JP6165216B2 - Method for manufacturing motor drive device - Google Patents

Description

The present invention relates to a method for manufacturing a motor drive device, and more particularly to a method for manufacturing a motor drive device that drives a motor of a hybrid vehicle or an electric vehicle.

  In recent years, hybrid vehicles and electric vehicles have been actively developed as environmentally friendly vehicles. A hybrid vehicle is a vehicle that uses a motor driven by an inverter in addition to an engine as a power source. In other words, the hybrid vehicle converts a DC voltage from a power source obtained by driving an engine and a high voltage battery such as a NiH battery or a Li-ion battery into an AC voltage by an inverter, and the converted AC voltage. Thus, the power source obtained by rotating the motor is appropriately switched and used. An electric vehicle is a vehicle that uses a motor driven by an inverter as a power source.

  Such a combination of an inverter and a motor generally includes (1) a configuration of a boost chopper + three-phase inverter + three-phase motor, or (2) a configuration of three-phase inverter + three-phase motor. In both cases, the inverter switching element needs to have a withstand voltage equal to or higher than the induced voltage of about 400 V of the motor, and since it is a power source of an automobile, it needs a rated current of 100A class. Therefore, generally, a parallel circuit of Si-IGBT (Insulated Gate Bipolar Transistor (IGBT) using a silicon (Si) semiconductor element) and a diode for reverse conduction is used.

  On the other hand, in hybrid vehicles and electric vehicles, low loss and high efficiency of inverters are desired in order to improve fuel efficiency and power consumption. Recently, the use of SiC (silicon carbide) semiconductor elements has attracted attention. The switching element of the inverter made of SiC can be used even in a high voltage region where unipolar operation is difficult with the Si semiconductor element, and it is expected that the switching loss generated at the time of switching can be greatly reduced and the power loss can be greatly reduced. Yes. As such a SiC semiconductor element, a SiC-MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is well known.

However, the manufacturing technology of SiC semiconductor elements is under development, and since the defect density in the device is large, it is difficult to produce a device having an area larger than about 5 mm square with a high yield. On the other hand, Si-IGBT can be formed with a 10 mm square or more.
Accordingly, since the SiC semiconductor element has a small current capacity and cannot flow a necessary current with one chip, it is necessary to use a plurality of chips having dimensions smaller than those of the Si-IGBT in parallel.

  On the other hand, the loss of the switching element includes a switching loss at the time of switching and a conduction loss at the time when a current continuously flows through the switching element that has been turned on after switching. When multi-parallelization is used, current deviations between chips due to differences in electrical characteristics due to individual variations in each chip of each chip, individual variations in chip driver circuit elements, and drive timing shifts due to differences in power module wiring layout Occurs.

  Here, FIG. 1 shows a circuit diagram of a leg composed of an upper arm formed of a SiC-MOSFET chip QH and a lower arm formed of a SiC-MOSFET chip QL when the power module is formed of a single chip. An example of a power module chip and wiring layout corresponding to this is shown in FIG. In FIG. 2, a configuration example of the lower arm will be described.

  As shown in the plan view of FIG. 2A, the SiC-MOSFET chip QL is bonded to the metal film ML bonded on the insulating substrate BP via the bonding agent CR. In this case, the bonding agent CR side of the SiC-MOSFET chip QL is called a back surface, and the bonding agent CF side is called a front surface. The surface of the SiC-MOSFET chip QL has a source potential and the back surface has a drain potential. The SiC-MOSFET chip QL is connected to the wiring WAC through the bonding agent CF. A gate terminal WGL and a source terminal WSL are provided on the end face of the substrate BP, and a drive signal from an external circuit is input.

As shown in the front view of FIG. 2B and the side view of FIG. 2C, a gate pad and a source pad are provided on the surface of the SiC-MOSFET chip QL, and the gate terminal WGL and the source terminal WSL The pads of the SiC-MOSFET chip QL are connected by wire bonding.
Since the upper arm has the same configuration as the lower arm, description thereof is omitted.

