JP7081180B2 - Rotating electric machine control device - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is a control device for a rotary electric machine applied to a control system including a power converter that transmits power between a DC power supply and a stator winding of the rotary electric machine by driving an upper arm switch and a lower arm switch. Regarding.

As a control device of this type, as seen in Patent Document 1, when shifting from sinusoidal PWM control to synchronous rectification control, a control device that switches in the order of sinusoidal PWM control, overmodulation PWM control, and synchronous rectification control is known. ing. That is, the overmodulation PWM control is interposed between the sinusoidal PWM control and the synchronous rectification control.

Japanese Unexamined Patent Publication No. 2016-189698

In the control device described in Patent Document 1, the torque fluctuation of the rotary electric machine is suppressed by interposing the overmodulation PWM control. However, it is desired to further increase the degree of suppression.

An object of the present invention is to provide a control device for a rotary electric machine capable of increasing the degree of suppression of torque fluctuation generated when shifting from one of sine wave PWM control and synchronous rectification control to the other.

The present invention has a rotary electric machine having a stator winding and a series connection body of an upper arm switch and a lower arm switch, and by driving the upper arm switch and the lower arm switch, a DC power supply and the stator winding are provided. In a rotary electric machine control device applied to a control system including a power converter that transmits power to and from, the peak value of each phase voltage applied to the stator winding is equal to or lower than the voltage of the DC power supply. If so, the sinusoidal control unit that drives the upper arm switch and the lower arm switch so that each phase voltage applied to the stator winding has a PWM voltage waveform, and each phase applied to the stator winding. When the peak value of the voltage exceeds the voltage of the DC power supply, the upper arm switch and the lower arm switch are overmodulated so as to have a PWM voltage waveform having a modulation factor higher than the PWM waveform voltage by the sinusoidal control unit. The control unit, the rectangular wave control unit that drives the upper arm switch and the lower arm switch on by rectangular wave control once each with a dead time in one electric angle cycle, and the generated voltage of the stator winding On condition that the upper arm switch is turned on for at least a part of the period exceeding the voltage of the DC power supply, the upper arm switch and the lower arm switch are operated once each with a dead time in one electric angular cycle. Synchronous rectification control unit that turns on one by one, and when shifting from driving by the sine wave control unit to driving by the synchronous rectification control unit, driving by the sine wave control unit, driving by the overmodulation control unit, and driving by the rectangular wave control unit When switching between driving by the synchronous rectification control unit and driving by the synchronous rectification control unit and shifting from driving by the synchronous rectification control unit to driving by the sine wave control unit, driving by the synchronous rectification control unit, driving by the rectangular wave control unit, A switching unit for switching between driving by the overmodulation control unit and driving by the sine wave control unit is provided.

In the present invention, when shifting from the drive by the sine wave control unit to the drive by the synchronous rectification control unit, the drive by the sine wave control unit, the drive by the overmodulation control unit, the drive by the square wave control unit, and the drive by the synchronous rectification control unit are performed. It can be switched in order. That is, the drive by the rectangular wave control unit is interposed between the drive by the overmodulation control unit and the drive by the synchronous rectification control unit. Therefore, it is applied to the stator winding in each of the case where the drive by the overmodulation control unit is switched to the drive by the rectangular wave control unit and the case where the drive by the rectangular wave control unit is switched to the drive by the synchronous rectification control unit. It is possible to suppress changes in the magnitude of the voltage vector.

Further, in the present invention, when shifting from the drive by the synchronous rectification control unit to the drive by the sine wave control unit, the drive by the synchronous rectification control unit, the drive by the square wave control unit, the drive by the overmodulation control unit, and the drive by the sine wave control unit are used. It can be switched in the order of driving. Therefore, it is applied to the stator winding in each of the case where the drive by the synchronous rectification control unit is switched to the drive by the rectangular wave control unit and the case where the drive by the rectangular wave control unit is switched to the drive by the overmodulation control unit. It is possible to suppress changes in the magnitude of the voltage vector.

According to the present invention capable of suppressing changes in the magnitude of the voltage vector, it is possible to increase the degree of suppression of torque fluctuations that occur when shifting from one of the drives by the sine wave control unit and the drive by the synchronous rectification control unit to the other. can.

