JP7380536B2 - Inverter control equipment and automotive fluid machinery - Google Patents

Description

The present invention relates to an inverter control device and a vehicle-mounted fluid machine.

For example, as shown in Patent Document 1, an inverter control device is known that is used to control an inverter circuit that drives an in-vehicle electric motor using an in-vehicle power storage device. Patent Document 1 describes that the in-vehicle electric motor is used as a motor for an automobile air conditioner and has a three-phase coil, and that the inverter circuit has a three-phase switching element. There is. Further, Patent Document 1 describes that a drive voltage as a three-phase voltage command value is calculated based on a two-phase voltage command value consisting of an excitation component voltage and a torque component voltage.

Japanese Patent Application Publication No. 2015-208187

Here, when a PWM signal is generated based on the three-phase voltage command value and the three-phase switching element is controlled using the PWM signal, noise at a specific frequency may occur due to switching of the switching element. . The inventors of the present invention have discovered that the noise at the specific frequency is caused by the waveform of the neutral point potential. For example, when the waveform of the neutral point potential is a square wave, the neutral point potential includes harmonic noise as noise of a specific frequency.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an inverter control device capable of reducing noise at a specific frequency caused by switching of switching elements, and an in-vehicle fluid machine equipped with the inverter control device. It is to be.

An inverter control device that achieves the above object is used to control an inverter circuit that drives an in-vehicle electric motor using an in-vehicle power storage device, the in-vehicle electric motor having a three-phase coil, The inverter circuit includes a three-phase switching element, and the inverter control device includes a three-phase voltage command value deriving unit that derives a three-phase voltage command value to be applied to the three-phase coil, and a three-phase voltage command value deriving unit that derives a three-phase voltage command value to be applied to the three-phase coil. a generation unit that generates a plurality of PWM signals for each phase within a predetermined control period based on a carrier signal, and PWM-controls the three-phase switching element using the PWM signal of each phase. The generation unit has a reference pulse width corresponding to the three-phase voltage command value, and generates the plurality of PWM signals within the control period for one phase within the control period. The present invention is characterized by comprising a pulse changing section that performs pulse changing control to make at least two pulse widths different from each other among the plurality of PWM signals so that the average pulse width of the PWM signals becomes the reference pulse width.

According to this configuration, by making the pulse widths of at least two of the plurality of PWM signals within the control period of one phase different from each other, it is possible to bring the neutral point potential closer to a trapezoidal wave. A trapezoidal wave has a waveform that is closer to a sine wave without harmonic noise than a square wave. Thereby, the waveform of the neutral point potential can be made closer to a waveform with less harmonic noise than a square wave, so that noise at a specific frequency caused by switching of the three-phase switching element can be reduced.

On the other hand, the average pulse width of the plurality of PWM signals within the control period is the reference pulse width corresponding to the three-phase voltage command value. Thereby, the interphase voltage applied to the three-phase coil becomes a value corresponding to the three-phase voltage command value. Therefore, a torque corresponding to the three-phase voltage command value is applied to the vehicle electric motor. Therefore, it is possible to suppress the inconvenience that different torques are applied due to bringing the neutral point potential close to a trapezoidal wave.

The inverter control device includes a voltage grasping section that grasps the power supply voltage that is the voltage of the vehicle-mounted power storage device, a speed grasping section that grasps the rotational speed of the vehicle-mounted electric motor, and an external command value transmitted from the outside. a two-phase voltage command value derivation unit that derives a two-phase voltage command value that is a target value of voltage to be applied to the d-axis and the q-axis of the in-vehicle electric motor based on the grasping result of the speed grasping unit; The 3-phase voltage command value derivation unit derives the 3-phase voltage command value based on the 2-phase voltage command value, and the generation unit determines the 2-phase voltage command value and the voltage grasping unit. The pulse change control by the pulse change unit may be performed when the voltage utilization rate calculated based on the result is less than or equal to a predetermined threshold utilization rate.

According to this configuration, by performing pulse change control when the voltage utilization rate is less than or equal to the threshold utilization rate, it is possible to reduce noise at a specific frequency that tends to increase when the voltage utilization rate is small.

To explain in detail, when the voltage utilization rate decreases, the amount of change in the three-phase voltage command value tends to decrease. In this case, since the three-phase voltage command value tends to be biased toward a specific value or a value close to it, the pulse width of the PWM signal of each phase is likely to bias toward a specific value or a value close to it. Under such circumstances, if the waveform of the neutral point potential is a square wave, harmonic noise corresponding to the above-mentioned specific pulse width tends to increase as noise at a specific frequency.

In this regard, according to the present configuration, when the voltage utilization rate is less than or equal to the threshold utilization rate, the waveform of the neutral point potential approaches a trapezoidal wave, so that the harmonic noise can be reduced. Thereby, the harmonic noise, which tends to increase when the voltage utilization factor is small, can be suitably reduced.

In the inverter control device, the pulse changing section performs the pulse changing control on the plurality of PWM signals within the control period in two variable phases among the three phases, and one of the three variable phases other than the variable phase. The pulse change control may not be performed on the plurality of PWM signals within the control period in one fixed phase.

According to this configuration, since one phase is a fixed phase, the processing load can be reduced compared to a case where all phases are variable phases.
Regarding the inverter control device, the plurality of first variable phase PWM signals, which are the plurality of PWM signals within the control period in the first variable phase of the two variable phases, have a pulse width wider than the reference pulse width. and a first narrow signal having a pulse width narrower than the reference pulse width, the plurality of PWM signals within the control period in a second variable phase of the two variable phases. A plurality of second variable-phase PWM signals are output when the first wide-width signal is output, and are a second narrow-width signal having a pulse width narrower than the reference pulse width; It is preferable to include a second wide signal that is output when the first narrow signal is output and has a pulse width wider than the reference pulse width.

According to this configuration, the pulse width in one of the two variable phases is wider than the reference pulse width, while the pulse width in the other variable phase is narrower than the reference pulse width. Thereby, the difference between the pulse widths of the two corresponding variable phases can be increased, and the waveform of the neutral point potential can be made into a trapezoidal wave that is closer to a sine wave.

The inverter control device includes a voltage grasping section that grasps the power supply voltage that is the voltage of the vehicle-mounted power storage device, a speed grasping section that grasps the rotational speed of the vehicle-mounted electric motor, and an external command value transmitted from the outside. a two-phase voltage command value derivation unit that derives a two-phase voltage command value that is a target value of voltage to be applied to the d-axis and the q-axis of the in-vehicle electric motor based on the grasping result of the speed grasping unit; The three-phase voltage command value derivation unit derives the three-phase voltage command value based on the two-phase voltage command value, and the three-phase voltage command value and the grasping result of the voltage grasping unit are configured to derive the three-phase voltage command value based on the two-phase voltage command value. When the voltage utilization rate calculated based on is the first voltage utilization rate, the neutral point potential of the three-phase voltage command value changes with the first neutral point amplitude as the three-phase voltage command value. If the voltage utilization rate is a second voltage utilization rate smaller than the first voltage utilization rate, the first shift command value obtained by It is preferable to derive a second shift command value obtained by changing the sex point potential with a second neutral point amplitude that is larger than the first neutral point amplitude.

According to this configuration, when the voltage utilization rate is the second voltage utilization rate smaller than the first voltage utilization rate, the second neutral point amplitude is larger than the first neutral point amplitude corresponding to the first voltage utilization rate. By changing the neutral point potential with the point amplitude, a second shift command value having a change range at least equal to or larger than the second neutral point amplitude can be obtained. Thereby, it is possible to suppress the range of change of the second shift command value from becoming narrower. Therefore, it is possible to suppress a local increase in noise at a specific frequency due to a narrowing of the range of change in the three-phase voltage command value.

In particular, normally, when the voltage utilization rate decreases, the range of change in the three-phase voltage command value tends to decrease. Therefore, when the voltage utilization rate is the second voltage utilization rate, the range of change in the three-phase voltage command value tends to become narrow.

In this regard, according to the present configuration, when the voltage utilization rate is the second voltage utilization rate, by changing the neutral point potential with a relatively large second neutral point amplitude, the voltage utilization rate becomes the second voltage utilization rate. Even when there is a two-voltage utilization rate, it is possible to suppress the range of change in the three-phase voltage command value from becoming narrower. Thereby, it is possible to suppress noise at a specific frequency from becoming locally large.

The inverter control device includes a voltage grasping section that grasps the power supply voltage that is the voltage of the vehicle-mounted power storage device, a speed grasping section that grasps the rotational speed of the vehicle-mounted electric motor, and an external command value transmitted from the outside. a two-phase voltage command value derivation unit that derives a two-phase voltage command value that is a target value of voltage to be applied to the d-axis and the q-axis of the in-vehicle electric motor based on the grasping result of the speed grasping unit; The three-phase voltage command value derivation unit derives the three-phase voltage command value based on the two-phase voltage command value, and the three-phase voltage command value and the grasping result of the voltage grasping unit are configured to derive the three-phase voltage command value based on the two-phase voltage command value. If the voltage utilization rate calculated based on is less than or equal to a predetermined threshold utilization rate, the phase-to-phase voltages of the three-phase coils are the same and the change range is the same for the same two-phase voltage command value. It is preferable to switch and derive mutually different three-phase voltage command values at a switching period.

According to this configuration, when the voltage utilization rate is less than or equal to the threshold utilization rate, the three-phase voltage command value is switched to a value with a different change range at a switching cycle while the phase-to-phase voltage of the three-phase coil remains the same. As a result, even if the two-phase voltage command values are the same, the three-phase voltage command values change at the switching period. Therefore, it is possible to reduce noise at a specific frequency that is caused by the three-phase voltage command values periodically being the same value under a situation where the voltage utilization rate is small.

