JP4096895B2 - High voltage DC power supply circuit for vehicles - Google Patents

Description

  The present invention relates to a high voltage DC power supply circuit for a vehicle. The vehicle high-voltage DC power supply circuit of the present invention is preferably applied to a vehicle (high-voltage DC power supply vehicle) equipped with a high-voltage DC power supply such as a hybrid vehicle or a fuel cell vehicle.

  In conventional hybrid vehicles, for the purpose of reducing wiring loss and downsizing of rotating electrical machines, the driving motor and the generator for charging the high-voltage DC power supply are set as high as possible within the range that the safety and insulation performance of the electrical insulation materials allow. It is expected to drive, and for this reason, the rotating electrical machine is now driven at a very high voltage level exceeding 600V. However, since various problems including safety can be considered in increasing the number of cell series stages of the assembled battery of the high-voltage DC power supply according to this boosting, a battery having a voltage lower than the motor driving voltage such as 200V is connected to the high-voltage DC power supply. Boost converter that is used as a power supply and boosts its output voltage to a very high DC voltage exceeding 600V as required by a boost converter (up converter) and applied to an inverter for three-phase AC voltage conversion for driving a rotating electrical machine. Adopting an inverter circuit system is preferred.

This boost converter / inverter circuit is configured by cascading a boost converter that boosts a battery voltage and an inverter that applies this boost DC voltage to an AC rotating electrical machine as an AC voltage. In a hybrid vehicle, the boost converter is connected to a generator inverter directly connected to the engine and an inverter for a traveling generator motor, and the boost converter is capable of bidirectional power transmission. Patent Document 1 below describes an example of this type of boost converter / inverter circuit.
Japanese Patent Publication No. 8-17597

  Further, a converter smoothing capacitor is connected to a pair of input terminals of a boost converter, an inverter smoothing capacitor is connected to a pair of input terminals of an inverter, and a safety discharge resistance element is connected in parallel to the inverter smoothing capacitor. Has been done. These smoothing capacitors are well-known ripple reducing capacitors. To reduce the switching surge voltage, the converter smoothing capacitor is placed close to the switching element of the boost converter, and the inverter smoothing capacitor is placed as close as possible to the switching element of the inverter. The

  The safety discharge resistance element is used when the safety switch connected in series with the battery is turned off for inspection or repair, or when the power cable between the battery and the boost converter is disconnected in the event of a vehicle collision. When power supply to the circuit is interrupted, the converter smoothing capacitor and the inverter smoothing capacitor are discharged within a predetermined short time (for example, several minutes) to improve electrical safety. That is, the safety discharge resistance element directly discharges the inverter smoothing capacitor and discharges the converter smoothing capacitor through a diode built in the boost converter. As a result, at least two (three when two inverters are used) smoothing capacitors can be discharged simultaneously by one safety discharge resistance element, so that the number of elements can be saved. In particular, since this safety discharge resistance element needs to discharge a large amount of charges in a short time within the allowable temperature rise range, the reduction of the number is beneficial in terms of reduction in the size of the circuit device. Further, since it is not necessary to provide a safety discharge resistance element in parallel with the converter smoothing capacitor, there is an advantage that the voltage of the DC power source is not applied to the safety discharge resistance element without going through the boost converter.

  In the above-described high-voltage DC power supply vehicle such as a hybrid vehicle, the high-voltage DC power supply such as a battery is usually mounted in the lower part of the vehicle compartment or the rear part of the vehicle from the viewpoints of safety and temperature environment. On the other hand, a rotating electric machine such as a traveling motor is disposed away from a heavy battery, preferably at the front of the vehicle in terms of the weight balance of the vehicle, and the inverter is close to the rotating electric machine such as a traveling motor for various reasons. Or it is usually arranged integrally. In the end, it is reasonable to place the inverter far away from the battery. The boost converter is preferably arranged close to the inverter in consideration of control and downsizing of the circuit system.

  When the power supply from the battery to the boost converter / inverter circuit is cut off due to a vehicle collision accident or the like, and the smoothing capacitor for converter and the smoothing capacitor for inverter are discharged by the safety discharge resistance element, the power connecting the battery and the boost converter Since the cable is long, the discharge of the converter smoothing capacitor connected to the above-described long power cable for battery connection is more important than the discharge of the inverter smoothing capacitor from the viewpoint of improving safety.

