JP2009112140A - Control device of motor and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a motor, which suppresses torque vibration, and its control method. <P>SOLUTION: The control device has a switch 103 for switching a rectangular wave generation part 107 to a PWM control part 105. The switch 103 performs the switching in accordance with the switching timing of a switching element. The rectangular wave generation part 107 operates an (n+1)-th control cycle tnow between (n+1)-th switching timing and (n+2)-th switching timing at n-th switching timing, and also operates a difference Δθ between (n+2)-th target switching timing, and the (n+2)-th switching timing based on the (n+1)-th control cycle tnow at the (n+1)-th switching timing. Immediately after the switching, the PWM control part 105 controls a voltage phase command valueα*(n+3) by using a value α(n+3) which is corrected on the basis of the difference Δθ. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor control device that controls an inverter capable of switching a rectangular wave voltage and a PWM (pulse width modulation) waveform voltage and outputting the voltage to the motor, and a control method therefor.

Conventionally, there is a drive control device for an AC motor that controls a motor by switching between a rectangular wave control that outputs a rectangular wave voltage from the inverter to the motor and a PWM control that outputs a PWM waveform voltage from the inverter to the motor (see Patent Document 1). ). In the drive control device, the rectangular wave control and the PWM control are switched to improve the voltage utilization rate.
Japanese Patent Laid-Open No. 2000-50686

  However, in the conventional drive control device, when switching from rectangular wave control to PWM control, the voltage phase of rectangular wave control is used as it is as the voltage phase of PWM control. For this reason, when switching from the rectangular wave control to the PWM control, there is a problem that the torque may vibrate if the rotation speed of the electric motor changes suddenly.

  The present invention has been made in view of these problems, and an object thereof is to provide an electric motor control device and a control method thereof that can suppress torque vibration.

  To achieve the above object, in the motor control device according to the present invention, switching from the rectangular wave control means for controlling the output voltage of the inverter to a rectangular wave shape to the pulse width modulation control means for controlling the voltage to a pseudo sine wave shape is performed. Switching means for performing is provided. The switching means performs the above switching in accordance with the switching timing of the switching elements constituting the inverter. The rectangular wave control means calculates an (n + 1) -th control cycle between the (n + 1) -th switching timing and the (n + 2) -th switching timing at the n (n = 1, 2,...) -Th switching timing. Further, at the (n + 1) th switching timing, the difference between the (n + 2) th target switching timing obtained from the voltage phase command value and the (n + 2) th switching timing based on the (n + 1) th control cycle is calculated. The pulse width modulation control means controls the voltage phase command value with a value corrected based on the difference immediately after switching by the switching means.

  According to the present invention, when switching from rectangular wave control to PWM control, it is possible to suppress torque vibration that occurs when the rotational speed of the motor changes rapidly.

  As an example of an apparatus including an electric motor control apparatus according to the present invention, an inverter system that switches between rectangular wave control for controlling a voltage output from an inverter to a motor in a rectangular wave form and PWM control for controlling the voltage in a pseudo sine wave form. explain. Hereinafter, inverter systems according to first to sixth embodiments of the present invention will be described with reference to FIGS. 1 to 21.

(First embodiment)
(Inverter system configuration)
Hereinafter, the configuration and operation of the inverter system will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of an inverter system according to the first embodiment of the present invention. As shown in FIG. 1, this inverter system mainly includes an inverter 1, a current sensor 2, a motor 3 that is an electric motor, and a controller 10 that is a control device. Here, the inverter 1 includes a DC power source B, U-phase switching elements Tu + and Tu−, V-phase switching elements Tv + and Tv−, and W-phase switching elements Tw + and Tw−. Furthermore, U-phase reflux elements Du + and Du−, V-phase reflux elements Dv + and Dv−, and W-phase reflux elements Dw + and Dw− are provided.

  Then, the inverter 1 converts the DC voltage value Vdc [V] (see FIG. 2) supplied from the DC power supply B into a rectangular wave shape or a pseudo sine wave shape based on the drive signal P (see FIG. 2) of the controller 10. . Here, the drive signal P controls the ON / OFF operation of the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− of the inverter 1. The switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− are semiconductor elements such as IGBTs. On the other hand, the reflux elements Du +, Du−, Dv +, Dv−, Dw +, Dw− are diodes. The motor 3 generates a torque corresponding to the rectangular-wave or pseudo-sine-wave output voltages Vu [V], Vv [V], and Vw [V] (see FIG. 3) supplied from the inverter 1. The current sensor 2 detects a three-phase current flowing through the motor 3. Here, the three-phase current is 0 [A] when all currents are summed. That is, if two of the three phases are detected, the other phase can be obtained by calculation. From this, the current sensor 2 detects two phases out of the three phases.

Next, the internal configuration of the controller 10 will be described with reference to FIG. FIG. 2 is a control block diagram showing an internal configuration of the controller 10 shown in FIG. The controller 10 includes a calculation device (CPU), and includes an α table reference unit 101, an α filter calculation unit 102 as a first filter calculation unit, and a switch unit 103 as a switching unit, as shown in FIG. Further, a PWM control unit 105 that is a pulse width modulation control unit, a rectangular wave generation unit 107 that is a rectangular wave control unit, a switch unit 108, a timer unit 109, and a flag control unit 110 are provided. Here, the α table reference unit 101 refers to a previously stored table based on the torque command value T [N · m], the motor rotation speed N [rpm], and the DC voltage value Vdc [V]. Then, the voltage phase command value α ′ ^* before fluctuation suppression is obtained from the table. The α filter calculation unit 102 uses the transfer function 1 / (τs + 1) to suppress fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression. The time constant τ is about several ms.

The switch unit 103 outputs the voltage phase command value α ^* whose fluctuation is suppressed by the α filter calculation unit 102 to the PWM control unit 105 or the rectangular wave generation unit 107. As will be described later, when the rectangular wave flag of the flag control unit 110 becomes 1, the switch unit 103 changes the contact from the terminal B to the terminal A at the calculation timing of the next control cycle command generated by the PWM control unit 105. Switch. Then, the voltage phase command value α ^* is output to the rectangular wave generation unit 107. On the other hand, when the rectangular wave flag of the flag control unit 110 changes from 1 to 0, the switch unit 103 changes the contact from the terminal A to the terminal B at the calculation timing of the next control cycle command generated by the rectangular wave generation unit 107. Switch. Then, the voltage phase command value α ^* is output to the PWM control unit 105.

The PWM control unit 105 switches the switching elements Tu + and Tu− so that the output voltages Vu [V], Vv [V], and Vw [V] (see FIG. 3) output from the inverter 1 to the motor 3 become pseudo sine waves. , Tv +, Tv−, Tw +, Tw− are controlled. This is referred to as PWM control. Specifically, the PWM control unit 105 includes a vd, vq command calculation unit 1051, a two-phase / three-phase conversion unit 1052, and a PWM generation unit 1053. Here, as shown in FIG. 2, the vd, vq command calculation unit 1051 calculates the d-axis voltage command value vd [V] and the q-axis voltage command value from the DC voltage value Vdc [V] and the voltage phase command value α ^*. vq [V] is calculated. The two-phase / three-phase converter 1052 converts the d-axis voltage command value vd [V] and the q-axis voltage command value vq [V] into the three-phase voltage command values vu [V] and vv [V] according to the rotor phase θ. , Vw [V]. The PWM generation unit 1053 compares the three-phase voltage command values vu [V], vv [V], and vw [V] with the magnitude relationship between the triangular wave carrier signal (see FIG. 3). A three-phase comparison value is generated according to the magnitude relationship. The PWM generation unit 1053 calculates a PWM cycle Tpwm (see FIG. 4), which is a predetermined control cycle, calculates the next calculation timing, and generates a next control cycle command.

On the other hand, the rectangular wave generator 107 switches the switching elements Tu +, Tu−, Tv +, so that the output voltages Vu [V], Vv [V], and Vw [V] output from the inverter 1 to the motor 3 are rectangular. Tv−, Tw +, and Tw− are controlled. This is rectangular wave control. Specifically, the rectangular wave generation unit 107 generates a three-phase comparison value. Similarly to the PWM control unit 105, the rectangular wave generation unit 107 calculates the next control cycle, calculates the next calculation timing, and generates the next control cycle command. Further, as will be described later, the rectangular wave generation unit 107 calculates an error Δα (n + 3) (see FIG. 3) of the next calculation timing with respect to the current calculation timing for each calculation timing.
Further, as described later, when switching from the rectangular wave generation unit 107 to the PWM control unit 105 in the switch unit 103 is performed, the rectangular wave generation unit 107 has an actual voltage phase α (n + 3) that is a corrected value. The α filter calculation unit 102 is initialized. Here, the initialization means that an actual voltage phase α (n + 3) is input and an infinite time has elapsed.

  The switch unit 108 operates in synchronization with the switch unit 103. That is, when the rectangular wave flag becomes 1, the switch unit 108 switches the contact from the terminal B to the terminal A in accordance with the operation timing of the switch unit 103. Then, the three-phase comparison value generated by the rectangular wave generation unit 107 and the next control cycle command are output to the timer unit 109. On the other hand, when the rectangular wave flag changes from 1 to 0, the switch unit 108 switches the contact from the terminal A to the terminal B in accordance with the operation timing of the switch unit 103. Then, the three-phase comparison value generated by the PWM control unit 105 and the next control cycle command are output to the timer unit 109. Timer unit 109 outputs drive signal P based on the three-phase comparison value to inverter 1 in accordance with the calculation timing of the next control cycle command. As described above, the drive signal P controls the ON / OFF operation of the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− of the inverter 1. Accordingly, the calculation timing of the next control cycle command becomes equal to the switching timing of the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw−.

  The flag control unit 110 stores a rectangular wave flag and controls the operations of the switch units 103 and 108 based on the rectangular wave flag. Specifically, when the rectangular wave flag becomes 1, the flag control unit 110 switches the contact points of the switch units 103 and 108 from the terminal B to the terminal A. From this, the rectangular wave generation unit 107 is caused to execute rectangular wave control for controlling the output voltages Vu [V], Vv [V], and Vw [V] into a rectangular wave shape. On the other hand, when the rectangular wave flag changes from 1 to 0, the flag control unit 110 switches the contact points of the switch units 103 and 108 from the terminal A to the terminal B. From this, the PWM control unit 105 is caused to execute PWM control for controlling the output voltages Vu [V], Vv [V], and Vw [V] in a pseudo sine wave shape.

(Calculation of rectangular wave control by the rectangular wave generator 107)
Next, calculation for rectangular wave control executed by the rectangular wave generation unit 107 will be described with reference to FIG. FIG. 3 is a timing chart showing the output of the rectangular wave control executed by the rectangular wave generator 107 shown in FIG. FIG. 3 shows an example of the carrier signal, output voltages Vu [V], Vv [V], Vw [V], switching timing, calculation timing, rotor phase θ, and actual motor angular frequency ωre [rad / s]. ing. As described above, the calculation timings coincide with the switching timings of the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw−. That is, the previous calculation is performed at the n (n = 1, 2,...) Switching timing, and the current calculation is performed at the (n + 1) th switching timing. The next calculation is executed at the (n + 2) -th switching timing, and the next calculation is executed at the (n + 3) -th switching timing. Note that at each switching timing, one of the output voltages Vu [V], Vv [V], and Vw [V] is inverted.

As shown in FIG. 3, in the first embodiment, it is assumed that the actual motor angular frequency ωre [rad / s] suddenly changes at the (n + 1) th switching timing, that is, the current calculation timing. In this case, the rectangular wave generation unit 107 calculates the rotor phase θnext at the next calculation timing that is the (n + 2) -th switching timing based on the current rotor phase θ, the motor rotation speed N [rpm], and the current control cycle tnow. Calculate. Here, the current control cycle tnow, which is the (n + 1) th control cycle, is calculated by the rectangular wave generation unit 107 at the nth switching timing, that is, the previous calculation timing. As described above, at the current calculation timing, the α filter calculation unit 102 suppresses fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression, and obtains the voltage phase command value α ^* (n + 2) at the next calculation timing.

At the current calculation timing, the rectangular wave generation unit 107 calculates the rotor phase target value θ ^* next at the (n + 2) th target switching timing based on the voltage phase command value α ^* (n + 2). Next, the rectangular wave generation unit 107 obtains an error Δθ between the rotor phase θnext and the rotor phase target value θ ^* next. In this way, the error Δθ is calculated. Next, at the current calculation timing, the rectangular wave generation unit 107 calculates the next control cycle tnext. The next control cycle tnext is the same as the current control cycle tnow. However, since the actual motor angular frequency ωre [rad / s] suddenly changes at the current calculation timing, an error Δθ from the rotor phase target value θ ^* next occurs at the next calculation timing. For this reason, it is necessary to correct the next control cycle tnext based on the error Δθ.