FIG. 3 shows a circuit diagram in the case where each arm is configured by parallel connection of four chips. An example of the power module chip and wiring layout corresponding to FIG. 3 is shown in FIG. 4 has the same basic configuration as that of FIG. 2, but since four chips are connected in parallel to each arm, the gate wiring (WGH, WGL) and the source wiring (WSH, WSL) are chips QH1 to QH4 and QL1. It extends to QL4. The length of one circuit consisting of the gate terminal WGL (WGH) → SiC-MOSFET gate pad → SiC-MOSFET source pad → source terminal WSL (WSH) differs from the source terminal WSL to each chip. Therefore, a shift occurs at the timing when the gate-source potential of each chip reaches the threshold value Vgs (th), and a large amount of current flows through the chip that has reached Vgs (th) earlier. Such a current bias is inevitable when chips are paralleled, and becomes more prominent as the number of parallelization increases.

  Therefore, it is necessary to design a heatsink in accordance with the power loss of a chip through which a large amount of current flows. Compared to a heatsink configured with one chip, a heatsink with a multi-parallel chip configuration is more current efficient. It is necessary to increase the capacity of the radiator by taking the bias into account.

  In order to suppress this, it is necessary to provide a balance resistor at the gate terminal of the switching element. As a result, the switching loss is equalized, but the switching speed is lowered. Therefore, the value of the individual switching loss is increased, and the loss reduction effect cannot be sufficiently obtained even if the SiC semiconductor device is formed.

  On the other hand, hybrid vehicles and electric vehicles require safe driving and quietness even when the power conversion means is abnormal. In order to satisfy this, there is a distributed inverter system in which the motor is made up of n-phase (n is a natural number of 2 or more) three-phase windings and each is driven by a large number of inverters using Si-IGBT semiconductor elements (for example, patents) Reference 1).

Japanese Patent No. 2889442

  In such a distributed inverter system, the ripple of the capacitor ripple current and the motor winding current can be reduced by giving a phase difference to the PWM carrier wave of each inverter. It is expected that high-order current pulsations can be reduced, and that the noise of motors and capacitors can be reduced.

  However, this distributed inverter system still requires a switching element with a high withstand voltage. When using Si-IGBT, tail current flows when switching off and switching loss is large. Since this is a bipolar device, there is a constant voltage drop even when the current is small. There is a problem that loss is large. For this reason, the switching frequency cannot be sufficiently increased in order to suppress the switching loss.

  Originally, in PWM control, the number of pulses is desirably about 15 pulses or more per cycle of the output frequency. In particular, when high torque is generated, the inverter conduction loss also increases and the amount of heat generation increases, so it is necessary to prevent overheating and reduce heat generation in this region.

  However, designing an inverter so that it can be driven at a high carrier frequency in the entire operation region increases the size of the inverter and increases the cost. Therefore, in general, square wave driving is used in the high speed region.

  However, in the case of square wave drive, since many 5th and 7th harmonic components of the output frequency are included, a torque pulsation that is 6 times the output frequency occurs. Since the torque pulsation does not contribute to the average torque, the harmonic component increases the copper loss of the motor. Further, noise is generated by torque pulsation. As the current pulsates, the capacitor beats.

For these reasons, the Si-IGBT semiconductor element has a problem that the effect of the distributed inverter system cannot be sufficiently exhibited.
In practice, for example, the battery is generally a lead battery, and its application is limited to a motor generator that charges and discharges an auxiliary battery having a low voltage of 12V.

The present invention has been made in order to solve the above-described problems, and its purpose is to perform switching at a high frequency with a high withstand voltage and low switching loss in a motor of a hybrid vehicle or an electric vehicle that requires high reliability. It is an object of the present invention to provide a method of manufacturing a motor drive device with high conversion efficiency that can be realized.

In order to achieve the above object, according to the present invention, in the method of manufacturing a motor driving apparatus that drives and controls a motor using an inverter in which the switching element of each arm is a chip of a wide gap semiconductor element, the arm is necessary for the inverter. In order to withstand a large current capacity, the inverters are provided in the number corresponding to the number of parallelization when the chips are assumed to be paralleled, and the three-phase windings of the motor are multiplexed in accordance with the number of inverters A method for manufacturing a motor drive device is provided.

