Inverter control device and vehicle-mounted fluid machinery

Abstract

The present invention provides an inverter control device and a vehicle-mounted fluid machine. An inverter control device capable of reducing noise of a specific frequency caused by switching of a switching element and a vehicle-mounted fluid machine having the inverter control device are provided. The inverter control device (14) is used to control an inverter circuit (13) that drives a vehicle-mounted electric motor (11) using a vehicle-mounted power storage device (104). A rotation control unit (36) of the inverter control device (14) performs processing to derive a three-phase voltage command value. Here, the rotation control unit (36) has a reference pulse width corresponding to the three-phase voltage command value and performs pulse change control on multiple PWM signals within a control period in one phase. The pulse change control is a control that makes the pulse widths of at least two of the multiple PWM signals different from each other so that the average pulse width becomes the reference pulse width.

Description

Technical Field

[0001] The present invention relates to an inverter control device and a vehicle-mounted fluid machine. Background Art

[0002] For example, as disclosed in Patent Document 1, an inverter control device is known for controlling an inverter circuit that drives an on-vehicle electric motor using an on-vehicle power storage device. Patent Document 1 describes the following: the on-vehicle electric motor is used as an air conditioner motor for an automobile and has a three-phase coil; and the inverter circuit includes three-phase switching elements. Patent Document 1 also describes the following: a driving voltage is calculated as a three-phase voltage command value based on a two-phase voltage command value consisting of an excitation component voltage and a torque component voltage.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-208187

[0006] When generating PWM signals based on the three-phase voltage command values and using these PWM signals to control the three-phase switching elements, the switching of the switching elements may generate noise of a specific frequency. The inventors of this application have discovered that this noise of a 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 contains harmonic noise, which is noise of a specific frequency. Summary of the Invention

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inverter control device capable of reducing noise of a specific frequency caused by switching of a switching element, and a vehicle-mounted fluid machine including the inverter control device.

[0008] An inverter control device for achieving the above-mentioned object is used in controlling an inverter circuit for driving an on-vehicle electric motor using an on-vehicle power storage device. The on-vehicle electric motor has a three-phase coil, and the inverter circuit has three-phase switching elements. The inverter control device includes: a three-phase voltage command value derivation unit for deriving three-phase voltage command values to be applied to the three-phase coil; and a generation unit for generating a plurality of PWM signals for each phase within a predetermined control cycle based on the three-phase voltage command values and a carrier signal, wherein the three-phase switching elements are PWM-controlled using the PWM signals for each phase. The generation unit includes a pulse changing unit for performing pulse changing control on the plurality of PWM signals within the control cycle in one phase, each having a reference pulse width corresponding to the three-phase voltage command value. In this pulse changing control, 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 of the plurality of PWM signals within the control cycle equals the reference pulse width.

[0009] According to this configuration, by making the pulse widths of at least two of the multiple PWM signals within a control cycle in a single phase different from each other, the neutral-point potential can be made to resemble a trapezoidal wave. A trapezoidal wave is a waveform that is closer to a sine wave than a square wave and has less harmonic noise. This allows the neutral-point potential waveform to resemble a waveform with less harmonic noise than a square wave, thereby reducing noise of a specific frequency caused by the switching of the three-phase switching elements.

[0010] Meanwhile, the average pulse width of the multiple PWM signals within the control cycle becomes the reference pulse width corresponding to the three-phase voltage command values. Consequently, the phase voltages applied to the three-phase coils become values corresponding to the three-phase voltage command values. Consequently, torque corresponding to the three-phase voltage command values is applied to the vehicle-mounted electric motor. This prevents the undesirable effect of applying different torques due to the neutral point potential being closer to a trapezoidal waveform.

[0011] Regarding the above-mentioned inverter control device, it can also be provided with: a voltage grasping unit that grasps the voltage of the vehicle-mounted power storage device, that is, the power supply voltage; a speed grasping unit that grasps the rotational speed of the vehicle-mounted electric motor; and a 2-phase voltage command value deriving unit that derives the target value of the voltage applied to the d-axis and q-axis of the vehicle-mounted electric motor based on the external command value sent from the outside and the grasping result of the speed grasping unit, that is, the 2-phase voltage command value, the 3-phase voltage command value deriving unit derives the 3-phase voltage command value based on the 2-phase voltage command value, and the generating unit performs the pulse change control of the pulse changing unit when the voltage utilization rate calculated based on the 2-phase voltage command value and the grasping result of the voltage grasping unit is below a predetermined threshold utilization rate.

[0012] According to this configuration, by performing pulse change control when the voltage utilization rate is equal to or lower than the threshold utilization rate, it is possible to reduce noise of a specific frequency that tends to increase when the voltage utilization rate is low.

[0013] To elaborate, as the voltage utilization rate decreases, the variation in the three-phase voltage command values tends to decrease. In this case, since the three-phase voltage command values tend to deviate toward or near specific values, the pulse width of the PWM signal for each phase tends to deviate toward or near specific values. In this case, if the neutral-point potential waveform is a square wave, harmonic noise corresponding to the specific pulse width tends to increase as noise of a specific frequency.

[0014] In this regard, according to this configuration, when the voltage utilization rate is below the threshold utilization rate, the neutral point potential waveform approaches a trapezoidal wave, thereby reducing the above-mentioned harmonic noise. This can appropriately reduce the above-mentioned harmonic noise that tends to increase when the voltage utilization rate is low.

[0015] Regarding the above-mentioned inverter control device, it may also be that the pulse change unit performs the pulse change control on the multiple PWM signals within the control period in two variable phases among the three phases, and on the other hand, does not perform the pulse change control on the multiple PWM signals within the control period in one fixed phase other than the variable phase among the three phases.

[0016] According to this configuration, since one phase becomes a fixed phase, the processing load can be reduced compared to a case where all phases are variable phases.

[0017] Regarding the above-mentioned inverter control device, it can also be that the multiple PWM signals within the control period in the first variable phase of the two variable phases, that is, the multiple first variable phase PWM signals, include: a first wide-width signal having a pulse width wider than the reference pulse width; and a first narrow-width signal having a pulse width narrower than the reference pulse width; the multiple PWM signals within the control period in the second variable phase of the two variable phases, that is, the multiple second variable phase PWM signals, include: a second narrow-width signal that is output when the first wide-width signal is output and has a pulse width narrower than the reference pulse width; and a second wide-width signal that is output when the first narrow-width signal is output and has a pulse width wider than the reference pulse width.

[0018] With this configuration, the pulse width of one of the two variable phases is wider than the reference pulse width, while the pulse width of the other variable phase is narrower than the reference pulse width. This increases the difference in pulse width between the two corresponding variable phases, allowing the neutral point potential waveform to become a trapezoidal wave closer to a sine wave.

[0019] The inverter control device may include: a voltage grasping unit for grasping the power supply voltage, which is the voltage of the vehicle-mounted power storage device; a speed grasping unit for grasping the rotational speed of the vehicle-mounted electric motor; and a two-phase voltage command value deriving unit for deriving two-phase voltage command values, which are target values of voltage applied to the d-axis and q-axis of the vehicle-mounted electric motor, based on an external command value transmitted from an external source and a grasping result of the speed grasping unit. The three-phase voltage command value deriving unit derives the three-phase voltage command values based on the two-phase voltage command values. When a voltage utilization rate calculated based on the two-phase voltage command values and the grasping result of the voltage grasping unit is a first voltage utilization rate, the three-phase voltage command value derives a first shift command value obtained by varying the neutral point potential of the three-phase voltage command value by a first neutral point amplitude as the three-phase voltage command value. When the voltage utilization rate is a second voltage utilization rate smaller than the first voltage utilization rate, the three-phase voltage command value derives a second shift command value obtained by varying the neutral point potential by a second neutral point amplitude larger than the first neutral point amplitude as the three-phase voltage command value.

[0020] According to this configuration, when the voltage utilization rate is a second voltage utilization rate that is lower than the first voltage utilization rate, the neutral point potential is varied by a second neutral point amplitude that is larger than the first neutral point amplitude corresponding to the first voltage utilization rate, thereby obtaining a second shift command value having a variation range that is at least equal to or greater than the second neutral point amplitude. This prevents the variation range of the second shift command value from being narrowed. Consequently, it is possible to prevent localized increases in noise of a specific frequency due to a narrowing of the variation range of the three-phase voltage command values.

[0021] In particular, generally, as the voltage utilization rate decreases, the variation range of the three-phase voltage command values tends to decrease. Therefore, when the voltage utilization rate is the second voltage utilization rate, the variation range of the three-phase voltage command values tends to narrow.

[0022] In this regard, according to this configuration, when the voltage utilization rate is the second voltage utilization rate, by varying the neutral-point potential with a relatively large second neutral-point amplitude, it is possible to suppress the narrowing of the variation range of the three-phase voltage command values even when the voltage utilization rate is the second voltage utilization rate. This can suppress the local amplification of noise of a specific frequency.