  Here, a correction process is performed after the error Δθ is multiplied by a predetermined correction coefficient K (around 0.1 to 0.5). That is, the error Δθ calculated at the next calculation timing is not corrected one time after the next calculation timing, but is corrected by multiplying the correction amount by K and taking several control cycles. Specifically, at the current calculation timing, the rectangular wave generation unit 107 calculates a corrected next control cycle tnext ′ by adding a correction amount KΔθ obtained by multiplying the error Δθ by K to the next control cycle tnext. Then, at the (n + 2) -th switching timing, that is, the next calculation timing, the rectangular wave generating unit 107 matches one cycle of the carrier signal with the corrected next control cycle tnext ′. Further, the rectangular wave generation unit 107 calculates the (n + 3) -th switching timing, that is, the next calculation timing from the corrected next control cycle tnext ′.

Next, actual voltage phase α and error Δα, which are values obtained by correcting voltage phase command value α ^* based on error Δθ, will be described. As shown in FIG. 3, the error Δα is 0 at the previous calculation timing and the current calculation timing. That is, at the previous calculation timing, the actual voltage phase αn is equal to the voltage phase command value α ^* n. Further, at the current calculation timing, the actual voltage phase α (n + 1) and the voltage phase command value α ^* (n + 1) are equal. On the other hand, since the error Δθ has occurred as described above at the next calculation timing, the error Δα (n + 2) = error Δθ. That is, at the next calculation timing, the actual voltage phase α (n + 2) = voltage phase command value α ^* (n + 2) + error Δα (n + 2) = voltage phase command value α ^* (n + 2) + error Δθ.

Further, as shown in FIG. 3, the error Δα (n + 3) = Δθ (1−K) at the next calculation timing. That is, at the next calculation timing, the actual voltage phase α (n + 3) = voltage phase command value α ^* (n + 3) + error Δα (n + 3) = voltage phase command value α ^* (n + 3) + Δθ (1-K). However, the error Δθ and the corrected next control cycle tnext ′ are calculated on the assumption that the motor rotation speed N [rpm] is constant from the current calculation timing to the next calculation timing. Therefore, the shorter the time from the current calculation timing to the next calculation timing, the higher the calculation accuracy of the error Δα (n + 3) of the next calculation timing with respect to the current calculation timing.

(Switching process from the rectangular wave generator 107 to the PWM controller 105)
Next, switching processing from the rectangular wave generating unit 107 that performs rectangular wave control to the PWM control unit 105 that performs PWM control in the first embodiment will be described with reference to FIG. FIG. 4 is a timing chart showing an output by the rectangular wave / PWM control switching process in the controller 10 shown in FIG. FIG. 4 shows switching timings of the output voltages Vu [V], Vv [V], Vw [V], carrier signals, switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw−. Here, the left side of the (n + 3) -th switching timing in FIG. 4 shows the rectangular wave control by the rectangular wave generation unit 107, and the right side shows the PWM control by the PWM control unit 105. Note that at each switching timing, one of the output voltages Vu [V], Vv [V], and Vw [V] is inverted.

  As shown in FIG. 4, until the (n + 1) th switching timing, the calculation for rectangular wave control (hereinafter, referred to as rectangular wave calculation) executed by the rectangular wave generation unit 107 is executed. Switching from the rectangular wave generator 107 to the PWM controller 105 is performed at the (n + 2) th switching timing. Thereafter, a calculation for PWM control (hereinafter referred to as PWM calculation) executed by the PWM control unit 105 is executed. However, the PWM control unit 105 starts the PWM control after the (n + 3) th switching timing. As described above, the PWM cycle Tpwm that is the (n + 3) th control cycle is calculated by the PWM control unit 105 at the (n + 2) th switching timing. For this reason, even if switching from the rectangular wave generation unit 107 to the PWM control unit 105 is performed at the (n + 2) th switching timing, the PWM control cannot be started from the (n + 2) th switching timing. PWM control is started with a delay of one switching timing. After the (n + 3) th switching timing, the PWM control unit 105 matches one cycle of the carrier signal with the PWM cycle Tpwm in order to perform PWM control.

  Here, when switching from the rectangular wave control to the PWM control, specifically, when switching from the rectangular wave calculation to the PWM calculation, if the motor rotation speed N [rpm] suddenly changes, the torque may vibrate. Therefore, the rectangular wave generation unit 107 according to the first embodiment calculates an error Δα (n + 3) = Δθ (1−K) of the (n + 3) -th switching timing with respect to the (n + 1) -th switching timing for each calculation timing. ing. That is, as shown in FIG. 3, at the (n + 1) th switching timing, the motor rotation speed N [rpm] suddenly changes, and immediately after that, until the (n + 3) th switching timing, the motor rotation speed N [rpm] is constant. Assume the case.

Further, as described above, at the (n + 2) -th switching timing, the α filter calculation unit 102 suppresses fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression. Then, the α filter calculation unit 102 outputs the voltage phase command value α ^* (n + 3) at the (n + 3) -th switching timing to the rectangular wave generation unit 107 via the switch unit 103. At the (n + 2) th switching timing, the rectangular wave generation unit 107 calculates the actual voltage phase α (n + 3) = voltage phase command value α ^* (n + 3) + Δθ (1-K) at the (n + 3) th switching timing. Next, the rectangular wave generation unit 107 initializes the α filter calculation unit 102 with the actual voltage phase α (n + 3). Thereafter, at the (n + 2) -th switching timing, the switch unit 103 performs switching from the rectangular wave generation unit 107 to the PWM control unit 105. Immediately after the switching, the PWM control unit 105 performs PWM control using the actual voltage phase α (n + 3).

Next, the effect when the switching process shown in FIG. 4 is executed will be described with reference to FIGS. 5 is a diagram showing an actual voltage phase α when the switching process shown in FIG. 4 is executed, and FIG. 6 is a diagram showing the motor rotation speed N [rpm] and the output power Pnt when the switching process shown in FIG. 4 is executed. It is a figure which shows [kw]. In the prior art shown in FIG. 5A, the voltage phase command value α ^* (n + 3) of rectangular wave control is used as it is as the voltage phase command value α ^* of PWM control at the (n + 3) -th switching timing. In the vicinity of switching from the rectangular wave control to the PWM control, when the motor rotation speed N [rpm] changes suddenly as shown in FIG. 6A, an error Δα (n + 3) occurs. As shown in FIG. 5A, the actual voltage phase α changes stepwise due to the error Δα (n + 3). When the actual voltage phase α changes stepwise, the output power Pnt [kw] oscillates after switching from rectangular wave control to PWM control. That is, the torque vibrates.

On the other hand, as described above, in the first embodiment, the rectangular wave generation unit 107 calculates the error Δα (n + 3) = Δθ (1-K) at the (n + 1) th switching timing. At the (n + 2) -th switching timing, the rectangular wave generation unit 107 calculates the actual voltage phase α (n + 3) = voltage phase command value α ^* (n + 3) + error Δα (n + 3), and the actual voltage phase α (n + 3). ) Initializes the α filter calculation unit 102. After the initialization, the switch unit 103 performs switching from the rectangular wave generation unit 107 to the PWM control unit 105. Immediately after the switching, the voltage phase command value α ^* output from the α filter calculation unit 102 to the PWM control unit 105 via the switch unit 103 is the actual voltage phase α (n + 3) as shown in FIG. Will be equal. Furthermore, as shown in FIG. 5B, the steep step-like change in the actual voltage phase α is mitigated by the filter action of the α filter calculation unit 102. From this, as shown in FIG. 6B, even when the motor rotation speed N [rpm] changes suddenly, the vibration of the output power Pnt [kw] can be suppressed. Therefore, torque vibration can be suppressed.

(Control method executed by the controller 10)
Next, a control method executed by the controller 10 according to the first embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing a control method executed by the controller 10 shown in FIG. This control method is implemented by incorporating the program of the flowchart shown in FIG. As shown in FIG. 3, it is assumed that the actual motor angular frequency ωre [rad / s] changes suddenly at the (n + 1) th switching timing. In addition, switching from the rectangular wave generation unit 107 to the PWM control unit 105 is performed at the (n + 2) th switching timing. As shown in FIG. 7, at the (n + 1) -th switching timing, the α table reference unit 101 executes an α table reference process (step S101). Here, the α table reference process refers to a table stored in advance based on the torque command value T [N · m], the motor rotation speed N [rpm], and the DC voltage value Vdc [V], and suppresses fluctuations. This is a control process for obtaining the previous voltage phase command value α ′ ^* .

Next, the flag control unit 110 determines whether or not the rectangular wave flag stored in the flag control unit 110 has changed from 1 to 0 (step S102). When the flag control unit 110 determines that the rectangular wave flag has not changed from 1 to 0 (step S102: No), the α filter calculation unit 102 performs α filter calculation (step S104). Specifically, the α filter calculation unit 102 suppresses fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression, and outputs the voltage phase command value α ^* (n + 2) to the switch unit 103. Next, the flag control unit 110 determines whether or not the rectangular wave flag is 1 (step S105). When the flag control unit 110 determines that the rectangular wave flag is 1 (step S105: Yes), the flag control unit 110 keeps the contacts of the switch units 103 and 108 in contact with the terminal B. Accordingly, the voltage phase command value α ^* (n + 2) is output to the rectangular wave generation unit 107 via the switch unit 103. Next, the flag control unit 110 causes the rectangular wave generation unit 107 to execute a rectangular wave generation process (step S109). Here, the rectangular wave generation process is a control process for generating a three-phase comparison value.

Next, the rectangular wave generation unit 107 performs Δα calculation (step S110). Here, in the Δα calculation, as shown in FIG. 3, the rotor at the (n + 2) -th switching timing is based on the current rotor phase θ, the motor rotation speed N [rpm], and the (n + 1) -th control cycle tnow. The phase θnext is calculated. In the Δα calculation, the rotor phase target value θ ^* next at the (n + 2) th target switching timing is calculated based on the voltage phase command value α ^* (n + 2). Further, an error Δθ between the rotor phase θnext and the rotor phase target value θ ^* next is obtained. Further, in the Δα calculation, the corrected (n + 2) th control cycle tnext ′ and the error Δα (n + 3) are calculated based on the error Δθ. Thus, the control process of the controller 10 at the (n + 1) th switching timing is completed.

When the flag control unit 110 determines that the rectangular wave flag has changed from 1 to 0 at the (n + 2) th switching timing (step S102: Yes), the process proceeds to the control process of step S103. In the control process of step S103, the flag control unit 110 causes the rectangular wave generation unit 107 to initialize the α filter calculation unit 102. Specifically, the actual voltage phase α (n + 3) is calculated by adding the error Δα (n + 3) to the voltage phase command value α ^* (n + 3) output via the switch unit 103. The rectangular wave generation unit 107 initializes the α filter calculation unit 102 with the actual voltage phase α (n + 3). Next, the α filter calculation unit 102 performs α filter calculation (step S104). In the control process of step S103, the α filter calculation unit 102 is initialized with the actual voltage phase α (n + 3), so that the voltage phase command value α ^* output from the α filter calculation unit 102 is the actual voltage phase. It is equal to α (n + 3).

Next, the flag control unit 110 determines whether or not the rectangular wave flag is 1 (step S105). In the control process of step S102 executed at the (n + 2) -th switching timing, it is determined that the rectangular wave flag has changed from 1 to 0, so the flag control unit 110 determines that the rectangular wave flag is not 1 (step) S105: No). When the flag control unit 110 determines that the rectangular wave flag is not 1, the flag control unit 110 switches the contacts of the switch units 103 and 108 from the terminal A to the terminal B. Thus, the voltage phase command value α ^* = actual voltage phase α (n + 3) is output to the PWM control unit 105 via the switch unit 103.

Next, the flag control unit 110 causes the PWM control unit 105 to execute PWM control. Specifically, the vd, vq command calculation unit 1051 calculates the d-axis voltage command value vd [V] and the q-axis voltage command value vq [V] from the DC voltage value Vdc [V] and the voltage phase command value α ^*. A control process is executed (step S106). Next, the two-phase / three-phase converter 1052 converts the d-axis voltage command value vd [V] and the q-axis voltage command value vq [V] into the three-phase voltage command values vu [V], vv based on the rotor phase θ. A control process for converting to [V] and vw [V] is executed (step S107). Next, the PWM generation unit 1053 compares the magnitude relationship between the three-phase voltage command values vu [V], vv [V], and vw [V] and a triangular wave carrier signal, and compares the three-phases according to the magnitude relationship. A control process for generating a value is executed (step S108). The PWM generation unit 1053 calculates the PWM cycle Tpwm, calculates the next calculation timing, and generates the next control cycle command. Thus, the control process of the controller 10 at the (n + 2) th switching timing is completed.

