JP2010178582A - Vehicular power conversion apparatus and electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable vehicular power conversion apparatus capable of driving an inverter circuit without being limited by a drop in withstand voltage at a low temperature in a drive mode. <P>SOLUTION: The vehicular power conversion apparatus includes an inverter circuit 144 for driving a rotary electric machine by providing a semiconductor switching device for an upper arm and a semiconductor switching device for a lower arm for each phase and a control circuit 172 for controlling the inverter circuit 144 by selecting either one of a drive mode for performing a switching operation based on a torque command by applying a first voltage Vb to between the upper and lower arms and a warming-up mode for performing a switching operation by applying a second voltage Vc lower than the first voltage Vb to between the upper and lower arms. When a vehicle start signal is input, the inverter circuit 144 is controlled in a warming-up mode to warm up IGBT328, 330. As a result, excessive withstand voltage in the drive mode is prevented, thus attaining high reliability. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle power converter and an electric vehicle including the vehicle power converter.

  2. Description of the Related Art A power supply device that supplies power to a switching element is known that reduces a power supply voltage that is supplied when the temperature of the switching element is low, and prevents a breakdown voltage from being exceeded due to generation of a surge at low temperature (for example, Patent Document 1). reference).

JP 2007-143293 A

  However, when the voltage is set to be low in this way, there is a problem that a situation occurs in which the output is restricted during vehicle operation.

According to a first aspect of the present invention, there is provided a vehicular power conversion device including an upper arm semiconductor switching element and a lower arm semiconductor switching element for each phase, and an inverter circuit for driving a rotating electrical machine and a first voltage between upper and lower arms. Select one of the drive mode to perform the switching operation during running and the warm-up mode to perform the switching operation by applying a second voltage lower than the first voltage between the upper and lower arms. And a control device that controls the inverter circuit. The control device controls the inverter circuit in a warm-up mode when a vehicle start signal is input.
According to a second aspect of the present invention, there is provided a vehicular power conversion device including an inverter circuit for driving a rotating electrical machine provided with an upper arm semiconductor switching element and a lower arm semiconductor switching element for each phase, and a driving mode for performing a switching operation during traveling. And a control device that controls the inverter circuit by selecting one of the warm-up mode in which the switching operation is performed by setting the turn-on period and the turn-off period of the semiconductor switching element to be longer than those in the drive mode The apparatus is characterized by controlling the inverter circuit in a warm-up mode when a vehicle activation signal is input.
According to a third aspect of the present invention, there is provided a vehicular power conversion device including an inverter circuit for driving a rotating electrical machine provided with an upper arm semiconductor switching element and a lower arm semiconductor switching element for each phase, and a driving mode for performing a switching operation during traveling. And a control device for controlling the inverter circuit by selecting any one of the warm-up mode in which the switching operation from the turn-on to the next turn-on of the semiconductor switching element is set shorter than that in the drive mode and the switching operation is performed. The control device controls the inverter circuit in a warm-up mode when a vehicle start signal is input.
An electrically powered vehicle according to a twelfth aspect of the invention includes a vehicular power converter according to any one of the first to eleventh aspects, a rotating electrical machine that is driven and controlled by the vehicular power converter, and information from the controller. And a notification device for notifying the passenger that the warm-up mode is being executed.

  According to the present invention, when the start signal is input, the temperature of the semiconductor switching element is raised in advance in the warm-up mode, so that it is possible to drive the inverter circuit without being limited to a reduction in withstand voltage at low temperatures in the drive mode. Reliability can be improved.

It is a figure which shows the control block of a hybrid vehicle. It is a figure explaining the electric circuit structure of an inverter apparatus. It is a figure which shows the waveform of the collector current ic at the time of switching, and the collector-emitter voltage Vce. It is a figure which shows the relationship between withstand voltage and temperature in IGBT. 3 is a flowchart for explaining a control operation of a control circuit 172. It is a time chart which shows operation | movement of each circuit in warm-up mode. It is a flowchart which shows the 1st modification of warm-up mode operation | movement. It is a flowchart which shows the 2nd modification of warm-up mode operation | movement. It is a flowchart which shows the 3rd modification of warm-up mode operation | movement. It is a figure explaining shortening of warming-up time by lengthening a switching period, increasing loss, and heat_generation | fever increase. It is a figure explaining shortening of warm-up time by shortening of a switching period. It is a figure which shows the structure in the case of warming up using the low voltage power supply different from a battery.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The vehicle power conversion device according to the embodiment of the present invention is applicable to an electric vehicle such as a hybrid vehicle or a pure electric vehicle. Here, as a representative example, a control configuration and a circuit configuration of the power conversion device when the vehicle power conversion device according to the embodiment of the present invention is applied to a hybrid vehicle will be described with reference to FIGS. 1 and 2.

  In the vehicle power conversion device according to the embodiment of the present invention, a vehicle drive inverter device having a very severe mounting environment and operational environment will be described as an example. A vehicle drive inverter device is provided in a vehicle drive electrical system as a control device for controlling the drive of a vehicle drive motor, and a DC power supplied from an in-vehicle battery or an in-vehicle power generator constituting an in-vehicle power source is a predetermined AC power. Then, the AC power obtained is supplied to the vehicle drive motor to control the drive of the vehicle drive motor. Further, since the vehicle drive motor also has a function as a generator, the vehicle drive inverter device also has a function of converting AC power generated by the vehicle drive motor into DC power according to the operation mode. ing. The converted DC power is supplied to the on-vehicle battery.

