaluation value N coincides with the specific value, the processing of the first embodiment may be executed.

[0087] <Other Implementation Methods> (1) In the above embodiments, a three-phase winding is used as an example. However, if the number of winding phases Q is multi-phase, it can also be set to any number such as 2 or 4. In this case, the specific value can be set to an evaluation value N that is an odd number and a value other than a multiple of the number of phases Q.

[0088] (2) In the above embodiments, a case where one set of three-phase windings is provided is described as an example. However, multiple sets of multi-phase windings may be provided. In this case, the processing of the above embodiments may be performed on the multiple windings of each set.

[0089] <Summary of each aspect of this application> Hereinafter, each aspect of the present application will be collectively described as a supplementary note.

[0090] (Supplementary Note 1) A control device for an AC rotating electric machine, The control device for an AC rotating electric machine controls an AC rotating electric machine having a multi-phase winding via an inverter, and includes: a voltage command calculation unit, which calculates and updates the multi-phase AC voltage command value applied to the multi-phase winding in an update cycle; a PWM control unit that generates a carrier signal having an amplitude corresponding to the DC voltage supplied to the inverter and vibrating at a carrier period, and performs on-off control of a plurality of switching elements of the inverter based on a comparison result between the multi-phase AC voltage command values ​​and the carrier signal; and a period changing unit, the period changing unit changing one or both of the carrier period and the update period, The period changing unit changes one or both of the carrier period and the update period so that an evaluation value calculated based on a value obtained by dividing the AC period of the AC voltage command value by the carrier period, i.e., the number of carrier signals, and the update period does not coincide with a specific value that increases a component with a frequency lower than the AC period for one or more of the current, voltage and power supplied to the multiple windings.

[0091] (Supplementary Note 2) The control device for the AC rotating electric machine as described in Supplementary Note 1, The period changing unit changes one or both of the carrier period and the update period so that the evaluation value does not coincide with the specific value when the vibration range of the AC voltage command value exceeds the vibration range of the carrier signal in an overmodulated state.

[0092] (Supplement 3) A control device for an AC rotating electric machine as described in Supplement 1 or 2, The update period is set to a value obtained by dividing the carrier period by n (n is a natural number).

[0093] (Supplement 4) The control device for the AC rotating electric machine as described in Supplement 3, The number of phases of the multi-phase winding is Q, When the evaluation value is N, the number of carrier signals is P, and the evaluation coefficient set as a natural number is K, the evaluation value is obtained by the formula N=n×P×K The calculated value, the evaluation coefficient is set to a natural number that makes the evaluation value the smallest natural number, The specific value is set to the evaluation value which is an odd number and a value other than a multiple of Q.

[0094] (Supplementary Note 5) The control device for the AC rotating electric machine as described in Supplementary Note 4, The specific value is set to the evaluation value which is an odd number, a value other than a multiple of Q, and is equal to or less than a threshold value.

[0095] (Supplementary Note 6) A control device for an AC rotating electrical machine as described in any one of Supplementary Notes 1 to 5, The period changing unit changes one or both of the carrier period and the update period based on the AC period so that the evaluation value does not coincide with the specific value.

[0096] (Supplementary Note 7) The control device for the AC rotating electric machine as described in Supplementary Note 6, The period change unit calculates and sets one or both of the setting value of the carrier period and the setting value of the update period corresponding to the current AC cycle, with reference to mapping data that pre-sets the relationship between the AC cycle and the setting value of the carrier period and the setting value of the update period when the evaluation value is inconsistent with the specific value.

[0097] (Supplementary Note 8) A control device for an AC rotating electrical machine as described in any one of Supplementary Notes 1 to 5, Under the specific condition that the evaluation value is close to the specific value when the carrier period is set to a pre-set first carrier period, the period changing unit sets the carrier period to a pre-set second carrier period so that the evaluation value is inconsistent with the specific value, and sets the carrier period to the first carrier period except for the specific condition.

[0098] (Supplementary Note 9) A control device for an AC rotating electrical machine as described in any one of Supplementary Notes 1 to 5, The period changing unit randomly changes the carrier period under a specific condition that the evaluation value approaches the specific value when the carrier period is set to a preset first carrier period, and sets the carrier period to the first carrier period except for the specific condition.

[0099] (Supplement 10) The control device for an AC rotating electric machine according to any one of Supplements 1 to 7, The PWM control unit executes a synchronous PWM mode in which the carrier cycle is changed in proportion to the AC cycle. The period changing unit sets a proportionality coefficient so that the evaluation value does not coincide with the specific value when the synchronous PWM mode is executed, and changes the carrier period in proportion to the AC period using the set proportionality coefficient.

[0100] (Supplementary Note 11) A control device for an AC rotating electrical machine as described in any one of Supplementary Notes 1 to 5, Under the specific condition that the evaluation value is close to the specific value when the update period is set to a predetermined first update period, the period changing unit sets the update period to a predetermined second update period so that the evaluation value is inconsistent with the specific value, and sets the update period to the first update period except for the specific condition.

