JP6376049B2 - Rotating machine control device - Google Patents

Description

  The present invention relates to a control device that operates a plurality of switching elements of a power converter to control energization of a rotating machine.

In recent years, in a control device that applies an AC voltage to a rotating machine using a voltage type PWM inverter or the like, the switching frequency is increased, and the surge voltage generated in the rotating machine tends to increase. Therefore, it is necessary to appropriately ensure the insulation between the windings of the rotating machine.
For example, Patent Document 1 discloses an insulating wire in which an insulating layer is thickened by sandwiching an enamel baking layer between a conductor and a film in order to increase a voltage at which partial discharge is generated.
In addition, the inverter device disclosed in Patent Document 2 can adjust the rising speed of the output voltage during the switching operation by switching the gate resistance in two stages. The surge voltage waveform when the first resistor is selected and the surge voltage waveform when the second resistor is selected cancel each other, reducing the surge voltage to the rotating machine.

JP 2013-041700 A JP 2010-206889 A

When the insulating layer of the winding is made thick as in Patent Document 1, the physique of the rotating machine becomes large. Moreover, there exists a problem that the space factor of a conductor falls and the performance of a rotary machine falls.
When the switching speed is lowered as in Patent Document 2, there is a problem that the switching loss increases.

  The present invention was created in view of the above points, and an object of the present invention is to control a rotating machine that reduces switching loss of a power converter while suppressing partial discharge between windings of the rotating machine. Is to provide.

The rotating machine control device of the present invention is used in a rotating machine drive system that converts a DC voltage into an AC voltage by a power converter including a plurality of switching elements and applies the AC voltage to a plurality of phase windings of the rotating machine. The switching element is operated to control the energization of the rotating machine.
This control device for a rotating machine includes a gate command calculation unit and a gate drive circuit.

The gate command calculation unit calculates gate commands for a plurality of switching elements based on a voltage command for the rotating machine. The gate drive circuit outputs gate signals generated based on the gate command to the plurality of switching elements, and can variably control the switching speed at which the plurality of switching elements operate.
When the timing at which the voltage vector applied to the rotating machine shifts to the zero vector state is “zero vector transition timing”, the gate drive circuit receives the “zero vector signal” notifying that it is the zero vector transition timing. The switching speed of the plurality of switching elements is increased.

  When attention is paid to the line voltage between the windings when a surge voltage is generated due to the switching operation, the target voltage of each phase is the same potential in the zero vector state. Therefore, the line voltage is only a voltage exceeding the target voltage due to the surge voltage, and is minimum as compared with other vector states. Therefore, at the zero vector transition timing, even if a surge voltage is generated to some extent, it is possible to avoid the occurrence of partial discharge.

Therefore, in the control device for a rotating machine according to the present invention, when the gate drive circuit receives the zero vector signal, the switching speed of the plurality of switching elements is increased. On the other hand, except for the zero vector transition timing, in principle, the switching speed is reduced to such an extent that partial discharge between the windings can be suppressed.
As a result, the line voltage when the surge voltage is generated is relatively small, and the switching loss can be reduced in a zero vector state that is advantageous for securing insulation between the windings. Therefore, the switching loss of the power converter can be effectively reduced while suppressing the partial discharge between the windings of the rotating machine.

For example, in a mode in which the gate command calculation unit calculates the gate command by PWM control based on the comparison between the voltage command and the carrier signal, the control device determines that “the zero vector transition timing is determined based on the gate command and the zero vector signal is driven by the gate. It is preferable to further include a “zero vector determination circuit that transmits to the circuit”.
In addition to absolute determination based on the gate command each time energization is performed, the zero vector determination circuit performs relative determination when the rotating machine is continuously energized with the same modulation method after absolute determination. Also good. In this relative determination, the number of times of switching from the previous zero vector shift timing is counted to determine the current zero vector shift timing.