[0023] Regarding the above-mentioned inverter control device, it can also be provided with: a voltage grasping unit that grasps the voltage of the vehicle-mounted power storage device, that is, the power supply voltage; a speed grasping unit that grasps the rotational speed of the vehicle-mounted electric motor; and a 2-phase voltage command value deriving unit that derives the target value of the voltage applied to the d-axis and q-axis of the vehicle-mounted electric motor based on the external command value sent from the outside and the grasping result of the speed grasping unit, that is, the 2-phase voltage command value. The 3-phase voltage command value deriving unit derives the 3-phase voltage command value based on the 2-phase voltage command value. When the voltage utilization rate calculated based on the 2-phase voltage command value and the grasping result of the voltage grasping unit is below a predetermined threshold utilization rate, for the same 2-phase voltage command value, the 3-phase voltage command value having the same line voltage of the 3-phase coil and different variation ranges is switched at a switching cycle and derived.

[0024] According to this configuration, when the voltage utilization rate is below the threshold utilization rate, the three-phase voltage command values are switched to values with different variation ranges at a switching cycle while maintaining the same line voltage across the three-phase coils. This allows the three-phase voltage command values to vary at the switching cycle even when the two-phase voltage command values remain the same. This reduces noise of a specific frequency caused by the three-phase voltage command values periodically being the same when the voltage utilization rate is low.

[0025] In particular, this configuration allows the line voltages applied to the three-phase coils to remain the same even when the three-phase voltage command values are switched. This allows the same torque to be applied to the vehicle-mounted electric motor. This prevents the inconvenience of applying different torques due to switching the three-phase voltage command values.

[0026] As described above, a state in which appropriate torque is applied to the vehicle-mounted electric motor can be maintained, and noise of a specific frequency generated by periodically having the same three-phase voltage command values under a low voltage utilization rate can be reduced.

[0027] A vehicle-mounted fluid machine that achieves the above-mentioned object is characterized by comprising the above-mentioned vehicle-mounted electric motor, the above-mentioned inverter circuit, and the above-mentioned inverter control device.

[0028] The vehicle-mounted fluid machine may be a vehicle-mounted electric compressor including a compression portion driven by the vehicle-mounted electric motor.

[0029] Effects of the Invention

[0030] According to this invention, noise of a specific frequency caused by switching of a switching element can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a block diagram showing an outline of an in-vehicle electric compressor.

[0032] Figure 2 This is a block diagram showing the electrical configuration of an inverter circuit and an inverter control device.

[0033] Figure 3 This is a flowchart showing the rotation control process according to the first embodiment.

[0034] Figure 4 (a) is a waveform diagram showing an example of a u-phase PWM signal, (b) is a waveform diagram showing an example of a v-phase PWM signal with pulse change control, (c) is a waveform diagram showing an example of a w-phase PWM signal with pulse change control, and (d) is a waveform diagram showing an example of a neutral point potential.

[0035] Figure 5 This is a flowchart showing the rotation control process according to the second embodiment.

[0036] Figure 6 (a) is a waveform diagram showing an example of a u-phase PWM signal, (b) is a waveform diagram showing an example of a v-phase PWM signal with pulse change control, (c) is a waveform diagram showing an example of a w-phase PWM signal with pulse change control, and (d) is a waveform diagram showing an example of a neutral point potential.

[0037] Description of Reference Signs

[0038] 10...In-vehicle electric compressor (in-vehicle fluid machinery), 11...In-vehicle electric motor, 12...Compression unit, 13...Inverter circuit, 14...Inverter control device, 22...Rotor, 24u, 24v, 24w...Three-phase coil, 31...Voltage sensor (voltage control unit), 34...Position / speed estimation unit (speed control unit), 35...Acquisition unit, 36...Rotation control unit, 104...In-vehicle power storage device, Qu1-Qw2...Three-phase switching elements, Vdr, Vqr...Two-phase voltage command value, Vur, Vvr, Vwr...Three-phase voltage command value, Vu0, Vv0, Vw0...Three-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...variation 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...first voltage utilization rate, R2...second voltage utilization rate, T...control period. DETAILED DESCRIPTION

[0039] (First embodiment)

[0040] A first embodiment of an inverter control device and a vehicle-mounted fluid machine equipped with the inverter control device will be described below. The following description is merely an example, and the inverter control device and the vehicle-mounted fluid machine are not limited to the contents of this embodiment.

[0041] 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. The vehicle-mounted air conditioner and the vehicle-mounted electric compressor will be briefly described.

[0042] like Figure 1 As shown, a vehicle air conditioning device 101 mounted on a vehicle 100 includes a vehicle electric compressor 10 and an external refrigerant circuit 102 for supplying a refrigerant as a fluid to the vehicle electric compressor 10 .

[0043] The external refrigerant circuit 102 includes, for example, a heat exchanger and an expansion valve, etc. The vehicle air conditioner 101 compresses the refrigerant using the vehicle electric compressor 10 and performs heat exchange and expansion of the refrigerant using the external refrigerant circuit 102 to provide cooling and heating in the vehicle.

[0044] 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 grasp the vehicle interior temperature, the vehicle air conditioner set temperature, etc., and sends various commands such as the command rotation speed Nc to the vehicle electric compressor 10 based on these parameters.

[0045] Vehicle 100 includes an onboard power storage device 104 . Any device capable of charging and discharging DC power may be used, such as a secondary battery or an electric double layer capacitor. Onboard power storage device 104 serves as a DC power source for onboard electric compressor 10 .

[0046] The vehicle-mounted electric compressor 10 includes: a vehicle-mounted electric motor 11; a compression unit 12 driven by the vehicle-mounted electric motor 11; an inverter circuit 13 that drives the vehicle-mounted electric motor 11 using a vehicle-mounted power storage device 104; and an inverter control device 14 used to control the inverter circuit 13.

[0047] The vehicle-mounted electric motor 11 includes a rotating shaft 21, a rotor 22 fixed to the rotating shaft 21, a stator 23 disposed opposite the rotor 22, and three-phase coils 24u, 24v, and 24w wound around the stator 23. The rotor 22 includes a permanent magnet 22a. Specifically, the permanent magnet 22a is embedded in the rotor 22. Figure 2 As shown, the three-phase coils 24u, 24v, and 24w are connected in a Y-connection, for example. The three-phase coils 24u, 24v, and 24w are energized in a predetermined pattern, causing the rotor 22 and the rotating shaft 21 to rotate. That is, the vehicle-mounted electric motor 11 of this embodiment is a three-phase electric motor.

[0048] The connection method of the three-phase coils 24u, 24v, and 24w is not limited to Y connection, and may be any connection method, such as Δ connection.

[0049] The compression unit 12 is driven by the vehicle-mounted electric motor 11 to compress the fluid (refrigerant in this embodiment). Specifically, the rotation of the rotary shaft 21 causes the compression unit 12 to compress the refrigerant supplied from the external refrigerant circuit 102 and discharge the compressed refrigerant. The specific structure of the compression unit 12 can be any type, such as a scroll type, a piston type, or a vane type.

[0050] The inverter circuit 13 converts direct current input from the vehicle-mounted power storage device 104 into alternating current, thereby driving the vehicle-mounted electric motor 11 using the vehicle-mounted power storage device 104 .

[0051] like Figure 2 As shown, the inverter circuit 13 has three-phase switching elements Qu1 to Qw2. Specifically, the inverter circuit 13 includes u-phase switching elements Qu1 and Qu2 corresponding to the u-phase coil 24u; v-phase switching elements Qv1 and Qv2 corresponding to the v-phase coil 24v; and w-phase switching elements Qw1 and Qw2 corresponding to the w-phase coil 24w.

[0052] The three-phase switching elements Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2 (hereinafter referred to as "three-phase switching elements Qu1-Qw2") are, for example, power switching elements such as IGBTs. However, the three-phase switching elements Qu1-Qw2 are not limited to IGBTs and may be any type, such as MOSFETs. Furthermore, the three-phase switching elements Qu1-Qw2 have freewheeling diodes (body diodes) Du1-Dw2.

[0053] The u-phase switching elements Qu1 and Qu2 are connected in series via a connecting line, which is connected to the u-phase coil 24u. The collector of the u-phase switching element Qu1 is connected to the positive terminal (+ terminal) on the high-voltage side of the on-board power storage device 104. The emitter of the u-phase switching element Qu2 is connected to the negative terminal (- terminal) on the low-voltage side of the on-board power storage device 104.

[0054] The connection configuration of the other switching elements Qv1, Qv2, Qw1, and Qw2 is identical to that of the u-phase switching elements Qu1 and Qu2, except for their corresponding coils. The inverter control device 14 is a controller comprising electronic components such as a CPU and memory. The inverter control device 14 drives the vehicle-mounted electric motor 11 by controlling the inverter circuit 13, specifically the three-phase switching elements Qu1 through Qw2.