In particular, with this configuration, even when the three-phase voltage command values are switched, the inter-phase voltages applied to the three-phase coils remain the same. As a result, the same torque is applied to the vehicle electric motor. Therefore, it is possible to suppress the inconvenience that different torques are applied due to switching the three-phase voltage command values.

From the above, the specific frequency that occurs when the three-phase voltage command value periodically becomes the same value under a situation where the voltage utilization rate is small while maintaining the state in which an appropriate torque is applied to the in-vehicle electric motor. can reduce noise.

An in-vehicle fluid machine that achieves the above object is characterized by comprising the in-vehicle electric motor, the inverter circuit, and the inverter control device described above.
The on-vehicle fluid machine may be an on-vehicle electric compressor including a compression section driven by the on-vehicle electric motor.

According to this invention, it is possible to reduce noise at a specific frequency caused by switching of a switching element.

FIG. 1 is a block diagram showing an overview of an on-vehicle electric compressor. FIG. 2 is a block diagram showing the electrical configuration of an inverter circuit and an inverter control device. 5 is a flowchart showing rotation control processing according to the first embodiment. (a) A waveform diagram showing an example of a U-phase PWM signal, (b) A waveform diagram showing an example of a v-phase PWM signal subjected to pulse change control, (c) A waveform diagram showing an example of a v-phase PWM signal subjected to pulse change control. A waveform diagram showing an example of a PWM signal, (d) a waveform diagram showing an example of a neutral point potential. 7 is a flowchart showing rotation control processing according to the second embodiment. (a) A waveform diagram showing an example of a U-phase PWM signal, (b) A waveform diagram showing an example of a v-phase PWM signal subjected to pulse change control, (c) A waveform diagram showing an example of a v-phase PWM signal subjected to pulse change control. A waveform diagram showing an example of a PWM signal, (d) a waveform diagram showing an example of a neutral point potential.

(First embodiment)
Hereinafter, a first embodiment of an inverter control device and a vehicle-mounted fluid machine equipped with the inverter control device will be described. Note that the following description shows an example, and the inverter control device and the vehicle-mounted fluid machine are not limited to the contents of this embodiment.

In this embodiment, the vehicle-mounted fluid machine is a vehicle-mounted electric compressor, and the vehicle-mounted electric compressor is used in a vehicle-mounted air conditioner. An overview of the in-vehicle air conditioner and in-vehicle electric compressor will be explained.

As shown in FIG. 1, an in-vehicle air conditioner 101 installed in a vehicle 100 includes an in-vehicle electric compressor 10 and an external refrigerant circuit 102 that supplies refrigerant as a fluid to the in-vehicle electric compressor 10. It is equipped with

The external refrigerant circuit 102 includes, for example, a heat exchanger and an expansion valve. The in-vehicle air conditioner 101 performs heating and cooling in the vehicle by compressing a refrigerant by the in-vehicle electric compressor 10 and performing heat exchange and expansion of the refrigerant by the external refrigerant circuit 102.

The vehicle air conditioner 101 includes an air conditioning ECU 103 that controls the entire vehicle air conditioner 101 . The air conditioning ECU 103 is configured to be able to grasp the temperature inside the vehicle, the set temperature of the car air conditioner, etc., and transmits various commands such as a command rotation speed Nc to the vehicle-mounted electric compressor 10 based on these parameters.

Vehicle 100 includes an on-vehicle power storage device 104. The vehicle-mounted power storage device 104 may be any device capable of charging and discharging DC power, such as a secondary battery or an electric double layer capacitor. The vehicle-mounted power storage device 104 is used as a DC power source for the vehicle-mounted electric compressor 10.

The on-board electric compressor 10 includes an on-board electric motor 11, a compression section 12 driven by the on-board electric motor 11, an inverter circuit 13 that drives the on-board electric motor 11 using an on-board power storage device 104, and an inverter. An inverter control device 14 used to control the circuit 13 is provided.

The in-vehicle electric motor 11 includes a rotating shaft 21, a rotor 22 fixed to the rotating shaft 21, a stator 23 disposed opposite to the rotor 22, and three-phase coils 24u and 24v wound around the stator 23. , 24w. The rotor 22 includes permanent magnets 22a. Specifically, the permanent magnet 22a is embedded within the rotor 22. As shown in FIG. 2, the three-phase coils 24u, 24v, and 24w are, for example, Y-connected. The rotor 22 and the rotating shaft 21 rotate when the three-phase coils 24u, 24v, and 24w are energized in a predetermined pattern. That is, the vehicle-mounted electric motor 11 of this embodiment is a three-phase motor.

Note that the connection mode of the three-phase coils 24u, 24v, and 24w is not limited to Y-connection, but may be arbitrary, and may be, for example, delta connection. Further, the rotational speed and acceleration of the vehicle-mounted electric motor 11 mean the rotational speed and acceleration of the rotor 22.

The compression unit 12 compresses fluid (refrigerant in this embodiment) when driven by the on-vehicle electric motor 11 . Specifically, the compression unit 12 compresses the suction refrigerant supplied from the external refrigerant circuit 102 by rotating the rotating shaft 21, and discharges the compressed refrigerant. The specific configuration of the compression section 12 is arbitrary, such as a scroll type, a piston type, a vane type, etc.

The inverter circuit 13 drives the vehicle electric motor 11 using the vehicle power storage device 104 by converting DC power input from the vehicle power storage device 104 into alternating current power.

As shown in FIG. 2, the inverter circuit 13 includes three-phase switching elements Qu1 to Qw2. Specifically, the inverter circuit 13 includes u-phase switching elements Qu1, Qu2 corresponding to the u-phase coil 24u, v-phase switching elements Qv1, Qv2 corresponding to the v-phase coil 24v, and w-phase switching elements Qv1, Qv2 corresponding to the w-phase coil 24w. It includes switching elements Qw1 and Qw2.

The three-phase switching elements Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2 (hereinafter referred to as "three-phase switching elements Qu1 to Qw2") are power switching elements such as IGBTs, for example. However, the three-phase switching elements Qu1 to Qw2 are not limited to IGBTs, and may be arbitrary, for example, MOSFETs. Note that the three-phase switching elements Qu1 to Qw2 have free-wheeling diodes (body diodes) Du1 to Dw2.

The u-phase switching elements Qu1 and Qu2 are connected in series to each other via a connection line, and the connection line is connected to the u-phase coil 24u. The collector of the u-phase switching element Qu1 is connected to a positive terminal (+ terminal) on the high voltage side of the vehicle-mounted power storage device 104. The emitter of the u-phase switching element Qu2 is connected to the negative terminal (-terminal), which is the low voltage side of the vehicle-mounted power storage device 104.

Note that the connection manner of the other switching elements Qv1, Qv2, Qw1, and Qw2 is the same as that of the u-phase switching elements Qu1 and Qu2, except that the corresponding coils are different.
The inverter control device 14 is a controller that includes electronic components such as a CPU and memory. The inverter control device 14 drives the vehicle electric motor 11 by controlling the inverter circuit 13, specifically the three-phase switching elements Qu1 to Qw2.

The inverter control device 14 includes a voltage sensor 31 as a voltage grasping section that grasps the power supply voltage Vin, which is the voltage of the vehicle-mounted power storage device 104. The voltage sensor 31 detects the input voltage of the inverter circuit 13 to determine the power supply voltage Vin.

The inverter control device 14 includes a current sensor 32 that detects a motor current flowing through the vehicle electric motor 11. The motor current in this embodiment is, for example, three-phase currents Iu, Iv, and Iw flowing through the three-phase coils 24u, 24v, and 24w.

As shown in FIG. 2, the inverter control device 14 converts the three-phase currents Iu, Iv, and Iw detected by the current sensor 32 into a d-axis current Id and a q-axis current Iq (hereinafter referred to as "two-phase current Id, It has a 3-phase/2-phase conversion circuit 33 for converting into 3-phase/2-phase converter 33 (referred to as "Iq").

Incidentally, the d-axis current Id can also be said to be a current in the axial direction of the magnetic flux of the rotor 22, that is, the excitation component current, and the q-axis current Iq can also be said to be a torque component current that contributes to the torque of the on-vehicle electric motor 11.

The inverter control device 14 includes a position/speed estimation section (position estimation section) 34 that estimates the rotational position and rotational speed of the rotor 22. The position/speed estimation unit 34 estimates the rotational position and actual rotational speed Nr of the rotor 22 based on at least one of the two-phase currents Id and Iq and the two-phase voltage command values Vdr and Vqr, for example. do. The units of the commanded rotational speed Nc and the actual rotational speed Nr are arbitrary, and for example, rpm can be considered.

The specific configuration of the position/velocity estimation section 34 is arbitrary. For example, the position/velocity estimation unit 34 calculates the induced voltage induced in the three-phase coils 24u, 24v, and 24w based on the two-phase currents Id and Iq, the d-axis voltage command value Vdr, the motor constant, etc. It may also include a voltage calculation section. In this case, the position/speed estimation unit 34 may estimate the rotational position and actual rotational speed Nr of the rotor 22 based on the induced voltage and the d-axis current Id of the two-phase currents Id and Iq. .

The position/speed estimating unit 34 periodically grasps the detection results of the current sensor 32, and periodically estimates the rotational position and actual rotational speed Nr of the rotor 22. Thereby, the position/speed estimating unit 34 follows changes in the rotational position and actual rotational speed Nr of the rotor 22. In this embodiment, the position/velocity estimating unit 34 corresponds to a “speed determining unit” that determines the rotational speed of the on-vehicle electric motor 11.