An overall configuration diagram of an in-vehicle control system according to an embodiment. Block diagram of sine wave PWM control and overmodulation PWM control. A time chart showing changes in switch drive mode, phase current, etc. during sinusoidal PWM control. A time chart showing changes in switch drive mode, phase current, etc. during overmodulation PWM control. Block diagram of square wave control and synchronous rectification control. A time chart showing changes in switch drive mode, phase current, etc. during square wave control. A time chart showing changes in switch drive mode, phase current, etc. during synchronous rectification control. The flowchart which shows the procedure of the control mode switching process. The figure which shows the voltage vector at the time of a sine wave PWM control. The figure which shows the voltage vector at the time of the overmodulation PWM control. The figure which shows the voltage vector at the time of a square wave control. The figure which shows the voltage vector at the time of synchronous rectification control.

Hereinafter, an embodiment in which the control device according to the present invention is mounted on a vehicle will be described with reference to the drawings.

As shown in FIG. 1, the vehicle includes an engine 10 as an in-vehicle main engine. The engine 10 is provided with a fuel injection valve or the like, and generates power by burning fuel such as gasoline or light oil injected from the fuel injection valve. The generated power is output from the output shaft 10a of the engine 10.

The vehicle includes a battery 20 as a DC power source and a rotary electric machine 21. The battery 20 is, for example, a lead storage battery having a rated voltage of 12 V. The rotary electric machine device 21 includes a capacitor 22, an AC-driven rotary electric machine 30, an inverter 40 as a power converter, a field energization circuit 41, and an MGECU 60 which is a control device for controlling the rotary electric machine 30. In the present embodiment, a winding field type synchronous machine is used as the rotary electric machine 30. Further, in the present embodiment, the MGECU 60 controls the rotary electric machine 30 so that the rotary electric machine 30 functions as an ISG (Integrated Starter Generator) which is both an electric motor and a generator. The rotary electric machine device 21 is a mechanical / electrical integrated drive device including a rotary electric machine, an inverter 40, a field energization circuit 41, and an MGECU 60.

The rotary electric machine 30 includes a rotor 31. The rotor 31 includes a field winding 32. The rotating shaft of the rotor 31 can transmit power to the output shaft 10a of the engine 10 via a pulley or the like (not shown). When the rotary electric machine 30 is driven as a generator, the rotor 31 is rotated by the rotational power supplied from the output shaft 10a, and the rotary electric machine 30 generates electricity. The battery 20 is charged by the generated power of the rotary electric machine 30. On the other hand, when the rotary electric machine 30 is driven as an electric machine, the output shaft 10a rotates with the rotation of the rotor 31, and a rotational force is applied to the output shaft 10a. This makes it possible to assist the traveling of the vehicle, for example. The drive wheels of the vehicle are connected to the output shaft 10a via a transmission or the like.

The rotary electric machine 30 includes a stator 33. The stator 33 includes a stator winding. The stator windings include U, V, W phase windings 34U, 34V, 34W arranged 120 ° apart from each other by electrical angle.

The inverter 40 includes a series connection body of U, V, W phase upper arm switches SUp, SVp, SWp and U, V, W phase lower arm switches Sun, SVn, SWn. U, V, W phase windings 34U, 34V, 34W are connected to the U, V, W phase upper arm switches SUp, SVp, SWp and the U, V, W phase lower arm switches Sun, SVn, SWn. The first end of is connected. The second ends of the U, V, W phase windings 34U, 34V, 34W are connected at a neutral point. That is, in the present embodiment, the U, V, W phase windings 34U, 34V, 34W are connected in a star shape.

In this embodiment, each switch SUP to SWn is an N-channel MOSFET. When the N-channel MOSFET is driven on, current flow is permitted between the drain, which is the high potential side terminal, and the source, which is the low potential side terminal. On the other hand, when the N-channel MOSFET is driven off, the flow of current between the drain and the source is blocked. The body diodes DUp, DVp, DWp, DUn, DVn, and DWn are connected in antiparallel to each switch SUp, SVp, SWp, Sun, SVn, and SWn.