[0055] The inverter control device 14 includes a voltage sensor 31 as a voltage detection unit that detects 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 detect the power supply voltage Vin.

[0056] The inverter control device 14 includes a current sensor 32 for detecting the motor current flowing through the vehicle-mounted electric motor 11. The motor current in this embodiment is, for example, the three-phase currents Iu, Iv, and Iw flowing through the three-phase coils 24u, 24v, and 24w.

[0057] like Figure 2As shown, the inverter control device 14 has a 3-phase / 2-phase conversion circuit 33 that converts the 3-phase currents Iu, Iv, and Iw detected by the current sensor 32 into mutually orthogonal d-axis currents Id and q-axis currents Iq (hereinafter referred to as "2-phase currents Id, Iq").

[0058] Incidentally, the d-axis current Id can also be considered as a current in the magnetic flux direction component of the rotor 22 , namely, an excitation component current, and the q-axis current Iq can also be considered as a torque component current contributing to the torque of the vehicle-mounted electric motor 11 .

[0059] The inverter control device 14 includes a position / speed estimating unit (position estimating unit) 34 that estimates the rotational position and rotational speed of the rotor 22. The position / speed estimating unit 34 estimates the rotational position of the rotor 22 and the actual rotational speed, or actual rotational speed Nr, based on, for example, at least one of the two-phase currents Id and Iq and the two-phase voltage command values Vdr and Vqr. The units of the command rotational speed Nc and the actual rotational speed Nr are arbitrary; for example, rpm is considered.

[0060] The specific configuration of position / speed estimation unit 34 is arbitrary. For example, position / speed estimation unit 34 may include an induced voltage calculation unit that calculates the induced voltage induced in three-phase coils 24u, 24v, and 24w based on two-phase currents Id and Iq, d-axis voltage command value Vdr, and motor constants. In this case, position / speed estimation unit 34 can estimate the rotational position and actual rotational speed Nr of rotor 22 based on the induced voltage and d-axis current Id of the two-phase currents Id and Iq.

[0061] The position / speed estimation unit 34 periodically obtains the detection results of the current sensor 32 and periodically estimates the rotational position and actual rotational speed Nr of the rotor 22. Thus, the position / speed estimation unit 34 tracks changes in the rotational position and actual rotational speed Nr of the rotor 22. In this embodiment, the position / speed estimation unit 34 corresponds to a "speed detection unit" that detects the rotational speed of the vehicle-mounted electric motor 11.

[0062] The inverter control device 14 includes: an acquisition unit 35 that acquires an external command value sent from the air-conditioning ECU 103 as an external part; and a rotation control unit (rotation control circuit) 36 that controls the rotation of the vehicle-mounted electric motor 11 based on the external command value acquired by the acquisition unit 35 and the actual rotation speed Nr.

[0063] 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, enabling information exchange. Furthermore, the acquisition unit 35 can be considered an input unit for various commands, such as the commanded rotational speed Nc.

[0064] The external command value is, for example, the command rotational speed Nc. Specifically, the air conditioning ECU 103 calculates the required refrigerant flow rate based on the operating conditions of the vehicle air conditioning unit 101, calculates the command rotational speed Nc that can achieve this flow rate, and sends the command rotational speed Nc to the inverter control device 14.

[0065] The external command value is not limited to the command rotation speed Nc, and its specific command content is arbitrary as long as it can specify the driving method of the vehicle-mounted electric motor 11. In addition, the output entity of the external command value is not limited to the air conditioning ECU 103, but can be any entity.

[0066] The rotation control unit 36 is electrically connected to the acquisition unit 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. In other words, the rotation control unit 36 receives the external command value from the air conditioning ECU 103 via the acquisition unit 35.

[0067] The rotation control unit 36 is electrically connected to the voltage sensor 31 and can detect the power supply voltage Vin.

[0068] The rotation control unit 36 is electrically connected to the position / speed estimation unit 34 . This allows the rotation control unit 36 to grasp the rotation position and actual rotation speed Nr of the rotor 22 estimated by the position / speed estimation unit 34 and to send parameters necessary for estimation to the position / speed estimation unit 34 .

[0069] Furthermore, the 3-phase / 2-phase conversion circuit 33 outputs the 2-phase currents Id and Iq to both the position / speed estimation unit 34 and the rotation control unit 36. Therefore, the rotation control unit 36 can grasp the 2-phase currents Id and Iq.

[0070] The rotation control unit 36 performs a rotation control process to control the rotation of the vehicle-mounted electric motor 11 (specifically, the rotor 22) by PWM controlling the three-phase switching elements Qu1 to Qw2 of the inverter circuit 13. The rotation control unit 36 repeatedly executes the rotation control process at a predetermined control period T.

[0071] 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 the rotation control process and necessary information, and a CPU that executes the rotation control process based on the program.

[0072] Furthermore, the rotation control unit 36 may be configured with one or more dedicated hardware circuits that execute part or all of the rotation control processing, or may be a combination of one or more dedicated hardware circuits and a CPU that executes software processing. In other words, the rotation control unit 36 may be implemented by at least one of one or more dedicated hardware circuits and one or more processors (control circuits) operating according to a computer program (software).

[0073] Here, for the convenience of explanation, Figure 3 The flowchart shown illustrates the rotation control process implemented by the rotation control unit 36 .

[0074] like Figure 3 As shown, in step S101, the rotation control unit 36 first derives two-phase current command values Idr and Iqr based on the external command value (in this embodiment, the command rotation speed Nc) acquired by the acquisition unit 35 and the actual rotation speed Nr determined (estimated in this embodiment) by the position / speed estimation unit 34. 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.

[0075] Next, in step S102, the rotation control unit 36 derives two-phase voltage command values Vdr and Vqr based on the two-phase current command values Idr and Iqr and the two-phase currents Id and Iq obtained by the three-phase / two-phase conversion circuit 33. 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 for the voltage applied to the d-axis of the vehicle-mounted electric motor 11, and the q-axis voltage command value Vqr is the target value for the voltage applied to the q-axis of the vehicle-mounted electric motor 11.

[0076] Incidentally, the rotation control unit 36 outputs the two-phase voltage command values Vdr and Vqr to the position / speed estimation unit 34. The position / speed estimation unit 34 uses at least one of the two-phase voltage command values Vdr and Vqr to estimate the rotation position of the rotor 22 and the actual rotation speed Nr.

[0077] In step S103 , the rotation control unit 36 executes a process of deriving three-phase voltage command values Vur, Vvr, and Vwr based on the two-phase voltage command values Vdr and Vqr.

[0078] 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 for the voltage applied to the u-phase coil 24u, the v-phase voltage command value Vvr is the target value for the voltage applied to the v-phase coil 24v, and the w-phase voltage command value Vwr is the target value for the voltage applied to the w-phase coil 24w. In step S103, the rotation control unit 36 derives three-phase reference command values Vu0, Vv0, and Vw0 as the three-phase voltage command values Vur, Vvr, and Vwr by, for example, performing a two-phase / three-phase conversion on the two-phase voltage command values Vdr and Vqr.

[0079] The three-phase reference command values Vu0, Vv0, and Vw0 vary according to the electrical angle, forming waveforms having a reference amplitude f0 with a period of, for example, 0° to 360°. The three-phase reference command values Vu0, Vv0, and Vw0 are mutually different in phase, for example, shifted by 120°. The waveforms of the three-phase reference command values Vu0, Vv0, and Vw0 can be any waveform, such as a sine wave, a triangular wave, a rectangular wave, or a variation of these waveforms.

[0080] Next, in step S104 , the rotation control unit 36 calculates the voltage utilization rate R based on the two-phase voltage command values Vdr and Vqr and the power supply voltage Vin.

[0081] The voltage utilization ratio R is the utilization ratio of the power supply voltage Vin required to apply the two-phase voltage command values Vdr and Vqr to the vehicle-mounted electric motor 11. For example, the voltage utilization ratio R is the 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 this ratio by a predetermined correction parameter.

[0082] Furthermore, considering that the line voltages of the three-phase coils 24u, 24v, and 24w change in response to the two-phase voltage command values Vdr and Vqr, the voltage utilization ratio R can also be considered the ratio of the effective value of the line voltages of the three-phase coils 24u, 24v, and 24w to the power supply voltage Vin. In other words, the voltage utilization ratio R can be considered a parameter that represents the utilization ratio of the power supply voltage Vin so that the line voltages of the three-phase coils 24u, 24v, and 24w are maintained at values corresponding to the two-phase voltage command values Vdr and Vqr.