According to the method for manufacturing a motor driving device of the present invention, the low-loss characteristics of the wide band gap semiconductor element can be sufficiently exhibited, and the conversion efficiency of the motor driving device is improved. In addition, by improving the conversion efficiency of the motor drive device, the motor drive device can be driven at a high frequency, so that the current ripple of the motor winding can be reduced, the torque ripple can be reduced, the inverter loss is reduced, the motor loss is reduced, and There is an effect that noise can be reduced.

It is a circuit diagram of the power module comprised by two arms in the single chip | tip conventionally used. FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a side view, illustrating an example of a chip and wiring layout in the power module of FIG. 1. It is a circuit diagram of a power module when each arm is configured by parallel connection of four chips. It is the figure which showed an example of the chip | tip and wiring layout in the power module of FIG. Is a circuit diagram showing an electrical system of a motor driving device Ru use in the embodiment 1 of the present invention. It is a block diagram of the control apparatus used for the motor drive device shown in FIG. It is a flowchart which shows the calculation process of the torque distribution calculating part used for the control apparatus shown in FIG. It is a flowchart which shows the process A in FIG. 7 concretely. It is a flowchart which shows the process B in FIG. 7 concretely. It is the graph which showed the time change of the temperature of the inverter in the manufacturing method of the motor drive unit concerning the present invention. FIG. 8 is a block diagram showing the torque distribution calculation unit shown in FIG. 7. 5 is a flowchart illustrating a process of switching between synchronous PWM and asynchronous PWM based on temperature in the method for manufacturing a motor drive device according to the present invention.

A method for manufacturing a motor drive device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

Embodiment 1 FIG.
Motor drive device 1 Ru use in the embodiment 1 of the present invention shown in FIG. 5 is for driving a double three-phase windings motor M1, a high-voltage battery 10, a capacitor 12, an inverter 14, an inverter , Current sensors SV14, SW14, SV34, SW34, a switching unit SRV14, SRW14, SRV34, SRW34, a motor M1, a resolver 24, and a control device 20. Paralleling when assuming that the switching element of each arm in the legs constituting the inverters 14 and 34 is a chip of a wide bandgap semiconductor element and each arm is paralleled to withstand the current capacity required for the inverter The motor M1 is driven by the duplexed inverters 14 and 34 corresponding to the number = 2.

  As the high voltage battery 10, for example, a secondary battery such as a nickel metal hydride battery, a lithium ion battery, or a lead storage battery can be used. Further, a large capacity capacitor or a fuel cell may be used together with or instead of the secondary battery.

  As the switching units SRV14, SRW14, SRV34, and SRW34, for example, a contactor or a semiconductor switching element can be used. The semiconductor switching element may be an IGBT or a series circuit of two MOSFETs in which source electrodes are connected to each other.

  Inverter 14 receives power supply potential Vpn from high-voltage battery 10 and drives AC motor M1. Preferably, the inverter 14 performs a regenerative operation during braking of the motor M1 (using the motor M1 as a generator), and returns the electric power generated in the AC motor M1 to the high voltage battery 10.

  Inverter 14 includes a U-phase leg 15, a V-phase leg 16, and a W-phase leg 17. The U-phase leg 15, the V-phase leg 16, and the W-phase leg 17 are connected in parallel between the output lines of the high voltage battery 10. A capacitor 12 is also connected between the output lines of the high voltage battery 10 in parallel with these legs.

U-phase leg 15 includes SiC-MOSFET elements Q1 and Q2 connected in series, and reverse conducting diodes D1 and D2 connected in parallel to these SiC-MOSFET elements Q1 and Q2, respectively.
V-phase leg 16 includes SiC-MOSFET elements Q3 and Q4 connected in series, and reverse conducting diodes D3 and D4 connected in parallel to these SiC-MOSFET elements Q3 and Q4, respectively.
W-phase leg 17 includes SiC-MOSFET elements Q5 and Q6 connected in series, and reverse conducting diodes D5 and D6 connected in parallel to these SiC-MOSFET elements Q5 and Q6, respectively.
Preferably, the diodes D1 to D6 are diodes using SiC semiconductor elements. The withstand voltage of the SiC semiconductor element is 600V or more.