The positive electrode terminal of the battery 20 is connected to the drains of the U, V, and W phase upper arm switches SUp, SVp, and SWp via the high potential side electric path Lp. The negative electrode terminal of the battery 20 is connected to the sources of the U, V, and W phase lower arm switches SUn, SVn, and SWn via the low potential side electric path Ln. Each electric path Lp, Ln is a conductive member such as a bus bar. Of the connection points between the drains of the upper arm switches SUp, SVp, and SWp and the high potential side electric path Lp, the connection point closest to the positive electrode terminal of the battery 20 and the high potential side electric path connecting the positive electrode terminal of the battery 20. The high potential side terminal of the capacitor 22 is connected to Lp. Of the connection points between the sources of the lower arm switches SUn, SVn, and SWn and the low-potential side electric path Ln, the connection point closest to the negative electrode terminal of the battery 20 and the low-potential side electric path connecting the negative electrode terminal of the battery 20. The low potential side terminal of the capacitor 22 is connected to Ln.

The field energization circuit 41 is a full bridge circuit, and includes a series connection body of the first upper arm switch SH1 and the first lower arm switch SL1 and a series connection body of the second upper arm switch SH2 and the second lower arm switch SL2. It is equipped with. The first end of the field winding 32 is connected to the connection point between the first upper arm switch SH1 and the first lower arm switch SL1 via a brush (not shown). The second end of the field winding 32 is connected to the connection point between the second upper arm switch SH2 and the second lower arm switch SL2 via a brush (not shown). In this embodiment, each arm switch SH1, SL1, SH2, SL2 is an N-channel MOSFET. Each body diode DH1, DL1, DH2, DL2 is connected in antiparallel to each switch SH1, SL1, SH2, SL2.

The drain of the first and second upper arm switches SH1 and SH2 is connected to the inverter 40 side of the high potential side electric path Lp from the connection point with the high potential side terminal of the capacitor 22. The source of the first and second lower arm switches SL1 and SL2 is connected to the inverter 40 side of the low potential side electric path Ln from the connection point with the low potential side terminal of the capacitor 22.

The rotary electric machine 21 includes a voltage detection unit 50, a phase current detection unit 51, a field current detection unit 52, and an angle detection unit 53. The voltage detection unit 50 detects the terminal voltage of the capacitor 22 as the power supply voltage VDC. The phase current detection unit 51 detects the phase current flowing through the U, V, W phase windings 34U, 34V, 34W. The field current detection unit 52 detects the field current flowing through the field winding 32. The angle detection unit 53 outputs an angle signal which is a signal corresponding to the rotation angle of the rotor 31. The output signals of the detection units 50 to 53 are input to the MGECU 60.

A part or all of each function of the MGECU 60 may be configured in hardware by, for example, one or a plurality of integrated circuits. Further, each function of the MGECU 60 may be configured by, for example, software recorded on a non-transitional substantive recording medium and a computer that executes the software.

The MGECU 60 generates a drive signal for each switch constituting the inverter 40 and the field energization circuit 41.

First, the inverter 40 will be described. The MGECU 60 acquires an angle signal of the angle detection unit 53, and generates a drive signal for driving each switch SUp to SWn constituting the inverter 40 on or off based on the acquired angle signal. Specifically, when the rotary electric machine 30 is driven as an electric motor, the MGECU 60 converts the DC power output from the battery 20 into AC power and supplies it to the U, V, W phase windings 34U, 34V, 34W. The drive signals of the arm switches SUp to SWn are generated, and the generated drive signals are supplied to the gates of the arm switches SUp to SWn. On the other hand, when the rotary electric machine 30 is driven as a generator, the MGECU 60 converts the AC power output from the U, V, W phase windings 34U, 34V, 34W into DC power and supplies the AC power to the battery 20. Generates drive signals for arm switches SUp to SWn.

Subsequently, the field energization circuit 41 will be described. The MGECU 60 drives each switch constituting the field energization circuit 41 in order to excite the field winding 32. Specifically, the MGECU 60 drives each switch so that the first state and the second state appear alternately. The first state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are driven on, and the second upper arm switch SH2 and the first lower arm switch SL1 are driven off. .. The second state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are driven off, and the second upper arm switch SH2 and the first lower arm switch SL1 are driven on. ..