The schematic block diagram of the system by which the control apparatus (PWM control) of the rotary machine by 1st-4th embodiment of this invention is applied. The figure explaining the surge voltage between windings. The time chart which shows the zero vector signal by PWM control. (A) Time chart explaining gate signal, (b) Truth table used in zero vector determination circuit (logic). The control block diagram of the control apparatus of the rotary machine by 1st Embodiment of this invention. The control block diagram of the control apparatus of the rotary machine by 2nd Embodiment of this invention. The control block diagram of the control apparatus of the rotary machine by 3rd Embodiment of this invention. The time chart which shows the zero vector transfer timing in (a) 3 phase modulation and (b) 2 phase modulation. The time chart explaining operation | movement of the zero vector determination circuit (pulse counter) of 3rd Embodiment. The control block diagram of the control apparatus of the rotary machine by 4th Embodiment of this invention. The schematic block diagram of the system by which the control apparatus (space vector modulation) of the rotary machine by 5th Embodiment of this invention is applied. (A) Space vector diagram of space vector modulation, (b) Component decomposition diagram of arbitrary space vector.

Hereinafter, a control device for a rotating machine according to an embodiment of the present invention will be described based on the drawings. In the plurality of embodiments, substantially the same configuration is denoted by the same reference numeral, and description thereof is omitted.
This control device for a rotating machine is applied as a control device for a main motor of a hybrid vehicle or an electric vehicle, for example. In the following description of the embodiment, the part corresponding to the “rotor” in the claims is referred to as “motor”. The “present embodiment” includes the first to fifth embodiments.

First, FIG. 1 shows an overall configuration of a motor drive system 90 to which the control device for a rotating machine according to the first to fourth embodiments is applied. The motor drive system 90 includes a battery (DC power supply) 50, an inverter 60 as a “power converter”, a motor 80 driven by AC power, and the like.
The motor 80 is, for example, a permanent magnet type synchronous three-phase AC motor, and is typically a motor generator capable of power running and regenerative operation. A U-phase winding 81, a V-phase winding 82, and a W-phase winding 83 are wound around the stator of the motor 80. Here, the line voltages between the U-phase and the V-phase and between the V-phase and the W-phase are denoted as Vu-v and Vv-w. The line voltage Vu-w between the U phase and the W phase is obtained from the sum of Vu-v and Vv-w.

A DC voltage is input from the battery 50 to the inverter 60. In the inverter 60, a plurality of switching elements 61 to 66 of upper and lower arms are bridge-connected. Specifically, the switching elements 61, 62, and 63 are upper-arm switching elements of the U phase, the V phase, and the W phase, respectively, and the switching elements 64, 65, and 66 are below the U phase, the V phase, and the W phase, respectively. This is an arm switching element. For example, IGBTs (insulated gate bipolar transistors) are used as the switching elements 61 to 66.
The inverter 60 converts a DC voltage into an AC voltage by the switching operation of the switching elements 61 to 66 and applies it to the phase windings 81, 82, 83 of the motor 80. Further, a smoothing capacitor 55 is connected to the input part of the inverter 60.

  In FIG. 1, reference numerals 101 to 104 of the motor control device respectively correspond to first to fourth embodiments described later. The motor control devices 101 to 104 are configured by a microcomputer or the like, and include a CPU, a ROM, an I / O, a bus line that connects these, and the like, all not shown. The motor control devices 101 to 104 execute control by software processing by executing a program stored in advance by the CPU or hardware processing by a dedicated electronic circuit.

Motor control devices 101 to 104 operate switching elements 61 to 66 of three-phase AC inverter 60 to control energization of motor 80. In particular, the motor control devices 101 to 104 of the first to fourth embodiments generate gate signals by PWM control and output the gate signals to the gates (base terminals) of the switching elements 61 to 66.
The motor control devices 101 to 104 include a voltage command calculator 11, a carrier generator 12, a gate command calculator (modulator) 21, and a gate drive circuit 40 as a general motor control configuration. Further, as a characteristic configuration, zero vector determination circuits 31 and 33 are provided.

The voltage command calculator 11 calculates a voltage command for the motor 80 based on the torque command and information indicating the current behavior of the motor 80. This calculation may be based on current or torque feedback control, or may be based on feedforward control. Alternatively, position sensorless control may be used. In FIG. 1, an input signal to the voltage command calculator 11 is not described.
The carrier generator 12 generates a carrier signal used for PWM control.
The gate command calculation unit (modulator) 21 compares the voltage command with the carrier signal and calculates the gate command. Further, the modulation method between three-phase modulation and two-phase modulation (upper two-phase modulation, lower two-phase modulation) is switched according to the modulation rate or voltage utilization rate.