  U-phase leg 15, V-phase leg 16, and W-phase leg 17 are connected to motor M1 by three drive lines from the connection points between SiC-MOSFET elements Q1-Q2, Q3-Q4, Q5-Q6, respectively. . The diodes D1, D3, D5 are connected with the direction from the corresponding drive line toward the positive electrode of the high-voltage battery 10 as the forward direction. The diodes D2, D4, D6 are connected with the direction from the negative electrode of the high-voltage battery 10 toward the corresponding drive line as the forward direction. Further, a temperature sensor 91 for detecting the temperature of the SiC-MOSFET element and the diode of the inverter 14 is arranged.

  The motor drive device 1 further detects a current sensor SV1 that detects a current flowing through a drive line that connects the V-phase leg 16 to the motor M1, and a current that flows through a drive line that connects the W-phase leg 17 to the motor M1. Current sensor SW1. A stator coil (not shown) of the motor M1 is Y-connected, and the V-phase coil, the W-phase coil, and the U-phase coil are connected to a neutral point. Therefore, if the V-phase and W-phase currents are given, the control device 20 can obtain the U-phase current by calculation.

  The current values detected by the current sensors SV14 and SW14 are transmitted to the control device 20 together with the rotational speed of the motor M1 detected by the resolver 24. Based on these, the control device 20 controls the rotation speed of the motor M1.

  The other inverter 34 includes a U-phase leg 35, a V-phase leg 36, and a W-phase leg 37. The U-phase leg 35, the V-phase leg 36, and the W-phase leg 37 are connected in parallel between the output lines of the high voltage battery 10.

U-phase leg 35 includes SiC-MOSFET elements Q12 and Q22 connected in series, and reverse conducting diodes D12 and D22 connected in parallel to these SiC-MOSFET elements Q12 and Q22, respectively.
V-phase leg 36 includes SiC-MOSFET elements Q32 and Q42 connected in series, and reverse conducting diodes D32 and D42 connected in parallel to these SiC-MOSFET elements Q32 and Q42, respectively.
W-phase leg 37 includes SiC-MOSFET elements Q52 and Q62 connected in series, and reverse conducting diodes D52 and D62 connected in parallel to these SiC-MOSFET elements Q52 and Q62, respectively.
Preferably, the diodes D12, D22, D32, D42, D52, and D62 are diodes using SiC semiconductor elements.

  The U-phase leg 35, the V-phase leg 36, and the W-phase leg 37 are connected to the motor M1 by three drive lines from connection points between the SiC-MOSFET elements Q12-Q22, Q32-Q42, and Q52-Q62, respectively. . The diodes D12, D32, and D52 are connected with the direction from the corresponding drive line toward the positive electrode of the high-voltage battery 10 as the forward direction. The diodes D22, D42, and D62 are connected with the direction from the negative electrode of the high-voltage battery 10 toward the corresponding drive line as the forward direction. Further, a temperature sensor 92 for detecting the temperature of the SiC-MOSFET element and the diode in the inverter 34 is arranged.

  The motor drive device 1 further detects a current sensor SV34 that detects a current flowing through a drive line that connects the V-phase leg 36 to the motor M1, and a current that flows through a drive line that connects the W-phase leg 37 to the motor M1. Current sensor SW34. The stator coil of the motor M1 is Y-connected, and the V-phase coil, W-phase coil, and U-phase coil are connected to the neutral point. Therefore, if the V-phase and W-phase currents are given, the control device 20 can obtain the U-phase current by calculation.

The current values detected by the current sensors SV34 and SW34 are transmitted to the control device 20 together with the rotational speed of the motor M1 detected by the resolver 24.
In addition to the temperature signals from the temperature sensors 91 and 92 and the motor rotation number signal from the resolver 24, the controller 20 receives a torque command from the host ECU 11 and an abnormality detection signal from the inverters 14 and 34. . Based on these input signals, control device 20 provides gate drive signals to inverters 14 and 34.

Below, the control apparatus 20 is demonstrated roughly with reference to FIG.
First, the configuration of the control device 20 will be described. The control device 20 includes a synchronous / asynchronous / phase difference calculation unit 100, a rotation speed calculation unit 102, a torque distribution calculation unit 104, a control unit 120 of the inverter 14, and a control unit 121 of the inverter 34. Furthermore, the control unit 120 of the inverter 14 includes a current command calculation unit 106, a voltage command calculation unit 108, and an inverter drive signal generation unit 114.
Since the configuration of the control unit 120 of the inverter 14 and the control unit 121 of the inverter 34 are the same, only the control unit 120 of the inverter 14 will be described below.