The MGECU 60 calculates the electric angle θe of the rotary electric machine 30 and the rotation speed Nm of the rotor 31 based on the angle signal of the angle detection unit 53.

Hereinafter, in the present embodiment, a case where the rotary electric machine 30 is driven as a generator will be described. FIG. 2 shows a block diagram of a sine wave PWM control and an overmodulation PWM control performed by the MGECU 60. In the present embodiment, of the MGECU 60, the configuration for performing the process shown in FIG. 2 corresponds to the sine wave control unit and the overmodulation control unit.

The voltage deviation calculation unit 61 calculates the voltage deviation ΔV by subtracting the power supply voltage VDC detected by the voltage detection unit 50 from the command power generation voltage VD *. The command power generation voltage VD * is a command value of the DC voltage output from the inverter 40 to the battery 20.

The torque calculation unit 62 calculates a command value of the control amount of the rotary electric machine 30 as an operation amount for feedback-controlling the voltage deviation ΔV to 0. In the present embodiment, the control amount is torque, and the command value thereof is command torque Trq *. Further, in the present embodiment, the feedback control used in the torque calculation unit 62 is a proportional integration control. The feedback control is not limited to the proportional integral control, and may be, for example, the proportional integral differential control.

The two-phase conversion unit 70 converts U, V, W phase currents IU, IV, and IW in the three-phase fixed coordinate system of the rotary electric machine 30 based on the phase current and the electric angle θe detected by the phase current detection unit 51. It is converted into d and q-axis currents Idr and Iqr in the dq coordinate system which is a two-phase rotation coordinate system.

The d-axis command setting unit 71 sets the d-axis command current Id * for setting the torque of the rotary electric machine 30 to the command torque Trq * based on the command torque Trq *. Specifically, the d-axis command setting unit 71 sets the d-axis command current Id * based on the map information in which the command torque Trq * and the d-axis command current Id * are related.

The q-axis command setting unit 72 sets the q-axis command current Iq * for setting the torque of the rotary electric machine 30 to the command torque Trq * based on the command torque Trq *. Specifically, the q-axis command setting unit 72 sets the q-axis command current Iq * based on the map information in which the command torque Trq * and the q-axis command current Iq * are related.

The stator control unit 73 calculates the d-axis command voltage Vd * as an operation amount for feedback-controlling the d-axis current Idr to the d-axis command current Id *. Specifically, the stator control unit 73 calculates the d-axis current deviation ΔId as a value obtained by subtracting the d-axis current Idr from the d-axis command current Id *, and feedback-controls the calculated d-axis current deviation ΔId to 0. The d-axis command voltage Vd * is calculated as the operation amount of.

The stator control unit 73 calculates the q-axis command voltage Vq * as an operation amount for feedback-controlling the q-axis current Iqr to the q-axis command current Iq *. Specifically, the stator control unit 73 calculates the q-axis current deviation ΔIq as a value obtained by subtracting the q-axis current Iqr from the q-axis command current Iq *, and feedback-controls the calculated q-axis current deviation ΔIq to 0. The q-axis command voltage Vq * is calculated as the operation amount of.

In the present embodiment, the feedback control used by the stator control unit 73 is proportional integration control. The feedback control is not limited to the proportional integral control, and may be, for example, the proportional integral differential control.

The d-axis command voltage Vd * and the q-axis command voltage Vq * determine the command voltage vector, which is the command value of the voltage vector in the dq coordinate system. Here, the voltage vector applied to the stator winding has a d-axis component of the d-axis voltage Vd and a q-axis component of the q-axis voltage Vq. The voltage phase, which is the phase of the voltage vector, is defined, for example, with reference to the positive direction of the d-axis, and the counterclockwise direction from this reference is defined as the positive direction.

The three-phase conversion unit 74 sets the d, q-axis command voltage Vd *, Vq * based on the d, q-axis command voltage Vd *, Vq * and the electric angle θe to U, V, W in the three-phase fixed coordinate system. Converts to the phase command voltage Vu *, Vv *, Vw *. In the present embodiment, the U, V, and W phase command voltages Vu *, Vv *, and Vw * are sinusoidal signals whose phases are 120 ° out of phase with respect to the electrical angle.