The gate drive circuit 40 generates gate signals UH, VH, WH, UL, VL, WL based on the gate command, and outputs them to the switching elements 61-66. Further, the gate drive circuit 40 of the present embodiment can variably control the switching speed at which the switching elements 61 to 66 are turned ON / OFF.
Since a general PWM control configuration is a well-known technique, a detailed description thereof is omitted. The zero vector determination circuits 31 and 33 will be described after the problem of the present invention is described.

  By the way, during the switching operation of the inverter 60, a surge voltage generally proportional to the current differential value is generated due to a rapid current change. In particular, when the switching frequency is increased, the surge voltage applied to each phase winding 81, 82, 83 of the motor 80 tends to increase. Therefore, it is important to prevent a short circuit due to partial discharge between the wires of the phase windings 81, 82, 83 and to ensure appropriate insulation.

Therefore, Patent Document 1 (Japanese Patent Laid-Open No. 2013-041700) discloses a technique for thickening the insulating layer of the winding. However, when the insulating layer of the winding is thickened, the size of the motor 80 increases. Moreover, there is a problem that the space factor of the conductor is lowered and the performance of the motor 80 is lowered.
Further, as disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 2010-206889), there is a method of reducing the surge voltage by reducing the switching speed. However, there is a problem that the loss increases as a contradiction. Therefore, reduce the switching speed as much as possible and reduce the loss by increasing the switching speed as much as possible in the area where there is no problem with the insulation between the windings in order to suppress the partial discharge between the windings. Is required.

The focus of the present invention on this problem will be described with reference to FIG.
FIG. 2 shows the time change of the phase voltage when the switching element of a certain phase is switched at time tsw. A sudden surge voltage appears immediately after switching, and then converges to the target voltage V while being attenuated. The difference between the peak voltage and the target voltage V is expressed as excess voltage ΔV.
Here, attention is paid to the line voltage Vu-v between the U phase and the V phase, for example. Then, when there is a difference between the U-phase target voltage Vu and the V-phase target voltage Vv, the voltage obtained by adding the excess voltage ΔV to the difference between the two-phase target voltages (| Vu−Vv |) becomes the line voltage. . On the other hand, in the “zero vector state” in which the target voltages of all phases are the same potential, the line voltage is only the excess voltage ΔV, and is minimum as compared with other vector states. Therefore, at the zero vector transition timing, even if a surge voltage is generated to some extent, it is possible to avoid the occurrence of partial discharge.

The present invention pays attention to this point, and is characterized in that the switching speed of the plurality of switching elements 61 to 66 is increased at the timing of transition to the zero vector state (hereinafter, “zero vector transition timing”). On the other hand, except for the zero vector transition timing, in principle, the switching speed is reduced to such an extent that partial discharge between the windings can be suppressed.
However, the switching speed may be increased if there are other conditions that are advantageous for securing the insulation between the windings even at timings other than the zero vector transition timing. This will be described later in “Other Embodiments”.

Next, the zero vector state in PWM control will be described with reference to FIGS.
As shown in FIG. 3, in PWM control, a pulse signal gate command is generated according to the magnitude relationship between each phase voltage command and a carrier (for example, a triangular wave). When the voltage command exceeds the carrier, the gate command pulse rises to a high level, and when the voltage command falls below the carrier, the gate command pulse falls to a low level. When all the U phase, V phase, and W phase gate commands are at a high level or a low level, a zero vector state is established. Then, a “zero vector signal” notifying that it is the zero vector transition timing is generated.

FIG. 4A shows the relationship between the gate signal generated based on the gate command and ON / OFF of the switching elements 61 to 66 of the upper and lower arms. When the gate signal is H (high level), it means that the upper arm switching element is turned on and the lower arm switching element is turned off. When the gate signal is L (low level), it means that the upper arm switching element is turned OFF and the lower arm switching element is turned ON. As described above, the switching elements 61, 62, and 63 of the upper arm of each phase and the switching elements 64, 65, and 66 of the lower arm are instructed to be complementarily turned ON / OFF.
Strictly speaking, a dead time DT is provided between the OFF timing of one switching element of the upper and lower arms and the ON timing of the other switching element. However, in the present specification, reference to dead time is omitted below.