Since the rectangular wave flag is already 0 at the (n + 3) -th switching timing, the flag control unit 110 determines that the rectangular wave flag has not changed from 1 to 0 (step S102: No). Thereafter, the control process of steps S104 to S108 is executed. Thus, the control process of the controller 10 at the (n + 3) th switching timing is completed. Thereafter, in the control process of step S105, the control processes of steps S101, S102, and S104 to S108 are sequentially repeated until the flag control unit 110 determines that the rectangular wave flag is 1. Thereafter, in the control process of step S105, when the flag control unit 110 determines that the rectangular wave flag is 1 (step S105: Yes), the flag control unit 110 connects the contact points of the switch units 103 and 108 from the terminal B to the terminal B. Switch to A. As a result, the voltage phase command value α ^* is output to the rectangular wave generation unit 107 via the switch unit 103. Thereafter, the control processes of steps S109 and S110 are executed. Thereafter, in the control process of step S102, the control processes of steps S101, S102, S104, S105, S109, and S110 are sequentially repeated until the flag control unit 110 determines that the rectangular wave flag has changed from 1 to 0.

  As described above, the inverter system according to the first embodiment includes the inverter 1, the motor 3, and the controller 10 including the plurality of switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw−. The controller 10 includes a rectangular wave generation unit 107 that controls the output voltages Vu [V], Vv [V], and Vw [V] from the inverter 1 to the motor 3 into a rectangular wave shape. Also included is a PWM controller 105 that controls the output voltages Vu [V], Vv [V], and Vw [V] in a pseudo sine wave form. Furthermore, the switch part 103 which switches from the rectangular wave production | generation part 107 to the PWM control part 105 according to the switching timing of switching element Tu +, Tu-, Tv +, Tv-, Tw +, Tw- is provided. The rectangular wave generation unit 107 calculates the (n + 1) th control cycle tnow between the (n + 1) th switching timing and the (n + 2) th switching timing at the nth switching timing.

At the (n + 1) th switching timing, the rotor phase θnext at the (n + 2) th switching timing based on the (n + 1) th control cycle tnow is calculated. Furthermore, the rotor phase target value θ ^* next at the (n + 2) th target switching timing obtained from the voltage phase command value α ^* based on the torque command value T [N · m] and the motor rotation speed N [rpm] is calculated. A difference Δθ between the rotor phase target value θ ^* next and the rotor phase θnext is calculated. Immediately after the switching by the switch unit 103, the PWM control unit 105 controls the voltage phase command value α ^* (n + 3) with the actual voltage phase α (n + 3) corrected based on the difference Δθ. In addition, at the (n + 2) -th switching timing and immediately before the switch unit 103 is switched, the rectangular wave generation unit 107 calculates the actual voltage phase α (n + 3). The actual voltage phase α (n + 3) is, (n + 3) th voltage phase command value in a switching timing α ^* (n + 3), the difference Δθ a and a predetermined value and K, α (n + 3) = α * (n + 3) + Δθ × (1−K). From this, even when the motor rotation speed N [rpm] changes suddenly before and after the switching, the PWM control is performed with the voltage phase command value α ^* = the actual voltage phase α (n + 3) immediately after the switching, so that torque vibration can be suppressed. .

Further, the controller 10 includes an α filter calculation unit 102 that outputs a voltage phase command value α ^* to the PWM control unit 105 or the rectangular wave generation unit 107. The rectangular wave generating unit 107 outputs the actual voltage phase α (n + 3) from the α filter calculation unit 102 to the PWM control unit 105 immediately after switching. As a result, a steep step-like change in the actual voltage phase α that occurs immediately after switching from the rectangular wave generation unit 107 to the PWM control unit 105 can be mitigated by the filter action of the α filter calculation unit 102. Therefore, torque vibration can be further suppressed.

(Second Embodiment)
Next, an inverter system according to the second embodiment will be described with reference to FIGS. 8 to 10 focusing on differences from the inverter system according to the first embodiment. Moreover, about the inverter system which concerns on 2nd Embodiment, the same number is attached | subjected to the structure similar to the inverter system which concerns on 1st Embodiment, and description is abbreviate | omitted. The inverter system according to the second embodiment is almost the same as the inverter system according to the first embodiment. FIG. 8 is a control block diagram showing the internal configuration of the controller 20 according to the second embodiment of the present invention. As shown in FIG. 8, the inverter system according to the second embodiment is different from the first embodiment in that a rectangular wave generation unit 207 that is a rectangular wave control unit included in the controller 20 and a flag control unit 210 are different. It is only that.

  The rectangular wave generator 207 performs rectangular wave control on the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− of the inverter 1 as in the first embodiment. Specifically, as in the first embodiment, the rectangular wave generation unit 207 generates a three-phase comparison value. Similarly to the first embodiment, the rectangular wave generation unit 207 calculates the next control cycle, calculates the next calculation timing, and generates the next control cycle command. Further, unlike the first embodiment, the rectangular wave generation unit 207 calculates an error Δα (n + 2) (see FIG. 3) of the next calculation timing with respect to the current calculation timing for each calculation timing. Further, when switching from the rectangular wave generation unit 207 to the PWM control unit 105 in the switch unit 103 is performed, the rectangular wave generation unit 207 initializes the α filter calculation unit 102 with the actual voltage phase α (n + 2). .

  As in the first embodiment, the flag control unit 210 stores a rectangular wave flag and controls the operations of the switch units 103 and 108 based on the rectangular wave flag. Specifically, when the rectangular wave flag becomes 1, the flag control unit 210 switches the contact points of the switch units 103 and 108 from the terminal B to the terminal A. From this, the rectangular wave generation unit 207 is caused to execute rectangular wave control for controlling the output voltages Vu [V], Vv [V], and Vw [V] into a rectangular wave shape. On the other hand, when the rectangular wave flag changes from 1 to 0, the flag control unit 210 switches the contact of the switch units 103 and 108 from the terminal A to the terminal B. From this, the PWM control unit 105 is caused to execute PWM control for controlling the output voltages Vu [V], Vv [V], and Vw [V] in a pseudo sine wave shape.

(Switching process from the rectangular wave generator 207 to the PWM controller 105)
Next, switching processing from the rectangular wave generating unit 207 that performs rectangular wave control to the PWM control unit 105 that performs PWM control in the second embodiment will be described with reference to FIG. FIG. 9 is a timing chart showing the output of the rectangular wave / PWM control switching process in the controller 20 shown in FIG. In FIG. 9, similarly to FIG. 4 of the first embodiment, output voltages Vu [V], Vv [V], Vw [V], carrier signals, switching elements Tu +, Tu−, Tv +, Tv−, Tw +, The switching timing of Tw− is shown. Here, the left side of the (n + 2) th switching timing in FIG. 9 shows the rectangular wave control by the rectangular wave generation unit 207, and the right side shows the PWM control by the PWM control unit 105. As in FIG. 4 of the first embodiment, one of the output voltages Vu [V], Vv [V], and Vw [V] is inverted at each switching timing.

  In the second embodiment, as shown in FIG. 9, the rectangular wave calculation is executed by the rectangular wave generation unit 207 until the n-th switching timing. Switching from the rectangular wave generator 207 to the PWM controller 105 is performed at the (n + 1) -th switching timing. Thereafter, the PWM calculation is performed by the PWM control unit 105. However, as in the first embodiment, the PWM cycle Tpwm that is the (n + 2) th control cycle is calculated by the PWM control unit 105 at the (n + 1) th switching timing. For this reason, after switching from the rectangular wave generator 207 to the PWM controller 105, the PWM control is started with a delay of one switching timing. That is, after the (n + 2) th switching timing, the PWM control unit 105 starts PWM control. After the (n + 2) th switching timing, the PWM control unit 105 matches one cycle of the carrier signal with the PWM cycle Tpwm in order to perform PWM control.

  As shown in FIG. 9, in the second embodiment, unlike the first embodiment, the rectangular wave generation unit 207 performs Δα calculation at the (n + 1) th switching timing. Unlike the first embodiment, after execution of the Δα calculation, switching from the rectangular wave generation unit 207 to the PWM control unit 105 is performed. Here, in the first embodiment, it is assumed that the actual motor angular frequency ωre [rad / s] (see FIG. 3), that is, the motor rotation speed N [rpm] changes suddenly at the (n + 1) th switching timing. is doing. Further, the Δα calculation is executed on the assumption that the motor rotation speed N [rpm] is constant from the (n + 1) th switching timing to the (n + 3) th switching timing. On the other hand, in the second embodiment, Δα is calculated on the assumption that the motor rotation speed N [rpm] changes from the n-th switching timing to the (n + 2) -th switching timing. That is, it is assumed that at the (n + 1) th switching timing, the actual motor angular frequency ωre [rad / s], that is, the motor rotation speed N [rpm] changes before the above switching.

Specifically, in the rectangular wave generation unit 207 according to the second embodiment, the error Δα (n + 2) = error Δθ (see FIG. 3) of the (n + 2) -th switching timing with respect to the (n + 1) -th switching timing is calculated as the calculation timing. It is calculated every time. Similar to the first embodiment, at the (n + 1) -th switching timing, the α filter calculation unit 102 suppresses fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression. Then, the α filter calculation unit 102 outputs the voltage phase command value α ^* (n + 2) (see FIG. 3) at the (n + 2) -th switching timing to the rectangular wave generation unit 207 via the switch unit 103. Unlike the first embodiment, at the (n + 1) -th switching timing, the rectangular wave generation unit 207 performs Δα calculation before switching from the rectangular wave generation unit 207 to the PWM control unit 105.

Here, in the Δα calculation according to the second embodiment, based on the current rotor phase θ, the motor rotation speed N [rpm], and the (n + 1) th control cycle tnow (see FIG. 3), the rotor phase θnext ( (See FIG. 3). In the Δα calculation, similarly to the first embodiment, based on the voltage phase command value α ^* (n + 2), the rotor phase target value θ ^* next at the (n + 2) th target switching timing (see FIG. 3). Is calculated. Further, as in the first embodiment, an error Δθ between the rotor phase θnext and the rotor phase target value θ ^* next is obtained. Further, in Δα calculation, error Δα (n + 2) = error Δθ is calculated based on error Δθ.

Thereafter, at the (n + 1) th switching timing, the rectangular wave generation unit 207 calculates the actual voltage phase α (n + 2) = voltage phase command value α ^* (n + 2) + error Δθ before performing the switching. Next, the rectangular wave generation unit 207 initializes the α filter calculation unit 102 with the actual voltage phase α (n + 2). Thereafter, at the (n + 1) -th switching timing, the switch unit 103 performs switching from the rectangular wave generation unit 207 to the PWM control unit 105. Immediately after the switching, the PWM control unit 105 performs PWM control using the actual voltage phase α (n + 2). From this, the same effects as those of the first embodiment shown in FIGS. 5 and 6 can be obtained.

(Control method executed by the controller 20)
Next, a control method executed by the controller 20 according to the second embodiment will be described with reference to FIG. FIG. 10 is a flowchart showing a control method executed by the controller 20 shown in FIG. This control method is implemented by incorporating the program of the flowchart shown in FIG. This control process is almost the same as the control process executed by the controller 10 according to the first embodiment. The only difference between the control process executed by the controller 10 according to the first embodiment and the present control process is that the rectangular wave generation unit 207 executes the Δα calculation in the control process of step S203.

As illustrated in FIG. 10, the α table reference unit 101 executes the α table reference process at the n-th switching timing, similarly to the control process in step S101 of the first embodiment (step S201). Next, the flag control unit 210 determines whether or not the rectangular wave flag stored in the flag control unit 210 has changed from 1 to 0 (step S202). When the flag control unit 210 determines that the rectangular wave flag has not changed from 1 to 0 (step S202: No), the α filter calculation unit 102 performs α filter calculation (step S205), similarly to the control process of step S104. ). Specifically, the α filter calculation unit 102 suppresses fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression, and outputs the voltage phase command value α ^* (n + 1) to the switch unit 103. Thereafter, the control processes of steps S206, S210, and S211 that are similar to the control processes of steps S105, S109, and S110, respectively, are executed. As described above, the control process of the controller 20 at the n-th switching timing is completed.