[0101] Although the present application describes various exemplary embodiments and examples, the various features, methods and functions described in one or more embodiments are not limited to the application of specific embodiments and can be applied to the embodiments individually or in various combinations. Therefore, it can be considered that countless variations that are not illustrated are also included in the technical scope disclosed in the present application specification. For example, it is set to include the case where at least one structural element is deformed, added or omitted, and the case where at least one structural element is extracted and combined with the structural elements of other embodiments. Description of symbols

[0102] 1 AC rotating electric machine control device, 5 AC rotating electric machine, 20 inverter, 32 voltage command calculation unit, 33 PWM control unit, 34 period change unit, B threshold value, CA carrier signal, K evaluation coefficient, N evaluation value, P number of carrier signals, Q number of phases, TAC AC period, Tca carrier period, Tca1 first carrier period, Tca2 second carrier period, Tup update period, Tup1 first update period, Tup2 second update period.

Claims

1. A control device for an AC rotating electric machine, The control device for an AC rotating electric machine controls an AC rotating electric machine having a multi-phase winding via an inverter, and is characterized in that: include: a voltage command calculation unit, which calculates and updates the multi-phase AC voltage command value applied to the multi-phase winding in an update cycle; a PWM control unit that generates a carrier signal having an amplitude corresponding to the DC voltage supplied to the inverter and vibrating at a carrier period, and performs on-off control of a plurality of switching elements of the inverter based on a comparison result between the multi-phase AC voltage command values ​​and the carrier signal; and a period changing unit, the period changing unit changing one or both of the carrier period and the update period, The period changing unit changes one or both of the carrier period and the update period so that an evaluation value calculated based on a value obtained by dividing the AC period of the AC voltage command value by the carrier period, i.e., the number of carrier signals, and the update period does not coincide with a specific value that increases a component with a frequency lower than the AC period for one or more of the current, voltage and power supplied to the multiple windings.

2. The control device for an AC rotating electrical machine according to claim 1, characterized in that: The period changing unit changes one or both of the carrier period and the update period so that the evaluation value does not coincide with the specific value when the vibration range of the AC voltage command value exceeds the vibration range of the carrier signal in an overmodulated state.

3. The control device for an AC rotating electrical machine according to claim 1 or 2, characterized in that: The update period is set to a value obtained by dividing the carrier period by n (n is a natural number).

4. The control device for an AC rotating electrical machine according to claim 3, characterized in that: The number of phases of the multi-phase winding is Q, When the evaluation value is N, the number of carrier signals is P, and the evaluation coefficient set as a natural number is K, the evaluation value is obtained by the formula N=n×P×K The calculated value, the evaluation coefficient is set to a natural number that makes the evaluation value the smallest natural number, The specific value is set to the evaluation value which is an odd number and a value other than a multiple of Q.

5. The control device for an AC rotating electrical machine according to claim 4, characterized in that: The specific value is set to the evaluation value which is an odd number, a value other than a multiple of Q, and is equal to or less than a threshold value.

6. The control device for an AC rotating electrical machine according to any one of claims 1 to 5, characterized in that: The period changing unit changes one or both of the carrier period and the update period based on the AC period so that the evaluation value does not coincide with the specific value.

7. The control device for an AC rotating electrical machine according to claim 6, characterized in that: The period change unit calculates and sets one or both of the setting value of the carrier period and the setting value of the update period corresponding to the current AC cycle, with reference to mapping data that pre-sets the relationship between the AC cycle and the setting value of the carrier period and the setting value of the update period when the evaluation value is inconsistent with the specific value.

8. The control device for an AC rotating electrical machine according to any one of claims 1 to 5, characterized in that: Under the specific condition that the evaluation value is close to the specific value when the carrier period is set to a pre-set first carrier period, the period changing unit sets the carrier period to a pre-set second carrier period so that the evaluation value is inconsistent with the specific value, and sets the carrier period to the first carrier period except for the specific condition.

9. The control device for an AC rotating electrical machine according to any one of claims 1 to 5, characterized in that: The period changing unit randomly changes the carrier period under a specific condition that the evaluation value approaches the specific value when the carrier period is set to a preset first carrier period, and sets the carrier period to the first carrier period except for the specific condition.

10. The control device for an AC rotating electrical machine according to any one of claims 1 to 7, characterized in that: The PWM control unit executes a synchronous PWM mode in which the carrier cycle is changed in proportion to the AC cycle. The period changing unit sets a proportionality coefficient so that the evaluation value does not coincide with the specific value when the synchronous PWM mode is executed, and changes the carrier period in proportion to the AC period using the set proportionality coefficient.

11. The control device for an AC rotating electrical machine according to any one of claims 1 to 5, characterized in that: Under the specific condition that the evaluation value is close to the specific value when the update period is set to a predetermined first update period, the period changing unit sets the update period to a predetermined second update period so that the evaluation value is inconsistent with the specific value, and sets the update period to the first update period except for the specific condition.

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