  FIG. 4B shows a truth table for determining a zero vector state from the H / L state of each phase gate command and generating a zero vector signal. The voltage vector applied to the three-phase motor 80 takes eight vector states. Of these, the state where the gate command for all phases is L corresponds to the zero vector state Z0, and the zero vector signal is H. Further, the state where the gate command for all phases is H corresponds to the zero vector state Z7, and the zero vector signal is set to H. In the other six effective voltage vector states, the zero vector signal is set to L.

Next, returning to the description of the configuration of the motor control devices 101 to 104, the zero vector determination circuits 31 and 33 will be described. The zero vector determination circuits 31 and 33 determine the zero vector transition timing based on the gate command calculated by the gate command calculation unit 21 and transmit a zero vector signal to the gate drive circuit 40. The gate drive circuit 40 that has received the zero vector signal increases the switching speed. Here, the zero vector signal is generated and communicated, for example, on the order of nsec between the gate command and the actual switching operation.
In FIG. 1, a zero vector determination circuit 31 is a logic circuit used in the first and second embodiments, and a zero vector determination circuit 33 is a pulse counter used in the third and fourth embodiments. Hereinafter, each embodiment will be described in detail.

(First and second embodiments)
A control device for a rotating machine according to the first and second embodiments will be described with reference to FIGS. 5 and 6. In both the motor control device 101 of the first embodiment shown in FIG. 5 and the motor control device 102 of the second embodiment shown in FIG. 6, the zero vector determination circuit 31 formed of a logic circuit is shown in FIG. The zero vector transition timing is determined using the truth table of b).
In FIGS. 5 and 6 and FIGS. 7 and 10 of the third and fourth embodiments, the voltage command calculator 11 and the carrier generator 12 (see FIG. 1) are not shown.
Zero vector determination by the zero vector determination circuit 31 is always performed with the same logic based on the commanded gate command every time power is supplied, including when the motor 80 is started and when the modulation method is switched. Hereinafter, the zero vector determination by this method is referred to as “absolute determination”.

The first embodiment and the second embodiment are different in the configuration for the gate drive circuit 40 to change the switching speed at the zero vector transition timing. Regarding the gate drive circuit, the gate drive circuit according to the first embodiment is denoted by “401”, and the gate drive circuit according to the second embodiment is denoted by “402”.
5 and 6, the inverter 60 is omitted, and only one switching element 61 to 66 is illustrated. Moreover, as a structure of the gate drive circuits 401 and 402, one structure is shown among six expressions corresponding to each switching element 61-66. In practice, it is preferable that one OFF speed and the other ON speed are changed in synchronism with the switching elements of the upper and lower arms in the same phase that are complementarily turned ON / OFF at the zero vector transition timing.

The gate drive circuit 401 shown in FIG. 5 includes a driver 41, a changeover switch 43, and resistors RG1 and RG2. Here, “RG1, RG2” serves as both the sign of the resistor and the resistance value of the resistor.
A gate command is input to the driver 41 from the gate command calculation unit 21. The resistors RG1 and RG2 are connected in series to a gate signal path that connects the driver 41 and the gates (base terminals) of the switching elements 61 to 66. The changeover switch 43 is connected in parallel with the resistor RG1 in a normally open (OFF) state, and closes (ON) when a zero vector signal is input from the zero vector determination circuit 31.

Since the changeover switch 43 is OFF when the state is other than the zero vector state, the sum of the resistance values RG1 and RG2 becomes the resistance of the gate signal path, that is, the gate resistance RG, as indicated by the broken line arrow. On the other hand, since the changeover switch 43 is turned ON when the zero vector state is entered, the resistance value RG2 becomes the gate resistance RG as indicated by the solid line arrow.
Therefore, the gate resistance RG becomes small when the zero vector state is entered, so that the switching speed is increased. Thus, the gate drive circuit 401 can change the switching speed by switching the gate resistance RG at the zero vector transition timing.