When the flag control unit 210 determines that the rectangular wave flag has changed from 1 to 0 at the (n + 1) th switching timing (step S202: Yes), the process proceeds to the control process of step S203. In the control process of step S203, the flag control unit 210 causes the rectangular wave generation unit 207 to execute Δα calculation. Next, the rectangular wave generation unit 207 initializes the α filter calculation unit 102 as in the control process of step S103 (step S204). Next, as in the control process in step S104, the α filter calculation unit 102 performs an α filter calculation (step S205). In the control process of step S204, the α filter calculation unit 102 is initialized with the actual voltage phase α (n + 2), so that the voltage phase command value α ^* output from the α filter calculation unit 102 is the actual voltage phase α. It becomes equal to (n + 2).

Next, similarly to the control process in step S105, the flag control unit 210 determines whether or not the rectangular wave flag is 1 (step S206). As in the first embodiment, since the flag control unit 210 determines that the rectangular wave flag is not 1 (step S206: No), the flag control unit 210 connects the contacts of the switch units 103 and 108 from the terminal A to the terminal B. Switch to. Thus, as in the first embodiment, the voltage phase command value α ^* = actual voltage phase α (n + 2) is output to the PWM control unit 105 via the switch unit 103. Thereafter, the control processes of steps S207 to S209, which are the same as the control processes of steps S106 to S108, respectively, are executed. Thus, the control process of the controller 20 at the (n + 1) th switching timing is completed.

As in the first embodiment, since the rectangular wave flag is already 0 at the (n + 2) -th switching timing, the flag control unit 210 determines that the rectangular wave flag has not changed from 1 to 0 ( Step S202: No). Thereafter, the control process of steps S205 to S209 is executed. Thus, the control process of the controller 20 at the (n + 2) th switching timing is completed. Thereafter, in the control process of step S206, the control processes of steps S201, S202, and S205 to S209 are sequentially repeated until the flag control unit 210 determines that the rectangular wave flag is 1. Thereafter, in the control process of step S206, when the flag control unit 210 determines that the rectangular wave flag is 1 (step S206: Yes), the flag control unit 210 connects the contacts of the switch units 103 and 108 from the terminal B to the terminal B. Switch to A. Thus, the voltage phase command value α ^* is output to the rectangular wave generation unit 207 via the switch unit 103 as in the first embodiment. Thereafter, the control processes of steps S209 and S210 are executed. Thereafter, in the control process of step S202, the control processes of steps S201, S202, S205, S206, S210, and S211 are sequentially repeated until the flag control unit 210 determines that the rectangular wave flag has changed from 1 to 0.

As described above, the rectangular wave generation unit 207 according to the second embodiment adds the voltage phase command value α ^* (n + 2) and the error Δθ at the (n + 2) -th switching timing to obtain the actual voltage phase α (n + 2). Calculate. The switch unit 103 performs switching from the rectangular wave generation unit 207 to the PWM control unit 105 after the calculation of the rectangular wave generation unit 207 at the (n + 1) -th switching timing. From this, the same effects as those of the first embodiment can be obtained. Furthermore, the error Δθ = the error Δα can be calculated based on the motor rotation speed N [rpm] acquired with a delay of one switching timing as compared with the first embodiment. Therefore, even when the motor rotation speed N [rpm] changes from the n-th switching timing to the (n + 2) -th switching timing, the Δα calculation can be executed with high accuracy.

  Next, a modification of the second embodiment will be described with reference to FIG. FIG. 11 is a timing chart showing an output by the rectangular wave / PWM control switching process in the modification of the second embodiment. The controller according to the modification of the second embodiment has the same structure as the controller 20 according to the second embodiment. The modification of the second embodiment differs from the second embodiment in that a rectangular wave is generated as rectangular wave control means for making the (n + 1) th control cycle tnow equal to the PWM cycle Tpwm, as shown in FIG. Only the parts are different. That is, in the modified example of the second embodiment, as in the second embodiment, the rectangular wave generation unit is switched before switching from the rectangular wave generation unit to the PWM control unit 105 at the (n + 1) th switching timing. Performs the Δα operation. Furthermore, as in the second embodiment, the rectangular wave generation unit initializes the α filter calculation unit 102 with the actual voltage phase α (n + 2). Thereafter, at the (n + 1) -th switching timing, the switch unit 103 performs switching from the rectangular wave generation unit to the PWM control unit 105. Therefore, the same effect as in the second embodiment can be obtained. Furthermore, since the (n + 1) th control cycle tnow is shortened, the Δα calculation can be executed with higher accuracy than in the second embodiment. The modification of the second embodiment can be realized by setting the (n + 1) th control cycle tnow calculated by the rectangular wave generator at the nth switching timing to be equal to the PWM cycle Tpwm.

  As described above, the rectangular wave generation unit makes the (n + 1) th control cycle tnow equal to the PWM cycle calculated by the PWM control unit 105. Accordingly, the (n + 1) th control cycle tnow is shortened. Therefore, even when the motor rotation speed N [rpm] changes from the n-th switching timing to the (n + 2) -th switching timing, the Δα calculation can be executed with higher accuracy.

(Third embodiment)
Next, an inverter system according to a third embodiment will be described with reference to FIGS. 12 to 15 focusing on differences from the inverter system according to the first embodiment. Moreover, about the inverter system which concerns on 3rd Embodiment, the same number is attached | subjected to the structure similar to the inverter system which concerns on 1st Embodiment, and description is abbreviate | omitted. Note that the inverter system according to the third embodiment is almost the same as the inverter system according to the first embodiment. FIG. 12 is a control block diagram showing the internal configuration of the controller 30 according to the third embodiment of the present invention. As shown in FIG. 12, the only difference between the inverter system according to the third embodiment and the first embodiment is that the controller 30 is different.

Here, unlike the first embodiment, the controller 30 includes a Δα filter calculation unit 311 that is a second filter calculation unit and an addition unit 312 that is a first addition unit. Further, unlike the first embodiment, an α table reference unit 301 included in the controller 30, an α filter calculation unit 302 as a first filter calculation unit, a rectangular wave generation unit 307 as a rectangular wave control unit, and a flag control unit 310 is different. As in the first embodiment, the α table reference unit 301 stores a table stored in advance based on the torque command value T [N · m], the motor rotation speed N [rpm], and the DC voltage value Vdc [V]. Refer to Unlike the first embodiment, the pre-addition voltage phase command value α ″ ^* is obtained from the table. The α filter calculation unit 302 uses the transfer function 1 / (τ1s + 1) to determine the voltage before fluctuation suppression described later. The variation of the phase command value α ′ ^* is suppressed, and the time constant τ1 is about several ms as in the first embodiment.

  The rectangular wave generating unit 307 performs rectangular wave control on the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− of the inverter 1 as in the first embodiment. Specifically, as in the first embodiment, the rectangular wave generation unit 307 generates a three-phase comparison value. Similarly to the first embodiment, the rectangular wave generation unit 307 also calculates the next control cycle, calculates the next calculation timing, and generates the next control cycle command. Similarly to the first embodiment, the rectangular wave generation unit 307 calculates an error Δα (n + 3) (see FIG. 3) of the next calculation timing with respect to the current calculation timing for each calculation timing. Similarly to the first embodiment, when switching from the rectangular wave generation unit 307 to the PWM control unit 105 in the switch unit 103 is performed, the rectangular wave generation unit 307 has an actual voltage phase α (n + 3), The α filter calculation unit 302 is initialized. At the same time, the rectangular wave generation unit 307 initializes the Δα filter calculation unit 311 with the error Δα (n + 3).

As in the first embodiment, the flag control unit 310 stores a rectangular wave flag and controls the operations of the switch units 103 and 108 based on the rectangular wave flag. Specifically, when the rectangular wave flag becomes 1, the flag control unit 310 switches the contact points of the switch units 103 and 108 from the terminal B to the terminal A. From this, the rectangular wave generation unit 307 is caused to execute rectangular wave control for controlling the output voltages Vu [V], Vv [V], and Vw [V] into a rectangular wave shape. On the other hand, when the rectangular wave flag changes from 1 to 0, the flag control unit 310 switches the contacts of the switch units 103 and 108 from the terminal A to the terminal B. From this, the PWM control unit 105 is caused to execute PWM control for controlling the output voltages Vu [V], Vv [V], and Vw [V] in a pseudo sine wave shape. The Δα filter calculation unit 311 is a filter having a transfer function 1 / (τ2s + 1), and outputs a post-filter error Δα ′ to the addition unit 312. The time constant τ2 is about several hundred ms. Adding section 312 outputs the filter after the error [Delta] [alpha] 'and the addition before the voltage phase command value alpha ^"* before the addition-obtained fluctuation suppressing voltage phase command value alpha' ^* to alpha filter operation unit 302.

(Switching process from the rectangular wave generator 307 to the PWM controller 105)
Next, switching processing from the rectangular wave generation unit 307 that performs rectangular wave control to the PWM control unit 105 that performs PWM control in the third embodiment will be described. The switching process in the third embodiment is the same as that in the first embodiment. That is, the rectangular wave calculation is executed until the (n + 1) th switching timing, the switching is performed at the (n + 2) th switching timing, and then the PWM calculation is executed. As in the first embodiment, the PWM control unit 105 executes PWM control after the (n + 3) th switching timing. Similarly to the first embodiment, the rectangular wave generation unit 307 determines that the actual voltage phase α (n + 3) = voltage phase command value α ^* (n + 3) + Δθ before the switching at the (n + 2) -th switching timing. (1-K) (see FIG. 3) is calculated. Similarly to the first embodiment, the rectangular wave generation unit 307 initializes the α filter calculation unit 302 with the actual voltage phase α (n + 3). Furthermore, unlike the first embodiment, the rectangular wave generation unit 307 initializes the Δα filter calculation unit 311 with an error Δα (n + 3) = Δθ (1-K). Thereafter, the switching is performed.

Next, the effect when the switching process similar to that of the first embodiment in the controller 30 shown in FIG. 12 is executed will be described with reference to FIGS. 13 and 14. FIG. 13 is a diagram showing the actual voltage phase α when the switching process similar to that of the first embodiment is executed in the controller 30 shown in FIG. FIG. 14 is a diagram illustrating the motor rotation speed N [rpm] and the output power Pnt [kw] when the switching process similar to that of the first embodiment in the controller 30 illustrated in FIG. 12 is executed. In the prior art shown in FIG. 13A, the rectangular wave control voltage phase command value α ^* (n + 3) is directly used as the PWM control voltage phase command value α ^* at the (n + 3) -th switching timing. In the vicinity of switching from the rectangular wave control to the PWM control, when the motor rotation speed N [rpm] changes suddenly as shown in FIG. 14A, an error Δα (n + 3) occurs. As shown in FIG. 13A, the actual voltage phase α changes stepwise due to the error Δα (n + 3). When the actual voltage phase α changes stepwise, the output power Pnt [kw] oscillates after switching from rectangular wave control to PWM control. That is, the torque vibrates.

On the other hand, in the first embodiment, the rectangular wave generation unit 107 calculates an error Δα (n + 3) = Δθ (1-K) at the (n + 1) th switching timing. At the (n + 2) -th switching timing, the rectangular wave generation unit 107 calculates the actual voltage phase α (n + 3) = voltage phase command value α ^* (n + 3) + error Δα (n + 3), and the actual voltage phase α (n + 3). ) Initializes the α filter calculation unit 302. After the initialization, the switch unit 103 performs switching from the rectangular wave generation unit 107 to the PWM control unit 105. Immediately after the switching, the voltage phase command value α ^* output from the α filter calculation unit 302 to the PWM control unit 105 via the switch unit 103 is the actual voltage phase α (n + 3) as shown in FIG. Will be equal. Furthermore, as shown in FIG. 13B, the steep step-like change in the actual voltage phase α is mitigated by the filter action of the α filter calculation unit 102. From this, as shown in FIG. 14B, even when the motor rotation speed N [rpm] suddenly changes, the vibration of the output power Pnt [kw] is suppressed. However, although the stepwise steep change of the actual voltage phase α is alleviated, it is not sufficient because the time constant τ of the α filter calculation unit 102 is short.