[0083] Incidentally, the reference amplitude f0, which represents the amplitude of the three-phase reference command values Vu0, Vv0, and Vw0, decreases as the voltage utilization rate R decreases. For example, if the reference amplitude f0 when the voltage utilization rate R is the first voltage utilization rate R1 is compared with the reference amplitude f0 when the voltage utilization rate R is the second voltage utilization rate R2, which is smaller than the first voltage utilization rate R1, the reference amplitude f0 when the voltage utilization rate R is the second voltage utilization rate R2 is smaller than the reference amplitude f0 when the voltage utilization rate R is the first voltage utilization rate R1. Furthermore, as the reference amplitude f0 decreases, the variation range (specifically, the range from the minimum value to the maximum value) of the three-phase reference command values Vu0, Vv0, and Vw0 tends to narrow.

[0084] After calculating the voltage utilization rate R, the rotation control unit 36 proceeds to step S105 to determine whether the voltage utilization rate R calculated in step S104 is less than or equal to a predetermined threshold utilization rate Rth. The threshold utilization rate Rth is arbitrary and can be, for example, less than or greater than 50%. Furthermore, the threshold utilization rate Rth can be set within a range of, for example, 40 to 70%.

[0085] When the voltage utilization rate R is greater than the threshold utilization rate Rth, the rotation control unit 36 proceeds to step S106 and generates reference PWM signals Pu0 , Pv0 , Pw0 based on the three-phase voltage command values Vur, Vvr, Vwr and the carrier signal.

[0086] The reference PWM signals Pu0, Pv0, and Pw0 are PWM signals corresponding to the three-phase voltage command values Vur, Vvr, and Vwr (specifically, the three-phase reference command values Vu0, Vv0, and 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.

[0087] Then, in step S107, the rotation control unit 36 outputs reference PWM signals Pu0, Pv0, and Pw0 to the three-phase switching elements Qu1 to Qw2 to perform switching control on 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 signals.

[0088] In this embodiment, the rotation control unit 36 generates multiple reference PWM signals Pu0, Pv0, and Pw0 in step S106. Specifically, the rotation control unit 36 generates multiple reference PWM signals Pu0, Pv0, and Pw0 for a single rotation control process. Considering that the rotation control process is repeated with a control period T, the rotation control unit 36 can also be said to generate multiple 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.

[0089] Then, in step S107 , the rotation control unit 36 outputs the reference PWM signals Pu0 , Pv0 , and Pw0 to the three-phase switching elements Qu1 to Qw2 a plurality of times to control switching of the three-phase switching elements Qu1 to Qw2 , and ends the rotation control process.

[0090] That is, when the voltage utilization rate R is greater than the threshold utilization rate Rth, the rotation control unit 36 of this embodiment uses a pulse signal with the same pulse width (specifically, the reference pulse width Wu0, Wv0, Ww0) within the control period T to perform multiple switching controls on the three-phase switching elements Qu1~Qw2.

[0091] On the other hand, Figure 3 As shown, when voltage utilization rate R is below threshold utilization rate Rth, rotation control unit 36 performs pulse variation control in steps S108 to S111, varying the pulse width so that the waveform of neutral point potential En approaches a trapezoidal waveform. Neutral point potential En is the potential at the neutral point of the three-phase voltage command values Vur, Vvr, and Vwr.

[0092] use Figure 3 as well as Figure 4 The pulse change control in steps S108 to S111 will be described in detail.

[0093] Pulse change control involves varying the pulse widths of at least two of the multiple PWM signals within a control period T, each having a reference pulse width corresponding to the three-phase voltage command values, so that the average pulse widths Wua, Wva, and Wwa are equal to the reference pulse widths Wu0, Wv0, and Ww0. In this embodiment, rotation control unit 36 performs pulse change control on the PWM signals for the v- and w-phases of the three phases, while not performing pulse change control on the u-phase. That is, in this embodiment, the v- and w-phases correspond to "variable phases," while the u-phase corresponds to a "fixed phase."

[0094] First, if Figure 3As shown, in step S108 , the rotation control unit 36 generates first PWM signals Pu1 , Pv1 , and Pw1 among the plurality of PWM signals within the control period T. The first PWM signals Pu1 , Pv1 , and Pw1 are pulse signals having first pulse widths Wu1 , Wv1 , and Ww1 .

[0095] Describing step S108 in detail, the rotation control unit 36 first derives reference pulse widths Wu0, Wv0, and Ww0 based on the three-phase voltage command values Vur, Vvr, and Vwr and the carrier signal, similarly to step S106.

[0096] Afterwards, if Figure 4 As shown in (a) of FIG. 1 , the rotation control unit 36 generates the first u-phase PWM signal Pu1 having the first u-phase pulse width Wu1 set to be the same as the u-phase reference pulse width Wu0. Figure 4 (b) and Figure 4 As shown in (c) of FIG. 8 , the rotation control unit 36 changes the first v-phase pulse width Wv1 and the first w-phase pulse width Ww1 from the v-phase reference pulse width Wv0 and the w-phase reference pulse width Ww0.

[0097] For example, the rotation control unit 36 has a first v-phase PWM signal Pv1 having a 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 set as the first v-phase pulse difference 8Wv1.

[0098] 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 a first w-phase pulse difference δWw1.

[0099] Here, in this embodiment, the 1st v-phase pulse differential δWv1 and the 1st w-phase pulse differential δWw1 are the same (δWv1 = δWw1). However, the magnitude relationship between the 1st v-phase pulse differential δWv1 and the 1st w-phase pulse differential δWw1 is arbitrary; for example, the 1st v-phase pulse differential δWv1 may be larger than the 1st w-phase pulse differential δWw1, or vice versa.

[0100] like Figure 3 As shown, after generating the first PWM signals Pu1, Pv1, and Pw1, the rotation control unit 36 performs primary switching control on the three-phase switching elements Qu1 to Qw2 using the first PWM signals Pu1, Pv1, and Pw1 in step S109.

[0101] In this case, if Figure 4 As shown, 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 aligned. In other words, the first w-phase PWM signal Pw1 can be said to be a signal that is output (or generated) when the first v-phase PWM signal Pv1 is output (or generated).

[0102] By the way, if Figure 4 As shown in (b), the rising timing of the first v-phase PWM signal Pv1 is offset from the rising timing of the v-phase reference PWM signal Pv0 by δWv1 / 2. Furthermore, the falling timing of the first v-phase PWM signal Pv1 is offset from the falling timing of the v-phase reference PWM signal Pv0 by δWv1 / 2. The same applies to the w-phase.

[0103] Next, in step S110, rotation control unit 36 generates second PWM signals Pu2, Pv2, and Pw2 from among the plurality of PWM signals within control period T. First PWM signals Pu1, Pv1, and Pw1 and second PWM signals Pu2, Pv2, and Pw2 are PWM signals generated and output within the same control period T. Second PWM signals Pu2, Pv2, and Pw2 are PWM signals output after first PWM signals Pu1, Pv1, and Pw1 within control period T. Second PWM signals Pu2, Pv2, and Pw2 have second pulse widths Wu2, Wv2, and Ww2.

[0104] If step S110 is described in detail, Figure 4 As shown in (a) of FIG. 1 , the rotation control unit 36 generates the second u-phase PWM signal Pu2 having the second u-phase pulse width Wu2 set to be the same as the u-phase reference pulse width Wu0. Figure 4 (b) and Figure 4 As shown in (c) of FIG. 8 , the rotation control unit 36 changes the second v-phase pulse width Wv2 and the second w-phase pulse width Ww2 from the v-phase reference pulse width Wv0 and the w-phase reference pulse width Ww0.

[0105] 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 a second v-phase pulse difference δWv2.

[0106] 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 a second w-phase pulse difference δWw2.

[0107] 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, and makes the pulse width of the other variable phase narrower than the reference pulse width.

[0108] Here, the rotation control unit 36 performs control so that the average pulse widths Wua, Wva, and Wwa of the phases within the control period T become the reference pulse widths Wu0, Wv0, and Ww0.

[0109] Specifically, regarding the u-phase as the fixed phase, since the first u-phase pulse width Wu1 and the second u-phase pulse width Wu2 are the u-phase reference pulse width Wu0 , the u-phase average pulse width Wua is the u-phase reference pulse width Wu0 .

[0110] Regarding the variable v 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.

[0111] 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 equals 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. In other words, the rotation control unit 36 changes the pulse width of each pulse signal to be changed so that the cumulative value of the change from the reference pulse width reaches "0."

[0112] In this embodiment, the second v-phase pulse differential δWv2 and the second w-phase pulse differential δWw2 are identical. However, the magnitude relationship between the second v-phase pulse differential δWv2 and the second w-phase pulse differential δWw2 is arbitrary; for example, the second v-phase pulse differential δWv2 may be larger than the second w-phase pulse differential δWw2, or vice versa.

[0113] like Figure 3As shown, after generating the second PWM signals Pu2, Pv2, and Pw2, the rotation control unit 36 uses the second PWM signals Pu2, Pv2, and Pw2 to perform switching control on the three-phase switching elements Qu1 to Qw2 once in step S111, and then terminates the rotation control process. In this case, the rotation control unit 36 adjusts the output timing, for example, so that the centers of the second PWM signals Pu2, Pv2, and Pw2 are aligned. This synchronizes the second u-phase PWM signal Pu2, the second v-phase PWM signal Pv2, and the second w-phase PWM signal Pw2. In other words, the second w-phase PWM signal Pw2 can be said to be output (in other words, generated) when the second v-phase PWM signal Pv2 is output (in other words, generated).