The gate drive circuit 402 shown in FIG. 6 includes a driver 42, a changeover switch 44, an insulated power supply 46, and resistors R1 and R2. Here, “R1 and R2” serve as both the sign of the resistor and the resistance value of the resistor.
A gate command is input from the gate command calculation unit 21 to the driver 42. The output terminal of the driver 42 is connected to the gates (base terminals) of the switching elements 61 to 66. The resistors R1 and R2 connected in series divide the voltage V0 of the insulated power supply 46. The divided voltage corresponds to the gate voltage VG output from the driver 42. The changeover switch 44 is connected in parallel with the resistor R1 in a normally open (OFF) state, and closes (ON) when a zero vector signal is input from the zero vector determination circuit 31.

Since the changeover switch 44 is OFF when other than the zero vector state, the gate voltage VG corresponds to “V0 × R1 / (R1 + R2)” obtained by dividing the voltage V0 of the insulated power supply 46. On the other hand, since the changeover switch 44 is turned ON when the zero vector state is entered, the gate voltage VG corresponds to the voltage V0 of the insulated power supply 46.
Therefore, when the transition to the zero vector state is made, the gate voltage VG is increased, so that the switching speed is increased. Thus, the gate drive circuit 402 can change the switching speed by switching the gate voltage VG at the zero vector transition timing.

As described above, in the motor control devices 101 and 102 according to the first and second embodiments, when the gate drive circuit 40 receives the zero vector signal, the switching speed of the switching elements 61 to 66 is increased. On the other hand, except for the zero vector transition timing, in principle, the switching speed is reduced to such an extent that partial discharge between the windings can be suppressed.
As a result, the line voltage when the surge voltage is generated is relatively small, and the switching loss can be reduced in a zero vector state that is advantageous for securing insulation between the windings. Therefore, the switching loss of the inverter 60 can be effectively reduced while suppressing the partial discharge between the windings of the motor 80.

In addition, the zero vector determination circuit 31 of the first and second embodiments always performs “absolute determination” of the zero vector with the same logic based on the gate signal acquired from the gate command calculation unit 21 every time power is supplied. To do. Thereby, the control configuration can be simplified.
Further, the switching speed can be appropriately changed by switching the gate resistance in the gate driving circuit 401 and switching the gate voltage in the gate driving circuit 402 at the zero vector transition timing.

(Third embodiment)
A control device for a rotating machine according to a third embodiment will be described with reference to FIGS.
The third embodiment and the fourth embodiment are used in combination with the absolute determination according to the first or second embodiment. In the following embodiments, the gate drive circuit 40 may employ any configuration such as the above-described gate resistance switching and gate voltage switching (see FIGS. 5 and 6).

  As shown in FIG. 7, the motor control device 103 according to the third embodiment includes a zero vector determination circuit 33 having a pulse counter function. The zero vector determination circuit 33 counts the number of times of switching from the previous zero vector transition timing after the zero vector transition timing is absolutely determined by the first and second embodiments, and determines the current zero vector transition timing. To do. This determination by the zero vector determination circuit 33 is referred to as “relative determination” with respect to absolute determination. Here, in order to execute the relative determination, it is assumed that the motor 80 is continuously energized with the same modulation method.

First, as shown in FIG. 8A, it is assumed that the voltage command is larger in the order of U phase> V phase> W phase in three-phase modulation. The gate signal of each phase rises when the voltage command exceeds the carrier signal, and falls when the voltage command falls below the carrier signal.
For example, when counting of the pulse edge is started from the rising edge of the U-phase gate signal, all phases become high level at the timing when the W-phase gate signal rises for the third time, and the state shifts to the zero vector state Z7. Further, at the timing when the U-phase gate signal falls for the sixth time, all phases become low level, and the state shifts to the zero vector state Z0.

Therefore, as shown in FIG. 9, the zero vector determination circuit 33 increments the pulse counter by 1 at the timing of the pulse edge. That is, it is increased from 0 to 1 at the time t1 when the U phase rises, and is increased from 1 to 2 at the time t2 when the V phase rises. The counter is reset from 2 to 0 at the time t3 when the W phase rises, and at the same time, a zero vector signal is output.
Further, it is increased from 0 to 1 at the time t4 when the W phase falls, and is increased from 1 to 2 at the time t5 when the V phase falls. The counter is reset from 2 to 0 at the time t6 when the U phase falls, and at the same time, a zero vector signal is output. In short, in the case of three-phase modulation, a zero vector signal is output every third pulse edge of the gate signal.