Therefore, in the third embodiment, a Δα filter calculation unit 311 and an addition unit 312 are added. Specifically, as in the first embodiment, the rectangular wave generation unit 307 calculates an error Δα (n + 3) = Δθ (1-K) at the (n + 1) th switching timing. At the (n + 2) -th switching timing, the rectangular wave generation unit 307 calculates actual voltage phase α (n + 3) = voltage phase command value α ^* (n + 3) + error Δα (n + 3). Thereafter, the rectangular wave generation unit 307 initializes the α filter calculation unit 302 with the actual voltage phase α (n + 3) and initializes the Δα filter calculation unit 311 with the error Δα (n + 3). Immediately after initialization, the Δα filter calculation unit 311 outputs a post-filter error Δα ′ = error Δα (n + 3) to the adder 312. The adding unit 312 outputs the voltage phase command value α ′ ^* before fluctuation suppression obtained by adding the voltage phase command value α ″ ^* before addition and the error Δα (n + 3) to the α filter calculating unit 302.

After initialization, as in the first embodiment, the switch unit 103 performs switching from the rectangular wave generation unit 307 to the PWM control unit 105. As in the first embodiment, immediately after switching, the voltage phase command value α ^* output from the α filter calculation unit 302 to the PWM control unit 105 via the switch unit 103 is as shown in FIG. It becomes equal to the actual voltage phase α (n + 3). Similar to the first embodiment, the steep change in step of the actual voltage phase α is mitigated by the filter action of the α filter calculation unit 302. Furthermore, since the time constant τ2 of the Δα filter calculation unit 311 is long, the actual voltage phase α changes sufficiently smoothly by the filter action of the Δα filter calculation unit 311. From this, as shown in FIG.14 (c), even when the motor rotation speed N [rpm] changes suddenly, the vibration of output electric power Pnt [kw] can be suppressed more. Therefore, torque vibration can be further suppressed as compared with the first embodiment. Since the input value of the Δα filter calculation unit 311 is 0, the post-filter error Δα ′ has no effect unless it is initialized.

(Control method executed by the controller 30)
Next, a control method executed by the controller 30 according to the third embodiment will be described with reference to FIG. FIG. 15 is a flowchart showing a control method executed by the controller 30 shown in FIG. This control method is implemented by incorporating the program of the flowchart shown in FIG. This control process is almost the same as the control process executed by the controller 10 according to the first embodiment. The only difference between this control process and the control process executed by the controller 10 according to the first embodiment is that the control processes in steps S304 to S306 are added.

Similar to the control process in step S101 of the first embodiment, at the (n + 1) th switching timing, the α table reference unit 301 executes the α table reference process (step S301). Here, the α table reference processing refers to a table stored in advance based on the torque command value T [N · m], the motor rotation speed N [rpm], and the DC voltage value Vdc [V]. This is a control process for obtaining the voltage phase command value α ″ ^* . Next, the flag control unit 310 determines whether or not the rectangular wave flag stored in the flag control unit 310 has changed from 1 to 0 (step S302). When the flag control unit 310 determines that the rectangular wave flag has not changed from 1 to 0 (step S302: No), the Δα filter calculation unit 311 performs a Δα filter calculation and outputs a post-filter error Δα ′ to the addition unit 312. (Step S305).

Next, the adding unit 312 adds the post-filtering error Δα ′ to the pre-addition voltage phase command value α ″ ^* . The pre-fluctuation voltage phase command value α ′ ^* obtained by the addition is sent to the α filter calculation unit 302. In step S306, the α filter calculation unit 302 performs α filter calculation (step S307) in the same manner as the control process in step S104. The fluctuation of the value α ′ ^* is suppressed, and the voltage phase command value α ^* (n + 2) is output to the switch unit 103. Thereafter, steps S308, S312 and S313, which are the same as the control processing of steps S105, S109 and S110, respectively. Thus, the control process of the controller 30 at the (n + 1) th switching timing is completed.

When the flag control unit 310 determines that the rectangular wave flag has changed from 1 to 0 at the (n + 2) -th switching timing (step S302: Yes), the process proceeds to the control process of step S303. In the control process of step S303, the flag control unit 310 causes the rectangular wave generation unit 307 to initialize the α filter calculation unit 302 with the actual voltage phase α (n + 3), similarly to the control process of step S103. Next, the rectangular wave generation unit 307 initializes the Δα filter calculation unit 311 with an error Δα (n + 3) (step S304). Next, the Δα filter calculation unit 311 performs a Δα filter calculation and outputs a post-filter error Δα ′ to the addition unit 312 (step S305). In the control process of step S304, the Δα filter calculation unit 311 is initialized with the error Δα (n + 3), so the post-filter error Δα ′ is equal to the error Δα (n + 3). Next, the adding unit 312 adds the post-filtering error Δα ′ to the pre-addition voltage phase command value α ″ ^* . The pre-fluctuation voltage phase command value α ′ ^* obtained by the addition is sent to the α filter calculation unit 302. Output (step S306).

Next, as in the control process in step S104, the α filter calculation unit 302 performs α filter calculation (step S307). In the control process of step S303, since the α filter calculation unit 302 is initialized with the actual voltage phase α (n + 3), the voltage phase command value α ^* output from the α filter calculation unit 302 is the actual voltage phase α. It becomes equal to (n + 3). Next, similarly to the control process in step S105, the flag control unit 310 determines whether or not the rectangular wave flag is 1 (step S308). As in the first embodiment, since the flag control unit 310 determines that the rectangular wave flag is not 1 (step S308: No), the flag control unit 310 connects the contacts of the switch units 103 and 108 from the terminal A to the terminal B. Switch to. Thus, as in the first embodiment, the voltage phase command value α ^* = the actual voltage phase α (n + 3) is output to the PWM control unit 105 via the switch unit 103. Thereafter, the control processes of steps S309 to S311 that are similar to the control processes of steps S106 to S108, respectively, are executed. Thus, the control process of the controller 30 at the (n + 2) th switching timing is completed.

As in the first embodiment, since the rectangular wave flag is already 0 at the (n + 3) -th switching timing, the flag control unit 310 determines that the rectangular wave flag has not changed from 1 to 0 ( Step S302: No). Thereafter, the control processing of steps S305 to S311 is executed. Thus, the control process of the controller 30 at the (n + 3) th switching timing is completed. Thereafter, in the control process of step S308, the control processes of steps S301, S302, S305 to S311 are sequentially repeated until the flag control unit 310 determines that the rectangular wave flag is 1. Thereafter, in the control process of step S308, when the flag control unit 310 determines that the rectangular wave flag is 1 (step S308: Yes), the flag control unit 310 connects the contact points of the switch units 103 and 108 from the terminal B to the terminal B. Switch to A. Accordingly, the voltage phase command value α ^* is output to the rectangular wave generation unit 307 via the switch unit 103 as in the first embodiment. Thereafter, the control processes of steps S312 and S313 are executed. Thereafter, in the control process of step S302, the control processes of steps S301, S302, S305 to S308, S312 and S313 are sequentially repeated until the flag control unit 310 determines that the rectangular wave flag has changed from 1 to 0.

As described above, the controller 30 according to the third embodiment includes the Δα filter calculation unit 311 that outputs the error Δα (n + 3) immediately after switching from the rectangular wave generation unit 307 to the PWM control unit 105 in the switch unit 103. Further, an addition for outputting the voltage phase command value α ′ ^* before fluctuation suppression obtained by adding the error Δα (n + 3) from the Δα filter calculation unit 311 and the voltage phase command value α ″ ^* before addition to the α filter calculation unit 302. From this, it is possible to obtain the same effect as in the first embodiment, and further, generated immediately after switching from the rectangular wave generation unit 307 to the PWM control unit 105 due to the filter action of the Δα filter calculation unit 311. As a result, the stepwise steep change in the actual voltage phase α can be sufficiently smoothed, so that torque vibration can be further suppressed as compared with the first embodiment.

(Fourth embodiment)
Next, an inverter system according to a fourth embodiment will be described with reference to FIGS. 16 to 17 focusing on differences from the inverter system according to the second embodiment. Moreover, about the inverter system which concerns on 4th Embodiment, the same number is attached | subjected to the structure similar to the inverter system which concerns on 2nd and 3rd embodiment, and description is abbreviate | omitted. Note that the inverter system according to the fourth embodiment is almost the same as the inverter system according to the second embodiment. FIG. 16 is a control block diagram showing an internal configuration of the controller 40 according to the fourth embodiment of the present invention. As shown in FIG. 16, the only difference between the inverter system according to the fourth embodiment and the second embodiment is that the controller 40 is different.

  Here, unlike the second embodiment, the controller 40 includes a Δα filter calculation unit 311 that is a second filter calculation unit and an addition unit 312 that is a first addition unit. Also, unlike the second embodiment, an α table reference unit 301 included in the controller 40, an α filter calculation unit 302 as a first filter calculation unit, a rectangular wave generation unit 407 as a rectangular wave control unit, and a flag control unit 410 is different. The rectangular wave generation unit 407 performs rectangular wave control on the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− of the inverter 1 as in the second embodiment. Specifically, as in the second embodiment, the rectangular wave generation unit 407 generates a three-phase comparison value.

  Further, similarly to the second embodiment, the rectangular wave generation unit 407 calculates the next control cycle, calculates the next calculation timing, and generates the next control cycle command. Further, similarly to the second embodiment, the rectangular wave generation unit 407 calculates an error Δα (n + 2) (see FIG. 3) of the next calculation timing with respect to the current calculation timing for each calculation timing. Furthermore, as in the second embodiment, when switching from the rectangular wave generating unit 407 to the PWM control unit 105 in the switch unit 103 is performed, the rectangular wave generating unit 407 has an actual voltage phase α (n + 2) (FIG. 3), the α filter calculation unit 302 is initialized. At the same time, the rectangular wave generation unit 407 initializes the Δα filter calculation unit 311 with an error Δα (n + 2).

  As in the second embodiment, the flag control unit 410 stores a rectangular wave flag and controls the operations of the switch units 103 and 108 based on the rectangular wave flag. Specifically, when the rectangular wave flag becomes 1, the flag control unit 410 switches the contact points of the switch units 103 and 108 from the terminal B to the terminal A. From this, the rectangular wave generation unit 407 is caused to execute rectangular wave control for controlling the output voltages Vu [V], Vv [V], and Vw [V] into a rectangular wave shape. On the other hand, when the rectangular wave flag changes from 1 to 0, the flag control unit 410 switches the contacts of the switch units 103 and 108 from the terminal A to the terminal B. From this, the PWM control unit 105 is caused to execute PWM control for controlling the output voltages Vu [V], Vv [V], and Vw [V] in a pseudo sine wave shape.

(Switching process from the rectangular wave generator 407 to the PWM controller 105)
Next, switching processing from the rectangular wave generating unit 407 that performs rectangular wave control to the PWM control unit 105 that performs PWM control in the fourth embodiment will be described. The switching process in the fourth embodiment is the same as that in the second embodiment. That is, the rectangular wave calculation is executed until the n-th switching timing, the switching is performed at the (n + 1) -th switching timing, and then the PWM calculation is executed. As in the second embodiment, the PWM control unit 105 executes PWM control after the (n + 2) th switching timing. Similarly to the second embodiment, the rectangular wave generation unit 407, at the (n + 1) -th switching timing, before the switching, the actual voltage phase α (n + 2) = voltage phase command value α ^* (n + 2) + The error Δα (n + 2) is calculated.

  Similarly to the second embodiment, the rectangular wave generation unit 407 initializes the α filter calculation unit 302 with the actual voltage phase α (n + 2). Furthermore, unlike the second embodiment, the rectangular wave generation unit 407 initializes the Δα filter calculation unit 311 with an error Δα (n + 2) = Δθ (see FIG. 3). Thereafter, the switching is performed. From this, the same effects as those of the second embodiment can be obtained. Further, even when the motor rotation speed N [rpm] suddenly changes before and after switching from the rectangular wave generation unit 407 to the PWM control unit 105, the time constant τ2 of the Δα filter calculation unit 311 is long, so that the actual voltage phase α is sufficient. It can be changed smoothly. That is, it becomes the same as the change shown in FIG. From this, the vibration of the output power Pnt [kw] can be further suppressed. Therefore, torque vibration can be further suppressed as compared with the second embodiment.

(Control method executed by the controller 40)
Next, a control method executed by the controller 40 according to the fourth embodiment will be described with reference to FIG. FIG. 17 is a flowchart showing a control method executed by the controller 40 shown in FIG. This control method is implemented by incorporating the program of the flowchart shown in FIG. This control process is almost the same as the control process executed by the controller 20 according to the second embodiment. The only difference between this control process and the control process executed by the controller 20 according to the second embodiment is that the control processes in steps S405 to S407 are added.