  FIG. 1 is a diagram showing a control block of a hybrid vehicle. In FIG. 1, a hybrid electric vehicle (hereinafter referred to as “HEV”) 110 is a kind of electric vehicle, and includes two vehicle drive systems. One of them is an engine system that uses an engine 120 that is an internal combustion engine as a power source. The engine system is mainly used as a drive source for HEV 110. The other is an in-vehicle electric system using motor generators 192 and 194 as a power source. The in-vehicle electric system is mainly used as a drive source for HEV 110 and a power generation source for HEV 110. The motor generators 192 and 194 are, for example, synchronous machines or induction machines, and operate as both a motor and a generator depending on the operation method.

  Motor generators 192 and 194 are synchronous machines having rotors with permanent magnets. The AC power supplied to the armature windings of the stator is controlled by the inverter devices 140 and 142, whereby the driving of the motor generators 192 and 194 is controlled. A battery 136 is connected to the inverter devices 140 and 142, and power can be exchanged between the battery 136 and the inverter devices 140 and 142. Here, direct-current power is directly input from the battery 136 to the inverter devices 140 and 142, but the present invention can be similarly applied to a configuration in which direct-current power is supplied via a relay unit or a converter.

  In the present embodiment, the HEV 110 includes two parts, a first motor generator unit composed of a motor generator 192 and an inverter device 140, and a second motor generator unit composed of a motor generator 194 and an inverter device 142, depending on the operating state. I use them properly. That is, in the situation where the vehicle is driven by the power from the engine 120, when assisting the driving torque of the vehicle, the second motor generator unit is operated by the power of the engine 120 as a power generation unit to generate power, and the power generation The first motor generator unit is operated as an electric unit by the electric power obtained by the above. Further, when assisting the vehicle speed in the same situation, the first motor generator unit is operated by the power of the engine 120 as a power generation unit to generate power, and the second motor generator unit is generated by the electric power obtained by the power generation. Operate as an electric unit.

  In the present embodiment, the vehicle can be driven only by the power of the motor generator 192 by operating the first motor generator unit as an electric unit by the electric power of the battery 136. Furthermore, in this embodiment, the battery 136 can be charged by operating the first motor generator unit or the second motor generator unit as a power generation unit by the power of the engine 120 or the power from the wheels to generate power.

  The battery 136 is also used as a power source for driving an auxiliary motor 195. Examples of the auxiliary machine include a motor that drives a compressor of an air conditioner, a motor that drives a hydraulic pump for control, and a motor that drives a refrigerant circulation pump of a cooling system of a power converter. In the present embodiment, the motor 195 drives the refrigerant circulation pump 196. The DC power supplied from the battery 136 to the inverter device 43 is converted into AC power by the inverter device 43 and supplied to the motor 195.

  The inverter device 43 has the same function as the inverter devices 140 and 142 and controls the phase, frequency, and power of alternating current supplied to the motor 195. For example, the motor 195 generates torque by supplying AC power having a leading phase with respect to the rotation of the rotor of the motor 195. On the other hand, by generating the delayed phase AC power, the motor 195 acts as a generator, and the motor 195 is operated in a regenerative braking state. The control function of the inverter device 43 is the same as the control function of the inverter devices 140 and 142. Since the capacity of the motor 195 is smaller than the capacity of the motor generators 192 and 194, the maximum conversion power of the inverter device 43 is smaller than the inverter devices 140 and 142, but the circuit configuration of the inverter device 43 is basically the circuit of the inverter devices 140 and 142. Same as the configuration.

  Next, the electric circuit configuration of the inverter devices 140 and 142 or the inverter device 43 will be described with reference to FIG. In the embodiment illustrated in FIGS. 1 to 2, the case where the inverter devices 140 and 142 or the inverter device 43 are individually configured will be described as an example. The inverter devices 140, 142, and 43 have the same configuration, operation, and function. Here, the inverter device 140 will be described as a representative example.

  As shown in FIG. 2, the power conversion device 200 includes an inverter device 140 and a capacitor module 500. The inverter device 140 includes an inverter circuit 144, a driver circuit 174 that drives and controls the inverter circuit 144, and a control circuit 172 that supplies a control signal to the driver circuit 174 through the signal line 176. Vehicle information is input to the control circuit 172 from a host controller (for example, a vehicle controller) 2 provided on the vehicle side. The vehicle information includes an ING signal indicating the on / off state of the ignition switch, a torque command τ for driving and controlling the generator motor 192, and outside air temperature information.