  The host ECU 11 is determined based on the acceleration request from the driver given by the accelerator pedal position sensor, the acceleration / deceleration request for maintaining the vehicle speed specified by the cruise control, the vehicle speed detected by the vehicle speed sensor, and the like. A torque command is output to the control device 20.

  The current command calculation unit 106 of the control device 20 calculates a current command value to be supplied to the inverters 14 and 34 based on the output of the torque distribution calculation unit 104 and the outputs of the current sensors SV14 and SW14 and SV34 and SW34. The voltage command calculation unit 108 receives the current command value of the current command calculation unit 106 and outputs a voltage command value of synchronous PWM / asynchronous PWM. The synchronous PWM control has a feature that it can be driven with a small number of switching pulses. When asynchronous PWM control is used, it can be driven at an arbitrary carrier frequency. Since these synchronous PWM and asynchronous PWM are known techniques, they will not be described again.

As shown in FIG. 7, the torque distribution calculation unit 104 calculates a torque distribution value to the inverters 14 and 34. Process A in FIG. 7 is shown in FIG. 8, and process B is shown in FIG.
In FIG. 7, the torque distribution calculation unit 104 receives a torque command input from the host ECU, temperature detection signals from the temperature sensors 91 and 92, and an abnormality detection signal from the inverters 14 and 34. First, the presence or absence of abnormality in the inverters 14 and 34 is determined in step S1. If there is an abnormality, an inverter having an abnormality is identified in step S2. If both inverters are abnormal, both inverters 14 and 34 are stopped in step S3. If only one inverter is abnormal, only the inverter having the abnormality is stopped (step S4).

  In step S3, switching of switching elements Q1 to Q6 of inverter 14 and switching elements Q12, Q22, Q32, Q42, Q52, and Q62 of inverter 34 is stopped and switching units SRV14, SRW14, SRV34, and SRW34 are opened. To do. In step S4, the switching elements (Q1 to Q6, or Q12, Q22, Q32, Q42, Q52, and Q62) of the inverter having an abnormality are stopped and the switching units SRV14 and SRW14 or SRV34 and SRW34 are opened. To.

When only one inverter is stopped in step S4, torque is controlled based on the temperature of the inverter in process A shown in FIG. The maximum torque can be output even with one inverter. Thereafter, abnormality detection is output to the host ECU 11 in step S5, and torque distribution is terminated.
If it is determined in step S1 that there is no abnormality, the process proceeds to process B shown in FIG.

In process A shown in FIG. 8, in step S7, a difference ΔTR between the torque command and the target torque at the time of calculation (previous target torque) is calculated. Thereafter, in step S8, the polarity of the difference ΔTR from the torque command is determined. If ΔTR> 0, the following torque distribution process corresponding to the inverter temperature is performed in step S9.
(1) If the temperature of the normal inverter <threshold value 1, the normal inverter torque is increased by a preset change ΔTR / y. Note that “y” indicates a width to be increased, and indicates that the amount of change is not necessarily the same as ΔTR / x or ΔTR / w, which will be described later.
(2) If normal inverter temperature ≧ threshold value 1, normal inverter torque is not changed.
On the other hand, if the result of determining the polarity of the difference ΔTR from the torque command in step S8 is not ΔTR> 0, in step S10, the normal inverter torque is set to the absolute value | ΔTR / w | Only reduce.

  In step S1 of FIG. 7, when both inverters 14 and 34 are normal, as shown in FIG. 9, first, in step S11, the target torque of inverter 14 and the target of inverter 34 are determined from the command torque. ΔTR (torque command−torque of inverter 14−torque of inverter 34) obtained by subtracting the torque (both of the previous target torques) is calculated. In step S12, the polarity of ΔTR is determined in the same manner as in step S8.