Similar to the control process in step S201 of the second embodiment, the α table reference unit 301 executes the α table reference process at the n-th switching timing (step S401). Here, the α table reference processing refers to a table stored in advance based on the torque command value T [N · m], the motor rotation speed N [rpm], and the DC voltage value Vdc [V]. This is a control process for obtaining the voltage phase command value α ″ ^* . Next, the flag control unit 410 determines whether or not the rectangular wave flag stored in the flag control unit 410 has changed from 1 to 0 (step S402). When the flag control unit 410 determines that the rectangular wave flag has not changed from 1 to 0 (step S402: No), the Δα filter calculation unit 311 performs a Δα filter calculation and outputs a post-filter error Δα ′ to the addition unit 312. (Step S406).

Next, the adding unit 312 adds the post-filtering error Δα ′ to the pre-addition voltage phase command value α ″ ^* . The pre-fluctuation voltage phase command value α ′ ^* obtained by the addition is sent to the α filter calculation unit 302. In step S407, the α filter calculation unit 302 performs α filter calculation in the same manner as the control process in step S205 (step S408) Specifically, the α filter calculation unit 302 outputs the voltage phase command before fluctuation suppression. The variation of the value α ′ ^* is suppressed, and the voltage phase command value α ^* (n + 1) is output to the switch unit 103. Thereafter, steps S409, S413, and S414, which are the same as the control processes in steps S206, S210, and S211, respectively. Thus, the control process of the controller 40 at the n-th switching timing is completed.

When the flag control unit 410 determines that the rectangular wave flag has changed from 1 to 0 at the (n + 1) th switching timing (step S402: Yes), the process proceeds to the control process of step S403. In the control process of step S403, the flag control unit 410 causes the rectangular wave generation unit 407 to execute Δα calculation, similarly to the control process of step S203. Next, the rectangular wave generation unit 407 initializes the α filter calculation unit 302 with the actual voltage phase α (n + 2), similarly to the control processing in step S204 (step S404). Next, the rectangular wave generation unit 407 initializes the Δα filter calculation unit 311 with an error Δα (n + 2) (step S405). Next, the Δα filter calculation unit 311 performs a Δα filter calculation and outputs a post-filter error Δα ′ to the addition unit 312 (step S406). In the control process of step S405, the Δα filter calculation unit 311 is initialized with the error Δα (n + 2), so the post-filter error Δα ′ is equal to the error Δα (n + 2). Next, the adding unit 312 adds the post-filtering error Δα ′ to the pre-addition voltage phase command value α ″ ^* . The pre-fluctuation voltage phase command value α ′ ^* obtained by the addition is sent to the α filter calculation unit 302. Output (step S407).

Next, as in the control process of step S205, the α filter calculation unit 302 performs α filter calculation (step S408). In the control processing of step S404, the α filter calculation unit 302 is initialized with the actual voltage phase α (n + 2), and therefore the voltage phase command value α ^* that is the output of the α filter calculation unit 302 is the actual voltage phase α. It becomes equal to (n + 2). Next, similarly to the control process in step S206, the flag control unit 410 determines whether or not the rectangular wave flag is 1 (step S409). As in the second embodiment, since the flag control unit 410 determines that the rectangular wave flag is not 1 (step S409: No), the flag control unit 410 connects the contacts of the switch units 103 and 108 from the terminal A to the terminal B. Switch to. Thus, as in the second embodiment, the voltage phase command value α ^* = actual voltage phase α (n + 2) is output to the PWM control unit 105 via the switch unit 103. Thereafter, the control processes of steps S410 to S412 that are similar to the control processes of steps S207 to S209 are executed. Thus, the control process of the controller 40 at the (n + 1) th switching timing is completed.

As in the second embodiment, since the rectangular wave flag is already 0 at the (n + 2) -th switching timing, the flag control unit 410 determines that the rectangular wave flag has not changed from 1 to 0 ( Step S402: No). Thereafter, the control processing of steps S406 to S412 is executed. Thus, the control process of the controller 40 at the (n + 2) th switching timing is completed. Thereafter, in the control process of step S409, the control processes of steps S401, S402, and S406 to S412 are sequentially repeated until the flag control unit 410 determines that the rectangular wave flag is 1. Thereafter, in the control process of step S409, when the flag control unit 410 determines that the rectangular wave flag is 1 (step S409: Yes), the flag control unit 410 connects the contact points of the switch units 103 and 108 from the terminal B to the terminal B. Switch to A. Accordingly, the voltage phase command value α ^* is output to the rectangular wave generation unit 407 via the switch unit 103 as in the second embodiment. Thereafter, the control processes of steps S413 and S414 are executed. Thereafter, in the control process of step S402, the control processes of steps S401, S402, S406 to 409, S413, and S414 are sequentially repeated until the flag control unit 410 determines that the rectangular wave flag has changed from 1 to 0.

As described above, the controller 40 according to the fourth embodiment includes the Δα filter calculation unit 311 that outputs the error Δα (n + 2) immediately after switching from the rectangular wave generation unit 407 to the PWM control unit 105 in the switch unit 103. Further, an addition for outputting the voltage phase command value α ′ ^* before fluctuation suppression obtained by adding the error Δα (n + 2) from the Δα filter calculation unit 311 and the voltage phase command value α ″ ^* before addition to the α filter calculation unit 302 From this, it is possible to acquire the same effect as in the second embodiment, and it occurs immediately after switching from the rectangular wave generation unit 307 to the PWM control unit 105 due to the filter action of the Δα filter calculation unit 311. As a result, the stepwise steep change of the actual voltage phase α can be sufficiently smoothed, so that torque vibration can be further suppressed as compared with the second embodiment.

(Fifth embodiment)
Next, an inverter system according to a fifth embodiment will be described with reference to FIGS. 18 to 19, focusing on differences from the inverter system according to the first embodiment. Moreover, about the inverter system which concerns on 5th Embodiment, the same number is attached | subjected to the structure similar to the inverter system which concerns on 1st and 3rd embodiment, and description is abbreviate | omitted. Note that the inverter system according to the fifth embodiment is almost the same as the inverter system according to the first embodiment. FIG. 18 is a control block diagram showing the internal configuration of the controller 50 according to the fifth embodiment of the present invention. As shown in FIG. 18, the inverter system according to the fifth embodiment is different from the first embodiment only in that the controller 50 is different.

Here, unlike the first embodiment, the controller 50 includes a ΔT filter calculation unit 511 that is a third filter calculation unit and an addition unit 512 that is a second addition unit. Further, unlike the first embodiment, an α table reference unit 501 included in the controller 50, an α filter calculation unit 302 as a first filter calculation unit, a rectangular wave generation unit 507 as a rectangular wave control unit, and a flag control unit 510 is different. The α table reference unit 501 is different from the first embodiment in advance based on an after-addition torque command value T ″ [N · m], a motor rotation speed N [rpm], and a DC voltage value Vdc [V]. The stored table is referred to, and the voltage phase command value α ′ ^* before fluctuation suppression is obtained from the table.

  The rectangular wave generation unit 507 performs rectangular wave control on the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− of the inverter 1 as in the first embodiment. Specifically, as in the first embodiment, the rectangular wave generation unit 507 generates a three-phase comparison value. Similarly to the first embodiment, the rectangular wave generation unit 507 also calculates the next control cycle, calculates the next calculation timing, and generates the next control cycle command. Further, as in the first embodiment, the rectangular wave generation unit 507 calculates an error Δα (n + 3) (see FIG. 3) of the next calculation timing with respect to the current calculation timing for each calculation timing. Similarly to the first embodiment, when switching from the rectangular wave generation unit 507 to the PWM control unit 105 in the switch unit 103 is performed, the rectangular wave generation unit 507 has the actual voltage phase α (n + 3), The α filter calculation unit 302 is initialized. At the same time, the rectangular wave generation unit 507 calculates a torque conversion value ΔT (n + 3) [N · m], which is a torque difference corresponding to the error Δα (n + 3), and ΔT with the torque conversion value ΔT (n + 3) [N · m]. The filter calculation unit 511 is initialized.

  Similarly to the first embodiment, the flag control unit 510 stores a rectangular wave flag and controls the operations of the switch units 103 and 108 based on the rectangular wave flag. Specifically, when the rectangular wave flag becomes 1, the flag control unit 510 switches the contact points of the switch units 103 and 108 from the terminal B to the terminal A. From this, the rectangular wave generation unit 507 is caused to execute rectangular wave control for controlling the output voltages Vu [V], Vv [V], and Vw [V] into a rectangular wave shape. On the other hand, when the rectangular wave flag changes from 1 to 0, the flag control unit 510 switches the contacts of the switch units 103 and 108 from the terminal A to the terminal B. From this, the PWM control unit 105 is caused to execute PWM control for controlling the output voltages Vu [V], Vv [V], and Vw [V] in a pseudo sine wave shape. The ΔT filter calculation unit 511 is a filter having a transfer function 1 / (τ3s + 1), and outputs a post-filter torque conversion value ΔT ′ [N · m] to the addition unit 512. The time constant τ3 is about several hundred ms. The adding unit 512 adds the filtered torque converted value ΔT ′ [N · m] and the torque command value T [N · m], and adds the added torque command value T ″ [N · m] to the α table reference unit 501. Output.

(Switching process from the rectangular wave generator 507 to the PWM controller 105)
Next, switching processing from the rectangular wave generating unit 507 that performs rectangular wave control to the PWM control unit 105 that performs PWM control in the fifth embodiment will be described. The switching process in the fifth embodiment is the same as that in the first embodiment. That is, the rectangular wave calculation is executed until the (n + 1) th switching timing, the switching is performed at the (n + 2) th switching timing, and then the PWM calculation is executed. As in the first embodiment, the PWM control unit 105 executes PWM control after the (n + 3) th switching timing. Similarly to the first embodiment, the rectangular wave generation unit 507 performs the actual voltage phase α (n + 3) = voltage phase command value α ^* (n + 3) + Δθ before the switching at the (n + 2) -th switching timing. (1-K) (see FIG. 3) is calculated. Similarly to the first embodiment, the rectangular wave generation unit 507 initializes the α filter calculation unit 302 with the actual voltage phase α (n + 3).

  Further, unlike the first embodiment, the rectangular wave generation unit 507 calculates a torque conversion value ΔT (n + 3) [N · m] obtained by converting the error Δα (n + 3) = Δθ (1−K) into torque. Then, the rectangular wave generation unit 507 initializes the ΔT filter calculation unit 511 with the torque conversion value ΔT (n + 3) [N · m]. Thereafter, the switching is performed. From this, the same effects as those of the first embodiment shown in FIGS. 5 and 6 can be obtained. Furthermore, even when the motor rotation speed N [rpm] suddenly changes before and after switching from the rectangular wave generation unit 507 to the PWM control unit 105, the time constant τ3 of the ΔT filter calculation unit 511 is long, so that the actual voltage phase α is sufficient. It can be changed smoothly. That is, it becomes the same as the change shown in FIG. From this, the vibration of the output power Pnt [kw] can be further suppressed. Therefore, torque vibration can be further suppressed as compared with the first embodiment. Since the input value of the ΔT filter calculation unit 511 is 0, the post-filter torque conversion value ΔT ′ [N · m] has no effect unless it is initialized.

(Control method executed by the controller 50)
Next, a control method executed by the controller 50 according to the fifth embodiment will be described with reference to FIG. FIG. 19 is a flowchart showing a control method executed by the controller 50 shown in FIG. This control method is implemented by incorporating the program of the flowchart shown in FIG. This control process is almost the same as the control process executed by the controller 10 according to the first embodiment. The only difference between the control process executed by the controller 10 according to the first embodiment and the present control process is that the control processes of steps S504 to S506 are added.

Similar to the control process in step S101 of the first embodiment, at the (n + 1) th switching timing, the α table reference unit 501 executes the α table reference process (step S501). Here, the α table reference processing refers to a table stored in advance based on the added torque command value T ″ [N · m], the motor rotation speed N [rpm], and the DC voltage value Vdc [V]. This is a control process for obtaining the voltage phase command value α ′ ^* before fluctuation suppression.Next, the flag control unit 510 determines whether or not the rectangular wave flag stored in the flag control unit 510 has changed from 1 to 0 ( (Step S502) When the flag control unit 510 determines that the rectangular wave flag has not changed from 1 to 0 (Step S502: No), the ΔT filter calculation unit 511 performs a ΔT filter calculation. The value ΔT ′ [N · m] is output to the adding unit 512 (step S505).