The inverter control device 14 includes an acquisition unit 35 that acquires an external command value transmitted from the air conditioning ECU 103 as an external device, and an in-vehicle electric motor 11 based on the external command value and the actual rotation speed Nr acquired by the acquisition unit 35. A rotation control section (rotation control circuit) 36 that performs rotation control.

The acquisition unit 35 is, for example, a connector for electrically connecting the air conditioning ECU 103 and the inverter control device 14. The acquisition unit 35 electrically connects the air conditioning ECU 103 and the inverter control device 14, making it possible to exchange information. Note that the acquisition unit 35 can also be said to be an input unit into which various commands such as the command rotational speed Nc are input.

The external command value is, for example, the command rotation speed Nc. Specifically, the air conditioning ECU 103 calculates the required flow rate of refrigerant from the operating status of the vehicle air conditioner 101, calculates a command rotation speed Nc that can realize the flow rate, and sets the command rotation speed Nc to the inverter control device 14. Send to.

Note that the external command value is not limited to the command rotational speed Nc, and the specific contents of the command are arbitrary as long as the driving manner of the on-vehicle electric motor 11 can be defined. Further, the main body for outputting the external command value is not limited to the air conditioning ECU 103, but is arbitrary.

The rotation control section 36 is electrically connected to the acquisition section 35. The rotation control unit 36 is electrically connected to the air conditioning ECU 103 via the acquisition unit 35, and the command rotation speed Nc acquired by the acquisition unit 35 is input to the rotation control unit 36. That is, the rotation control unit 36 receives an external command value from the air conditioning ECU 103 via the acquisition unit 35.

The rotation control unit 36 is electrically connected to the voltage sensor 31 and is capable of grasping the power supply voltage Vin.
The rotation control section 36 is electrically connected to the position/velocity estimation section 34. As a result, the rotation control unit 36 can grasp the rotational position and actual rotational speed Nr of the rotor 22 estimated by the position/speed estimation unit 34, and the rotation control unit 36 can grasp the rotational position and actual rotational speed Nr of the rotor 22 estimated by the position/speed estimation unit 34. parameters can be sent.

Furthermore, the three-phase/two-phase conversion circuit 33 outputs the two-phase currents Id and Iq to both the position/velocity estimation section 34 and the rotation control section 36. Therefore, the rotation control unit 36 can grasp the two-phase currents Id and Iq.

The rotation control unit 36 performs rotation control processing to control the rotation of the vehicle electric motor 11 (specifically, the rotor 22) by controlling the three-phase switching elements Qu1 to Qw2 of the inverter circuit 13 using PWM control. Here, the rotation control unit 36 repeatedly executes the rotation control process at a predetermined control period T.

The specific hardware configuration of the rotation control unit 36 is arbitrary. For example, the rotation control unit 36 may include a memory storing a program for performing rotation control processing and necessary information, and a CPU for executing rotation control processing based on the program.

Further, the rotation control unit 36 may have a configuration including one or more dedicated hardware circuits that execute part or all of the rotation control processing, or may include one or more dedicated hardware circuits and a CPU that executes software processing. It may be a combination of In other words, the rotation control unit 36 may be realized by at least one of, for example, one or more dedicated hardware circuits and one or more processors (control circuits) that operate according to a computer program (software). .

Here, for convenience of explanation, the rotation control process realized by the rotation control unit 36 will be explained in the form of a flowchart shown in FIG. 3.
As shown in FIG. 3, first in step S101, the rotation control unit 36 uses an external command value (in this embodiment, the command rotation speed Nc) acquired by the acquisition unit 35, and the position/speed estimation unit 34 ascertains ( Two-phase current command values Idr and Iqr are derived based on the estimated actual rotational speed Nr (estimated in this embodiment). The two-phase current command values Idr and Iqr are the d-axis current command value Idr, which is the target value of the d-axis current Id, and the q-axis current command value Iqr, which is the target value of the q-axis current Iq.

Thereafter, in step S102, the rotation control unit 36 sets the two-phase voltage command value based on the two-phase current command values Idr, Iqr and the two-phase currents Id, Iq obtained by the three-phase/two-phase conversion circuit 33. Derive Vdr and Vqr. The two-phase voltage command values Vdr and Vqr are composed of a d-axis voltage command value Vdr and a q-axis voltage command value Vqr. The d-axis voltage command value Vdr is the target value of the voltage applied to the d-axis of the vehicle electric motor 11, and the q-axis voltage command value Vqr is the target value of the voltage applied to the q-axis of the vehicle electric motor 11. be.

Incidentally, the rotation control section 36 outputs the two-phase voltage command values Vdr and Vqr to the position/velocity estimating section 34. The position/speed estimation unit 34 uses at least one of the two-phase voltage command values Vdr and Vqr to estimate the position and actual rotational speed Nr of the rotor 22.

In step S103, the rotation control unit 36 executes a process of deriving three-phase voltage command values Vur, Vvr, and Vwr based on two-phase voltage command values Vdr and Vqr.
The three-phase voltage command values Vur, Vvr, and Vwr are composed of a u-phase voltage command value Vur, a v-phase voltage command value Vvr, and a w-phase voltage command value Vwr. The u-phase voltage command value Vur is the target value of the voltage applied to the u-phase coil 24u, the v-phase voltage command value Vvr is the target value of the voltage applied to the v-phase coil 24v, and the w-phase voltage command value Vwr is: This is the target value of the voltage applied to the w-phase coil 24w. In step S103, the rotation control unit 36 converts the two-phase voltage command values Vdr, Vqr into two-phase/three-phase, for example, to obtain three-phase reference command values Vu0, Vv0, Derive Vw0.

The three-phase reference command values Vu0, Vv0, and Vw0 change according to the electrical angle, and have a waveform having a reference amplitude f0 with one cycle ranging from 0° to 360° of the electrical angle, for example. The phases of the three-phase reference command values Vu0, Vv0, and Vw0 are different from each other, and are shifted by 120 degrees from each other, for example. The waveforms of the three-phase reference command values Vu0, Vv0, and Vw0 are arbitrary, such as a sine wave, a triangular wave, a rectangular wave, or a modified version of these waveforms.

In subsequent step S104, the rotation control unit 36 calculates the voltage utilization rate R based on the two-phase voltage command values Vdr, Vqr and the power supply voltage Vin.
The voltage utilization rate R is the utilization rate of the power supply voltage Vin necessary for applying the two-phase voltage command values Vdr and Vqr to the on-vehicle electric motor 11. For example, the voltage utilization rate R is a ratio of the effective values of the two-phase voltage command values Vdr and Vqr to the power supply voltage Vin, or a parameter obtained by adding or multiplying the ratio by a predetermined correction parameter.

Note that if we pay attention to the fact that the interphase voltages of the three-phase coils 24u, 24v, and 24w change according to the two-phase voltage command values Vdr and Vqr, the voltage utilization rate R is calculated as follows: It can also be said to be the ratio of the effective value of the phase-to-phase voltage of 24W. In other words, the voltage utilization rate R can be said to be a parameter indicating the utilization rate of the power supply voltage Vin since the inter-phase voltages of the three-phase coils 24u, 24v, and 24w have values corresponding to the two-phase voltage command values Vdr and Vqr.

Incidentally, the reference amplitude f0, which is the amplitude of the three-phase reference command values Vu0, Vv0, and Vw0, decreases as the voltage utilization rate R decreases. For example, the reference amplitude f0 when the voltage utilization rate R is the first voltage utilization rate R1, and the reference amplitude f0 when the voltage utilization rate R is the second voltage utilization rate R2 smaller than the first voltage utilization rate R1. When compared, the reference amplitude f0 in the case of the second voltage utilization rate R2 is smaller than the reference amplitude f0 in the case of the first voltage utilization rate R1. When the reference amplitude f0 becomes smaller, the range of change (specifically, the range from the minimum value to the maximum value) of the three-phase reference command values Vu0, Vv0, and Vw0 tends to become narrower.

After calculating the voltage utilization rate R, the rotation control unit 36 proceeds to step S105 and determines whether the voltage utilization rate R calculated in step S104 is equal to or less than a predetermined threshold utilization rate Rth. . The threshold utilization rate Rth is arbitrary, and may be smaller than or larger than 50%, for example. Further, the value utilization rate Rth may be set within a range of 40 to 70%, for example.

If the voltage utilization rate R is larger than the threshold utilization rate Rth, the rotation control unit 36 proceeds to step S106 and sets the reference PWM signals Pu0, Pv0, based on the three-phase voltage command values Vur, Vvr, Vwr and the carrier signal. Generate Pw0.

The reference PWM signals Pu0, Pv0, Pw0 are PWM signals corresponding to the three-phase voltage command values Vur, Vvr, Vwr (specifically, the three-phase reference command values Vu0, Vv0, Vw0) derived in step S103. Specifically, the u-phase reference PWM signal Pu0 is a pulse signal having a u-phase reference pulse width Wu0 corresponding to the u-phase reference command value Vu0. The v-phase reference PWM signal Pv0 is a pulse signal having a v-phase reference pulse width Wv0 corresponding to the v-phase reference command value Vv0. The w-phase reference PWM signal Pw0 is a pulse signal having a w-phase reference pulse width Ww0 corresponding to the w-phase reference command value Vw0.

After that, in step S107, the rotation control unit 36 performs switching control of the three-phase switching elements Qu1 to Qw2 by outputting the reference PWM signals Pu0, Pv0, and Pw0 toward the three-phase switching elements Qu1 to Qw2. That is, the inverter control device 14 performs PWM control on the three-phase switching elements Qu1 to Qw2 using the PWM signal.