As a result, when ΔTR> 0, the following torque distribution processing is performed in step S13.
(1) When the temperature of the inverter 14 <threshold 1 and the temperature of the inverter 34 <threshold 1, both the target torques of the inverters 14 and 34 are increased by a preset change ΔTR / x.
(2) When the temperature of the inverter 14 <the threshold value 1 and the temperature of the inverter 34 ≧ the threshold value 1, the target torque of the inverter 14 is increased by a preset change ΔTR / y.
(3) When the temperature of the inverter 14 ≧ the threshold value 1 and the temperature of the inverter 34 <the threshold value 1, the target torque of the inverter 34 is increased by a preset change ΔTR / y.
(4) When the temperature of the inverter 14 ≧ threshold 1 and the temperature of the inverter 34 ≧ threshold 1, both the target torques of the inverters 14 and 34 are not changed.

  When the temperature of both inverters 14 and 34 has reached the threshold value by the process of step S13, the inverter having sufficient temperature can be given torque, and the temperature of one of the inverters is high However, it is possible to avoid torque suppression. In addition, by setting the change in torque to ΔTR / x and ΔTR / y, it is possible to prevent the temperature from changing sharply and overshooting.

If ΔTR <0, the following torque distribution process is performed in step S14.
(1) When the temperature of the inverter 14 <the threshold value 2 and the temperature of the inverter 34 <the threshold value 2, both of the target torques of the inverters 14 and 34 are reduced by a preset absolute value | ΔTR / z |.
(2) When the temperature of the inverter 14 <the threshold value 2 and the temperature of the inverter 34 ≧ the threshold value 2, the target torque of the inverter 14 is reduced by an absolute value | ΔTR / w |
(3) When the temperature of the inverter 14 ≧ the threshold value 2 and the temperature of the inverter 34 <the threshold value 2, the target torque of the inverter 14 is reduced by an absolute value | ΔTR / w |
(4) When the temperature of the inverter 14 is equal to or greater than the threshold 2 and the temperature of the inverter 34 is equal to or greater than the threshold 2, both the target torques of the inverters 14 and 34 are reduced by an absolute value | ΔTR / z |

  The conceptual diagram of the time change of inverter temperature at the time of performing the process of step S13 and S14 is shown in FIG. In FIG. 10, ΔTR> 0 at time t1, and the torque needs to be increased. Since the temperature of both inverters is equal to or lower than the threshold value 1 at time t1, the torque of both inverters is increased. As the torque increases, the temperatures of the inverters 14 and 34 increase, and the temperature of the inverter 14 reaches the threshold 1 at time t2. In this case, ΔTR> 0, but the torque of the inverter 14 is not increased, and the process of increasing the torque of the inverter 34 is performed until time t3.

When ΔTR <0 at time t4, the temperature of both inverters 14 and 34 has reached the threshold value 2, so the torque of both inverters 14 and 34 is decreased. The temperature of the inverter 14 reaches the threshold value 2 at time t5.
On the other hand, since the temperature of the inverter 34 is equal to or higher than the threshold value 2, processing for reducing only the torque of the inverter 34 is performed until time t6. After time t6, the torques of both inverters 14, 34 are reduced.

  By the processing in steps S13 and S14, the temperature divergence of both the inverters 14 and 34 can be suppressed until the inverter temperature is limited by the threshold value 1. That is, the control device 20 performs torque distribution so that the temperatures of the inverters 14 and 34 are substantially equal.

  It is well known as Arrhenius' law that the deterioration of a semiconductor is temperature dependent, and that the deterioration is accelerated at a higher temperature. Since the threshold value 1 and the threshold value 2 are set in a high temperature range where the deterioration is severe, the temperature deviation in the high temperature range can be suppressed, so that the life of each inverter can be made comparable.

The processing in steps S13 and S14 of the torque distribution calculation unit 104 may be replaced with the block diagram shown in FIG.
That is, in FIG. 11, 50% of the torque command is calculated as the initial value of the target torque of each inverter in step S20. In step S21, the temperature difference of each inverter is calculated, and in step S22, the weight coefficient K is multiplied to convert it into a correction torque. The correction torque is added and subtracted from the initial value of the target torque in steps S23 and S24, respectively, to obtain the target torque of each inverter.
Each step may be a calculation unit.

  According to this configuration, since the inverter temperatures are always substantially equal, it can be expected that the lifetimes of both inverters will be approximately the same, and the lifetime when an inverter failure occurs due to deterioration of the power module can be maximized.