Next, the adding unit 512 adds the post-filter torque conversion value ΔT ′ [N · m] to the torque command value T [N · m]. The added torque command value T ″ [N · m] obtained by the addition is output to the α table reference unit 501 (step S506). Next, the α filter calculation unit 302 performs the same process as the control process of step S104. (Alpha) filter calculation (step S507) Specifically, the α filter calculation unit 302 suppresses fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression, and sends the voltage phase command value α ^* (n + 2) to the switch unit 103. Thereafter, the control processes of steps S508, S512, and S513, which are the same as the control processes of steps S105, S109, and S110, respectively, are executed, As described above, the control process of the controller 50 at the (n + 1) th switching timing. Exit.

  When the flag control unit 510 determines that the rectangular wave flag has changed from 1 to 0 at the (n + 2) -th switching timing (step S502: Yes), the process proceeds to the control process of step S503. In the control process of step S503, the flag control unit 510 causes the rectangular wave generation unit 507 to initialize the α filter calculation unit 302 with the actual voltage phase α (n + 3), similarly to the control process of step S103. Next, the rectangular wave generation unit 507 initializes the ΔT filter calculation unit 511 with the torque conversion value ΔT (n + 3) [N · m] (step S504). Next, the ΔT filter calculation unit 511 performs a ΔT filter calculation, and outputs the filtered torque conversion value ΔT ′ [N · m] to the addition unit 512 (step S505). In the control process of step S504, since the ΔT filter calculation unit 511 is initialized with the torque conversion value ΔT (n + 3) [N · m], the post-filter torque conversion value ΔT ′ [N · m] is the torque conversion value ΔT. It is equal to (n + 3) [N · m]. Next, the adding unit 512 adds the filtered torque conversion value ΔT ′ [N · m] to the torque command value T [N · m]. The added torque command value T ″ [N · m] obtained by the addition is output to the α table reference unit 501 (step S506).

Next, as in the control process of step S104, the α filter calculation unit 302 performs α filter calculation (step S507). In the control process of step S503, the α filter calculation unit 302 is initialized with the actual voltage phase α (n + 3), so the voltage phase command value α ^* that is the output of the α filter calculation unit 302 is the actual voltage phase α. It becomes equal to (n + 3). Next, similarly to the control process in step S105, the flag control unit 510 determines whether or not the rectangular wave flag is 1 (step S508). As in the first embodiment, since the flag control unit 510 determines that the rectangular wave flag is not 1 (step S508: No), the flag control unit 510 connects the contacts of the switch units 103 and 108 from the terminal A to the terminal B. Switch to. Thus, as in the first embodiment, the voltage phase command value α ^* = the actual voltage phase α (n + 3) is output to the PWM control unit 105 via the switch unit 103. Thereafter, the control processing of steps S509 to S511, which is the same as the control processing of steps S106 to S108, respectively, is executed. Thus, the control process of the controller 50 at the (n + 2) th switching timing is completed.

As in the first embodiment, since the rectangular wave flag is already 0 at the (n + 3) -th switching timing, the flag control unit 510 determines that the rectangular wave flag has not changed from 1 to 0 ( Step S502: No). Thereafter, the control processing of steps S505 to S511 is executed. Thus, the control process of the controller 50 at the (n + 3) th switching timing is completed. Thereafter, in the control process of step S508, the control processes of steps S501, S502, S505 to S511 are sequentially repeated until the flag control unit 510 determines that the rectangular wave flag is 1. Thereafter, in the control process of step S508, when the flag control unit 510 determines that the rectangular wave flag is 1 (step S508: Yes), the flag control unit 510 connects the contact points of the switch units 103 and 108 from the terminal B to the terminal B. Switch to A. Accordingly, the voltage phase command value α ^* is output to the rectangular wave generation unit 507 via the switch unit 103 as in the first embodiment. Thereafter, the control processes of steps S512 and S513 are executed. Thereafter, the control processes of steps S501, S502, S505 to S508, S512, and S513 are sequentially repeated until the flag control unit 510 determines that the rectangular wave flag has changed from 1 to 0 in the control process of step S502.

  As described above, the controller 50 according to the fifth embodiment includes the ΔT filter calculation unit 511. The ΔT filter calculation unit 511 outputs a torque conversion value ΔT (n + 3) [N · m] corresponding to an error Δα (n + 3) = Δθ (1-K) immediately after switching from the rectangular wave generation unit 507 to the PWM control unit 105. To do. An addition unit 512 that adds the torque conversion value ΔT (n + 3) [N · m] and the torque command value T [N · m] is provided. From this, the same effects as those of the first embodiment can be obtained. Further, the filter action of the ΔT filter calculation unit 511 can sufficiently smooth the stepwise steep change of the actual voltage phase α that occurs immediately after switching from the rectangular wave generation unit 507 to the PWM control unit 105. Therefore, torque vibration can be further suppressed as compared with the first embodiment.

(Sixth embodiment)
Next, an inverter system according to a sixth embodiment will be described with reference to FIGS. 20 to 21 with a focus on differences from the inverter system according to the second embodiment. Moreover, about the inverter system which concerns on 6th Embodiment, the same number is attached | subjected to the structure similar to the inverter system which concerns on 2nd, 3rd and 5th embodiment, and description is abbreviate | omitted. Note that the inverter system according to the sixth embodiment is almost the same as the inverter system according to the second embodiment. FIG. 20 is a control block diagram showing the internal configuration of the controller 60 according to the sixth embodiment of the present invention. As shown in FIG. 20, the only difference between the inverter system according to the sixth embodiment and the second embodiment is that the controller 60 is different.

  Here, unlike the second embodiment, the controller 60 includes a ΔT filter calculation unit 511 that is a third filter calculation unit and an addition unit 512 that is a second addition unit. Also, unlike the second embodiment, an α table reference unit 501 included in the controller 60, an α filter calculation unit 302 as a first filter calculation unit, a rectangular wave generation unit 607 as a rectangular wave control unit, and a flag control unit 610 is different. The rectangular wave generator 607 performs rectangular wave control on the switching elements Tu +, Tu−, Tv +, Tv−, Tw +, and Tw− of the inverter 1 as in the second embodiment. Specifically, as in the second embodiment, the rectangular wave generation unit 607 generates a three-phase comparison value.

  Similarly to the second embodiment, the rectangular wave generation unit 607 calculates the next control cycle, calculates the next calculation timing, and generates the next control cycle command. Further, as in the second embodiment, the rectangular wave generation unit 607 calculates an error Δα (n + 2) (see FIG. 3) of the next calculation timing with respect to the current calculation timing for each calculation timing. Further, as in the second embodiment, when switching from the rectangular wave generating unit 607 to the PWM control unit 105 in the switch unit 103 is performed, the rectangular wave generating unit 607 determines the actual voltage phase α (n + 2) (FIG. 3), the α filter calculation unit 302 is initialized. At the same time, the rectangular wave generating unit 607 calculates a torque conversion value ΔT (n + 2) [N · m], which is a torque difference corresponding to the error Δα (n + 2), and ΔT with the torque conversion value ΔT (n + 2) [N · m]. The filter calculation unit 511 is initialized.

  Similarly to the second embodiment, the flag control unit 610 stores a rectangular wave flag, and controls the operations of the switch units 103 and 108 based on the rectangular wave flag. Specifically, when the rectangular wave flag becomes 1, the flag control unit 610 switches the contact points of the switch units 103 and 108 from the terminal B to the terminal A. From this, the rectangular wave generation unit 607 is caused to execute rectangular wave control for controlling the output voltages Vu [V], Vv [V], and Vw [V] into a rectangular wave shape. On the other hand, when the rectangular wave flag changes from 1 to 0, the flag control unit 610 switches the contact points of the switch units 103 and 108 from the terminal A to the terminal B. From this, the PWM control unit 105 is caused to execute PWM control for controlling the output voltages Vu [V], Vv [V], and Vw [V] in a pseudo sine wave shape.

(Switching process from the rectangular wave generator 607 to the PWM controller 105)
Next, switching processing from the rectangular wave generation unit 607 that performs rectangular wave control to the PWM control unit 105 that performs PWM control in the sixth embodiment will be described. The switching process in the sixth embodiment is the same as that in the second embodiment. That is, the rectangular wave calculation is executed until the n-th switching timing, the switching is performed at the (n + 1) -th switching timing, and then the PWM calculation is executed. As in the second embodiment, the PWM control unit 105 executes PWM control after the (n + 2) th switching timing. Similarly to the second embodiment, the rectangular wave generation unit 607 determines that the actual voltage phase α (n + 2) = voltage phase command value α ^* (n + 2) + before the switching at the (n + 1) th switching timing. The error Δα (n + 2) is calculated.

  Similarly to the second embodiment, the rectangular wave generation unit 607 initializes the α filter calculation unit 302 with the actual voltage phase α (n + 2). Further, unlike the second embodiment, the rectangular wave generation unit 607 calculates a torque converted value ΔT (n + 2) [N · m] obtained by converting the error Δα (n + 2) = Δθ into torque. Then, the rectangular wave generation unit 607 initializes the ΔT filter calculation unit 511 with the torque conversion value ΔT (n + 2) [N · m]. Thereafter, the switching is performed. From this, the same effects as those of the second embodiment can be obtained. Furthermore, even when the motor rotation speed N [rpm] suddenly changes before and after switching from the rectangular wave generation unit 607 to the PWM control unit 105, the time constant τ3 of the ΔT filter calculation unit 511 is long, so that the actual voltage phase α is sufficient. It can be changed smoothly. That is, it becomes the same as the change shown in FIG. From this, the vibration of the output power Pnt [kw] can be further suppressed. Therefore, torque vibration can be further suppressed as compared with the second embodiment.

(Control method executed by the controller 60)
Next, a control method executed by the controller 60 according to the sixth embodiment will be described with reference to FIG. FIG. 21 is a flowchart showing a control method executed by the controller 60 shown in FIG. This control method is implemented by incorporating the program of the flowchart shown in FIG. This control process is almost the same as the control process executed by the controller 20 according to the second embodiment. The only difference between the control process executed by the controller 20 according to the second embodiment and the present control process is that the control processes in steps S605 to S607 are added.

Similar to the control process in step S201 of the second embodiment, the α table reference unit 501 executes the α table reference process at the n-th switching timing (step S601). Here, the α table reference processing refers to a table stored in advance based on the added torque command value T ″ [N · m], the motor rotation speed N [rpm], and the DC voltage value Vdc [V]. This is a control process for obtaining the voltage phase command value α ′ ^* before fluctuation suppression.Next, the flag control unit 610 determines whether or not the rectangular wave flag stored in the flag control unit 610 has changed from 1 to 0 ( Step S602) When the flag control unit 610 determines that the rectangular wave flag has not changed from 1 to 0 (Step S602: No), the ΔT filter calculation unit 511 performs ΔT filter calculation. The value ΔT ′ [N · m] is output to the adding unit 512 (step S606).

Next, the adding unit 512 adds the post-filter torque conversion value ΔT ′ [N · m] to the torque command value T [N · m]. The added torque command value T ″ [N · m] obtained by the addition is output to the α table reference unit 501 (step S607). The α filter calculation unit 302 performs the α filter similarly to the control process of step S205. More specifically, the α filter calculation unit 302 suppresses fluctuations in the voltage phase command value α ′ ^* before fluctuation suppression, and outputs the voltage phase command value α ^* (n + 1) to the switch unit 103. Thereafter, the control processes of steps S609, S613, and S614, which are the same as the control processes of steps S206, S210, and S211, respectively, are executed, and the control process of the controller 60 at the n-th switching timing is ended.

  When the flag control unit 610 determines that the rectangular wave flag has changed from 1 to 0 at the (n + 1) -th switching timing (step S602: Yes), the process proceeds to the control process of step S603. In the control process of step S603, the flag control unit 610 causes the rectangular wave generation unit 607 to execute Δα calculation, similarly to the control process of step S203. Next, the rectangular wave generation unit 607 initializes the α filter calculation unit 302 with the actual voltage phase α (n + 2), similarly to the control processing in step S204 (step S604). Next, the rectangular wave generation unit 607 initializes the ΔT filter calculation unit 511 with the torque conversion value ΔT (n + 2) [N · m] (step S605). Next, the ΔT filter calculation unit 511 performs a ΔT filter calculation, and outputs a post-filter torque conversion value ΔT ′ [N · m] to the addition unit 512 (step S606). In the control process of step S605, since the ΔT filter calculation unit 511 is initialized with the torque conversion value ΔT (n + 2) [N · m], the post-filter torque conversion value ΔT ′ [N · m] is the torque conversion value ΔT. It is equal to (n + 2) [N · m]. Next, the adding unit 512 adds the filtered torque conversion value ΔT ′ [N · m] to the torque command value T [N · m]. The added torque command value T ″ [N · m] obtained by the addition is output to the α table reference unit 501 (step S607).