  However, when the boost converter / inverter circuit is configured by connecting one or more individually connected inverters and the boost converter by a power line such as a bus bar, the power line is disconnected due to a collision shock. It is also necessary to assume.

  In this case, although the safety discharge resistance element built in the inverter and connected in parallel with the inverter smoothing capacitor can discharge the inverter smoothing capacitor without hindrance, the converter smoothing capacitor may be discharged by disconnection of the power line. As a result, the power cable that is connected to the converter smoothing capacitor and connects the boost converter and the battery is held at a high voltage for a long period of time, which is problematic in terms of ensuring electrical safety.

  In addition, in hybrid vehicles and fuel cell vehicles, if it is attempted to shorten the time to complete discharge of the smoothing capacitor, it is necessary to reduce the resistance value of the safety discharge resistance element connected in parallel with the smoothing capacitor. There is also a problem that power loss that is wasted in a normal state increases.

  The present invention has been made in view of the above problems, and an object thereof is to provide a high-voltage DC power supply circuit for a vehicle that is excellent in safety.

The vehicle high-voltage DC power supply circuit of the present invention that solves the above-described problems includes a high-voltage DC power supply, a boost converter that is built into the converter case and boosts the high voltage that is fed from the DC power supply, and is built into the inverter case. In addition, one or more inverters that convert the boosted voltage input from the boost converter into an AC voltage and supply power to the rotating electrical machine, a pair of output terminals of the boost converter, and a pair of input terminals of the inverter Step-up power supply lines that are individually connected, a converter smoothing capacitor that is built in the converter case and connects a pair of input terminals of the step-up converter inside the converter case, and the inverter case that is built in the inverter case A smoothing inverter for inverter that connects a pair of input terminals of the inverter inside the inverter In high-voltage direct-current power supply circuit for a vehicle and a capacitors, a pair of input terminals or the boosting of the boost converter at the interior of the converter case with the said inverter case it is built only in the converter case without being built is connected to a power supply line provided with a safety discharging circuits for discharging said both smoothing capacitor, the boost converter and the safety discharge circuit is arranged close to the one main surface of the converter metal cooling plate, said inverter, It is arranged on one main surface of the inverter metal cooling plate, and the converter metal cooling plate and the inverter metal cooling plate are arranged to face each other through a gap forming a coolant passage. Thereby, the high voltage direct current power supply circuit for vehicles excellent in safety is realizable.

  That is, according to the present invention, the boost converter and one or more inverters fed from the boost converter are separately manufactured and housed in different cases, and are connected by a power supply line. In this case, the safety discharge resistance element connected in parallel with the smoothing capacitor for the inverter is provided on the boost converter side, so that the above-mentioned power line connected between the boost converter and the inverter is connected to the vehicle by a vehicle collision impact. Even when disconnected due to a collision accident or the like, the safety discharge resistance element can discharge the converter smoothing capacitor, which is the smoothing capacitor of the boost converter, without any hindrance, so that safety can be improved.

  In addition, according to the present invention, since the boost converter and the inverter are built in separate cases, the above-described discharge failure of the smoothing capacitor for the converter due to disconnection or disconnection of the power supply line connecting them is avoided. The safety discharge circuit wiring can be easily repaired and replaced, and the degree of freedom in arrangement is improved.

  It is preferable that the inverter be arranged as close as possible to the rotating electrical machine (travel MG or generator) that supplies AC power, and the inverter smoothing capacitor connected to the pair of input terminals of the inverter is an inverter as much as possible. It is preferable that the switching elements are connected in proximity to each other. This is to suppress an increase in wiring loss or to suppress a ripple voltage caused by wiring inductance. The safety discharge circuit discharges both the smoothing capacitor for the inverter and the smoothing capacitor for the converter. These actions are conventional.

In the present invention, the step-up converter and the safety discharge circuit are arranged close to one main surface of the converter metal cooling plate, and the inverter is arranged on one main surface of the inverter metal cooling plate. The metal cooling plate for inverter and the metal cooling plate for inverter are arranged to face each other through a gap forming a coolant passage.