Here, in this embodiment, the rotation control unit 36 generates a plurality of reference PWM signals Pu0, Pv0, and Pw0 in step S106. That is, the rotation control unit 36 generates a plurality of reference PWM signals Pu0, Pv0, and Pw0 for one rotation control process. Considering that the rotation control process is repeatedly executed in the control period T, it can be said that the rotation control section 36 generates a plurality of PWM signals for each phase within the control period T. In this embodiment, the number of PWM signals generated within the control period T is two.

Then, in step S107, the rotation control unit 36 controls the switching of the three-phase switching elements Qu1 to Qw2 by outputting the reference PWM signals Pu0, Pv0, and Pw0 to the three-phase switching elements Qu1 to Qw2 multiple times. , the main rotation control process ends.

That is, when the voltage utilization rate R is larger than the threshold utilization rate Rth, the rotation control unit 36 of the present embodiment has the same pulse width (specifically, reference pulse width Wu0, Wv0, Ww0) within the control period T. The pulse signals are used to control the switching of the three-phase switching elements Qu1 to Qw2 multiple times.

On the other hand, as shown in FIG. 3, when the voltage utilization rate R is less than or equal to the threshold utilization rate Rth, the rotation control unit 36 causes the waveform of the neutral point potential En to approach a trapezoidal wave in steps S108 to S111. Pulse change control is performed to vary the pulse width. The neutral point potential En is the potential at the neutral point of the three-phase voltage command values Vur, Vvr, and Vwr.

The pulse change control in steps S108 to S111 will be explained in detail using FIGS. 3 and 4.
The pulse change control has a reference pulse width corresponding to the three-phase voltage command value, and the average pulse widths Wua, Wva, Wwa of the plurality of PWM signals within the control period T in at least one phase are the reference pulse width Wu0. , Wv0, Ww0, the pulse widths of at least two of the plurality of PWM signals are made different from each other. In this embodiment, the rotation control unit 36 performs pulse change control on the v-phase and w-phase PWM signals among the three phases, but does not perform pulse change control on the u-phase. That is, in this embodiment, the v-phase and the w-phase correspond to a "variable phase", and the u-phase corresponds to a "fixed phase".

First, as shown in FIG. 3, the rotation control unit 36 generates first PWM signals Pu1, Pv1, and Pw1 among the plurality of PWM signals within the control period T in step S108. The first PWM signals Pu1, Pv1, Pw1 are pulse signals having first pulse widths Wu1, Wv1, Ww1.

To explain step S108 in detail, the rotation control unit 36 first derives reference pulse widths Wu0, Wv0, Ww0 based on the three-phase voltage command values Vur, Vvr, Vwr and the carrier signal, as in step S106. .

Thereafter, as shown in FIG. 4A, the rotation control unit 36 generates the 1u-phase PWM signal Pu1 having the 1u-phase pulse width Wu1 set to be the same as the u-phase reference pulse width Wu0. On the other hand, as shown in FIGS. 4(b) and 4(c), the rotation control unit 36 controls the v-phase reference pulse width Wv0 and the w-phase reference pulse width for the first v-phase pulse width Wv1 and the first w-phase pulse width Ww1. The width is changed from Ww0.

For example, the rotation control unit 36 generates the first v-phase PWM signal Pv1 having the first v-phase pulse width Wv1 set wider than the v-phase reference pulse width Wv0. In this case, the difference between the first v-phase pulse width Wv1 and the v-phase reference pulse width Wv0 is defined as the first v-phase pulse difference δWv1.

Similarly, the rotation control unit 36 generates a first w-phase PWM signal Pw1 having a first w-phase pulse width Ww1 set narrower than the w-phase reference pulse width Ww0. In this case, the difference between the first w-phase pulse width Ww1 and the w-phase reference pulse width Ww0 is defined as the first w-phase pulse difference δWw1.

Here, in this embodiment, the first v-phase pulse difference δWv1 and the first w-phase pulse difference δWw1 are the same (δWv1=δWw1). However, the magnitude relationship between the first v-phase pulse difference δWv1 and the first w-phase pulse difference δWw1 is arbitrary; for example, the first v-phase pulse difference δWv1 may be larger than the first w-phase pulse difference δWw1, or vice versa. .

As shown in FIG. 3, after generating the first PWM signals Pu1, Pv1, Pw1, the rotation control unit 36 uses the first PWM signals Pu1, Pv1, Pw1 to control the three-phase switching elements Qu1 to Qw2 in step S109. Control switching once.

In this case, as shown in FIG. 4, the first u-phase PWM signal Pu1, the first v-phase PWM signal Pv1, and the first w-phase PWM signal Pw1 are synchronized with each other. For example, the rotation control unit 36 adjusts the output timing so that the centers of the first PWM signals Pu1, Pv1, and Pw1 are the same. That is, the first w-phase PWM signal Pw1 can be said to be a signal that is output (in other words, generated) when the first v-phase PWM signal Pv1 is output (in other words, generated).

Incidentally, as shown in FIG. 4(b), the rising timing of the first v-phase PWM signal Pv1 and the rising timing of the v-phase reference PWM signal Pv0 are shifted by δWv1/2. The falling timing of the first v-phase PWM signal Pv1 and the falling timing of the v-phase reference PWM signal Pv0 are different from each other by δWv1/2. The same applies to the w phase.

After that, the rotation control unit 36 generates second PWM signals Pu2, Pv2, and Pw2 among the plurality of PWM signals within the control period T in step S110. The first PWM signals Pu1, Pv1, Pw1 and the second PWM signals Pu2, Pv2, Pw2 are PWM signals generated/output within the same control period T. The second PWM signals Pu2, Pv2, Pw2 are PWM signals output after the first PWM signals Pu1, Pv1, Pw1 within the control period T. The second PWM signals Pu2, Pv2, Pw2 have second pulse widths Wu2, Wv2, Ww2.

To explain step S110 in detail, as shown in FIG. 4(a), the rotation control unit 36 outputs a second u-phase PWM signal Pu2 having a second u-phase pulse width Wu2 set to be the same as the u-phase reference pulse width Wu0. generate. On the other hand, as shown in FIGS. 4(b) and 4(c), the rotation control unit 36 controls the v-phase reference pulse width Wv0 and the w-phase reference pulse width for the second v-phase pulse width Wv2 and the second w-phase pulse width Ww2. The width is changed from Ww0.

For example, the rotation control unit 36 generates a second v-phase PWM signal Pv2 having a second v-phase pulse width Wv2 set narrower than the v-phase reference pulse width Wv0. In this case, the difference between the second v-phase pulse width Wv2 and the v-phase reference pulse width Wv0 is defined as the second v-phase pulse difference δWv2.

Similarly, the rotation control unit 36 generates a second w-phase PWM signal Pw2 having a second w-phase pulse width Ww2 set wider than the w-phase reference pulse width Ww0. In this case, the difference between the second w-phase pulse width Ww2 and the w-phase reference pulse width Ww0 is defined as the second w-phase pulse difference δWw2.

That is, the rotation control unit 36 of this embodiment makes the pulse width of one of the two variable phases wider than the reference pulse width, while making the pulse width of the other variable phase narrower than the reference pulse width.

Here, the rotation control unit 36 controls the average pulse widths Wua, Wva, and Wwa of each phase within the control period T to become the reference pulse widths Wu0, Wv0, and Ww0.
Specifically, for the u-phase, which is a fixed phase, the first u-phase pulse width Wu1 and the second u-phase pulse width Wu2 are the u-phase reference pulse width Wu0, so the u-phase average pulse width Wua is the u-phase reference pulse width Wu0. It is.

Regarding the v-phase, which is a variable phase, the first v-phase pulse width Wv1 and the second v-phase pulse width Wv2 are set so that the v-phase average pulse width Wva becomes the v-phase reference pulse width Wv0. Specifically, the first v-phase pulse difference δWv1 and the second v-phase pulse difference δWv2 are set to be the same.

Similarly, for the w-phase, the first w-phase pulse width Ww1 and the second w-phase pulse width Ww2 are set so that the w-phase average pulse width Wwa becomes the w-phase reference pulse width Ww0. Specifically, the first w-phase pulse difference δWw1 and the second w-phase pulse difference δWw2 are set to be the same. That is, the rotation control unit 36 changes the pulse width of each pulse signal to be changed so that the integrated value of the amount of change from the reference pulse amplitude becomes "0".

Note that in this embodiment, the second v-phase pulse difference δWv2 and the second w-phase pulse difference δWw2 are the same. However, the magnitude relationship between the second v-phase pulse difference δWv2 and the second w-phase pulse difference δWw2 is arbitrary; for example, the second v-phase pulse difference δWv2 may be larger than the second w-phase pulse difference δWw2, or vice versa. .

As shown in FIG. 3, after generating the second PWM signals Pu2, Pv2, Pw2, the rotation control unit 36 uses the second PWM signals Pu2, Pv2, Pw2 to turn the three-phase switching elements Qu1 to Qw2 into 1 The switching control is performed once, and the main rotation control process ends. In this case, the rotation control unit 36 adjusts the output timing so that the centers of the second PWM signals Pu2, Pv2, and Pw2 are the same, for example. Thereby, the second u-phase PWM signal Pu2, the second v-phase PWM signal Pv2, and the second w-phase PWM signal Pw2 are synchronized with each other. That is, the second w-phase PWM signal Pw2 can be said to be a signal that is output (in other words, generated) when the second v-phase PWM signal Pv2 is output (in other words, generated).

In this embodiment, the rotation control unit 36 that executes the processing in steps S101 and S102 corresponds to a “two-phase voltage command value derivation unit”, and the rotation control unit 36 that executes the processing in step S103 corresponds to a “three-phase voltage command value derivation unit”. "Derivation part". The rotation control unit 36 that executes the processing in steps S106, S108, and S110 corresponds to a “generation unit”, and particularly the rotation control unit 36 that executes the processing in steps S108 and S110 corresponds to a “pulse change unit”.