  The synchronous / asynchronous / phase difference calculation unit 100 shown in FIG. 6 receives the temperature detection signals from the temperature sensors 91 and 92 and the rotation speed from the rotation speed calculation unit 102. The synchronous / asynchronous / phase difference calculation unit 100 calculates switching between synchronous PWM control and asynchronous PWM control based on the temperature detection signals of the temperature sensors 91 and 92 and the rotation speed.

  Whether to perform synchronous PWM or asynchronous PWM is determined based on the inverter internal temperature detected by the temperature sensors 91 and 92, as shown in FIG. That is, when the internal temperature of the inverter 14 <threshold and the internal temperature of the inverter 34 <threshold and the rotational speed <threshold, the asynchronous PWM is selected, and in other cases, the synchronous PWM is selected.

  The inverter drive signal generator 114 shown in FIG. 6 generates a signal for driving the SiC-MOSFET elements of the inverters 14 and 34. This inverter drive signal generation unit 114 inputs a synchronization / asynchronous switching signal output from the synchronous / asynchronous / phase difference calculation unit 100, a phase difference signal, and a sine wave based on the voltage command generated by the voltage command calculation unit 108. Switching between synchronous PWM and asynchronous PWM based on the synchronous / asynchronous switching signal, comparing the triangular wave of the carrier frequency with the sine wave generated by the voltage command calculation unit 108, and outputting the waveform that is synchronous PWM or asynchronous PWM To do. An inverter drive signal is provided to the inverter 14 from the control unit 120, and an inverter drive signal is provided to the inverter 34 from the control unit 121.

Further, when both of the abnormality detection signals from the inverters 14 and 34 are enabled, the inverter drive signal generator 114 outputs a signal for stopping the switching operation of the inverter in the abnormal state. If both inverters 14 and 34 are in an abnormal state, both stop the switching operation. At the same time, an abnormality detection signal is sent to the host ECU 11.

  In the synchronous PWM control, the carrier frequency fc cannot be freely determined with respect to the vehicle speed proportional to the motor rotation speed. However, the controllability of current is better with synchronous PWM control than with asynchronous PWM control, and the number of pulses can be reduced.

Although the fundamental frequency is high in the low torque / high speed rotation region, in the vehicle of the first embodiment described above, good controllability and quietness can be obtained by using the SiC-MOSFET and increasing the carrier frequency. Can do.
Thus, in the vehicle of the first embodiment, it is possible to increase the power conversion efficiency of the motor drive device, maintain controllability in a high rotation range, and suppress noise.

  Further, even when there is an abnormality in a part of the inverter, the traveling can be continued only with the inverter having no abnormality. When the traveling continuation function is not required when there is an abnormality, the switching units SRV14, SRW14, SRV34, and SRW34 are unnecessary, and the determinations of S2 and S4 are also unnecessary. That is, if an abnormality occurs in S1, both inverters are stopped in S3, and an error detection signal is output in S5. In this way, it is possible to obtain the effects of maintaining controllability and noise suppression only in the high rotation range.

  In addition, SiC-MOSFET elements do not need to take into account variations in current between chips as compared to those used in multi-parallel connection, and the capacity of the radiator can be reduced, so that the radiator can be downsized. Further, since the current ripple of the capacitor is also reduced, the capacitor can be reduced in size.

  In general, since the volume of these radiators and capacitors occupies most of the volume of the motor drive device, even with the distributed inverter method, the power conversion efficiency is improved while avoiding the increase in size of the motor drive device, and in the high rotation range. Controllability and noise suppression are possible.

  In the above description, the SiC semiconductor element has been described. However, the present invention can be applied to a wide band gap semiconductor material including the SiC semiconductor element. The manufacturing technology of this wide band gap semiconductor material is under development like the SiC semiconductor element, and it is difficult to produce a chip having a large size with a high yield. Therefore, the inverter is configured by paralleling multiple small-sized chips in order to reduce the defect density in the chips.

  In the embodiment shown in FIG. 5, the number of parallelization is 2, but it goes without saying that the number of parallelization is not limited to this.

  In the first embodiment, the power switching element made of the SiC semiconductor element is shown. However, the power switching element may be made of, for example, a gallium nitride material or diamond.