  As a result, a metal cooling plate that can cool the boost converter and the safety discharge circuit satisfactorily can be used, and the wiring length between the boost converter and the safety discharge circuit can be shortened to reduce the possibility of disconnection. . Also, the converter metal cooling plate and the inverter metal cooling plate face each other across the coolant passage, so that the cooling is good and the wiring length of the power line between the boost converter and the inverter is shortened. Can do. In order to shorten the wiring length of the power supply line, the power supply line is preferably disposed through the converter metal cooling plate, the coolant passage, and the inverter metal cooling plate.

In a preferred aspect, the safety discharge circuit has a circuit characteristic in which a discharge resistance value decreases as the terminal voltage of the smoothing capacitor decreases.

For example, this aspect can be configured by a switching circuit that detects a decrease in the terminal voltage of the smoothing capacitor and reduces the resistance value of the electrical resistance connected in parallel with the smoothing capacitor.

  In this case, the power cable connecting the high-voltage DC power supply (for example, battery) and the boost converter that feeds the boost converter to the boost converter is cut, or the power cable connecting the high-voltage DC power supply and the inverter is cut, or checked. Therefore, when the high-voltage DC power supply is disconnected from the circuit, the safety discharge circuit can complete the discharge of the smoothing capacitor more quickly than the discharge resistance element having a certain electric resistance value. Alternatively, when the time until the completion of discharge is equalized, the power consumption of the safety discharge circuit during normal use can be reduced. Note that the input voltage applied to the boost converter or inverter rarely falls below a predetermined voltage level in normal use.

  In a preferred aspect, the safety discharge circuit includes a posistor having the positive resistance temperature characteristic. In this way, the current flowing through the posistor decreases with the voltage drop of the smoothing capacitor, the heat generation is reduced, and the electrical resistance value is reduced, so that the discharge of the smoothing capacitor does not increase the normal power consumption. Completion can be expedited. Or power consumption at the normal time can be reduced without delaying the completion of discharge.

And a control circuit for controlling the boost converter and the inverter, wherein the control circuit is configured such that when the voltage of the smoothing capacitor for the inverter is lower than a predetermined level compared to an output voltage command to the boost converter, the inverter Each of the switching elements is turned on or the discharge resistance value of the safety discharge circuit is lowered.

  That is, according to the present invention, in the boost converter / inverter circuit in which each of the boost converter and the inverter has a smoothing capacitor and has a safety discharge circuit in parallel with the smoothing capacitor for the inverter, the inverter is compared with the output voltage command to the boost converter. When the voltage of the smoothing capacitor is lower than a predetermined level, it is determined that the power supply from the DC power supply is abnormal, and each switching element of the inverter is turned on, or the discharge resistance value of the safety discharge circuit is set Therefore, electrical safety is improved by prompt discharge of the converter smoothing capacitor and the inverter smoothing capacitor, and circuit inspection can be performed at an early stage.

  In addition, each switching element of the inverter may be turned on, for example, by simultaneously turning on all the switching elements, the stored power of the smoothing capacitor may be consumed by the inverter, or the switching element on the upper arm side of the predetermined arm may be different from the switching arm. By turning on the switching element on the lower arm side, the stored power of the smoothing capacitor may be consumed by the coil in the rotating machine. The control circuit turns on each switching element of the inverter or decreases the discharge resistance value of the safety discharge circuit immediately after the start-up command of the boost converter input from the outside. Is preferably prohibited. As a result, no malfunction occurs in the initial startup of the boost converter.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a hybrid vehicle power supply device using a vehicle high voltage DC power supply circuit of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following examples, and it is natural that the technical idea of the present invention can be implemented by a known technique or a combination of equivalent techniques. For example, a fuel cell may be used instead of the battery.

  FIG. 1 shows a circuit diagram of a hybrid vehicle power supply device according to the first embodiment. 1 is a motor generator, 2 is an inverter, 3 is a boost converter, 4 is a battery having a rated voltage of 200 V, 5 is a discharge resistance element (safety discharge circuit in the present invention), and 6 is a smoothing capacitor (smoothing for an inverter in the present invention). (Capacitor), 7 is a smoothing capacitor (smoothing capacitor for converter referred to in the present invention), and 8 is a safety switch.