[0114] In this embodiment, the rotation control unit 36 that performs the processing of steps S101 and S102 corresponds to the "two-phase voltage command value derivation unit," and the rotation control unit 36 that performs the processing of step S103 corresponds to the "three-phase voltage command value derivation unit." The rotation control unit 36 that performs the processing of steps S106, S108, and S110 corresponds to the "generation unit," and in particular, the rotation control unit 36 that performs the processing of steps S108 and S110 corresponds to the "pulse changer."

[0115] Furthermore, in this embodiment, the two v-phase PWM signals Pv1 and Pv2 correspond to "a plurality of first variable-phase PWM signals." Specifically, the first v-phase PWM signal Pv1 corresponds to a "first wide-width signal," and the second v-phase PWM signal Pv2 corresponds to a "first narrow-width signal." Furthermore, the two w-phase PWM signals Pw1 and Pw2 correspond to "a plurality of second variable-phase PWM signals." Specifically, the first w-phase PWM signal Pw1 corresponds to a "second narrow-width signal," and the second w-phase PWM signal Pw2 corresponds to a "second wide-width signal."

[0116] Next, use Figure 4 The function of this embodiment will be described. Figure 4 (a) is a waveform diagram showing an example of a u-phase PWM signal. Figure 4 (b) is a waveform diagram showing an example of a v-phase PWM signal subjected to pulse change control. Figure 4 (c) is a waveform diagram showing an example of a w-phase PWM signal subjected to pulse change control. Figure 4 (d) is a waveform diagram showing an example of the neutral point potential En. For the sake of convenience, in each control period T, it is assumed that the three-phase voltage command values Vur, Vvr, and Vwr are the same.

[0117] like Figure 4As shown, as already described, in this embodiment, a plurality of (for example, two) PWM signals are generated within the control period T, and the two PWM signals are repeatedly generated within the control period T.

[0118] In this case, since the u phase is a fixed phase that does not undergo pulse change control, Figure 4 As shown in (a) of FIG. 2 , in the u-phase, u-phase PWM signals Pu1 and Pu2 having the same pulse width (specifically, the u-phase reference pulse width Wu0 ) are generated within the control period T.

[0119] like Figure 4 (b) and Figure 4 As shown in (c) of FIG. 1 , when the first u-phase PWM signal Pu1 is generated, the first v-phase PWM signal Pv1 and the first w-phase PWM signal Pw1 are generated with pulse change control. In this case, the pulse width of the first v-phase PWM signal Pv1, that is, the first v-phase pulse width Wv1, becomes wider than the v-phase reference pulse width Wv0. On the other hand, the pulse width of the first w-phase PWM signal Pw1, that is, the first w-phase pulse width Ww1, becomes narrower than the w-phase reference pulse width Ww0. As a result, as shown in FIG. Figure 4 As shown in (d) of FIG. 8 , the waveform of the neutral point potential En obtained from the first PWM signals Pu1 , Pv1 , and Pw1 is close to a trapezoidal wave.

[0120] 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, Figure 4 As shown by the dotted line in (d), the waveform of the neutral point potential En becomes a square wave. On the other hand, when the pulse change control is performed, as shown in FIG. Figure 4 As shown by the solid line in (d), the waveform of the neutral point potential En is close to a trapezoidal wave with a gently rising and falling slope.

[0121] Similarly, the pulse width of the second v-phase PWM signal Pv2, i.e., the second v-phase pulse width Wv2, becomes narrower than the v-phase reference pulse width Wv0. On the other hand, the pulse width of the second w-phase PWM signal Pw2, i.e., the second w-phase pulse width Ww2, becomes wider than the w-phase reference pulse width Ww0. Figure 4 As shown by the solid line in (d), the waveform of the neutral point potential En obtained from the second PWM signals Pu2, Pv2, and Pw2 is close to a trapezoidal wave.

[0122] In addition, the average pulse width Wua, Wva, Wwa of each phase within the control period T becomes the pulse width corresponding to the three-phase voltage command values Vur, Vvr, Vwr, that is, the reference pulse width Wu0, Wv0, Ww0. Therefore, the vehicle-mounted electric motor 11 is given a torque corresponding to the three-phase voltage command values Vur, Vvr, Vwr (in other words, the target torque).

[0123] According to the present embodiment described in detail above, the following effects are achieved.

[0124] (1-1) The inverter control device 14 is used to control the inverter circuit 13 that drives the vehicle-mounted electric motor 11 using the vehicle-mounted power system 104. The vehicle-mounted electric motor 11 has three-phase coils 24u, 24v, and 24w, and the inverter circuit 13 has three-phase switching elements Qu1 to Qw2.

[0125] The inverter control device 14 includes a position / speed estimation unit 34 that determines the actual rotational speed Nr of the vehicle-mounted electric motor 11, and a rotation control unit 36. The rotation control unit 36 derives two-phase voltage command values Vdr and Vqr, which are target values for the voltages applied to the d-axis and q-axis of the vehicle-mounted electric motor 11, based on an externally transmitted external command value and the actual rotational speed Nr. The rotation control unit 36 then derives 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. Based on the three-phase voltage command values Vur, Vvr, and Vwr and a carrier signal, the rotation control unit 36 generates multiple PWM signals for each phase within a predetermined control period T. These generated PWM signals are used to perform PWM control on the three-phase switching elements Qu1 to Qw2.

[0126] The rotation control unit 36 has a reference pulse width corresponding to the three-phase voltage command values and performs pulse change control on multiple PWM signals within a control period T in a single phase. Pulse change control varies the pulse widths of at least two of the multiple PWM signals so that the average pulse width equals the reference pulse width. In this 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 on the first w-phase PWM signal Pw1 and the second w-phase PWM signal Pw2.

[0127] With this configuration, pulse variation control can be performed to make the neutral-point potential En approach a trapezoidal waveform. A trapezoidal waveform is closer to a sine wave than a square wave, resulting in less harmonic noise. This allows the neutral-point potential waveform to approach a square wave, which has less harmonic noise, thereby reducing noise of specific frequencies caused by the switching of the three-phase switching elements.

[0128] Meanwhile, the average pulse width of the phase subject to pulse change control becomes the reference pulse width corresponding to the three-phase voltage command values. For example, the average pulse width of the first v-phase PWM signal Pv1 and the second v-phase PWM signal Pv2, i.e., the v-phase average pulse width Wva, becomes the v-phase reference pulse width Wv0. Consequently, the phase voltages applied to the three-phase coils 24u, 24v, and 24w become values corresponding to the three-phase voltage command values Vur, Vvr, and Vwr. Consequently, a torque corresponding to the three-phase voltage command values Vur, Vvr, and Vwr is applied to the vehicle-mounted electric motor 11. This can prevent the inconvenience of applying different torques due to making the neutral point potential En closer to a trapezoidal waveform.

[0129] (1-2) The inverter control device 14 includes a voltage sensor 31 for detecting the power supply voltage Vin 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 and Vqr and the power supply voltage Vin is equal to or less than the threshold utilization rate Rth.

[0130] According to this configuration, by performing pulse change control when the voltage utilization rate R is equal to or lower than the threshold utilization rate Rth, it is possible to reduce noise of a specific frequency that tends to increase when the voltage utilization rate R is low.

[0131] Specifically, as the voltage utilization rate R decreases, the range of variation of 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 deviate toward or near specific values, the pulse width of the PWM signal for each phase tends to deviate toward or near specific values. In this case, if the waveform of the neutral-point potential En is a square wave, harmonic noise corresponding to the specific pulse width tends to increase, representing noise of a specific frequency.

[0132] In this regard, according to this configuration, when the voltage utilization rate R is below the threshold utilization rate Rth, the waveform of the neutral point potential En approaches a trapezoidal waveform, thereby reducing the aforementioned harmonic noise. This effectively reduces the aforementioned harmonic noise, which tends to increase when the voltage utilization rate R is low.

[0133] (1-3) When the voltage utilization rate R is greater than the threshold utilization rate Rth, the rotation control unit 36 does not perform the pulse change control.

[0134] When the voltage utilization rate R is greater than the threshold utilization rate Rth, noise of a specific frequency tends to be reduced. In this regard, according to this configuration, when the voltage utilization rate R is greater than the threshold utilization rate Rth, pulse change control is not performed, thereby reducing the processing burden associated with pulse width change control.

[0135] (1-4) The rotation control unit 36 performs pulse change control on multiple PWM signals within a control period T in two variable phases of the three-phase, for example, the first v-phase PWM signal Pv1 and the second v-phase PWM signal Pv2, and the first w-phase PWM signal Pw1 and the second w-phase PWM signal Pw2. On the other hand, the rotation control unit 36 does not perform pulse change control on multiple PWM signals within a control period T in a fixed phase other than the variable phase of the three-phase, in this embodiment, the u-phase (specifically, the first u-phase PWM signal Pu1 and the second u-phase PWM signal Pu2).