Further, in the present embodiment, both v-phase PWM signals Pv1 and Pv2 correspond to "a plurality of first variable phase PWM signals", and in particular, the first v-phase PWM signal Pv1 corresponds to a "first wide signal", and the second v-phase PWM signal Pv1 corresponds to a "first wide signal", and Phase PWM signal Pv2 corresponds to the "first narrow width signal". Both w-phase PWM signals Pw1 and Pw2 correspond to "a plurality of second variable-phase PWM signals", and in particular, the first w-phase PWM signal Pw1 corresponds to a "second narrow width signal", and the second w-phase PWM signal Pw2 corresponds to the "second wide signal".

Next, the operation of this embodiment will be explained using FIG. 4. FIG. 4(a) is a waveform diagram showing an example of a u-phase PWM signal. FIG. 4(b) is a waveform diagram showing an example of a v-phase PWM signal subjected to pulse change control. FIG. 4(c) is a waveform diagram showing an example of a w-phase PWM signal subjected to pulse change control. FIG. 4(d) is a waveform diagram showing an example of the neutral point potential En. For convenience of explanation, it is assumed that the three-phase voltage command values Vur, Vvr, and Vwr are the same in each control cycle T.

As shown in FIG. 4, as described above, in this embodiment, a plurality of (for example, two) PWM signals are generated within the control period T, and these two PWM signals are repeatedly generated in the control period T.

In this case, since the u-phase is a fixed phase in which pulse change control is not performed, the u-phase has the same pulse width within the control period T (in detail, the u-phase reference U-phase PWM signals Pu1 and Pu2 with a pulse width Wu0) are generated.

As shown in FIGS. 4(b) and 4(c), when the 1u-phase PWM signal Pu1 is generated, the 1v-phase PWM signal Pv1 and the 1w-phase PWM signal Pw1 are subjected to pulse change control. is generated. In this case, the first v-phase pulse width Wv1, which is the pulse width of the first v-phase PWM signal Pv1, is wider than the v-phase reference pulse width Wv0, while the first w-phase pulse width, which is the pulse width of the first w-phase PWM signal Pw1, is wider than the v-phase reference pulse width Wv0. The pulse width Ww1 is narrower than the w-phase reference pulse width Ww0. As a result, as shown in FIG. 4(d), the waveform of the neutral point potential En obtained from the first PWM signals Pu1, Pv1, and Pw1 approaches a trapezoidal wave.

Specifically, when the first v-phase pulse width Wv1 is the v-phase reference pulse width Wv0 and the first w-phase pulse width Ww1 is the w-phase reference pulse width Ww0, as shown by the broken line in FIG. The waveform of the sex point potential En is a square wave. On the other hand, when pulse change control is performed, as shown by the solid line in FIG. 4(d), the waveform of the neutral point potential En approaches a trapezoidal wave whose rising and falling edges are gently sloped.

Similarly, the 2nd v-phase pulse width Wv2, which is the pulse width of the 2nd v-phase PWM signal Pv2, is narrower than the v-phase reference pulse width Wv0. The pulse width Ww2 is wider than the w-phase reference pulse width Ww0. As a result, as shown by the solid line in FIG. 4(d), the waveform of the neutral point potential En obtained from the second PWM signals Pu2, Pv2, and Pw2 approaches a trapezoidal wave.

In addition, the average pulse widths Wua, Wva, and Wwa of each phase within the control period T are the reference pulse widths Wu0, Wv0, and Ww0, which are the pulse widths corresponding to the three-phase voltage command values Vur, Vvr, and Vwr. Torque (in other words, target torque) corresponding to the three-phase voltage command values Vur, Vvr, and Vwr is applied to the on-vehicle electric motor 11 .

According to this embodiment described in detail above, the following effects are achieved.
(1-1) The inverter control device 14 is used to control the inverter circuit 13 that drives the vehicle electric motor 11 using the vehicle power storage device 104. The on-vehicle electric motor 11 has three-phase coils 24u, 24v, and 24w, and the inverter circuit 13 has three-phase switching elements Qu1 to Qw2.

The inverter control device 14 includes a position/speed estimating section 34 that grasps the actual rotational speed Nr that is the rotational speed of the on-vehicle electric motor 11, and a rotation control section 36. The rotation control unit 36 sets a two-phase voltage command value Vdr, which is a target value of the voltage to be applied to the d-axis and the q-axis of the vehicle electric motor 11, based on the external command value and the actual rotation speed Nr transmitted from the outside. , Vqr. The rotation control unit 36 then performs a process of deriving three-phase voltage command values Vur, Vvr, and Vwr to be applied to the three-phase coils 24u, 24v, and 24w based on the two-phase voltage command values Vdr and Vqr. The rotation control unit 36 generates a plurality of PWM signals for each phase within a predetermined control period T based on the three-phase voltage command values Vur, Vvr, and Vwr and the carrier signal, and the generated PWM signals The signals are used to perform PWM control on the three-phase switching elements Qu1 to Qw2.

The rotation control unit 36 has a reference pulse width corresponding to the three-phase voltage command value, and performs pulse change control on a plurality of PWM signals within a control period T in one phase. The pulse change control is a control in which the pulse widths of at least two of the plurality of PWM signals are made different from each other so that the average pulse width becomes the reference pulse width. In the present embodiment, the rotation control unit 36 performs pulse change control on the first v-phase PWM signal Pv1 and the second v-phase PWM signal Pv2, and also performs pulse change control on the first w-phase PWM signal Pw1 and the second w-phase PWM signal Pw2. conduct.

According to this configuration, by performing pulse change control, the neutral point potential En can be brought closer to a trapezoidal wave. A trapezoidal wave has a waveform that is closer to a sine wave without harmonic noise than a square wave. Thereby, the waveform of the neutral point potential can be made closer to a waveform with less harmonic noise than a square wave, so that noise at a specific frequency caused by switching of the three-phase switching element can be reduced.

On the other hand, the average pulse width of the phase targeted for pulse change control is the reference pulse width corresponding to the three-phase voltage command value. For example, the v-phase average pulse width Wva, which is the average pulse width of the first v-phase PWM signal Pv1 and the second v-phase PWM signal Pv2, is the v-phase reference pulse width Wv0. Thereby, the interphase voltages applied to the three-phase coils 24u, 24v, and 24w take on values corresponding to the three-phase voltage command values Vur, Vvr, and Vwr. Therefore, the vehicle electric motor 11 is given a torque corresponding to the three-phase voltage command values Vur, Vvr, and Vwr. It is possible to suppress the inconvenience that different torques are applied due to bringing the neutral point potential En closer to a trapezoidal wave.

(1-2) The inverter control device 14 includes a voltage sensor 31 that detects the power supply voltage Vin, which is the voltage of the vehicle-mounted power storage device 104. The rotation control unit 36 performs pulse change control when the voltage utilization rate R calculated based on the two-phase voltage command values Vdr, Vqr and the power supply voltage Vin is equal to or less than the threshold utilization rate Rth.

According to this configuration, by performing pulse change control when the voltage utilization rate R is less than or equal to the threshold utilization rate Rth, it is possible to reduce noise at a specific frequency that tends to increase when the voltage utilization rate R is small.

To explain in detail, when the voltage utilization rate R decreases, the amount of change in the three-phase voltage command values Vur, Vvr, and Vwr tends to decrease. In this case, since the three-phase voltage command values Vur, Vvr, and Vwr tend to be biased toward a specific value or a value close to it, the pulse width of the PWM signal of each phase is likely to bias toward a specific value or a value close to it. Under such circumstances, if the waveform of the neutral point potential En is a square wave, harmonic noise corresponding to the above-mentioned specific pulse width is likely to increase as noise of a specific frequency.

In this regard, according to the present configuration, when the voltage utilization rate R is equal to or less than the threshold utilization rate Rth, the waveform of the neutral point potential En approaches a trapezoidal wave, so that the harmonic noise can be reduced. Thereby, the harmonic noise, which tends to increase when the voltage utilization rate R is small, can be suitably reduced.

(1-3) The rotation control unit 36 does not perform pulse change control when the voltage utilization rate R is larger than the threshold utilization rate Rth.
Under a situation where the voltage utilization rate R is larger than the threshold utilization rate Rth, noise at a specific frequency tends to be relatively small. In this regard, according to the present configuration, in a situation where the voltage utilization rate R is larger than the threshold utilization rate Rth, the processing load related to the pulse width change control can be reduced by not performing the pulse change control.

(1-4) The rotation control unit 36 generates a plurality of PWM signals within the control period T in two variable phases among the three phases, for example, the 1st v-phase PWM signal Pv1, the 2nd v-phase PWM signal Pv2, and the 1st w-phase PWM signal. Pulse change control is performed for Pw1 and the second w-phase PWM signal Pw2. On the other hand, the rotation control unit 36 receives a plurality of PWM signals within a control period T in a fixed phase other than the variable phase among the three phases, in this embodiment a u-phase (specifically, a first u-phase PWM signal Pu1 and a second u-phase PWM signal Pu1). Pulse change control is not performed for signal Pu2).

According to this configuration, since one phase is a fixed phase, the processing load can be reduced compared to a case where all phases are variable phases.
(1-5) The PWM signal within the control period T in the first variable phase (eg, v-phase) of the two variable phases includes the first v-phase PWM signal Pv1 and the second v-phase PWM signal Pv2. The first v-phase PWM signal Pv1 has a first v-phase pulse width Wv1 that is wider than the v-phase reference pulse width Wv0. The second v-phase PWM signal Pv2 has a second v-phase pulse width Wv2 narrower than the v-phase reference pulse width Wv0.