  The inverter circuit 144 is configured by a three-phase bridge circuit, and corresponds to the U-phase, V-phase, and W-phase, and the upper arm side semiconductor switch units Up, Vp, Wp and the lower arm side semiconductor switch units Un, Vn, Wn. It has. Each of the upper arm side semiconductor switch units Up to Wp is provided with an IGBT 328 (insulated gate bipolar transistor) and a diode 156, and each of the lower arm side semiconductor switch units Un to Wn is provided with an IGBT 330 and a diode 166. An AC power line (AC bus bar) 186 to the motor generator 192 is connected to a middle point portion between the upper and lower arms. AC power line 186 is electrically connected to a corresponding phase winding of the armature winding of motor generator 192 via AC connector 188.

  IGBTs 328 and 330 provided on the upper and lower arms are switching power semiconductor elements, operate in response to a drive signal output from the driver circuit 174, and convert DC power supplied from the battery 136 into three-phase AC power. The converted electric power is supplied to the armature winding of the motor generator 192, and the rotation of the motor generator 192 is controlled by controlling the generated rotating magnetic field. As described above, the inverter device 140 can also convert the three-phase AC power generated by the motor generator 192 into DC power.

  Either a bipolar type or a field effect type may be applied as the power semiconductor element for switching. In the present embodiment, an IGBT will be described as an example. Diodes 156 and 166 are electrically connected between the collector electrodes and emitter electrodes of the IGBTs 328 and 330 as shown in the figure. The diodes 156 and 166 have two electrodes, a cathode electrode and an anode electrode, and the cathode electrode serves as the collector electrode of the IGBTs 328 and 330 so that the direction from the emitter electrode to the collector electrode of the IGBTs 328 and 330 is the forward direction. The anode electrodes are electrically connected to the emitter electrodes of the IGBTs 328 and 330, respectively.

  When a MOSFET (metal oxide semiconductor field effect transistor) is used as the switching power semiconductor element, the direction from the drain electrode to the source electrode is the forward direction between the source electrode and the drain electrode. Since the parasitic diode is provided, it is not necessary to provide a separate diode (diode 156 or diode 166) unlike the IGBT.

  The semiconductor switch units Up to Wp and Un to Wn of the upper and lower arms of each phase are connected in series for each phase, and the upper and lower arm series circuits of each phase are connected to the P (Positive) line and the N (Negative) line of the battery 136. Are connected in parallel. The collector electrodes of the IGBTs 328 of the upper arm side semiconductor switch units Up to Wp are respectively connected to the positive electrode of the capacitor module 500 via the P line. On the other hand, the emitter electrodes of the IGBTs 330 of the lower arm side semiconductor switch units Un to Wn are connected to the negative electrode of the capacitor module 500 via N lines, respectively. Capacitor module 500 forms a smoothing circuit that suppresses fluctuations in DC voltage caused by the switching operation of IGBTs 328 and 330.

  The P line between the capacitor module 500 and the battery 136 is provided in parallel with a main relay 61, a sub relay 63 and a charging resistor 64 connected in series, and an N line between the capacitor module 500 and the battery 136. Is provided with a main relay 62. These relays 61 to 63 are turned on / off based on a control signal from the control circuit 172. The main relays 61 and 62 function as a safety device that connects and disconnects between the inverter circuit 144 and the capacitor module 500 and the battery 136. When the vehicle travels, the main relays 61 and 62 are controlled to be on. The sub-relay 63 and the charging resistor 64 are provided to perform a precharging operation of the capacitor module 500, and the inrush current when the battery 136 and the capacitor module 500 are connected is determined by the precharging operation (precharging). I try to relax. The preliminary charging operation will be described later.

  The control circuit 172 is based on input information such as a torque command τ from the host controller 2, a motor current value detected by the current sensor 180, a detected temperature from the temperature sensor 60 provided in the inverter circuit 144, and the like. , 330 generates a timing signal for controlling the switching timing. Based on the timing signal output from the control circuit 172, the driver circuit 174 generates a drive signal for switching the IGBTs 328 and 330.

  The control circuit 172 includes a microcomputer (hereinafter referred to as “microcomputer”) for calculating the switching timing of the IGBTs 328 and 330. The microcomputer receives as input information a target torque value required for the motor generator 192, a current value supplied to the armature winding of the motor generator 192 from the upper and lower arm series circuit 150, and a magnetic pole of the rotor of the motor generator 192. The position is entered. The target torque value is based on the torque command τ output from the host controller 2. The current value is detected based on the detection signal output from the current sensor 180. The magnetic pole position θ is detected by a rotating magnetic pole sensor 65 provided in the motor generator 192. In the present embodiment, the case where the current values of three phases are detected will be described as an example, but the current values for two phases may be detected.

  The microcomputer in the control circuit 172 calculates the d and q axis current command values of the motor generator 192 based on the target torque value, and the calculated d and q axis current command values and the detected d and q The voltage command values for the d and q axes are calculated based on the difference from the current value of the shaft, and the calculated voltage command values for the d and q axes are calculated based on the detected magnetic pole position. Convert to W phase voltage command value. Then, the microcomputer generates a pulse-like modulated wave based on a comparison between the fundamental wave (sine wave) and the carrier wave (triangular wave) based on the voltage command values of the U phase, V phase, and W phase, and the generated modulation wave The wave is output to the driver circuit 174 as a PWM (pulse width modulation) signal.