The stator generation unit 75 turns on / off each switch SUP to SWn of the inverter 40 by sinusoidal PWM control or overmodulation PWM control based on the carrier signal, each phase command voltage Vu *, Vv *, Vw * and the power supply voltage VDC. Generate each drive signal to drive.

First, the sine wave PWM control will be described. When the peak value of each phase command voltage Vu *, Vv *, Vw * is equal to or less than the power supply voltage VDC, the stator generation unit 75 divides each phase command voltage Vu *, Vv *, Vw * by "VDC / 2". The drive signals of the switches SUp to SWn of the inverter 40 are generated based on the magnitude comparison between the obtained value and the carrier signal. In the present embodiment, the carrier signal is a triangular wave signal. In the sinusoidal PWM control, the value obtained by dividing the amplitude of each phase command voltage Vu *, Vv *, Vw * by "VDC / 2" is equal to or less than the amplitude of the carrier signal.

Subsequently, the overmodulation PWM control will be described. When the peak value of each phase command voltage Vu *, Vv *, Vw * exceeds the power supply voltage VDC, the stator generation unit 75 divides each phase command voltage Vu *, Vv *, Vw * by "VDC / 2". The drive signals of the switches SUp to SWn of the inverter 40 are generated based on the magnitude comparison between the value and the carrier signal. In the overmodulation PWM control, the value obtained by dividing the amplitude of each phase command voltage Vu *, Vv *, Vw * by "VDC / 2" is larger than the amplitude of the carrier signal.

The field command setting unit 80 sets the field command current If * based on the command torque Trq *. Specifically, the field command setting unit 80 sets the field command current If * based on the map information in which the command torque Trq * and the field command current If * are related.

The field current control unit 81 calculates the field command voltage Vf * as an operation amount for feedback-controlling the field current Ifr detected by the field current detection unit 52 to the field command current If *. Specifically, the field current control unit 81 calculates the field current deviation ΔIf as the value obtained by subtracting the field current Ifr from the field command current If *, and feedback-controls the calculated field current deviation ΔIf to 0. The field command voltage Vf * is calculated as the operation amount for the operation. In the present embodiment, the feedback control used in the field current control unit 81 is proportional integration control. The feedback control is not limited to the proportional integral control, and may be, for example, the proportional integral differential control.

The field generation unit 82 sets the applied voltage of the field winding 32 to the field command voltage based on the magnitude comparison between the value obtained by dividing the field command voltage Vf * by the power supply voltage VDC and the carrier signal which is a triangular wave signal. Each drive signal of each switch SH1 to SL2 of the field energization circuit 41 for controlling to Vf * is generated.

FIG. 3 shows the transition of each waveform for one phase when the sinusoidal PWM control is executed. FIG. 3A shows the transition of the gate signal of the upper arm switch, FIG. 3B shows the transition of the gate signal of the lower arm switch, and FIG. 3C shows the transition of the phase current and the phase voltage. Is shown.

FIG. 4 shows the transition of each waveform for one phase when the overmodulation PWM control is executed. 4 (a) to 4 (c) correspond to FIGS. 3 (a) to 3 (c).

Subsequently, FIG. 5 shows a block diagram of the rectangular wave control and the synchronous rectification control performed by the MGECU 60. In the present embodiment, of the MGECU 60, the configuration for performing the process shown in FIG. 5 corresponds to the rectangular wave control unit and the synchronous rectification control unit.

In the square wave control, the peak value of each phase command voltage Vu *, Vv *, Vw * exceeds the power supply voltage VDC, and the peak value of the generated voltage (that is, the counter electromotive voltage) of each phase winding 34U to 34W is It is carried out when the power supply voltage is VDC or less.