  The voltage of the battery 4 is applied between the pair of input terminals 9 and 10 of the boost converter 3 through the safety switch 8, and the voltage between the pair of output terminals 11 and 12 of the boost converter 3 is the pair of input terminals 13 and 14 of the inverter 2. A three-phase AC voltage applied between them and output from the inverter 2 is output to the motor generator (MG) 1. The pair of low potential side input terminals 10 and 12 of the boost converter 3 can be made common. In this embodiment, the battery 4 is arranged from the center of the vehicle to the rear. The inverter 2 is fixed to the housing of the MG 1 and constitutes an inverter integrated type MG together with the MG 1, and this inverter integrated type MG is arranged at the front of the vehicle.

  The smoothing capacitor 6 is housed in a case 15 that houses the inverter 2, and the pair of terminals 16 and 17 of the smoothing capacitor 7 are individually connected to the pair of input terminals 13 and 14 of the inverter 2 through the bus bar wiring in the case 15. Has been. The smoothing capacitor 7 is housed in a case 18 housing the boost converter 3, and the pair of terminals 19, 20 of the smoothing capacitor 7 are individually connected to the pair of input terminals 9, 10 of the boost converter 3 through the bus bar wiring in the case 18. It is connected to the. Discharge resistance element 5 is built in case 18 of boost converter 3, and both ends thereof are individually connected to a pair of output terminals 11 and 12 of boost converter 3.

  The safety switch 8 and the high potential input terminal 9 of the boost converter 3 and the low potential input terminal 10 of the battery 4 are connected by a two-core power cable 21. The high potential output terminal 11 of the boost converter 3 and the high potential input terminal 13 of the inverter 2 are connected by a power line 22, and the low potential output terminal 12 of the boost converter 3 and the low potential input terminal 14 of the inverter 2 are connected to each other. Are connected by a power line 23. In this embodiment, in order to ensure safety and to make the boost converter / inverter circuit compact, the boost converter 3 and the inverter 2 are integrated, and the power supply lines 22 and 23 are bus-bar connected. The step-up converter 3 supplies power to other rotating machines (not shown) through the cable 24.

  The inverter 2 is an ordinary motor driving three-phase inverter having an IGBT as a switching element and a flywheel diode, and a description thereof is omitted because it has a well-known configuration. Boost converter 3 is also a normal chopper type boost converter including reactor L, IGBTs 26a and 27a, and a flywheel diode. IGBT 26a is turned off, IGBT 27a is turned on to store in reactor 25, IGBT 26a is turned on, and IGBT 27a is turned on. Since this is a normal configuration for turning off and outputting the boosted voltage, description thereof is omitted. Of course, other circuit systems may be employed as the boost converter 3 and the inverter 2. However, the smoothing capacitor 7 needs to discharge to the discharge resistance element 5 through the flywheel diode D1 of the boost converter 3 or an equivalent element.

  Next, the case where the safety switch 8 is opened in the boost converter / inverter circuit will be described. A case is considered where the power cable 21 is disconnected due to an accident or the like, or the power cable 21 is disconnected from the battery 4 due to destruction of the connection portion. In this case, it is assumed that each IGBT of the inverter 2 is off.

  In this case, the smoothing capacitor 6 charged up to now is discharged by the discharge resistance element 5 through the power supply lines 22 and 23, and the smoothing capacitor 7 through the diode D1. Further, a smoothing capacitor of another inverter (not shown) is also discharged to the discharge resistance element 5 through the power cable 24, thereby rapidly reducing the internal voltage of the boost converter / inverter circuit and other inverters fed from the boost converter / inverter circuit. Inspection and repair can be performed quickly, and safety against electric leakage accidents can be improved.

  That is, in this embodiment, since the discharge of the smoothing capacitor of the boost converter 3, the inverter 2 and the other inverter 2 (not shown) is performed by one discharge resistance element 5, the number of circuit elements that are large and require cooling is reduced. And the size of the circuit device can be reduced. Moreover, even if the power supply lines 22 and 23 and the power cable 24 are disconnected, the discharge resistance element 5 can discharge the smoothing capacitor 7 without any trouble, and is excellent in safety.

  A schematic partial longitudinal sectional view of this boost converter / inverter circuit is shown in FIG. Although this boost converter / inverter circuit is integrally fixed to the housing of MG1, it is obvious that it may be separate.