The PWM signal within the control period T in the second variable phase (eg, w phase) of the two variable phases includes a first w-phase PWM signal Pw1 and a second w-phase PWM signal Pw2. The first w-phase PWM signal Pw1 is a PWM signal that is output when the first v-phase PWM signal Pv1 is output (in other words, generated), and has a first w-phase pulse width Ww1 narrower than the w-phase reference pulse width Ww0. has. The second w-phase PWM signal Pw2 is a PWM signal that is output when the second v-phase PWM signal Pv2 is output, and has a second w-phase pulse width Ww2 that is wider than the w-phase reference pulse width Ww0.

For example, the larger the difference between the first v-phase pulse width Wv1 and the first w-phase pulse width Ww1, the more likely the waveform of the neutral point potential En becomes a trapezoidal wave close to a sine wave. Here, if the first v-phase pulse width Wv1 is made narrower than the v-phase reference pulse width Wv0 and the first w-phase pulse width Ww1 is made narrower than the w-phase reference pulse width Ww0, the pulse width must be varied within the reference pulse width. Therefore, the difference between the first v-phase pulse width Wv1 and the first w-phase pulse width Ww1 tends to become small. The same applies to the case where the first v-phase pulse width Wv1 is made wider than the v-phase reference pulse width Wv0 and the first w-phase pulse width Ww1 is made wider than the w-phase reference pulse width Ww0.

In this respect, according to the present configuration, the pulse width in one of the two variable phases is wider than the reference pulse width, while the pulse width in the other variable phase is narrower than the reference pulse width. Thereby, the difference between the pulse widths of the two corresponding variable phases can be increased, and the waveform of the neutral point potential En can be made into a trapezoidal wave that is closer to a sine wave.

(Second embodiment)
This embodiment differs from the first embodiment in the process of deriving the three-phase voltage command values Vur, Vvr, and Vwr. The rotation control process of this embodiment will be explained using FIG. 5.

As shown in FIG. 5, the rotation control unit 36 calculates the voltage utilization rate R in step S201 after deriving the two-phase voltage command values Vdr and Vqr in step S102. Thereafter, in step S202, the rotation control unit 36 derives three-phase reference command values Vu0, Vv0, and Vw0 corresponding to the two-phase voltage command values Vdr and Vqr.

Then, in step S203, the rotation control unit 36 derives a neutral point amplitude fn, which is the amplitude of the neutral point potential En to be changed, based on the voltage utilization rate R. The rotation control unit 36 varies the neutral point amplitude fn according to the voltage utilization rate R. Specifically, when the voltage utilization rate R is the first voltage utilization rate R1, the rotation control unit 36 derives the first neutral point amplitude fn1 as the neutral point amplitude fn, and the rotation control unit 36 derives the first neutral point amplitude fn1 as the neutral point amplitude fn. When the second voltage utilization rate R2 is smaller than the first voltage utilization rate R1, a second neutral point amplitude fn2 larger than the first neutral point amplitude fn1 is derived as the neutral point amplitude fn. In this embodiment, the rotation control unit 36 increases the neutral point amplitude fn as the voltage utilization rate R decreases.

After deriving the three-phase reference command values Vu0, Vv0, Vw0 and the neutral point amplitude fn, the rotation control unit 36 sets the neutral point potential as the three-phase voltage command values Vur, Vvr, Vwr in step S204. Shift command values Vux, Vvx, and Vwx obtained by changing En by the neutral point amplitude fn are derived, and the present derivation process ends.

Specifically, the rotation control unit 36 derives the shift command values Vux, Vvx, Vwx by superimposing the neutral point potential En of the neutral point amplitude fn on the three-phase reference command values Vu0, Vv0, Vw0. . That is, the rotation control unit 36 adds the three-phase reference command values Vu0, Vv0, and Vw0, which change according to the electrical angle, while changing the neutral point potential En with the neutral point amplitude fn according to the electrical angle. (or subtraction) to derive shift command values Vux, Vvx, and Vwx. In other words, the rotation control unit 36 superimposes the waveform of the neutral point potential En of the neutral point amplitude fn on the waveform of the three-phase reference command values Vu0, Vv0, Vw0, thereby generating the shift command values Vux, Vvx, It can also be said that Vwx is derived. Note that the period of the neutral point potential En to be superimposed is, for example, 120°.

For example, when the voltage utilization rate R is the first voltage utilization rate R1, the rotation control unit 36 controls the first intermediate The first shift command values Vux1, Vvx1, and Vwx1 are derived by superimposing the neutral point potential En of the sex point amplitude fn1. The range of change of the first shift command values Vux1, Vvx1, and Vwx1 is larger than at least the first neutral point amplitude fn1.

Further, when the voltage utilization rate R is the second voltage utilization rate R2, the rotation control unit 36 controls the second intermediate Second shift command values Vux2, Vvx2, and Vwx2 are derived by superimposing the neutral point potential En of the sex point amplitude fn2. The range of change of the second shift command values Vux2, Vvx2, and Vwx2 is larger than at least the second neutral point amplitude fn2. Moreover, the change range of the second shift command values Vux2, Vvx2, Vwx2 is larger than the three-phase reference command values Vu0, Vv0, Vw0.

As already explained, the second neutral point amplitude fn2 is larger than the first neutral point amplitude fn1. Therefore, even if the reference amplitude f0 becomes small due to the voltage utilization rate R becoming the second voltage utilization rate R2, the change range of the second shift command values Vux2, Vvx2, and Vwx2 is unlikely to become narrow.

For convenience of explanation, the neutral point amplitude fn of the shift command values Vux, Vvx, and Vwx will be referred to as the shift amplitude fx. As described above, the shift amplitude fx is a parameter determined according to the voltage utilization rate R, and includes the first neutral point amplitude fn1 and the second neutral point amplitude fn2.

In subsequent step S205, the rotation control unit 36 determines whether the voltage utilization rate R is larger than the threshold utilization rate Rth. The process is similar to step S105.
When the rotation control unit 36 makes an affirmative determination in step S205, in step S206, based on the shift command values Vux, Vvx, Vwx as the three-phase voltage command values Vur, Vvr, Vwr derived in step S204. Generate a PWM signal. Then, in step S207, the rotation control unit 36 performs switching control using the PWM signal generated in step S206. In this embodiment, the rotation control unit 36 outputs the PWM signal twice within the control period T.

On the other hand, if the voltage utilization rate R is less than or equal to the threshold utilization rate Rth, the rotation control unit 36 proceeds to step S208 and generates the first PWM signals Pu1, Pv1, Pw1 based on the shift command values Vux, Vvx, Vwx. In this case, similarly to the first embodiment, the rotation control unit 36 performs pulse change control for the variable phase. Then, in step S209, the rotation control unit 36 performs switching control using the first PWM signals Pu1, Pv1, and Pw1.

Thereafter, in step S210, the rotation control unit 36 of this embodiment derives change command values Vuy, Vvy, and Vwy that have different change ranges from the shift command values Vux, Vvx, and Vwx.
The change command values Vuy, Vvy, Vwy are values obtained by superimposing the neutral point potential En of the change amplitude fy on the three-phase reference command values Vu0, Vv0, Vw0. The change amplitude fy is a different amplitude from the shift amplitude fx. As a result, the change range of change command values Vuy, Vvy, Vwy is different from the change range of shift command values Vux, Vvx, Vwx, and the change command values Vuy, Vvy, Vwy and shift command values Vux, Vvx, Vwx are different from each other. They tend to have different values. The range of change is the range from the minimum value to the maximum value.

Note that the change amplitude fy may be larger or smaller than the shift amplitude fx. Further, the change amplitude fy may be a variable value that is changed every control period T, or may be a fixed value that is not changed every control period T.

In subsequent step S211, the rotation control unit 36 generates second PWM signals Pu2, Pv2, Pw2 based on the change command values Vuy, Vvy, Vwy. In this case, similarly to the first embodiment, the rotation control unit 36 performs pulse change control for the variable phase. Then, in step S212, the rotation control unit 36 performs switching control using the second PWM signals Pu2, Pv2, and Pw2.

As described above, in this embodiment, the rotation control unit 36 changes the three-phase voltage command values Vur, Vvr, and Vwr by changing the neutral point potential En. In particular, the rotation control unit 36 changes the three-phase voltage command values Vur, Vvr, and Vwr according to the voltage utilization rate R, and also changes the three-phase voltage command values Vur, Vvr, and Vwr within the control period T. Switching is performed between shift command values Vux, Vvx, and Vwx and change command values Vuy, Vvy, and Vwy.

Incidentally, both the shift command values Vux, Vvx, Vwx and the change command values Vuy, Vvy, Vwy are values obtained by changing the neutral point potential En with respect to the three-phase reference command values Vu0, Vv0, Vw0. be. Therefore, even if the shift command values Vux, Vvx, Vwx and the change command values Vuy, Vvy, Vwy differ due to the difference in the neutral point potential En, the phase-to-phase voltage will change. do not.

That is, when the voltage utilization rate R is equal to or lower than the threshold utilization rate Rth, the rotation control unit 36 determines that the phase-to-phase voltage of the vehicle electric motor 11 is the same and changes for the same two-phase voltage command values Vdr and Vqr. Three-phase voltage command values Vur, Vvr, and Vwr having different ranges are switched and derived at a switching cycle. In this embodiment, the three-phase voltage command values Vur, Vvr, and Vwr having different change ranges are shift command values Vux, Vvx, and Vwx, and change command values Vuy, Vvy, and Vwy. The rotation control unit 36 then performs switching control based on the derived three-phase voltage command values Vur, Vvr, and Vwr. In this embodiment, the switching period is the same as the carrier period, which is the period of the carrier signal. However, the switching period is not limited to this, and the switching period is arbitrary.