On the other hand, in the synchronous rectification control, the peak value of each phase command voltage Vu *, Vv *, Vw * exceeds the power supply voltage VDC, and the peak value of the generated voltage of each phase winding 34U to 34W exceeds the power supply voltage VDC. It is carried out when it exceeds. In the synchronous rectification control, the switch connected in antiparallel to the diode on which the current is going to flow is turned on during the period when the current is going to flow in the body diode connected in antiparallel to the switch of the inverter 40. In each phase, the period in which the current tends to flow in the body diode is the period in which the peak value of the generated voltage of each phase exceeds the power supply voltage VDC. In the synchronous rectification control, the upper arm switch is turned on once in at least a part of the period in which the generated voltage exceeds the power supply voltage VDC in one electric angular period in each phase. As a result, the alternating current output from each phase winding 34U to 34W is converted into a direct current.

The synchronization generation unit 90 drives each switch SUp to SWn of the inverter 40 on and off based on the electric angle θe, the dead time DT of the upper and lower arm switches of the inverter 40, and the command value δ of the voltage phase. Generate a signal. The drive signal generated by the synchronization generation unit 90 is a signal for turning on each of the upper arm switch and the lower arm switch once in one electric angle cycle of each phase. The phase of this drive signal is 120 ° out of phase with respect to each phase.

In FIG. 5, the voltage deviation calculation unit 61, the torque calculation unit 62, the field command setting unit 80, the field current control unit 81, and the field generation unit 82 have the same configuration as shown in FIG. Therefore, even when the sinusoidal PWM control or the synchronous rectification control is switched from one to the other, the continuity of the field current control based on the command torque Trq * is maintained.

FIG. 6 shows the transition of each waveform for one phase when the square wave control is executed. 6 (a) to 6 (c) correspond to FIGS. 3 (a) to 3 (c). FIG. 6 shows the dead time set in the rectangular wave control by DT1.

FIG. 7 shows the transition of each waveform for one phase when the synchronous rectification control is executed. 7 (a) to 7 (c) correspond to FIGS. 3 (a) to 3 (c). FIG. 7 shows the dead time set in the synchronous rectification control by DT2. In this embodiment, DT2 is longer than DT1 shown in FIG. The DT 2 is set to a time longer than the maximum value of the dead time range that can be set in, for example, the sine wave PWM control, the overmodulation PWM control, and the rectangular wave control.

In the present embodiment, when shifting from the sinusoidal PWM control unit to the synchronous rectification control in the power generation control process, the sinusoidal PWM control, the overmodulation PWM control, the square wave control, and the synchronous rectification control are switched in this order. On the other hand, when shifting from synchronous rectification control to sinusoidal PWM control, the order is switched to synchronous rectification control, square wave control, overmodulation PWM control, and sinusoidal PWM control.

FIG. 8 shows a procedure of power generation control processing according to the present embodiment. This process is repeatedly executed by the MGECU 60, for example, at predetermined control cycles. In the present embodiment, the MGECU 60 includes a switching unit.

In step S10, the modulation factor Mr is calculated based on the power supply voltage VDC and the voltage amplitude Vn, which is the magnitude of the voltage vector. In this embodiment, the modulation factor Mr is calculated as "Vn / VDC". The voltage amplitude Vn may be calculated based on, for example, the d-axis command voltage Vd * and the q-axis command voltage Vq *.

In step S11, it is determined whether or not the control in the previous control cycle was the sinusoidal PWM control.

If it is determined in step S11 that the sine wave PWM control has been performed, the process proceeds to step S12, and it is determined whether or not the modulation factor Mr is equal to or less than the first modulation factor Ma. In this embodiment, the first modulation factor Ma is set to 1.

Incidentally, when the third harmonic is superimposed on each phase command voltage Vu *, Vv *, Vw *, the first modulation factor Ma may be set to 1.15.

If an affirmative determination is made in step S12, the process proceeds to step S13, and sine wave PWM control is performed according to the configuration shown in FIG. On the other hand, if a negative determination is made in step S12, the process proceeds to step S14, and overmodulation PWM control is performed according to the configuration shown in FIG.

If a negative determination is made in step S11, the process proceeds to step S15, and it is determined whether or not the control in the previous control cycle was overmodulation PWM control.

If it is determined in step S15 that the overmodulation PWM control has been performed, the process proceeds to step S16 to determine whether or not the modulation factor Mr is the second modulation factor Mb. The second modulation factor Mb is set to a value larger than that of the first modulation factor Ma, and is set to 1.27 in the present embodiment.