  The converter metal cooling plate 25 and the inverter metal cooling plate 26 are fastened with the packing 27 interposed therebetween, and a coolant passage 28 is formed therein. A converter cover plate 29 is fastened to the converter metal cooling plate 25, and an inverter cover plate 30 is fastened to the inverter metal cooling plate 26, and a boost converter housing space 31 and an inverter housing space 32 are formed inside each. A compartment is formed. The boost converter housing space 31 houses the boost converter 3 and the converter smoothing capacitor 7, and the inverter housing space 32 houses the inverter 2 and the inverter smoothing capacitor 6. However, the smoothing capacitors 6 and 7 are not shown in FIG.

  In order to improve heat dissipation, the heat generating components of the boost converter 3 and the inverter 2 are fixed to the converter metal cooling plate 25 and the inverter metal cooling plate 26 through an electrically insulating film having good heat conductivity. A discharge resistance element 5 constituting a safety discharge circuit referred to in the present invention is fixed to the converter metal cooling plate 25. The converter metal cooling plate 25 and the converter lid plate 29 constitute a converter case referred to in the present invention, and the inverter metal cooling plate 26 and the inverter lid plate 30 constitute an inverter case referred to in the present invention. In FIG. 2, the side walls of the converter and the inverter case are integrated with the converter cover plate 29 and the inverter cover plate 30, but the side walls extend from the converter metal cooling plate 25 and the inverter metal cooling plate 26. Structure may be sufficient.

  The converter metal cooling plate 25 and the inverter metal cooling plate 26 are formed with bus bar through holes 33 that are separated from the coolant passage 28 by the packing and communicate with each other, and the bus bar through holes 33 have the power line 22 shown in FIG. , 23 is inserted through the laminated bus bar 34. Therefore, the laminated bus bar 34 is connected to the safety discharge resistance element 5, the IGBTs 26 and 27, and the converter smoothing capacitor 7 shown in FIG. 1 in the boost converter accommodating space 31. The inverter smoothing capacitor 6 shown in FIG.

  In this way, the liquid-cooled step-up converter / inverter circuit can be made compact, and the laminated bus bar 34 can be cut even if the converter metal cooling plate 25 and the inverter metal cooling plate 26 are displaced due to a collision impact or the like. The converter smoothing capacitor 7 and the power cable 21 connected thereto can be discharged without hindrance.

A hybrid vehicle power supply device according to the second embodiment will be described below. In this embodiment, a positive temperature coefficient thermistor (PTC ) , which is a resistance element whose resistance value has a positive correlation with temperature, is employed as the discharge resistance element 5. In this way, the power loss of the discharge resistance element 5 can be reduced without delaying the discharge completion time. Further description will be made with reference to FIG. 3. Discharge resistance in a normal state (room temperature) in which a voltage of about 730 V is applied to the discharge resistance element 5 of the first embodiment and the PTC of the second embodiment that replaces the discharge resistance element 5. The power loss of the element 5 is 17.5 W, and that of the posistor is 2.8 W. At this time, the time required for the terminal voltage of the capacitor having a predetermined capacitance value to drop to 42 V was 5 minutes as shown in FIG. This is because the discharge of the capacitor is promoted because the heat generation of the PTC decreases as the discharge of the capacitor progresses and the electrical resistance decreases. That is, according to this embodiment, the power loss can be reduced without deteriorating the discharge performance of the safety discharge resistance element.

  A hybrid vehicle power supply device according to Embodiment 3 will be described below with reference to FIG. In this embodiment, an auxiliary safety discharge circuit 50 is connected in parallel with the discharge resistance element 5 in the circuit of FIG. The battery voltage is 200V. The safety discharge circuit 50 includes a Zener diode 51, resistance elements 52 to 56, and emitter-grounded transistors 57 and 58. Hereinafter, this operation will be described. Resistive elements 53 and 55 are base current limiting resistors of the transistors 57 and 58, and resistive elements 54 and 56 are collector resistors of the transistors 57 and 58. The Zener diode 51 and the resistance element 52 are connected in series and connected in parallel with the discharge resistance element 5. Therefore, in a high voltage range where the voltage drop of the discharge resistance element 5 exceeds 250 V, a current flows through the Zener diode 51, the transistor 57 is turned on, the transistor 58 is turned off, and the resistance having a resistance value smaller than that of the discharge resistance element 5 No current flows through the element 56. Note that the resistance element 54 has a large resistance value. Next, in a low voltage range where the voltage drop of the discharge resistance element 5 is 250 V or less, no current flows through the Zener diode 51, the transistor 57 is turned off, the transistor 58 is turned on, and a resistance having a smaller resistance value than the discharge resistance element 5. A current flows through the element 56, and the smoothing capacitors 6 and 7 can be discharged rapidly.