On the other hand, in the case of two-phase modulation, any one phase is always at a high level or a low level. In FIG. 8B, since the U phase is always at a high level, there is no zero vector state Z0 in which all phases are at a low level. Then, once every four pulse edges, the phase shifts to a zero vector state Z7 in which all phases are at a high level. Therefore, the zero vector determination circuit 33 outputs a zero vector signal every fourth pulse edge of the gate signal.
As described above, the motor control device 103 changes the number of times of switching counted in the relative determination according to the modulation method employed by the gate command calculation unit 21.

  The gate drive circuit 40 that has received the zero vector signal increases the switching speed as in the first and second embodiments. As described above, in the third embodiment, after the absolute determination, when the motor 80 is continuously energized with the same modulation method, the timing for increasing the switching speed is determined by the relative determination. When the calculation time of the pulse counter is shorter than that of the logic circuit, the relative determination is executed at the time of starting or the change of the modulation method that requires the absolute determination. Time can be shortened.

(Fourth embodiment)
A control device for a rotating machine according to a fourth embodiment will be described with reference to FIG. The motor control device 104 according to the fourth embodiment further includes a failure determination circuit 34 and zero vector determination circuits (logic) 35 and 36 as compared with the third embodiment.
The zero vector determination circuits 35 and 36 determine the zero vector transition timing based on the gate signals of the upper arm and the lower arm output from the gate drive circuit 40, respectively.

  The failure determination circuit 34 acquires the zero vector signal from the zero vector determination circuit 33 and the zero vector signal from the zero vector determination circuits 35 and 36. When the zero vector signals do not match, it is determined that the zero vector determination circuit 33 or the gate drive circuit 40 has failed, and a failure signal is output to the gate command calculation unit 21. When receiving the failure signal, the gate command calculation unit 21 stops outputting the gate command.

For example, when the zero vector signals based on the gate signals of the upper and lower arms determined by the zero vector determination circuits 35 and 36 do not coincide with each other, and one of them coincides with the zero vector signal by the zero vector determination circuit 33, the gate drive circuit It is estimated that one of the upper and lower arm circuits at 40 is faulty.
As described above, in the fourth embodiment, when the circuit breaks down, the output of the gate command can be stopped early and the drive of the motor 80 can be stopped based on the fail-safe concept.

(Fifth embodiment)
A control device for a rotating machine according to a fifth embodiment will be described with reference to FIGS. 11 and 12. The motor control devices 101 to 104 of the first to fourth embodiments generate gate signals by PWM control, whereas the gate command calculation unit (modulator) of the motor control device 105 of the fifth embodiment shown in FIG. 25 generates a gate command by “space vector modulation”. Then, the gate command calculation unit 25 outputs both the gate command and the zero vector signal to the gate drive circuit 40. Therefore, a zero vector determination circuit is not required for space vector modulation.

The outline of the space vector modulation will be described with reference to FIG. Spatial vector modulation is a method in which a three-phase waveform is replaced with a vector diagram as shown in FIG. 12A and considered with eight switching patterns, and three-phase signals can be handled collectively. In FIG. 12A, “1” means that the upper arm element of each phase is ON and the lower arm element is OFF, and “0” means that the upper arm element of each phase is OFF. This means that the lower arm element is ON.
When the three phases are U, V, and W phases, E (100) is the maximum voltage of the U phase, E (010) is the maximum voltage of the V phase, and E (001) is the maximum voltage of the W phase. By these vector displays, the three-phase AC waveform is shown as a vector diagram as shown in FIG.

  As shown in FIG. 12B, the magnitude of the vector in each block can be calculated as the sum of E (100) × T1 and E (110) × T2 using the following equation (1). . Here, T is a carrier period. By changing T1 and T2, the vector is changed in each block and rotated to draw a circle to output a three-phase alternating current.

  In space vector modulation, a zero vector command can be generated at an arbitrary timing. Therefore, a zero vector signal is output from the gate command calculation unit (modulator) 25 to the gate drive circuit 40 without using the zero vector determination circuit. Can do. The operation of the gate drive circuit 40 is the same as in the above embodiment. Therefore, 5th Embodiment has an effect similar to the said embodiment.