If it is determined in step S16 that the modulation factor Mr is not the second modulation factor Mb, the process proceeds to step S17, and whether or not the modulation factor Mr is larger than the first modulation factor Ma and smaller than the second modulation factor Mb. Is determined. If an affirmative determination is made in step S17, the process proceeds to step S14 to maintain the overmodulation PWM control. On the other hand, if a negative determination is made in step S17, the process proceeds to step S13, and the overmodulation PWM control is switched to the sinusoidal PWM control.

If it is determined in step S16 that the modulation factor Mr is the second modulation factor Mb, the process proceeds to step S18, and the overmodulation PWM control is switched to the rectangular wave control. The square wave control is performed by the configuration shown in FIG. 5 above.

If a negative determination is made in step S15, the process proceeds to step S19, and it is determined whether or not the control in the previous control cycle was rectangular wave control.

If it is determined in step S19 that the square wave control has been performed, the process proceeds to step S20, and it is determined whether or not the modulation factor Mr is the second modulation factor Mb. When it is determined in step S20 that the modulation factor Mr is not the second modulation factor Mb, it is determined that the modulation factor Mr is less than the second modulation factor Mb, and the process proceeds to step S14, from the rectangular wave control to the overmodulation PWM control. Switch.

If an affirmative judgment is made in step S20, the process proceeds to step S21, and it is determined whether or not the rotation speed Nm is higher than the threshold speed Nth. This process is a process for determining whether or not the generated voltage of the phase winding exceeds the output voltage of the battery 20. Therefore, the threshold speed Nth is set to a value at which it can be determined whether or not the generated voltage is higher than the output voltage of the battery 20.

If a negative determination is made in step S21, the process proceeds to step S18, and the rectangular wave control is maintained. On the other hand, if an affirmative determination is made in step S21, the process proceeds to step S22, and the rectangular wave control is switched to the synchronous rectification control. Synchronous rectification control is performed by the configuration shown in FIG. 5 above.

If a negative determination is made in step S19, it is determined that the control in the previous control cycle was synchronous rectification control, and the process proceeds to step S23. In step S23, it is determined whether or not the rotation speed Nm is higher than the threshold speed Nth. If an affirmative determination is made in step S23, the process proceeds to step S22 to maintain synchronous rectification control. On the other hand, if a negative determination is made in step S23, the process proceeds to step S18, and the synchronous rectification control is switched to the rectangular wave control.

9 to 12 show a voltage vector applied to the stator windings (each phase winding 34U, 34V, 34W) at each control. In the examples shown in FIGS. 9 to 12, the field currents are the same. In FIGS. 9 to 12, VINV indicates a command voltage vector determined by the d, q-axis voltages Vd * and Vq * commanded in each control, and VK is induced in the stator winding by the flow of a field current. The voltage vector indicates a voltage drop, and VR indicates a voltage vector corresponding to the amount of voltage drop due to the resistance component of the stator winding. Further, C1 shows a virtual circle drawn by the command voltage vector when the modulation factor Mr is 1, and C2 shows a virtual circle drawn by the command voltage vector when the modulation factor Mr is 1.27.

FIG. 9 shows a voltage vector at the time of sinusoidal PWM control. V1 indicates a voltage vector finally applied to the stator winding, and is a composite vector of VINV, VK, and VR. FIG. 10 shows a voltage vector at the time of overmodulation PWM control. V2 indicates a voltage vector finally applied to the stator winding, and is a composite vector of VINV, VK, and VR.

FIG. 11 shows a voltage vector at the time of rectangular wave control. V3 indicates a voltage vector finally applied to the stator winding, and is a composite vector of VINV, VK, and VR. FIG. 12 shows a voltage vector at the time of synchronous rectification control. In FIG. 12, VDT indicates a voltage vector corresponding to dead time DT2. V4 indicates a voltage vector finally applied to the stator winding, and is a composite vector of VINV, VK, VR, and VDT. In the synchronous rectification control, since the dead time DT2 is long, the influence of VDT cannot be ignored.