  In most cases, the normal output voltage of the boost converter 3 is 250 V or more when the maximum output voltage is 700 V, and is rarely used at a battery voltage of less than 200 V. Therefore, since it is abnormal for the output voltage of boost converter 3 to be such a low voltage, discharge of smoothing capacitors 6 and 7 can be promoted by resistance element 56 for safety.

  A hybrid vehicle power supply apparatus according to Embodiment 4 will be described below with reference to FIG. In this embodiment, in the step-up converter / inverter circuit of FIG. 1 having the auxiliary safety discharge circuit 50 shown in FIG. 4, the voltage of the smoothing capacitor 6 is supplied to the controller 100 (control circuit in the present invention) that controls the inverter 2. Is input. However, in this circuit, the auxiliary safety discharge circuit 50 shown in FIG. 4 does not have the Zener diode 51, the resistance elements 52 to 55, and the transistor 57, but includes only the resistance element 56 and the transistor 58. The transistor 58 is controlled by a control voltage from the controller 100. The operation of this circuit will be described below. The controller 100 includes a microcomputer, but may be configured by a hardware circuit that does not have a microcomputer.

  The controller 100 compares the input voltage drop of the smoothing capacitor 6 or the discharge resistance element 5 with its own threshold value, and does not turn on the transistor 58 in the high voltage range in which it exceeds 250V. Further, when the voltage drop of the smoothing capacitor 6 or the discharge resistance element 5 falls within a low voltage range of 250 V or less, the transistor 58 is turned on. As a result, the same effects as those of the third embodiment can be achieved. It is preferable that the auxiliary safety discharge circuit 50 is not activated immediately after the safety switch 8 is turned on.

  A hybrid vehicle power supply device according to Embodiment 5 will be described below with reference to FIG. However, in this embodiment, the auxiliary safety discharge circuit 50 shown in FIG. 5 is omitted. The operation of this circuit will be described below.

  The controller 100 compares the input voltage drop of the smoothing capacitor 6 or the discharge resistance element 5 with its own threshold value, and when it becomes less than 200 V, it is determined that there is an abnormality and the upper arm IGBT of the U-phase of the inverter 2 Turn on the lower arm IGBT of the V and W phases. However, at this time, MG1 is assumed to be stopped. As a result, the discharge current of the smoothing capacitors 6 and 7 sequentially flows through the U-phase upper arm IGBT of the inverter 2, the MG1 stator coil, the V-phase or W-phase lower arm IGBT, and discharges the smoothing capacitors 6 and 7 quickly. can do. Since the IGBT 2 and MG 1 of the inverter 2 have good cooling performance, the discharge completion time does not become long even if the discharge resistance element 5 is small and has a high resistance value. It is preferable that the auxiliary safety discharge circuit 50 is not activated immediately after the safety switch 8 is turned on.

  A hybrid vehicle power supply device according to Embodiment 6 will be described below with reference to FIG. However, in this embodiment, the auxiliary safety discharge circuit 50 shown in FIG. 5 is omitted. The operation of this circuit will be described below.

  The controller 100 that controls the boost converter 3 determines a voltage value to be output by the boost converter 3 based on an external command or by an internal calculation, and performs switching control of the IGBT of the boost converter 3 with a duty ratio corresponding to the voltage value. The boost ratio of the converter 3 is adjusted.