[0136] According to this configuration, since one phase becomes a fixed phase, the processing load can be reduced compared to a case where all phases are variable phases.

[0137] (1-5) The PWM signal within the control period T of the first variable phase (e.g., the v phase) of the two variable phases includes a first v-phase PWM signal Pv1 and a 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 that is narrower than the v-phase reference pulse width Wv0.

[0138] The PWM signals within the control period T of the second variable phase (e.g., the w-phase) of the two variable phases include 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 output when the first v-phase PWM signal Pv1 is output (in other words, generated), and has a first w-phase pulse width Ww1 that is narrower than the w-phase reference pulse width Ww0. The second w-phase PWM signal Pw2 is a PWM signal 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.

[0139] For example, if the difference between the first V-phase pulse width Wv1 and the first W-phase pulse width Ww1 is large, the waveform of the neutral-point potential En tends to be a trapezoidal wave close to a sine wave. Here, assuming that the first V-phase pulse width Wv1 is narrower than the V-phase reference pulse width Wv0 and the first W-phase pulse width Ww1 is narrower than the W-phase reference pulse width Ww0, the difference between the first V-phase pulse width Wv1 and the first W-phase pulse width Ww1 tends to decrease due to fluctuations within the reference pulse width. The same applies to the case where the first V-phase pulse width Wv1 is wider than the V-phase reference pulse width Wv0 and the first W-phase pulse width Ww1 is wider than the W-phase reference pulse width Ww0.

[0140] In this regard, according to this configuration, the pulse width of one of the two variable phases is wider than the reference pulse width, while the pulse width of the other variable phase is narrower than the reference pulse width. This increases the difference in pulse width between the two corresponding variable phases, allowing the waveform of the neutral-point potential En to be a trapezoidal wave closer to a sine wave.

[0141] (Second embodiment)

[0142] In this embodiment, the derivation process of the three-phase voltage command values Vur, Vvr, and Vwr is different from that of the first embodiment. Figure 5 The rotation control process of this embodiment will be described.

[0143] like Figure 5 As shown, the rotation control unit 36 derives two-phase voltage command values Vdr and Vqr in step S102 and then calculates the voltage utilization rate R in step S201. Thereafter, 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 in step S202.

[0144] Next, in step S203, the rotation control unit 36 derives the neutral-point amplitude fn, which is the amplitude of the neutral-point potential En to be varied, based on the voltage utilization rate R. The rotation control unit 36 makes the neutral-point amplitude fn variable 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. When the voltage utilization rate R is the second voltage utilization rate R2, which is smaller than the first voltage utilization rate R1, the rotation control unit 36 derives the second neutral-point amplitude fn2, which is larger than the first neutral-point amplitude fn1, 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.

[0145] After deriving the three-phase reference command values Vu0, Vv0, Vw0 and the neutral point amplitude fn, the rotation control unit 36 derives the shift command values Vux, Vvx, Vwx obtained by changing the neutral point potential En with the neutral point amplitude fn as the three-phase voltage command values Vur, Vvr, Vwr in step S204, and ends this derivation process.

[0146] Specifically, the rotation control unit 36 derives the shift command values Vux, Vvx, and Vwx by superimposing the neutral-point potential En with a neutral-point amplitude fn on the three-phase reference command values Vu0, Vv0, and Vw0. Specifically, the rotation control unit 36 derives the shift command values Vux, Vvx, and Vwx by adding (or subtracting) the neutral-point potential En from the three-phase reference command values Vu0, Vv0, and Vw0, which vary according to the electrical angle, while varying the neutral-point potential En with a neutral-point amplitude fn according to the electrical angle. In other words, the rotation control unit 36 derives the shift command values Vux, Vvx, and Vwx by superimposing the waveform of the neutral-point potential En with a neutral-point amplitude fn on the waveforms of the three-phase reference command values Vu0, Vv0, and Vw0. The period of the superimposed neutral-point potential En is set to, for example, 120 degrees.

[0147] For example, when the voltage utilization rate R is the first voltage utilization rate R1, the rotation control unit 36 derives the first shift command values Vux1, Vvx1, and Vwx1 by superimposing the neutral point potential En having the first neutral point amplitude fn1 on the three-phase reference command values Vu0, Vv0, and Vw0 corresponding to the first voltage utilization rate R1. The first shift command values Vux1, Vvx1, and Vwx1 have a variation range that is at least greater than the first neutral point amplitude fn1.

[0148] Furthermore, when the voltage utilization rate R is the second voltage utilization rate R2, the rotation control unit 36 derives the second shift command values Vux2, Vvx2, and Vwx2 by superimposing the neutral point potential En corresponding to the second neutral point amplitude fn2 on the three-phase reference command values Vu0, Vv0, and Vw0 corresponding to the second voltage utilization rate R2. The variation range of the second shift command values Vux2, Vvx2, and Vwx2 is at least greater than the second neutral point amplitude fn2. Furthermore, the variation range of the second shift command values Vux2, Vvx2, and Vwx2 is greater than that of the three-phase reference command values Vu0, Vv0, and Vw0.

[0149] As described above, the second neutral point amplitude fn2 is larger than the first neutral point amplitude fn1. Therefore, even when the voltage utilization rate R reaches the second voltage utilization rate R2 and the reference amplitude f0 decreases, the variation range of the second shift command values Vux2, Vvx2, and Vwx2 is unlikely to be narrowed.

[0150] For convenience of explanation, the neutral point amplitude fn in the shift command values Vux, Vvx, and Vwx is referred to as a shift amplitude fx. As described above, the shift amplitude fx is a parameter determined according to the voltage utilization factor R and includes a first neutral point amplitude fn1 and a second neutral point amplitude fn2.

[0151] Next, in step S205 , the rotation control unit 36 determines whether the voltage utilization rate R is greater than the threshold utilization rate Rth. This process is the same as that in step S105 .

[0152] If the determination in step S205 is affirmative, the rotation control unit 36 generates a PWM signal in step S206 based on the shift command values Vux, Vvx, and Vwx as the three-phase voltage command values Vur, Vvr, and Vwr derived in step S204. 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.

[0153] On the other hand, if the voltage utilization rate R is below the threshold utilization rate Rth, the rotation control unit 36 proceeds to step S208 and generates first PWM signals Pu1, Pv1, and Pw1 based on the shift command values Vux, Vvx, and Vwx. In this case, similar 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.

[0154] Thereafter, in step S210 , the rotation control unit 36 of the present embodiment derives the change command values Vuy, Vvy, and Vwy having a different change range from that of the shift command values Vux, Vvx, and Vwx.

[0155] The change command values Vuy, Vvy, and Vwy are the values of the neutral point potential En obtained by superimposing the change amplitude fy on the three-phase reference command values Vu0, Vv0, and Vw0. The change amplitude fy is different from the shift amplitude fx. Therefore, the change range of the change command values Vuy, Vvy, and Vwy differs from the change range of the shift command values Vux, Vvx, and Vwx, making it easy for the change command values Vuy, Vvy, and Vwy to differ from the shift command values Vux, Vvx, and Vwx. The change range refers to the range from the minimum value to the maximum value.

[0156] The change amplitude fy may be larger or smaller than the displacement amplitude fx. The change amplitude fy may be a variable value that changes every control cycle T, or a fixed value that does not change every control cycle T.

[0157] Next, in step S211, the rotation control unit 36 generates second PWM signals Pu2, Pv2, and Pw2 based on the variation command values Vuy, Vvy, and Vwy. In this case, similar to the first embodiment, the rotation control unit 36 performs pulse variation 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.

[0158] 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. Specifically, the rotation control unit 36 changes the three-phase voltage command values Vur, Vvr, and Vwr according to the voltage utilization rate R, and switches the three-phase voltage command values Vur, Vvr, and Vwr between the shift command values Vux, Vvx, and Vwx and the change command values Vuy, Vvy, and Vwy within the control period T.

[0159] Incidentally, both the shift command values Vux, Vvx, and Vwx and the variation command values Vuy, Vvy, and Vwy are obtained by varying the neutral point potential En relative to the three-phase reference command values Vu0, Vv0, and Vw0. Therefore, even if the shift command values Vux, Vvx, and Vwx differ from the variation command values Vuy, Vvy, and Vwy due to a difference in the neutral point potential En, the line voltage does not change.

[0160] Specifically, when the voltage utilization rate R is below the threshold utilization rate Rth, the rotation control unit 36 switches the switching cycle to derive three-phase voltage command values Vur, Vvr, and Vwr, each with the same line voltage for the vehicle-mounted electric motor 11 but with different variation ranges, for the same two-phase voltage command values Vdr and Vqr. In this embodiment, the three-phase voltage command values Vur, Vvr, and Vwr with different variation ranges are the shift command values Vux, Vvx, and Vwx, and the variation 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 cycle is the same as the carrier signal cycle, or carrier period. However, this is not limiting, and the switching cycle can be arbitrary.