In other words, the rotation control unit 36 derives a plurality of three-phase voltage command values Vur, Vvr, and Vwr with different neutral point potentials En within the same control period T, and generates a plurality of PWM signals corresponding to them. It's okay. In this case, the reference pulse widths of each PWM signal generated within the control period T may be different even if they have the same phase. In this configuration, the reference pulse widths Wu0, Wv0, Ww0 corresponding to the three-phase voltage command values Vur, Vvr, Vwr are the average of the reference pulse widths of the same phase among each PWM signal within the control period T.

The average pulse widths Wua, Wva, Wwa of the first PWM signals Pu1, Pv1, Pw1 and the second PWM signals Pu2, Pv2, Pw2 are the reference pulse widths Wu0, Wv0 even when pulse change control is performed. , Ww0. In this embodiment, the rotation control section 36 that executes the processes of steps S201 to S204 and S210 corresponds to a "three-phase voltage command value derivation section."

Next, the operation of this embodiment will be explained using FIG. 6. 6(a) to 6(c) are waveforms showing an example of PWM signals of each phase in the second embodiment, and FIG. 6(d) is a waveform showing an example of the neutral point potential En in the second embodiment. be.

In this embodiment, compared to the first embodiment, the three-phase voltage command values Vur, Vvr, and Vwr change due to a change in the neutral point potential En. Therefore, as shown in FIG. 6, the pulse widths of the PWM signals of each phase tend to vary.

Specifically, in this embodiment, when the voltage utilization rate R is a relatively small second voltage utilization rate R2, the second shift command value Vux2, which is changed with a relatively large second neutral point amplitude fn2, Vvx2 and Vwx2 are derived. As a result, the amount of change with respect to the change in electrical angle becomes larger for the second shift command values Vux2, Vvx2, Vwx2 than for the three-phase reference command values Vu0, Vv0, Vw0. Therefore, the pulse width of the neutral point potential En tends to change.

Furthermore, within the control period T, the first PWM signals Pu1, Pv1, Pw1 corresponding to the shift command values Vux, Vvx, Vwx and the shift command values Vux, Vvx, Vwx have a different neutral point amplitude fn. , Vvy, and Vwy are alternately output. Therefore, even within the same control period T, the pulse width of the neutral point potential En varies. From the above, the pulse width of the neutral point potential En is less likely to be biased toward a specific value.

Furthermore, even if the neutral point potential En changes, the phase-to-phase voltage applied to the three-phase coils 24u, 24v, and 24w does not change. Therefore, a torque equivalent to the three-phase reference command values Vu0, Vv0, and Vw0 is applied to the on-vehicle electric motor 11.

According to the present embodiment described in detail above, in addition to the effects of the first embodiment, the following effects are achieved.
(2-1) In the process of deriving the three-phase voltage command values Vur, Vvr, and Vwr, the rotation control unit 36 calculates the voltage utilization rate calculated based on the two-phase voltage command values Vdr and Vqr and the power supply voltage Vin. Depending on R, different three-phase voltage command values Vur, Vvr, and Vwr are derived.

Specifically, when the voltage utilization rate R is the first voltage utilization rate R1, the rotation control unit 36 sets the neutral point potential En to the first neutral point as the three-phase voltage command values Vur, Vvr, and Vwr. First shift command values Vux1, Vvx1, and Vwx1 obtained by changing with amplitude fn1 are derived. Further, when the voltage utilization rate R is a second voltage utilization rate R2 smaller than the first voltage utilization rate R1, the rotation control unit 36 sets the neutral point potential as the three-phase voltage command values Vur, Vvr, and Vwr. Second shift command values Vux2, Vvx2, and Vwx2 obtained by changing En by the second neutral point amplitude fn2 are derived. The second neutral point amplitude fn2 is larger than the first neutral point amplitude fn1.

According to this configuration, when the voltage utilization rate R is the second voltage utilization rate R2 smaller than the first voltage utilization rate R1, the voltage utilization rate R is smaller than the first neutral point amplitude fn1 corresponding to the first voltage utilization rate R1. The neutral point potential En changes with the large second neutral point amplitude fn2. As a result, second shift command values Vux2, Vvx2, and Vwx2 having a variation range of at least the second neutral point amplitude fn2 are obtained. Therefore, it is possible to suppress the variation range of the second shift command values Vux2, Vvx2, and Vwx2 from becoming narrower. Therefore, it is possible to suppress noise at a specific frequency from increasing due to narrowing of the change range of the three-phase voltage command values Vur, Vvr, and Vwr.

In particular, normally, when the voltage utilization rate R becomes smaller, the range of change in the three-phase voltage command values Vur, Vvr, and Vwr tends to become narrower. Therefore, when the voltage utilization rate R is the second voltage utilization rate R2, the change range of the three-phase voltage command values Vur, Vvr, and Vwr tends to become narrow.

In this regard, according to the present configuration, when the voltage utilization rate R is the second voltage utilization rate R2, by changing the neutral point potential En with the relatively large second neutral point amplitude fn2, the voltage Even when the utilization rate R is the second voltage utilization rate R2, it is possible to suppress the change range of the three-phase voltage command values Vur, Vvr, and Vwr from becoming narrower. Thereby, it is possible to suppress noise at a specific frequency from increasing.

Further, the first shift command values Vux1, Vvx1, Vwx1 derived when the voltage utilization rate R is the first voltage utilization rate R1 are the first shift command values Vux1, Vvx1, Vwx1 derived when the voltage utilization rate R is the first voltage utilization rate R1. 1 by changing the neutral point amplitude fn1. Thereby, it is possible to suppress the variation range of the first shift command values Vux1, Vvx1, and Vwx1 from expanding excessively.

(2-2) When the voltage utilization rate R is less than or equal to the threshold utilization rate Rth, the rotation control unit 36 determines that the phase-to-phase voltage of the vehicle electric motor 11 is the same for the same two-phase voltage command values Vdr and Vqr. The three-phase voltage command values Vur, Vvr, and Vwr, which have different change ranges, are switched and derived at a switching cycle (carrier cycle in this embodiment). For example, the rotation control unit 36 derives shift command values Vux, Vvx, Vwx and change command values Vuy, Vvy, Vwy having different change ranges for one two-phase voltage command value Vdr, Vqr.

According to this configuration, when the voltage utilization rate R is equal to or lower than the threshold utilization rate Rth, the three-phase voltage command values Vur, Vvr, and Vwr change within the range of change while the phase-to-phase voltages of the three-phase coils 24u, 24v, and 24w remain the same. is switched to a different one at a switching cycle. As a result, even if the two-phase voltage command values Vdr and Vqr are the same, the three-phase voltage command values Vur, Vvr, and Vwr change at the switching cycle. Therefore, it is possible to reduce noise at a specific frequency caused by the three-phase voltage command values Vur, Vvr, and Vwr periodically being the same value under a situation where the voltage utilization rate R is small.

To be more specific, if the same three-phase voltage command values Vur, Vvr, and Vwr are periodically derived or a plurality of PWM signals are generated for one three-phase voltage command value Vur, Vvr, and Vwr, The three-phase voltage command values Vur, Vvr, and Vwr have the same value periodically. In this case, noise with a specific frequency corresponding to the derivation cycle of the three-phase voltage command values Vur, Vvr, and Vwr or the output cycle of the PWM signal will occur. The influence of noise at the specific frequency tends to be large when the voltage utilization rate R is small.

In this regard, according to the present embodiment, when the voltage utilization rate R is equal to or less than the threshold utilization rate Rth, three-phase voltage command values Vur, Vvr, and Vwr having different change ranges are derived at a switching cycle. Thereby, it is possible to vary the three-phase voltage command values Vur, Vvr, and Vwr for each switching cycle. Therefore, it is possible to reduce the frequency with which the three-phase voltage command values Vur, Vvr, and Vwr are periodically the same value, and through this, the noise at the specific frequency can be reduced.

In particular, according to this configuration, even when the three-phase voltage command values Vur, Vvr, and Vwr are switched, the interphase voltages applied to the three-phase coils 24u, 24v, and 24w are the same. As a result, the same torque is applied to the vehicle-mounted electric motor 11. Therefore, it is possible to suppress the inconvenience that different torques are applied due to switching the three-phase voltage command values Vur, Vvr, and Vwr.

From the above, while maintaining the state in which an appropriate torque is applied to the on-vehicle electric motor 11, the three-phase voltage command values Vur, Vvr, and Vwr are periodically kept at the same value under a situation where the voltage utilization rate R is small. It is possible to reduce noise at specific frequencies caused by this.

Note that each of the above embodiments may be modified as follows. Further, the above embodiment and the following other examples may be combined as appropriate within a range that does not cause any technical contradiction.
The number of PWM signals generated within the control period T is not limited to two, but may be any number, and may be three or more. In this case, there may be a PWM signal whose pulse width is not changed. In other words, under the condition that three or more PWM signals are generated within the control period T, making the plurality of PWM signals different means that at least two of the PWM signals are different, and the PWM signal having the reference pulse width It may also include a signal.

○ The stationary phase is not limited to the u phase, but is arbitrary. Moreover, two of the u-phase, v-phase, and w-phase may be a fixed phase, and one may be a variable phase.
○ There is no need for a stationary phase. That is, the rotation control unit 36 may perform pulse change control for all of the u-phase, v-phase, and w-phase.