  DESCRIPTION OF SYMBOLS 1 Motor drive device, 10 Battery, 11 High-order ECU, 12 Capacitor, 14, 34 Inverter, 15-17, 35-37 Leg, 20 Control device, 24 Resolver, 91, 92 Temperature sensor, Q1-Q6, Q12, Q22, Q32, Q42, Q52, Q62 SiC-MOSFET, D1-D6, D12, D22, D32, D42, D52, D62 Diode, SV14, SW14, SV34, SW34 Current sensor, SRV14, SRW14, SRV34, SRW34 Switching unit, 100 synchronization / Asynchronous / phase difference calculation unit, 102 rotational speed calculation unit, 104 torque distribution calculation unit, 106 current command calculation unit, 108 voltage command calculation unit, 114 inverter drive signal generation unit.

Claims (11)

In the manufacturing method of the motor drive device that drives and controls the motor using an inverter in which the switching element of each arm is a chip of a wide gap semiconductor element ,
The number corresponding to the parallel number of the case where the arm is assumed to have parallel the chip to withstand the current capacity required for the inverter provided with the inverter,
Manufacturing method of a motor drive device you multiplexes three-phase windings of the motor corresponding to the number of the inverter. The method for manufacturing a motor driving device according to claim 1, wherein the switching element is configured by a single chip. The method for manufacturing a motor driving device according to claim 1, wherein the wide band gap semiconductor element is a semiconductor element using silicon carbide. The method of manufacturing a motor driving device according to claim 3, wherein the semiconductor element using silicon carbide is a unipolar element. The method for manufacturing a motor driving device according to claim 4, wherein the unipolar element is a MOSFET. The method for manufacturing a motor drive device according to claim 1, wherein a withstand voltage of the switching element is 600 V or more. A temperature sensor for detecting the temperature of the inverter;
The motor drive device manufacturing method according to claim 1, further comprising: a control device that receives a command torque from a host ECU and distributes the command torque to the torque of each inverter according to the temperature of the inverter. The inverter has a first inverter and a second inverter corresponding to the parallelization number,
The method for manufacturing a motor driving device according to claim 7, wherein the control device performs torque distribution so that temperatures of the first and second inverters are substantially equal. The motor drive according to claim 8, wherein the control device performs the following four processes when a value obtained by subtracting the target torque of the first inverter and the target torque of the second inverter from the command torque is positive. Device manufacturing method .
(1) when said temperature of the first and second inverters is below together first threshold value, said first and both predetermined variation by increasing or to a target torque of the second inverter.
(2) When the temperature of the first inverter is lower than the first threshold and the temperature of the second inverter is equal to or higher than the first threshold, the target torque of the first inverter is set in advance. Increase by the set change.
(3) The target torque of the second inverter 2 when the temperature of the first inverter is equal to or higher than the first threshold and the temperature of the second inverter is lower than the first threshold. Is increased by a preset change.
(4) When the temperatures of the first and second inverters are both equal to or higher than the first threshold value, the target torques of the first and second inverters are not changed. 9. The motor drive according to claim 8, wherein the control device performs the following four processes when a value obtained by subtracting the target torque of the first inverter and the target torque of the second inverter from the command torque is negative. Device manufacturing method .
(1) When both the temperatures of the first and second inverters are below the second threshold, both target torques of the first and second inverters are reduced by an absolute value of a preset change.
(2) When the temperature of the first inverter is lower than the second threshold and the temperature of the second inverter is equal to or higher than the second threshold, a target torque of the second inverter is set in advance. Decrease by the absolute value of the change made.
(3) When the temperature of the first inverter is equal to or higher than the second threshold and the temperature of the second inverter is lower than the second threshold, the target torque of the first inverter is reduced. Decrease by the absolute value of the preset change.
(4) When the temperatures of the first and second inverters are both equal to or higher than the second threshold value, the target torques of the first and second inverters are both reduced by an absolute value of a preset change. The control device obtains a correction torque by multiplying a value obtained by subtracting the temperature of the second inverter from the temperature of the first inverter to obtain a correction torque, and sets the target torque of the first inverter to 50% of the command torque. The method for manufacturing a motor drive device according to claim 8, wherein a value obtained by subtracting the correction torque from a value is used, and a target torque of the second inverter is a value obtained by adding the correction torque to a value of 50% of the command torque.

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