  When driving the lower arm, the driver circuit 174 amplifies the PWM signal and outputs it as a drive signal to the gate electrode of the IGBT 330 of the lower arm. On the other hand, when driving the upper arm, the PWM signal is amplified after shifting the level of the reference potential of the PWM signal to the level of the reference potential of the upper arm, and this is used as a drive signal to the gate electrode of the IGBT 328 of the upper arm. Output. As a result, each IGBT 328, 330 performs a switching operation based on the input drive signal. The switching operation switches on and off the IGBTs 328 and 330 of the upper and lower arms of the inverter circuit 144 in a certain order, and the current of the stator winding of the motor generator 192 at the time of switching is a circuit formed by the diodes 156 and 166. Flowing.

  By the way, in the switching circuit, a surge voltage due to the wiring inductance is generated at the time of switching. FIG. 3 shows waveforms (collector current ic and collector-emitter voltage Vce) during switching of a general semiconductor device. The period during which the semiconductor element is turned on is ton, the period during which the semiconductor element is turned off is toff, and the repetition period is ST. The jump of the voltage Vce due to the surge voltage occurs mainly during the off transition period toff, and the maximum voltage of the collector-emitter voltage Vce becomes Vcep. When using a switching element, it is necessary to keep this maximum voltage Vcep smaller than the withstand voltage of the element.

  On the other hand, the breakdown voltage of the switching element (IGBT) depends on the element temperature, and decreases as the element temperature decreases, as shown in FIG. For example, if the breakdown voltage at a temperature of 25 ° C. is 1, the breakdown voltage is reduced to 0.9 at −40 ° C. Therefore, when the vehicle is driven in a low temperature state where the withstand voltage is low, the maximum voltage at the time of switching off may exceed the withstand voltage due to the generation of a surge voltage. Therefore, in this embodiment, as will be described below, the element temperature is increased by performing the warm-up mode in advance to increase the breakdown voltage of the element, and then the motor drive mode is entered.

  FIG. 5 is a flowchart for explaining the control operation of inverter devices 140, 142, and 43 in the present embodiment, and FIG. 6 is a time chart showing the operation of each circuit in the warm-up mode. The program shown in the flowchart of FIG. 5 is executed by the microcomputer of the control circuit 172. When the ignition switch of the vehicle is turned on and the IGN on signal is input from the host controller 2 to the control circuit 172, the process shown in FIG. 5 starts.

(Step S90)
In step S90 of FIG. 5, it is determined whether or not the junction temperature Tj is higher than the threshold value Tth. Actually, since the junction temperature cannot be directly measured, whether or not the detected temperature T of the temperature sensor 60 provided in the vicinity of the IGBT is higher than the temperature T (Tth) corresponding to the temperature Tth at the junction. Determine. If it is determined in step S90 that Tj ≦ Tth, precharge processing is performed in step S100, and warm-up driving is performed in subsequent step S110. That is, the warm-up operation mode is continued until it is determined in step S90 that Tj> Tth. If it is determined in step S90 that Tj> Tth, the warm-up operation mode is terminated and the process proceeds to step S150.

(Step S100)
In step S100 of FIG. 5, by turning on the main relay 62 and the sub relay 63, a precharge process for charging the capacitor module 500 to the voltage Vc is performed. This voltage Vc is set lower than the power supply voltage Vb so that the voltage jump due to the surge voltage at the time of switching does not exceed the withstand voltage of the element. For example, when Vb = 400V, Vc is set to about 200V. At this time, since the capacitor module 500 is charged through the charging resistor 64, it is possible to prevent a large inrush current from flowing. When the voltage of the capacitor module 500 detected by the voltage sensor 66 becomes Vc, the main relay 62 and the sub relay 63 are turned off, and the precharge process is completed. A time tc shown in FIG. 6 indicates a precharge operation time.

(Step S110)
In step S110 of FIG. 5, the inverter circuit 144 is warmed up to increase the temperature of the IGBTs 328 and 330. In the warm-up driving, the electric charge stored in the capacitor module 500 is discharged by the switching operation, and the semiconductor element is warmed up by heat generated at that time. For this reason, the voltage between the PN lines is equal to or lower than the voltage Vc between the terminals of the capacitor module 500, and even when the element temperature is low and the withstand voltage is reduced, the surge of voltage due to the surge voltage exceeds the withstand voltage. Can be prevented. During the switching operation, heat is generated due to loss (steady loss + turn-on loss + turn-off loss). As a result, the temperatures of the IGBTs 328 and 330 rise. In this way, the element temperature is raised by performing warm-up driving. In the warm-up drive, the inverter is configured so that the q-axis current, which is a torque component current, is zero and only the d-axis current (excitation current) is supplied so that the motor generator 192 does not rotate, that is, torque is not generated. The switching operation of the circuit 144 is controlled.

  Normally, when driving the motor generator 192, the control circuit 172 is based on the magnetic pole position θ detected by the rotating magnetic pole sensor 65, the motor current value detected by the current sensor 180, and the torque command τ from the host controller 2. The inverter circuit 144 is controlled by known vector control. In the vector control, the primary current is divided into an excitation current (d-axis current) for generating magnetic flux and a torque current (q-axis current) for generating motor torque and individually controlled. It is.