For example, when the overmodulation PWM control is directly switched to the synchronous rectification control, the difference between the voltage amplitude of the voltage vector V2 during the overmodulation PWM control and the voltage amplitude of the voltage vector V4 during the synchronous rectification control is large. The torque fluctuation of the rotary electric machine 30 becomes large. On the other hand, in the present embodiment, the overmodulation PWM control can be switched to the synchronous rectification control via the rectangular wave control. By interposing the rectangular wave control, the difference between the voltage amplitude of the voltage vector V2 at the time of overmodulation PWM control and the voltage amplitude of the voltage vector V3 at the time of the rectangular wave control, and the voltage amplitude of the voltage vector V3 at the time of the rectangular wave control. Each of the differences from the voltage amplitude of the voltage vector V4 at the time of synchronous rectification control can be made smaller than the difference between the voltage amplitude of the voltage vector V2 at the time of overmodulation PWM control and the voltage amplitude of the voltage vector V4 at the time of synchronous rectification control. As a result, it is possible to suppress the fluctuation of the voltage amplitude that occurs when shifting from one of the sinusoidal PWM control and the synchronous rectification control to the other, and it is possible to increase the degree of suppression of the torque fluctuation of the rotary electric machine 30.

<Other embodiments>
The above embodiment may be modified as follows.

The switch on period set in the rectangular wave control may be a period shorter than the period shown in FIG. 6, such as 120 °.

-The field energization circuit is not limited to the full bridge circuit, and may be, for example, a half bridge circuit.

-The switch used in the inverter and the field energization circuit is not limited to the N-channel MOSFET, and may be, for example, an IGBT.

The control amount of the rotary electric machine is not limited to torque, and may be, for example, the generated power of the rotary electric machine 30.

-The rotary electric machine is not limited to the one connected in a star shape, and may be connected in a Δ shape, for example. Further, the rotary electric machine is not limited to the winding field type having a field winding, and may be, for example, a permanent magnet type having a permanent magnet in the rotor.

30 ... rotary electric machine, 34U to 34W ... U, V, W phase winding, 40 ... inverter, 60 ... MGECU.

Claims (2)

A rotary electric machine (30) having a stator winding (34U to 34W) and
It has a series connection of an upper arm switch (SUP to SWp) and a lower arm switch (Sun to SWn), and by driving the upper arm switch and the lower arm switch, a DC power supply (20) and the stator winding are used. In a power converter (40) for transmitting power to and from a rotary electric machine control device (60) applied to a control system including the power converter (40).
When the peak value of each phase voltage applied to the stator winding is equal to or lower than the voltage of the DC power supply, the upper arm switch and the upper arm switch so that each phase voltage applied to the stator winding has a PWM voltage waveform. The sine wave control unit that drives the lower arm switch,
When the peak value of each phase voltage applied to the stator winding exceeds the voltage of the DC power supply, the upper arm switch so as to have a PWM voltage waveform having a modulation factor higher than the PWM waveform voltage by the sine wave control unit. And the overmodulation control unit that drives the lower arm switch,
A rectangular wave control unit that drives the upper arm switch and the lower arm switch on by square wave control once each with a dead time in between in one electric angle cycle.
On condition that the upper arm switch is turned on for at least a part of the period in which the generated voltage of the stator winding exceeds the voltage of the DC power supply, the upper arm switch and the upper arm switch and the upper arm switch have a dead time in one electric angular cycle. A synchronous rectification control unit that turns on the lower arm switch once each,
When shifting from the drive by the sine wave control unit to the drive by the synchronous rectification control unit, the drive by the sine wave control unit, the drive by the overmodulation control unit, the drive by the square wave control unit, and the drive by the synchronous rectification control unit. When switching in the order of drive and shifting from the drive by the synchronous rectification control unit to the drive by the sine wave control unit, the drive by the synchronous rectification control unit, the drive by the square wave control unit, the drive by the overmodulation control unit, and the above. A control device for a rotating electric machine equipped with a switching unit that switches the order of driving by a sine wave control unit. The control device for a rotary electric machine according to claim 1, wherein the dead time set in the synchronous rectification control unit is longer than the dead time set in the rectangular wave control unit.

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