The rotation control unit 36 may be configured to perform pulse change control regardless of the voltage utilization rate R.
The first v-phase pulse width Wv1 may be wider than the v-phase reference pulse width Wv0, and the first w-phase pulse width Ww1 may be wider than the w-phase reference pulse width Ww0. In this case, the second v-phase pulse width Wv2 is preferably narrower than the v-phase reference pulse width Wv0, and the second w-phase pulse width Ww2 is preferably narrower than the w-phase reference pulse width Ww0.

In the second embodiment, two-phase modulation values may be adopted as the change command values Vuy, Vvy, and Vwy. Even in this case, the change range of the change command values Vuy, Vvy, Vwy is different from the change range of the shift command values Vux, Vvx, Vwx.

The specific configuration of the acquisition unit 35 is arbitrary as long as it can receive the external command value transmitted from the air conditioning ECU 103. For example, in a configuration in which the air conditioning ECU 103 transmits commands by wireless signals, the acquisition unit 35 may be a module that receives the wireless signals.

The configuration for determining the power supply voltage Vin, which is the voltage of the vehicle-mounted power storage device 104, is not limited to the voltage sensor 31, but is arbitrary. For example, when the on-vehicle power storage device 104 is provided with a voltage sensor 31 that detects the power supply voltage Vin and a battery CPU electrically connected to the voltage sensor 31, the rotation control unit 36 communicates with the battery CPU. The configuration may be such that the power supply voltage Vin is obtained by performing the following. In this case, the rotation control section 36 that communicates with the battery CPU corresponds to the "voltage grasping section."

The on-vehicle electric compressor 10 is not limited to the configuration used in the on-vehicle air conditioner 101, and may be used in other devices. For example, if the vehicle 100 is a fuel cell vehicle, the on-vehicle electric compressor 10 may be used as an air supply device that supplies air to the fuel cell. That is, the fluid to be compressed is not limited to refrigerant, but may be any fluid such as air.

The on-vehicle fluid machine is not limited to the on-vehicle electric compressor 10 that includes the compression section 12 that compresses fluid. For example, when vehicle 100 is a fuel cell vehicle, the on-vehicle fluid machine may be an electric pump device that includes a pump that supplies hydrogen to the fuel cell and an on-vehicle electric motor that drives the pump. In this case, the inverter control device 14 may be used to control an on-vehicle electric motor that drives the pump.

The on-vehicle electric motor 11 is not limited to that used in the on-vehicle electric compressor 10, and may be any motor as long as it is mounted on a vehicle. For example, the in-vehicle electric motor 11 may be a running motor that drives the vehicle.

Next, a preferred example that can be understood from the above embodiment and other examples will be described below.
(a) The three-phase voltage command value derivation unit includes a reference generation unit that generates a three-phase reference command value having a reference amplitude based on the two-phase voltage command value, and a reference generation unit that generates a three-phase reference command value having a reference amplitude based on the two-phase voltage command value; a superimposition unit that derives the three-phase voltage command value by superimposing a neutral point potential, and the superimposition unit is configured to derive the three-phase voltage command value when the voltage utilization rate is the first voltage utilization rate. When the neutral point potential of the first neutral point amplitude is superimposed on the reference command value, and the voltage utilization rate is the second voltage utilization rate, the neutral point potential of the first neutral point amplitude is superimposed on the reference command value. It is preferable that neutral point potentials of two neutral point amplitudes are superimposed.

DESCRIPTION OF SYMBOLS 10... Vehicle-mounted electric compressor (vehicle-mounted fluid machine), 11... Vehicle-mounted electric motor, 12... Compression part, 13... Inverter circuit, 14... Inverter control device, 22... Rotor, 24u, 24v, 24w... 3-phase coil , 31... Voltage sensor (voltage grasping unit), 34... Position/speed estimation unit (speed grasping unit), 35... Acquisition unit, 36... Rotation control unit, 104... Vehicle power storage device, Qu1 to Qw2... Three-phase switching element , Vdr, Vqr...2-phase voltage command value, Vur, Vvr, Vwr...3-phase voltage command value, Vu0, Vv0, Vw0...3-phase reference command value, Vux, Vvx, Vwx...shift command value, Vux1, Vvx1, Vwx1 ...First shift command value, Vux2, Vvx2, Vwx2...Second shift command value, Vuy, Vvy, Vwy...Change command value, Pu0, Pv0, Pw0...Reference PWM signal, Pu1, Pv1, Pw1...First PWM signal , Pu2, Pv2, Pw2...Second PWM signal, Wu0, Wv0, Ww0...Reference pulse width, Wu1, Wv1, Ww1...First pulse width, Wu2, Wv2, Ww2...Second pulse width, Wua, Wva, Wwa...Average Pulse width, En...neutral point potential, fn...neutral point amplitude, fn1...first neutral point amplitude, fn2...second neutral point amplitude, R...voltage utilization rate, Rth...threshold utilization rate, R1...th 1 voltage utilization rate, R2...second voltage utilization rate, T...control period.

Claims (8)

An inverter control device used to control an inverter circuit that drives an in-vehicle electric motor using an in-vehicle power storage device, the inverter control device comprising:
The in-vehicle electric motor has a three-phase coil,
The inverter circuit has a three-phase switching element,
The inverter control device includes:
a three-phase voltage command value derivation unit that derives a three-phase voltage command value to be applied to the three-phase coil;
a generation unit that generates a plurality of PWM signals for each phase within a predetermined control period based on the three-phase voltage command value and the carrier signal;
and PWM-controls the three-phase switching element using the PWM signal of each phase,
The generation unit has a reference pulse width corresponding to the three-phase voltage command value, and generates an average pulse of the plurality of PWM signals within the control period for the plurality of PWM signals within the control period in one phase. An inverter control device comprising: a pulse changing unit that performs pulse changing control to make at least two pulse widths different from each other among the plurality of PWM signals so that the width becomes the reference pulse width. a voltage grasping unit that grasps a power supply voltage that is the voltage of the in-vehicle power storage device;
a speed grasping unit that grasps the rotational speed of the in-vehicle electric motor;
Deriving two-phase voltage command values, which are target values of voltages to be applied to the d-axis and q-axis of the vehicle electric motor, based on the external command value transmitted from the outside and the grasping result of the speed grasping section. A phase voltage command value derivation unit,
Equipped with
The three-phase voltage command value derivation unit derives the three-phase voltage command value based on the two-phase voltage command value,
The generating unit is configured to change the pulse by the pulse changing unit when the voltage utilization rate calculated based on the two-phase voltage command value and the grasping result of the voltage grasping unit is equal to or lower than a predetermined threshold utilization rate. The inverter control device according to claim 1, wherein change control is performed. The pulse changing unit performs the pulse changing control on the plurality of PWM signals within the control period in two variable phases among the three phases, and performs the pulse changing control on one fixed phase other than the variable phase among the three phases. The inverter control device according to claim 1 or 2, wherein the pulse change control is not performed for the plurality of PWM signals within a period. The plurality of first variable phase PWM signals that are the plurality of PWM signals within the control period in the first variable phase of the two variable phases are:
a first wide signal having a pulse width wider than the reference pulse width;
a first narrow signal having a pulse width narrower than the reference pulse width;
including;
The plurality of second variable phase PWM signals that are the plurality of PWM signals within the control period in the second variable phase of the two variable phases are:
a second narrow signal that is output when the first wide signal is output and has a pulse width narrower than the reference pulse width;
a second wide signal that is output when the first narrow signal is output and has a pulse width wider than the reference pulse width;
The inverter control device according to claim 3, comprising: a voltage grasping unit that grasps a power supply voltage that is the voltage of the in-vehicle power storage device;
a speed grasping unit that grasps the rotational speed of the in-vehicle electric motor;
Deriving two-phase voltage command values, which are target values of voltages to be applied to the d-axis and q-axis of the vehicle electric motor, based on the external command value transmitted from the outside and the grasping result of the speed grasping section. A phase voltage command value derivation unit,
Equipped with
The three-phase voltage command value derivation unit derives the three-phase voltage command value based on the two-phase voltage command value,
When the voltage utilization rate calculated based on the two-phase voltage command value and the grasping result of the voltage grasping section is the first voltage utilization rate, the three-phase voltage command value is set as the three-phase voltage command value. Derive a first shift command value obtained by changing the neutral point potential with the first neutral point amplitude,
When the voltage utilization rate is a second voltage utilization rate smaller than the first voltage utilization rate, the three-phase voltage command value is a second voltage utilization rate whose neutral point potential is greater than the first neutral point amplitude. 5. The inverter control device according to claim 1, wherein the second shift command value is derived by changing the amplitude at two neutral points. a voltage grasping unit that grasps a power supply voltage that is the voltage of the in-vehicle power storage device;
a speed grasping unit that grasps the rotational speed of the in-vehicle electric motor;
Deriving two-phase voltage command values, which are target values of voltages to be applied to the d-axis and q-axis of the vehicle electric motor, based on the external command value transmitted from the outside and the grasping result of the speed grasping section. A phase voltage command value derivation unit,
Equipped with
The three-phase voltage command value derivation unit derives the three-phase voltage command value based on the two-phase voltage command value,
If the voltage utilization rate calculated based on the two-phase voltage command value and the grasping result of the voltage grasping section is less than or equal to a predetermined threshold utilization rate, the The inverter control device according to any one of claims 1 to 5, wherein three-phase voltage command values having the same phase-to-phase voltage of the three-phase coils and different change ranges are derived by switching at a switching period. the in-vehicle electric motor;
the inverter circuit;
An inverter control device according to any one of claims 1 to 6,
An in-vehicle fluid machine characterized by comprising: The vehicle-mounted fluid machine according to claim 7, wherein the vehicle-mounted fluid machine is a vehicle-mounted electric compressor including a compression section driven by the vehicle-mounted electric motor.