  When an excitation current (d-axis current) is supplied to the motor generator 192 and a torque current (q-axis current) is supplied, the motor generator 192 generates torque and rotates. Therefore, if the torque component current (q-axis current) is set to zero and only the excitation component current (d-axis current) is controlled to flow, no torque is generated in the motor generator 192. The control circuit 172 performs two-phase three-phase conversion from a current command value (d-axis current, q-axis current = 0) to a current command value (U-phase current, V-phase current, W-phase current), and the driver circuit 174 The inverter circuit 144 performs a switching operation based on the current command values (U-phase current, V-phase current, W-phase current). Since the q-axis current is zero, the currents iu, iv, iw supplied to the motor generator 192 correspond to the d-axis current.

  As described above, the control circuit 172 controls the inverter circuit 144 so as to prohibit traveling in the warm-up mode. Conversely, during traveling, that is, when a torque signal of τ ≠ 0 is input from the host controller 2, execution of the warm-up mode is prohibited.

  As shown in FIG. 6, the electric charge of the capacitor module 500 is discharged by this warm-up drive, and when the warm-up drive time tn elapses, the voltage of the capacitor module 500 becomes zero and the warm-up drive is temporarily stopped. As the warm-up drive stop timing, the time tn may be determined in advance, and may be stopped when the time tn has elapsed from the start of the warm-up drive, or the voltage detected by the voltage sensor 66 becomes substantially zero. You may make it stop at the time. Further, during warm-up driving, the junction temperature T of the semiconductor elements (IGBTs 328 and 330) rises from the low temperature state Tj0 to the temperature Tj1 due to heat generated by the switching operation. When the warm-up driving is stopped once the time tn has elapsed, heat escapes from the semiconductor element to the metal base 304 and the cooling water, so that the junction temperature Tj starts to decrease.

  In the present embodiment, in consideration of such a temperature drop due to heat dissipation, the warm-up mode is terminated if the junction temperature Tj at the time when the pause time ta has elapsed after the warm-up driving is stopped exceeds the threshold Tth. To do. Since the withstand voltage of the IGBT has temperature dependence as shown in FIG. 8, the withstand voltage also rises due to the temperature rise by warm-up driving as shown in FIG. The threshold value Tth is set to a temperature at which the voltage jump when the switching operation is performed with the power supply voltage Vd does not exceed the withstand voltage.

  As described above, the power module 300 is configured to directly cool the metal base 304 with the cooling water so that heat at the time of the switching operation is efficiently radiated. Therefore, it is necessary to consider the temperature drop due to heat radiation by providing the above-described pause time ta. However, in the case of the structure in which the cooling water is directly cooled as in the present embodiment, the refrigerant circulation pump 196 (see FIG. 1) is stopped in the warm-up mode, and the cooling water does not flow. Compared with the case where the metal base 304 is fixed to the surface of the metal cooling jacket, heat radiation is reduced. Therefore, the downtime ta can be shortened compared with the conventional structure, and the warm-up time can be shortened.

(Step S150)
In step S150, the process shifts to a normal motor drive mode. That is, the main relay 62 and the sub-relay 63 are turned on to precharge the capacitor module 500 to the voltage Vb, and then the sub-relay 63 is turned off and then the main relay 61 is turned on to connect the battery 136 and the inverter circuit 144. The switching operation of the inverter circuit 144 based on vehicle information such as a command is started.

  The flowchart shown in FIG. 7 shows a first modification of the warm-up mode operation shown in FIG. In the first modified example, instead of determining the end of the warm-up mode by comparing the junction temperature Tj and the threshold temperature Tth, the control circuit 172 is provided with a counter for counting the number of times of the warm-up drive. When the number N reaches the preset number N0, the warm-up mode is terminated (step S200). The predetermined number N0 is set to the number of times necessary for the junction temperature Tj to increase from -40 ° C to Tth if the assumed use environment is -40 ° C to 125 ° C, for example.

FIG. 8 is a diagram showing a second modification.
(Step S300)
In step 300, it is determined whether the warm-up mode is necessary based on the input temperature information. If it is determined in step S300 that warm-up is necessary (yes), the process proceeds to step S100. If it is determined that warm-up is not required, the process proceeds to step S130. The temperature information here may be information detected by the temperature sensor 60, but may also be motor temperature information from a temperature sensor provided in the motor generator 192, outside air temperature information from the vehicle side, or the like.

  In a state where the vehicle is stopped for a long time, it is considered that the entire vehicle is substantially the same as the outside air temperature, and therefore the motor temperature and the outside air temperature can be used instead of the junction temperature Tj. Further, when the ignition is turned on immediately after the vehicle is stopped, the motor temperature is higher than the normal temperature, and the temperature of the power module 300 is not so lowered from the running state. Therefore, whether or not the warm-up mode is necessary can be determined based on the motor temperature.

  As a situation in which it is determined in step S300 that the warm-up is unnecessary, for example, there is a case where the ignition is turned off once after the vehicle travels, and then the ignition is turned on for a short time. In that case, it is considered that the temperature drop of the junction temperature Tj is small and larger than the threshold value Tth. In the modified example 2, since the warm-up mode is omitted in such a case, there is an advantage that the vehicle can be started quickly.