Next, as in the control process in step S205, the α filter calculation unit 302 performs α filter calculation (step S608). In the control processing of step S604, the α filter calculation unit 302 is initialized with the actual voltage phase α (n + 2), so that the voltage phase command value α ^* that is the output of the α filter calculation unit 302 is the actual voltage phase α It becomes equal to (n + 2). Next, similarly to the control process in step S206, the flag control unit 610 determines whether or not the rectangular wave flag is 1 (step S609). As in the second embodiment, since the flag control unit 610 determines that the rectangular wave flag is not 1 (step S609: No), the flag control unit 610 connects the contacts of the switch units 103 and 108 from the terminal A to the terminal B. Switch to. Thus, as in the second embodiment, the voltage phase command value α ^* = actual voltage phase α (n + 2) is output to the PWM control unit 105 via the switch unit 103. Thereafter, the control processes of steps S610 to S612 that are similar to the control processes of steps S207 to S209 are executed. Thus, the control process of the controller 60 at the (n + 1) th switching timing is completed.

As in the second embodiment, since the rectangular wave flag is already 0 at the (n + 2) -th switching timing, the flag control unit 610 determines that the rectangular wave flag has not changed from 1 to 0 ( Step S602: No). Thereafter, the control process of steps S606 to S612 is executed. Thus, the control process of the controller 60 at the (n + 2) th switching timing is completed. Thereafter, in the control process of step S609, the control processes of steps S601, S602, and S606 to S612 are sequentially repeated until the flag control unit 610 determines that the rectangular wave flag is 1. Thereafter, in the control process of step S609, when the flag control unit 610 determines that the rectangular wave flag is 1 (step S609: Yes), the flag control unit 610 connects the contacts of the switch units 103 and 108 from the terminal B to the terminal B Switch to A. Accordingly, the voltage phase command value α ^* is output to the rectangular wave generation unit 607 via the switch unit 103 as in the second embodiment. Thereafter, the control processes of steps S613 and S614 are executed. Thereafter, in the control process in step S602, the control processes in steps S601, S602, S606 to 609, S613, and S614 are sequentially repeated until the flag control unit 610 determines that the rectangular wave flag has changed from 1 to 0.

  As described above, the controller 60 according to the sixth embodiment includes the ΔT filter calculation unit 511. The ΔT filter calculation unit 511 outputs a torque conversion value ΔT (n + 2) [N · m] corresponding to an error Δα (n + 2) = Δθ immediately after switching from the rectangular wave generation unit 607 to the PWM control unit 105. An addition unit 512 that adds the torque conversion value ΔT (n + 2) [N · m] and the torque command value T [N · m] is provided. From this, the same effects as those of the second embodiment can be obtained. Further, the filter action of the ΔT filter calculation unit 511 can sufficiently smooth the stepwise steep change of the actual voltage phase α that occurs immediately after switching from the rectangular wave generation unit 607 to the PWM control unit 105. Therefore, torque vibration can be further suppressed as compared with the second embodiment.

  The embodiment described above is an example of the implementation of the present invention, and the scope of the present invention is not limited thereto, and other various embodiments are within the scope described in the claims. It is applicable to. For example, the inverter 1 according to the first to sixth embodiments includes the reflux elements Du +, Du−, Dv +, Dv−, Dw +, and Dw−. However, the present invention is not particularly limited to this. Also good.

  In the first, third, and fifth embodiments, the case where the actual motor angular frequency ωre [rad / s] suddenly changes at the (n + 1) th switching timing is described. However, the present invention is not particularly limited to this, and can also be applied to a case where the actual motor angular frequency ωre [rad / s] changes suddenly at the n-th switching timing. That is, when the error Δθ occurs at the n-th switching timing, the error Δθ ′ = Δθ (1-K) is obtained at the (n + 1) -th switching timing by the next control cycle tnext ′ corrected based on the error Δθ. Therefore, the error Δα (n + 3) may be calculated based on the error Δθ ′. Similarly, the timing at which the actual motor angular frequency ωre [rad / s] suddenly changes and the error Δθ is generated is applicable even if it is unrelated to the switching timing from the rectangular wave generation unit to the PWM control unit.

  In the second, fourth, and sixth embodiments, the case where the actual motor angular frequency ωre [rad / s] changes suddenly at the (n + 1) th switching timing is described. However, the present invention is not particularly limited to this, and can also be applied to a case where the actual motor angular frequency ωre [rad / s] changes suddenly at the n-th switching timing. That is, when the error Δθ occurs at the n-th switching timing, the error Δθ ′ = Δθ (1-K) is obtained at the (n + 1) -th switching timing by the next control cycle tnext ′ corrected based on the error Δθ. Therefore, the error Δα (n + 2) may be calculated based on the error Δθ ′. Similarly, the timing at which the actual motor angular frequency ωre [rad / s] suddenly changes and the error Δθ is generated is applicable even if it is unrelated to the switching timing from the rectangular wave generation unit to the PWM control unit.

  In the controllers 40 and 60 of the fourth and sixth embodiments, the (n + 1) th control cycle tnow is set to the rectangular wave generation units 407 and 607 at the (n + 1) th switching timing, as in the second embodiment. Arithmetic. However, the present invention is not particularly limited to this, and the (n + 1) th control cycle tnow may be set equal to the PWM cycle Tpwm as in the modification of the second embodiment.

1 is a schematic configuration diagram of an inverter system according to a first embodiment of the present invention. Control block diagram showing the internal configuration of the controller shown in FIG. Timing chart showing output of rectangular wave control executed by the rectangular wave generator shown in FIG. Timing chart showing output by rectangular wave / PWM control switching process in controller shown in FIG. The figure which shows the actual voltage phase when the switching process shown in FIG. 4 is performed The figure which shows the rotation speed and output power at the time of performing the switching process shown in FIG. The flowchart which shows the control method performed with the controller shown in FIG. The control block diagram which shows the internal structure of the controller which concerns on the 2nd Embodiment of this invention. Timing chart showing output by rectangular wave / PWM control switching process in controller shown in FIG. The flowchart which shows the control method performed with the controller shown in FIG. Timing chart showing output by rectangular wave / PWM control switching process in modification of second embodiment The control block diagram which shows the internal structure of the controller which concerns on the 3rd Embodiment of this invention. The figure which shows the actual voltage phase when performing the switching process similar to 1st Embodiment in the controller shown in FIG. The figure which shows the rotation speed and output power when the switching process similar to 1st Embodiment in the controller shown in FIG. 12 is performed. The flowchart which shows the control method performed with the controller shown in FIG. The control block diagram which shows the internal structure of the controller which concerns on the 4th Embodiment of this invention. The flowchart which shows the control method performed with the controller shown in FIG. The control block diagram which shows the internal structure of the controller which concerns on the 5th Embodiment of this invention. The flowchart which shows the control method performed with the controller shown in FIG. Control block diagram showing an internal configuration of a controller according to a sixth embodiment of the present invention The flowchart which shows the control method performed with the controller shown in FIG.

Explanation of symbols

1 Inverter, 2 Current sensor, 3 Motor as motor
10, 20, 30, 40, 50, 60 Controller which is a control device,
101, 301, 501 α table reference section,
102, 302 α filter calculation unit as first filter calculation means,
103 a switch unit which is a switching means,
105 PWM controller as pulse width modulation control means,
107, 207, 307, 407, 507, 607, rectangular wave generation unit that is rectangular wave control means, 108 switch unit, 109 timer unit,
110, 210, 310, 410, 510, 610 flag control unit,
311 is a Δα filter calculation unit which is a second filter calculation unit;
312 is an adding unit as first adding means;
511, a ΔT filter calculation unit which is a third filter calculation unit,
512, an addition unit as second addition means,
1051 vd, vq command calculation unit, 1052 2 phase / 3 phase conversion unit,
1053 PWM generator, B DC power supply, Du +, Du− U-phase reflux element,
Dv +, Dv− V-phase reflux element, Dw +, Dw− W-phase reflux element,
K correction coefficient which is a predetermined value, N motor speed, P drive signal,
Pnt output power, tnow (n + 1) th control cycle, which is the current control cycle,
tnext next control cycle, tnext 'next control cycle after correction,
Tpwm PWM cycle which is a predetermined control cycle, T torque command value,
ΔT (n + 2), ΔT (n + 3) Torque conversion value which is a torque difference,
ΔT 'Torque converted value after filtering, T "Torque command value after addition,
Tu +, Tu- U phase switching element,
Tv +, Tv- V-phase switching element,
Tw +, Tw- W phase switching element,
Vdc DC voltage value, vd d-axis voltage command value, vq q-axis voltage command value,
vu U phase voltage command value, vv V phase voltage command value, vw W phase voltage command value,
Vu U phase output voltage, Vv V phase output voltage, Vw W phase output voltage,
α, αn, α (n + 1), α (n + 2), α (n + 3) The actual voltage phase as corrected values, α ^* , α ^* n, α ^* (n + 1), α ^* (n + 2), α ^* ( n + 3) Voltage phase command value, α ′ ^* Voltage phase command value before fluctuation suppression,
α ” ^* Voltage phase command value before addition,
Δα, Δα (n + 2), Δα (n + 3) error, Δα ′ filtered error θ, θnext rotor phase, θ ^* next rotor phase target value,
Δθ difference error, τ, τ1, τ2, τ3 time constants,
ωre Actual motor angular frequency

Claims (8)

Switching from the rectangular wave control means for controlling the voltage output from the inverter including the plurality of switching elements to the electric motor in a rectangular wave form to the pulse width modulation control means for controlling the voltage in a pseudo sine wave form, the switching timing of the switching elements Switching means to be adapted to the
The rectangular wave control means controls the (n + 1) th time between the (n + 1) th switching timing and the (n + 2) th switching timing at the n (n = 1, 2,...) Th switching timing of the switching element. Calculate the period,
At the (n + 1) -th switching timing, the (n + 2) -th target switching timing obtained from the torque command value and the voltage phase command value based on the rotation speed of the motor, and the (n + 2) -th time based on the (n + 1) -th control cycle. Calculate the difference with the switching timing,
Immediately after the switching by the switching unit, the pulse width modulation control unit controls the voltage phase command value with a value corrected based on the difference. The rectangular wave control means calculates the corrected value at the (n + 2) -th switching timing and immediately before the switching means switches,
The corrected value α is expressed as follows, where the voltage phase command value at the (n + 3) th switching timing is α ^* , the difference is Δθ, and the predetermined value is K.
α = α ^* + Δθ × (1-K)
The motor control device according to claim 1, wherein: The rectangular wave control means adds the voltage phase command value and the difference at the (n + 2) -th switching timing to calculate the corrected value,
2. The motor control device according to claim 1, wherein the switching unit performs the switching after the calculation of the rectangular wave control unit at the (n + 1) -th switching timing.   4. The motor control device according to claim 3, wherein the rectangular wave control means makes the (n + 1) th control cycle equal to a predetermined control cycle calculated by the pulse width modulation control means. The pulse width modulation control unit or the rectangular wave control unit includes a first filter calculation unit that outputs the voltage phase command value,
5. The electric motor according to claim 1, wherein the rectangular wave control unit causes the pulse width modulation control unit to output the corrected value immediately after the switching from the first filter calculation unit. Control device. Second filter computing means for outputting the difference immediately after the switching;
First addition means for outputting the voltage phase command value before fluctuation suppression obtained by adding the difference from the second filter calculation means and the voltage phase command value before addition to the first filter calculation means. The motor control device according to claim 5. Immediately after the switching, a third filter calculating means for outputting a torque difference corresponding to the difference;
The motor control device according to claim 5, further comprising second addition means for adding the torque difference and the torque command value. From the rectangular wave control means for controlling the voltage output from the inverter including the plurality of switching elements to the electric motor in the form of a rectangular wave, to the pulse width modulation control means for controlling the voltage in the form of a pseudo sine wave, in accordance with the switching timing of the switching elements. A method for controlling an electric motor to be switched,
(N + 1) -th control between the (n + 1) -th switching timing and the (n + 2) -th switching timing at the n (n = 1, 2,...) -Th switching timing of the switching element by the rectangular wave control means. Calculate the period,
At the (n + 1) -th switching timing, the (n + 2) -th target switching timing obtained from the torque command value and the voltage phase command value based on the rotation speed of the motor, and the (n + 2) -th time based on the (n + 1) -th control cycle. Calculate the difference with the switching timing,
The method for controlling an electric motor, wherein the pulse width modulation control means controls the voltage phase command value with a value corrected based on the difference immediately after the switching by the switching means.

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