  Further, the controller 100 reads the terminal voltage of the smoothing capacitor 6 or the voltage drop of the discharge resistance element 5, and the read voltage deviates significantly from the voltage value (voltage command) to be output for a predetermined time (about 10 seconds). ) It is determined whether or not it has elapsed, and if it has elapsed, the U-phase upper arm IGBT and the V and W-phase lower arm IGBT of the inverter 2 are turned on because it is abnormal. However, at this time, MG1 is assumed to be stopped. As a result, the discharge current of the smoothing capacitors 6 and 7 sequentially flows through the U-phase IGBT of the inverter 2, the stator coil of MG1, and the V-phase or W-phase IGBT, so that the smoothing capacitors 6 and 7 can be discharged quickly. . Since the IGBT 2 and MG 1 of the inverter 2 have good cooling performance, the discharge completion time does not become long even if the discharge resistance element 5 is small and has a high resistance value. It is preferable that the auxiliary safety discharge circuit 50 is not activated immediately after the safety switch 8 is turned on.

(Modification)
In addition, the controller 100 determines whether or not a predetermined time (about 20 seconds) has elapsed after the read voltage has deviated significantly from the voltage value (voltage command) to be output. As an alternative, the auxiliary safety discharge circuit 50 shown in FIG. 5 may be turned on. Of course, in this case, the safety discharge circuit 50 can be configured by only the resistor 56 and the transistor 58. It is preferable that the auxiliary safety discharge circuit 50 is not activated immediately after the safety switch 8 is turned on.

It is a circuit diagram of the power supply device for hybrid vehicles of one example. FIG. 2 is a schematic partial longitudinal sectional view of an inverter-integrated MG (generator motor) in which the boost converter / inverter circuit of FIG. 1 is integrated. It is a characteristic view which shows the discharge characteristic of the posistor and discharge resistance element as a safety discharge resistance element of another Example. It is a circuit diagram which shows the safety discharge circuit of another Example. FIG. 6 is a block circuit diagram showing a boost converter / inverter circuit according to another embodiment. FIG. 6 is a block circuit diagram showing a boost converter / inverter circuit according to another embodiment.

Explanation of symbols

MG generator motor 1 MG (inverter-integrated generator motor)
2 Inverter 3 Boost converter 4 Battery 5 Discharge resistance element (safety discharge circuit)
6 Smoothing capacitor (smoothing capacitor for inverter)
7 Smoothing capacitor (smoothing capacitor for converter)
8 Safety switch 9, 10 Input terminal 11, 12 Output terminal 13, 14 Input terminal 15 Case 18 Case 21 Power cable 22, 23 Power line 24 Power cable

Claims (4)

A high voltage DC power supply,
A boost converter that boosts a high voltage that is built in a converter case and fed from the DC power supply;
One or a plurality of inverters that are built in an inverter case and that convert the boosted voltage input from the boost converter to an AC voltage and supply power to the rotating electrical machine;
A boost power supply line for individually connecting a pair of output terminals of the boost converter and a pair of input terminals of the inverter;
A converter smoothing capacitor that is built in the converter case and connects a pair of input terminals of the boost converter inside the converter case;
A smoothing capacitor for an inverter that is built in the inverter case and connects a pair of input terminals of the inverter inside the inverter case;
In a vehicle high-voltage DC power supply circuit comprising:
It is not built in the inverter case, but is built only in the converter case and connected to the pair of input terminals of the boost converter or the boost power supply line inside the converter case to discharge the both smoothing capacitors. Equipped with a safety discharge circuit ,
The boost converter and the safety discharge circuit are disposed close to one main surface of the converter metal cooling plate,
The inverter is arranged on one main surface of a metal cooling plate for inverter,
A high-voltage DC power supply circuit for a vehicle, wherein the converter metal cooling plate and the inverter metal cooling plate are arranged to face each other through a gap forming a coolant passage. The vehicle high-voltage DC power supply circuit according to claim 1,
The safety discharge circuit is:
A high-voltage DC power supply circuit for a vehicle having a circuit characteristic in which a discharge resistance value decreases as the terminal voltage of the smoothing capacitor decreases. In the vehicle high voltage DC power supply circuit according to claim 2 ,
The safety discharge circuit is:
A vehicle high-voltage DC power supply circuit comprising the PTC thermistor having the positive resistance temperature characteristic. The vehicle high-voltage DC power supply circuit according to claim 1,
And a control circuit for controlling the boost converter and the inverter, the control circuit, the voltage of the inverter smoothing capacitor as compared with the output voltage command to the previous SL boost converter of the inverter when a predetermined level or more lower A high-voltage DC power supply circuit for vehicles, wherein a switching element is turned on or a discharge resistance value of the safety discharge circuit is lowered.