(Other embodiments)
(A) As described above, the switching speed may be increased when there are other advantageous conditions for securing the insulation between the windings other than the zero vector transition timing. For example, U-phase, V-phase, and W-phase windings are arranged in a line, and partial discharge between the U-phase and V-phase, and between the V-phase and W-phase must be considered. Assuming a form that does not need to be considered. In this embodiment, the line voltage is considered to decrease relatively at the timing when the U phase and the V phase are the same potential, or the V phase and the W phase are the same potential, so the switching speed can be increased. it can.

  (A) The zero vector transition timing may be determined by a method other than the above. For example, in PWM control three-phase modulation, the peak and valley timings of the carrier signal are always in the zero vector state (see FIG. 8A). Therefore, the peak and valley timings of the carrier signal can be acquired, and the switching timing immediately before the peak and valley timings can be determined as the zero vector transition timing.

(C) In FIG. 3 of the above embodiment, an example of sine wave PWM control is shown, but the same can be considered for overmodulation PWM control.
(D) The rotating machine to be controlled in the present invention is not limited to a three-phase rotating machine, and may be a four-phase or more multi-phase rotating machine.
(E) The switching speed may be changed to three or more stages, such as when the level of the line voltage exists in multiple stages according to the voltage vector state.

(F) The present invention may be applied not only to a rotating machine used as a main motor of a hybrid vehicle or an electric vehicle, but also to a rotating machine used in an auxiliary motor for a vehicle, an elevator other than a vehicle, a general machine, or the like. Good.
As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

101-105... Control device for rotating machine,
21, 25... Gate command calculation unit,
31, 33 ... Zero vector determination circuit,
40: Gate drive circuit,
60: Inverter (load circuit, power converter),
61-66... Switching elements,
80 ... motor (rotary machine),
81, 82, 83... Each phase winding,
90: Rotating machine drive system.

Claims (8)

A rotating machine that converts a DC voltage into an AC voltage by a power converter (60) including a plurality of switching elements (61 to 66) and applies the AC voltage to a plurality of windings (81, 82, 83) of the rotating machine (80). A control device for a rotating machine that is used in a drive system (90) and operates the plurality of switching elements to control energization of the rotating machine,
Based on a voltage command for the rotating machine, a gate command calculation unit (21, 25) that calculates a gate command for the plurality of switching elements;
A gate drive circuit (40) for outputting a gate signal generated based on the gate command to the plurality of switching elements and capable of variably controlling a switching speed at which the plurality of switching elements operate;
With
When the timing at which the voltage vector applied to the rotating machine shifts to the zero vector state is the zero vector transition timing,
The control apparatus for a rotating machine, wherein the gate driving circuit increases a switching speed of the plurality of switching elements when receiving a zero vector signal notifying that the timing is the zero vector transition timing. The gate command calculation unit (21) calculates the gate command by PWM control based on a comparison between the voltage command and a carrier signal,
2. The rotation according to claim 1, further comprising a zero vector determination circuit (31, 33) that determines the zero vector transition timing based on the gate command and transmits the zero vector signal to the gate drive circuit. Machine control device. The zero vector determination circuit (31)
The control apparatus for a rotating machine according to claim 2, wherein an absolute determination for determining the zero vector shift timing is executed based on the gate command each time power is supplied. The zero vector determination circuit (33)
After the absolute determination, when the rotating machine is continuously energized with the same modulation method, the relative number for determining the current zero vector transition timing is counted by counting the number of times of switching from the previous zero vector transition timing. 4. The rotating machine control device according to claim 3, wherein the determination is executed.   5. The control device for a rotating machine according to claim 4, wherein the zero vector determination circuit changes the number of times of switching counted in the relative determination in accordance with a modulation method.   When the zero vector signal by the zero vector determination circuit and the zero vector signal based on the gate signal output from the gate drive circuit do not match, it is determined that the zero vector determination circuit or the gate drive circuit has failed. The control device for a rotating machine according to any one of claims 2 to 5, further comprising a failure determination circuit (34) for performing the operation. The gate drive circuit (401) is at the zero vector transition timing,
The control device for a rotating machine according to any one of claims 1 to 6, wherein a resistance of a path of the gate signal output to the switching element is switched. The gate drive circuit (402) is at the zero vector transition timing,
The control device for a rotating machine according to any one of claims 1 to 6, wherein a voltage applied to a gate of the switching element is switched.

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