[0161] In other words, the rotation control unit 36 may derive multiple three-phase voltage command values Vur, Vvr, and Vwr with different neutral point potentials En within the same control period T and generate multiple corresponding PWM signals. In this case, the reference pulse widths of the PWM signals generated within the control period T will differ even for the same phase. In this configuration, the reference pulse widths Wu0, Wv0, and Ww0 corresponding to the three-phase voltage command values Vur, Vvr, and Vwr are the average of the reference pulse widths of the same phases in the PWM signals within the control period T.

[0162] Furthermore, the average pulse widths Wua, Wva, and Wwa of the first PWM signals Pu1, Pv1, and Pw1 and the second PWM signals Pu2, Pv2, and Pw2 are the reference pulse widths Wu0, Wv0, and Ww0, even when pulse change control is performed. In this embodiment, the rotation control unit 36 that performs the processing of steps S201 to S204 and S210 corresponds to the "three-phase voltage command value derivation unit."

[0163] Next use Figure 6 The function of this embodiment will be described. Figure 6 (a) to (c) are waveforms showing examples of PWM signals of each phase in the second embodiment. Figure 6 (d) is a waveform showing an example of the neutral point potential En in the second embodiment.

[0164] In this embodiment, compared with the first embodiment, the three-phase voltage command values Vur, Vvr, and Vwr are changed by changing the neutral point potential En. Figure 6 As shown, the pulse width of the PWM signal of each phase becomes easy to vary.

[0165] Specifically, in this embodiment, when the voltage utilization rate R is relatively low at the second voltage utilization rate R2, second shift command values Vux2, Vvx2, and Vwx2 are derived, varying with a relatively large second neutral-point amplitude fn2. Consequently, the range of variation of the second shift command values Vux2, Vvx2, and Vwx2 relative to changes in electrical angle is greater than that of the three-phase reference command values Vu0, Vv0, and Vw0. Consequently, the pulse width of the neutral-point potential En is easily varied.

[0166] Furthermore, within a control period T, first PWM signals Pu1, Pv1, Pw1 corresponding to shift command values Vux, Vvx, Vwx and second PWM signals Pu2, Pv2, Pw2 corresponding to variable command values Vuy, Vvy, Vwy whose neutral-point amplitudes fn differ from those of the shift command values Vux, Vvx, Vwx are alternately output. Consequently, the pulse width of the neutral-point potential En also fluctuates within the same control period T. Consequently, the pulse width of the neutral-point potential En is less likely to deviate toward a specific value.

[0167] Even if the neutral point potential En changes, the line voltage applied to the three-phase coils 24u, 24v, and 24w does not change. Therefore, the vehicle-mounted electric motor 11 is provided with a torque equivalent to the three-phase reference command values Vu0, Vv0, and Vw0.

[0168] According to the present embodiment described in detail above, in addition to the effects of the first embodiment, the following effects are achieved.

[0169] (2-1) In the process of deriving the three-phase voltage command values Vur, Vvr, and Vwr, the rotation control unit 36 derives different three-phase voltage command values Vur, Vvr, and Vwr according to the voltage utilization rate R calculated based on the two-phase voltage command values Vdr and Vqr and the power supply voltage Vin.

[0170] Specifically, when the voltage utilization rate R is the first voltage utilization rate R1, the rotation control unit 36 derives first shift command values Vux1, Vvx1, and Vwx1 as the three-phase voltage command values Vur, Vvr, and Vwr, obtained by varying the neutral-point potential En by a first neutral-point amplitude fn1. Furthermore, when the voltage utilization rate R is the second voltage utilization rate R2, which is smaller than the first voltage utilization rate R1, the rotation control unit 36 derives second shift command values Vux2, Vvx2, and Vwx2 as the three-phase voltage command values Vur, Vvr, and Vwr, obtained by varying the neutral-point potential En by a second neutral-point amplitude fn2. The second neutral-point amplitude fn2 is larger than the first neutral-point amplitude fn1.

[0171] According to this configuration, when the voltage utilization rate R is the second voltage utilization rate R2, which is smaller than the first voltage utilization rate R1, the neutral-point potential En varies with a second neutral-point amplitude fn2, which is larger than the first neutral-point amplitude fn1 corresponding to the first voltage utilization rate R1. This results in second shift command values Vux2, Vvx2, and Vwx2 having a variation range that is at least equal to or greater than the second neutral-point amplitude fn2. This prevents the variation range of the second shift command values Vux2, Vvx2, and Vwx2 from narrowing. Consequently, it is possible to suppress an increase in noise of a specific frequency due to a narrow variation range of the three-phase voltage command values Vur, Vvr, and Vwr.

[0172] In particular, the variation range of the three-phase voltage command values Vur, Vvr, and Vwr tends to narrow as the voltage utilization rate R decreases. Therefore, when the voltage utilization rate R is the second voltage utilization rate R2, the variation range of the three-phase voltage command values Vur, Vvr, and Vwr tends to narrow.

[0173] In this regard, according to this configuration, when the voltage utilization rate R is the second voltage utilization rate R2, by varying the neutral-point potential En with a relatively large second neutral-point amplitude fn2, even when the voltage utilization rate R is the second voltage utilization rate R2, the variation range of the three-phase voltage command values Vur, Vvr, and Vwr can be suppressed from becoming narrower. This can suppress the increase in noise of a specific frequency.

[0174] Furthermore, the first shift command values Vux1, Vvx1, and Vwx1 derived when the voltage utilization rate R is the first voltage utilization rate R1 are obtained by varying the neutral point potential En by a first neutral point amplitude fn1 that is smaller than the second neutral point amplitude fn2. This prevents the variation range of the first shift command values Vux1, Vvx1, and Vwx1 from becoming excessively wide.

[0175] (2-2) When the voltage utilization rate R is less than or equal to the threshold utilization rate Rth, the rotation control unit 36 switches the three-phase voltage command values Vur, Vvr, and Vwr, each having the same line voltage for the vehicle-mounted electric motor 11 but different variation ranges, at a switching cycle (in this embodiment, a carrier cycle), for the same two-phase voltage command values Vdr and Vqr. For example, the rotation control unit 36 derives shift command values Vux, Vvx, and Vwx and variation command values Vuy, Vvy, and Vwy, each having different variation ranges, for a single two-phase voltage command value Vdr and Vqr.

[0176] According to this configuration, when the voltage utilization rate R is below the threshold utilization rate Rth, the three-phase voltage command values Vur, Vvr, and Vwr are switched to values with different variation ranges at a switching cycle, while the line voltages of the three-phase coils 24u, 24v, and 24w remain the same. Thus, even when the two-phase voltage command values Vdr and Vqr are the same, the three-phase voltage command values Vur, Vvr, and Vwr vary at the switching cycle. Consequently, when the voltage utilization rate R is low, noise of a specific frequency caused by the three-phase voltage command values Vur, Vvr, and Vwr periodically being the same can be reduced.

[0177] Specifically, if the same three-phase voltage command values Vur, Vvr, and Vwr are periodically derived, or if multiple PWM signals are generated for a single three-phase voltage command value Vur, Vvr, and Vwr, the three-phase voltage command values Vur, Vvr, and Vwr periodically become identical. In this case, noise of a specific frequency corresponding to the derivation period of the three-phase voltage command values Vur, Vvr, and Vwr or the output period of the PWM signal is generated. The impact of this specific frequency noise tends to be greater when the voltage utilization rate R is low.

[0178] In this regard, according to this embodiment, when the voltage utilization rate R is below the threshold utilization rate Rth, three-phase voltage command values Vur, Vvr, and Vwr are derived with varying ranges at each switching cycle. This allows the three-phase voltage command values Vur, Vvr, and Vwr to vary within each switching cycle. This reduces the frequency with which the three-phase voltage command values Vur, Vvr, and Vwr periodically reach the same value, thereby reducing the aforementioned specific frequency noise.

[0179] In particular, this configuration allows the line voltages applied to the three-phase coils 24u, 24v, and 24w to remain the same even when the three-phase voltage command values Vur, Vvr, and Vwr are switched. This allows the same torque to be applied to the vehicle-mounted electric motor 11. This prevents problems such as different torques being applied due to switching of the three-phase voltage command values Vur, Vvr, and Vwr.

[0180] As described above, a state in which appropriate torque is applied to the vehicle-mounted electric motor 11 can be maintained, and noise of a specific frequency generated when the three-phase voltage command values Vur, Vvr, and Vwr periodically become the same when the voltage utilization rate R is low can be reduced.

[0181] In addition, the above-mentioned embodiments can be modified as follows. In addition, the above-mentioned embodiments and the following other examples can be appropriately combined within the scope of no technical contradiction.