  FIG. 9 is a diagram showing a third modification. In this case as well, it is determined in step S400 whether or not the warm-up mode is necessary based on the temperature information. If the warm-up mode has been entered, it is determined in step S410 whether or not the number N of warm-up driving has reached the predetermined number N0. If the number N has reached the predetermined number N0, the warm-up mode is terminated. . That is, the warm-up driving is performed a predetermined number of times N0 and the warm-up mode is terminated.

  In step S90 of FIG. 5, it is determined whether or not to end the warm-up mode depending on whether or not the junction temperature Tj after the suspension time ta has elapsed since the warm-up driving stop is greater than the threshold value Tt. The end of the warm-up mode may be determined based on the temperature change (temperature gradient) during the warm-up drive. That is, when the temperature gradient is larger than the predetermined value, the warm-up mode is continued, and when the temperature gradient becomes equal to or less than the predetermined value, the warm-up mode is terminated and the motor drive mode is entered.

  In the above-described embodiment, the warm-up mode is executed only immediately after the ignition-on operation is performed. However, even after entering the motor drive mode, the vehicle is stopped and the junction temperature Tj is lower than Tth. In this case, the warm-up mode may be executed. For example, in a low-temperature environment, when the vehicle is stopped (IGN is on) and the motor stop state is measured after traveling for a short time, the junction temperature Tj may be lower than Tth when the next attempt is made. Arise. In such a case, the warm-up mode is executed based on the temperature T detected by the temperature sensor 60.

  In the above-described embodiment, the switching is controlled so that the torque component current (q-axis current) becomes zero in the warm-up mode so that the vehicle travel is prohibited. Other methods may be used. For example, the current at the time of warm-up driving is not sent to the motor generator 192, but the semiconductor between the upper arm side semiconductor switch unit Up and the upper arm side semiconductor switch unit Un as shown by currents icup and icun in FIG. A current may be passed through the element. In this case, all the semiconductor switch units Up to Wp and Un to Wn are warmed up by flowing (icup, icun), (iccvp, icvn), (icwp, icwn) in the order of U, V, and W. To do.

  Moreover, you may make it flow an electric current with the torque of the grade which does not start a vehicle. For example, forward rotation and reverse rotation are repeatedly performed depending on whether the phase moves or not.

  In the case of a vehicle in which a clutch is provided between the transmission 118 and the motor generator 192 in FIG. 1, the input shaft of the transmission 118 and the output shaft of the motor generator 192 are separated by this clutch in the warm-up mode. Thus, the vehicle travel is prohibited. In this case, when the warm-up mode is entered when the ignition is on, a travel inhibition signal is input from the control circuit 172 to the host controller 2 on the vehicle side, and the host controller 2 receives the input shaft of the transmission 118 and the output shaft of the motor generator 192. The clutch is controlled so that is disconnected. When the warm-up mode ends, the travel prohibition signal is canceled.

  As described above, during the warm-up mode, traveling by motor driving is prohibited, so it is better that the time required for the warm-up mode is short. FIG. 10 is a diagram showing voltage / current waveforms in a case where the loss is increased by increasing the switching periods ton and toff, and the warm-up time is shortened due to increased heat generation. In the switching operation shown in FIG. 10, the switching repetition cycle ST is the same as that in the normal switching operation shown in FIG. 3 (for example, in the motor drive mode). The length of toffw was set longer than ton and toff in the case of FIG. As a result, the number of times of warm-up driving can be reduced due to increased heat generation, and the motor drive mode can be entered more quickly.

  As described above, by smoothing the switching operation during the transition periods ton and toff, it is possible to increase the loss that is the product of the current and voltage generated during this period. As a result, the effect of increasing the element temperature can be increased by increasing the loss, and the time required for the warm-up mode can be shortened.

  Further, by smoothing the switching operation, the surge voltage is reduced, and the maximum jumping voltage Vcepw applied to the semiconductor elements (IGBTs 328 and 330) is smaller than Vcep shown in FIG. Even if the capacitor charging voltage Vc in the warm-up mode is set higher by the amount that the jump voltage becomes smaller, the breakdown voltage of the semiconductor element is not exceeded. Setting the voltage Vc large contributes to an increase in heat generation. In this case, warming-up driving may be performed with the voltage Vb if the maximum jumping voltage Vcepw at the time of switching can be suppressed to a withstand voltage or less even when Vc → Vb by smoothing the switching operation.

  FIG. 11 is a diagram illustrating another example related to time reduction in the warm-up mode. In the example shown in FIG. 11, the on-transition period ton and the off-transition period toff have the same length as that shown in FIG. 7, and the repetition cycle STs is shorter than the cycle ST in FIG. In this case, the heat generation (loss) per cycle is almost the same because the steady loss portion is slightly reduced. However, since ST> STs, the time for one warm-up drive is shortened, and the time for the warm-up mode can be shortened.