[0182] The number of PWM signals generated within the control period T is not limited to two and can be any number, including three or more. In this case, the PWM signals may have unchanged pulse widths. In other words, when three or more PWM signals are generated within the control period T, the multiple PWM signals only need to be different in at least two of them, and may include a PWM signal with a reference pulse width.

[0183] The stationary phase is not limited to the u phase and may be any phase. Alternatively, two of the u phase, v phase, and w phase may be stationary phases and one may be a variable phase.

[0184] There may not be a fixed phase. That is, the rotation control unit 36 may perform pulse change control on all of the u-phase, v-phase, and w-phase.

[0185] The rotation control unit 36 may be configured to perform pulse change control regardless of the voltage utilization rate R.

[0186] Alternatively, 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 may be narrower than the v-phase reference pulse width Wv0, and the second w-phase pulse width Ww2 may be narrower than the w-phase reference pulse width Ww0.

[0187] In the second embodiment, two-phase modulation values are used as the change command values Vuy, Vvy, and Vwy. In this case as well, the change ranges of the change command values Vuy, Vvy, and Vwy are different from the change ranges of the shift command values Vux, Vvx, and Vwx.

[0188] The acquisition unit 35 may have any specific configuration as long as it can receive external command values transmitted from the air conditioning ECU 103. For example, if the air conditioning ECU 103 transmits commands via wireless signals, the acquisition unit 35 may be a module that receives the wireless signals.

[0189] The structure for detecting the voltage of the on-board power storage device 104, namely, the power supply voltage Vin, is not limited to the voltage sensor 31 and may be any structure. For example, if the on-board power storage device 104 is provided with the voltage sensor 31 for detecting the power supply voltage Vin and a battery CPU electrically connected to the voltage sensor 31, the rotation control unit 36 may also be configured to obtain the power supply voltage Vin by communicating with the battery CPU. In this case, the rotation control unit 36 communicating with the battery CPU corresponds to the "voltage detecting unit."

[0190] The vehicle-mounted electric compressor 10 is not limited to use in the vehicle-mounted air conditioning system 101 and can also be used in other devices. For example, if the vehicle 100 is a fuel cell vehicle, the vehicle-mounted electric compressor 10 can also be used in an air supply system that supplies air to the fuel cell. In other words, the fluid to be compressed is not limited to refrigerant and can be any other fluid, such as air.

[0191] The on-vehicle fluid machinery is not limited to the on-vehicle electric compressor 10 having a compression unit 12 for compressing fluid. For example, if the vehicle 100 is a fuel cell vehicle, the on-vehicle fluid machinery may also be an electric pump device having 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 can be used to control the on-vehicle electric motor that drives the pump.

[0192] The vehicle-mounted electric motor 11 is not limited to being used in the vehicle-mounted electric compressor 10, and any type of motor may be used as long as it is mounted on a vehicle. For example, the vehicle-mounted electric motor 11 may be a driving motor for driving the vehicle.

[0193] Next, a suitable example that can be grasped from the above-mentioned embodiment and other examples will be described below.

[0194] The three-phase voltage command value derivation unit includes: a reference generation unit that generates a three-phase reference command value with a reference amplitude based on the two-phase voltage command value; and a superposition unit that derives the three-phase voltage command value by superimposing the neutral point potential on the three-phase reference command value, wherein the superposition unit superimposes the neutral point potential of the first neutral point amplitude on the three-phase reference command value when the voltage utilization rate is the first voltage utilization rate, and superimposes the neutral point potential of the second neutral point amplitude on the three-phase reference command value when the voltage utilization rate is the second voltage utilization rate.

Claims

1. An inverter control device for controlling an inverter circuit for driving an on-vehicle electric motor using an on-vehicle power storage device, wherein: The vehicle-mounted electric motor has a three-phase coil. The inverter circuit has three-phase switching elements. The inverter control device comprises: a three-phase voltage command value deriving unit for deriving three-phase voltage command values to be applied to the three-phase coils; and a generating unit for generating a plurality of PWM signals for each phase within a predetermined control period based on the three-phase voltage command values and a carrier signal; The inverter control device performs PWM control on the three-phase switching elements using the PWM signals of the respective phases. The generating unit includes a pulse changing unit that performs pulse changing control on the multiple PWM signals within the control period in one phase, each having a reference pulse width corresponding to the three-phase voltage command value. In the pulse changing control, at least two pulse widths among the multiple PWM signals are made different from each other so that an average pulse width of the multiple PWM signals within the control period becomes the reference pulse width.

2. The inverter control device according to claim 1, characterized in that: The inverter control device comprises: a voltage grasping unit for grasping the voltage of the vehicle-mounted power storage device, ie, the power supply voltage; a speed grasping unit for grasping the rotational speed of the vehicle-mounted electric motor; and a two-phase voltage command value deriving unit for deriving two-phase voltage command values as target values of voltages applied to the d-axis and q-axis of the vehicle-mounted electric motor based on an external command value sent from the outside and a grasping result of the speed grasping unit; The three-phase voltage command value deriving unit derives the three-phase voltage command value based on the two-phase voltage command value. The generating unit performs the pulse changing control of the pulse changing unit when a voltage utilization rate calculated based on the two-phase voltage command values and the grasping result of the voltage grasping unit is equal to or less than a predetermined threshold utilization rate.

3. The inverter control device according to claim 1 or 2, characterized in that: 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, while not performing the pulse changing control on the plurality of PWM signals within the control period in one fixed phase other than the variable phase among the three phases.

4. The inverter control device according to claim 3, characterized in that: The plurality of PWM signals in the control period in the first variable phase of the two variable phases, that is, the plurality of first variable phase PWM signals, include: a first wide-amplitude signal having a pulse width wider than the reference pulse width; and a first narrow-amplitude signal having a pulse width narrower than the reference pulse width, The plurality of PWM signals in the control period in the second variable phase of the two variable phases, that is, the plurality of second variable phase PWM signals, include: a second narrow-width signal which is output when the first wide-width signal is output and has a pulse width narrower than the reference pulse width; and A second wide-width signal is output when the first narrow-width signal is output and has a pulse width wider than the reference pulse width.

5. The inverter control device according to claim 1, characterized in that: The inverter control device comprises: a voltage grasping unit for grasping the voltage of the vehicle-mounted power storage device, ie, the power supply voltage; a speed grasping unit for grasping the rotational speed of the vehicle-mounted electric motor; and a two-phase voltage command value deriving unit for deriving two-phase voltage command values as target values of voltages applied to the d-axis and q-axis of the vehicle-mounted electric motor based on an external command value sent from the outside and a grasping result of the speed grasping unit; The three-phase voltage command value deriving 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 values and the grasping result of the voltage grasping unit is a first voltage utilization rate, a first shift command value obtained by changing the neutral point potential of the three-phase voltage command values by a first neutral point amplitude is derived as the three-phase voltage command value. When the voltage utilization rate is a second voltage utilization rate smaller than the first voltage utilization rate, a second shift command value obtained by changing the neutral point potential by a second neutral point amplitude larger than the first neutral point amplitude is derived as the three-phase voltage command value. The three-phase voltage command value deriving unit includes: a reference generating unit for generating a three-phase reference command value having a reference amplitude based on the two-phase voltage command value; and a superimposition unit deriving the three-phase voltage command values by superimposing the neutral point potential on the three-phase reference command values, The superimposing unit superimposes the neutral point potential of the first neutral point amplitude on the three-phase reference command value when the voltage utilization rate is the first voltage utilization rate. When the voltage utilization rate is the second voltage utilization rate, the neutral point potential of the second neutral point amplitude is superimposed on the three-phase reference command value.

6. The inverter control device according to claim 1, characterized in that: The inverter control device comprises: a voltage grasping unit for grasping the voltage of the vehicle-mounted power storage device, ie, the power supply voltage; a speed grasping unit for grasping the rotational speed of the vehicle-mounted electric motor; and a two-phase voltage command value deriving unit for deriving two-phase voltage command values as target values of voltages applied to the d-axis and q-axis of the vehicle-mounted electric motor based on an external command value sent from the outside and a grasping result of the speed grasping unit; The three-phase voltage command value deriving unit derives the three-phase voltage command value based on the two-phase voltage command value. When the voltage utilization calculated based on the two-phase voltage command value and the control result of the voltage control unit is below a predetermined threshold utilization, for the same two-phase voltage command value, the three-phase voltage command values having the same line voltage of the three-phase coil and different variation ranges are switched and derived in a switching cycle.

7. A vehicle-mounted fluid machinery, characterized in that: have: the vehicle-mounted electric motor; the inverter circuit; and The inverter control device according to any one of claims 1 to 6.

8. The vehicle-mounted fluid machinery according to claim 7, characterized in that: The vehicle-mounted fluid machine is a vehicle-mounted electric compressor including a compression portion driven by the vehicle-mounted electric motor.

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