  In the configuration shown in FIG. 2, warm-up driving is performed using power from the battery 136 even in the warm-up mode. Therefore, during pre-charging, the inter-terminal voltage Vc of the capacitor module 500 is made lower than the battery voltage Vb so that the collector-emitter voltage Vce of the IGBT does not exceed the withstand voltage from the generation of the surge voltage.

  Therefore, in the example shown in FIG. 12, a low-voltage power supply 70 different from the battery 136 is provided, and the warm-up drive is performed by the power of the low-voltage power supply 70 in the warm-up mode. The battery 71 is an auxiliary battery, for example, the terminal voltage is 14V. When used for warm-up driving, the DC / DC converter 72 is used to boost the voltage to a predetermined warm-up driving voltage Vc. In the warm-up mode, relays 61 to 63 are turned off and relay 73 is turned on. When the warm-up mode is completed, the relay 73 is turned off and the mode is shifted to the motor drive mode.

  In the configuration shown in FIG. 2, the charge stored in the capacitor module 500 is discharged by a switching operation to perform warm-up driving, and thus an operation for charging the capacitor module 500 is required. The warm-up drive was repeated. On the other hand, in the configuration of FIG. 12, since the voltage of the low-voltage power supply 70 is as low as Vc, the warm-up drive can be continuously performed, and the warm-up time can be shortened. When determining the end of the warm-up mode based on the temperature of the temperature sensor 60, for example, if the junction temperature Tj estimated from the temperature T exceeds the threshold Tth, the warm-up drive is stopped, and the warm-up drive after precharging is performed. If the temperature change at that time becomes smaller than a predetermined value, the warm-up mode is terminated.

  In FIG. 12, the charging resistance for charging the capacitor module 500 is omitted by keeping Vc low, but a charging resistance may be provided. 74 is a notification device provided on the vehicle side, and this notification device 74 notifies that it is warming up. For example, a liquid crystal display panel may be provided on the instrument panel to serve as the notification device 74, and the driver can easily know that it is warming up by displaying the liquid crystal display device (for example, a mark indicating warming up). Can do. Here, although the notification device 74 is a liquid crystal display device, it may be notified by voice that it is warming up.

As described above, the vehicle power conversion device of the present embodiment has the following operational effects.
(1) The control circuit 172 can select either the motor drive mode or the warm-up mode to control the inverter circuit 144. In the motor drive mode, the control circuit 172 applies the voltage Vb between the upper and lower arms of the inverter circuit 144. In the warm-up mode, a voltage Vc lower than the voltage Vb is applied between the upper and lower arms to perform the switching operation. When an ignition on signal (vehicle activation signal) is input, first, the inverter circuit 144 is controlled in the warm-up mode. As a result, the temperature of the IGBTs 328 and 330 is raised in advance in the warm-up mode, so that a decrease in breakdown voltage due to a low temperature can be prevented, and a voltage in the motor drive mode can be prevented from exceeding the breakdown voltage.
(2) Further, the turn-on period and turn-off period of the IGBTs 328 and 330 in the warm-up mode are set longer than those in the drive mode, and the switching cycle from the turn-on to the next turn-on is set shorter than in the drive mode. Thus, in addition to the warming up of the IGBTs 328 and 330 when the ignition on signal (vehicle start signal) is input, the time required for the warming up mode can be shortened. Furthermore, by setting the voltage between the upper and lower arms in the warm-up mode to a voltage Vc lower than that in the motor drive mode, it is possible to reliably prevent the breakdown voltage from being exceeded in the warm-up mode.
(3) The smoothing capacitor module 500 provided in the inverter device is charged so that the terminal voltage is Vc, and the IGBT 328 and 330 are warmed up by discharging the charge accumulated by the charging by the switching operation. Anyway. Thus, by using the smoothing capacitor conventionally provided for warm-up driving, warm-up can be performed while suppressing an increase in the cost of the apparatus.
(4) In the warm-up mode, by controlling the switching operation of the inverter circuit 144 so that the q-axis current to the motor generator 192 becomes substantially zero, it is possible to reliably prevent the vehicle from starting due to the rotation of the motor generator 192. Can do. Further, instead of setting the q-axis current to almost zero, a switching operation may be performed so that the upper and lower arms are short-circuited.
(5) Further, based on temperature information input to the control circuit 172, for example, the junction temperature, the motor temperature, and the outside air temperature, it is determined whether or not to execute the warm-up mode when the ignition on signal is input. You may do it. By doing so, when the junction temperature Tj of the IGBTs 328 and 330 exceeds the threshold value Tth, an unnecessary warm-up mode is not executed.
(6) When performing the warm-up mode, when the temperature near the element T is detected by the temperature sensor 60 as a temperature correlated with the junction temperature Tj of the IGBTs 328 and 330, and the detected temperature T exceeds the temperature corresponding to the threshold value Tth End the warm-up mode. By doing so, the warm-up mode can be performed for a necessary and sufficient time. Further, the warm-up mode may be terminated if the gradient of temperature change during execution of the warm-up mode becomes smaller than a predetermined value.
(7) By controlling so that the warm-up mode is not executed when a torque command is input from the vehicle side, it is possible to prevent the warm-up mode from being started during traveling.
(8) In the electric vehicle equipped with the vehicle power conversion device that executes the warm-up mode when the ignition switch is turned on as described above, the notification device 74 notifies the occupant that the warm-up mode is being executed. The occupant can automatically recognize that the warm-up mode is being executed, which is useful for grasping the vehicle situation.
(9) By disengaging the clutch on the vehicle side during execution of the warm-up mode, even if the motor generator 192 rotates in the warm-up mode, it is possible to reliably prevent the vehicle from starting to move.

  The above description is merely an example, and the present invention is not limited to the configuration of the above embodiment. For example, in the above-described embodiment, the inverter circuit 144 is described as a three-phase output type. However, the inverter circuit 144 is not limited to three phases, and the upper and lower arms of each phase may be obtained by connecting two units in parallel. Good. Moreover, it is not limited to the electric power converter for a rotary electric machine drive, It can also be utilized for all power converters, such as an inverter and a converter.

  2: host controller, 20: control circuit board, 22: drive circuit board, 43, 140, 142: inverter device, 60: temperature sensor, 61, 62: main relay, 63: sub relay, 64: charging resistance, 70: low voltage Power supply, 71, 136: Battery, 72: DC / DC converter, 73: Relay, 74: Notification device, 144: Inverter circuit, 156, 166: Diode, 172: Control circuit, 174: Driver circuit, 192, 194: Motor Generator, 196: Pump for circulating refrigerant, 200: Power converter for vehicle, 300: Power module, Up to Wp: Upper arm side semiconductor switch unit, Un to Wp: Lower arm side semiconductor switch unit

Claims (13)

An inverter circuit for driving a rotating electrical machine with an upper arm semiconductor switching element and a lower arm semiconductor switching element for each phase;
A driving mode in which a first voltage is applied between the upper and lower arms to perform a switching operation during traveling, and a warm mode in which a second voltage lower than the first voltage is applied between the upper and lower arms to perform a switching operation. A control device for controlling the inverter circuit by selecting any one of the machine modes,
When the vehicle activation signal is input, the control device controls the inverter circuit in the warm-up mode. An inverter circuit for driving a rotating electrical machine with an upper arm semiconductor switching element and a lower arm semiconductor switching element for each phase;
Select one of a drive mode for performing a switching operation during traveling, and a warm-up mode in which a turn-on period and a turn-off period of the semiconductor switching element are set longer than those in the drive mode to perform a switching operation. A control device for controlling the inverter circuit,
When the vehicle activation signal is input, the control device controls the inverter circuit in the warm-up mode. An inverter circuit for driving a rotating electrical machine with an upper arm semiconductor switching element and a lower arm semiconductor switching element for each phase;
One of a drive mode for performing a switching operation during traveling and a warm-up mode for performing a switching operation by setting a switching cycle from the turn-on of the semiconductor switching element to the next turn-on shorter than that in the drive mode. A controller for selecting and controlling the inverter circuit;
When the vehicle activation signal is input, the control device controls the inverter circuit in the warm-up mode. In the vehicle power converter device according to claim 2 or 3,
The control device applies a first voltage between the upper and lower arms in the driving mode, and applies a second voltage lower than the first voltage between the upper and lower arms in the warm-up mode. Vehicle power conversion device. The vehicular power converter according to claim 1 or 4,
A smoothing capacitor connected in parallel with the inverter circuit between the upper and lower arms,
In the warm-up mode, the vehicle power conversion device is characterized in that the terminal voltage of the smoothing capacitor is charged so as to be the second voltage, and the charged charge of the smoothing capacitor is discharged by a switching operation. In the vehicle power converter according to any one of claims 1 to 5,
In the warm-up mode, the control device controls a switching operation of the inverter circuit so that a q-axis current for the rotating electrical machine becomes substantially zero. In the vehicle power converter according to any one of claims 1 to 5,
The control device controls the switching operation of the inverter circuit so that the upper and lower arms are short-circuited. In the vehicular power converter according to any one of claims 1 to 7,
The said control apparatus determines whether to perform the said warming-up mode when a vehicle starting signal is input based on the input temperature information, The vehicle power converter device characterized by the above-mentioned. In the vehicle power converter according to any one of claims 1 to 8,
A temperature detector for detecting a temperature correlated with a junction temperature of the semiconductor switching element;
The vehicle power converter according to claim 1, wherein the control device ends the warm-up mode when the temperature detected by the temperature detector reaches a predetermined temperature. In the vehicle power converter according to any one of claims 1 to 9,
The power conversion device for a vehicle according to claim 1, wherein the control device ends the warm-up mode if a gradient of temperature change becomes smaller than a predetermined value during the switching operation during execution of the warm-up mode. In the vehicle power converter according to any one of claims 1 to 10,
The power conversion device for a vehicle, wherein the control device does not execute the warm-up mode when a torque command is input from the vehicle side. The vehicle power conversion device according to any one of claims 1 to 11,
A rotating electrical machine that is driven and controlled by the vehicle power converter;
An electric vehicle comprising: a notification device for notifying an occupant that the warm-up mode is being executed based on information from the control device. The electric vehicle according to claim 12,
An electric vehicle characterized in that the power from the rotating electrical machine to the axle is cut off during execution of the warm-up mode.

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