JPH09140004A - Power controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and optimum power controller for a vehicle capable of power control of a generator-motor. SOLUTION: A power controller 2 is composed of a plurality of switching elements 21 consisting of public IGBTs, inverter modules consisting of diodes 22 connected in parallel with several switching elements, a capacitors 23 connected in parallel with the inverter modules, and a control circuit 24 for controlling the switching operation of the switching element 21. In the case that the current capacity at power generation becomes larger than the current capacity of at electric drive, the power conversion with one inverter module is made possible, and also the quantity of overshoot at the time of on and off of the switching element generated by the diode can be lightened, by putting the current capacity of the diode of the inverter module in such magnitude as is decided by the output at power generation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle power control device, and more particularly to a power control device suitable for a hybrid electric vehicle that uses a generator as an electric motor for starting an engine for driving the generator.

[0002]

2. Description of the Related Art A power control device for driving a generator as an electric motor is provided with a switching element and a plurality of diodes called flywheels provided in parallel with the switching element for the purpose of commutation and protection of the switching element. Inverter module is used. At the time of power generation, this diode is used as a rectifier to perform control such as charging the battery.

[0003]

However, in the conventional inverter module, since the current capacity of the diode is set to be equal to or less than that of the switching element, the power generation output is to be used in a configuration that greatly exceeds the electric output. Then, an inverter module having a large-capacity switching element and a diode is required, resulting in an increase in cost and size. Further, as disclosed in Japanese Patent Laid-Open No. 5-111110, in the case where a rectifier that is separate from the inverter is provided separately, the size of the power control device becomes large, and the diode 22 in the inverter module has a capacitance. There is a problem that a configuration for balancing with the external diode is required so that the generated current does not flow in, the circuit configuration becomes complicated, and the cost increases. Therefore, the idea is to make the current capacity of the diode in the inverter module different from the current capacity of the switching element to a current capacity corresponding to the output at the time of power generation, so that the vehicle can be compact and optimal for power control of the generator motor. An object of the present invention is to provide a power control device for use.

[0004]

In order to solve the above-mentioned problems, according to the present invention, in the vehicle power control device according to any one of claims 1 to 3, the current capacity of the diode connected in antiparallel to the switching element is set to the switching element. The current capacity is set to be larger than the current capacity of, and by such a configuration, in a generator such as a hybrid electric vehicle, for example, a small capacity corresponding to the current capacity when operating the switching element as an electric motor. It is possible to use the same inverter module as the power control device of a generator with a large current capacity while adopting elements, and it is possible to realize an optimal control device without increasing the size of the control device. it can. In addition, when the switching element is switched from the ON state to the OFF state, a small current that flows backward through the diode may flow and the current of the switching element may overshoot.However, when a diode with a large current capacity is used, Can reduce the amount of current flowing back, reduce the amount of overshoot, and can realize appropriate switching operation.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 is a schematic block diagram of a so-called parallel type hybrid vehicle in which the power control device of the present invention is used. Reference numeral 1 denotes a generator-motor, which is a rotating electric machine that functions as a generator and an electric motor, and is connected to an engine 8 so as to be rotatable.

An electric power control device 2 is connected to the generator motor 1, and when the generator motor 1 acts as a generator, the electric power is converted into direct current and supplied to the battery 3 and also acts as an electric motor. In this case, the electric power of the battery is supplied to the generator motor 1 to rotate the generator motor 1. An inverter 4 for controlling the electric motor 5 is connected to the battery 3, and by appropriately controlling the inverter 4, the electric motor 5 is rotationally driven to give a predetermined rotational torque to the drive wheels 7 to drive the vehicle. Let A known speed reducer 6 such as that used in a general gasoline-powered vehicle is interposed between the electric motor 5 and the drive wheels 7, and converts the rotational output of the electric motor 5 into a predetermined rotational speed and torque. Is transmitted to the drive wheels 7. Next, detailed structures of the power control device 2 and the generator motor 1 will be described with reference to FIG.

The generator motor 1 is composed of a stator coil 11 composed of a Y-connected three-phase coil and a magnetized rotatable rotor (not shown). The rotor is mechanically connected to the rotating shaft of the engine. There is. The power control device 2 includes a plurality of switching elements 21 made of known IGBTs and diodes 2 connected in parallel to each switching element 21.
2, an inverter module, a capacitor 23 connected in parallel to the inverter module, and a control circuit 24 for controlling the switching operation of the switching element 21.
It is composed of

Each of the switching elements 21 and the diode 22 is composed of a total of 6 elements in each of which 2 sets are connected in series and 3 sets are arranged in parallel to form an integrally packaged inverter module. One end of each stator coil 11 is connected to an intermediate point of switching elements connected in series. Diode 2
2 is connected in parallel to each switching element 21 such that the direction opposite to the direction in which the current flows becomes the forward direction, and a fast recovery type diode is provided so that ON / OFF control of each switching element can be realized at high speed. It is used.

The capacitor 23 is connected in parallel to these inverter modules and plays a role of smoothing the current flowing through the inverter modules. A battery 3 in which a plurality of battery units are connected in series is electrically connected to the power control device 2, and power can be transferred to and from the power control device 2. Since the power control device and the generator motor have the above-described configurations, when the generator motor 1 is rotationally driven by the engine to perform the power generation operation, the power is generated in the stator coil by using each diode 22 and the capacitor 23. The AC power is rectified to DC and supplied to the battery 3 to charge the battery 3. At this time, the rectified current flowing through the diode does not affect the switching element 21 because the diodes are connected in anti-parallel. Therefore, if the current capacity of the switching element 21 is left unchanged and only the current capacity of the diode 22 is increased,
The breakdown of the diode 22 can be prevented. Normally, a hybrid vehicle requires a power generation output of a number + kw corresponding to the running output, and therefore each diode 22 also requires a current capacity corresponding to this output.

Further, when the generator motor 1 drives as a starter motor for starting the engine, it acts as an electric motor, and the DC power from the battery 3 is applied to the stator coil 11 by the switching operation of the switching element 21. The rotor is rotated by the engine 8
Is driven to rotate. Generally, it can be started by an electric motor of several kw, and the current value at this time is significantly smaller than the current value at the time of power generation. Therefore, the switching element 21 is set to a capacity determined by the phase current at the engine start, that is, at the time of electric operation. . The diode 22 clamps the commutation at the time of off and the voltage generated in the stator coil 11 to the voltage of the battery 3,
The switching element 21 is protected.

When the switching element is switched from the ON state to the OFF state, a small current that flows backward through the diode 22 may flow and the current of the switching element may overshoot. However, the current capacity of the diode is the current of the switching element. Since the capacitance is larger than the capacitance, the overshoot amount can be reduced more than that of the diode having a current capacitance similar to that of the switching element.

The capacity of the diode 22 of the inverter module enclosed in a package, which is composed of a general switching element 21 and a diode 22, is equal to that of the switching element 2.
The capacity is equal to or less than the capacity of 1,
Sufficient when rotating the motor. However, when using a generator as an electric motor like a hybrid vehicle, if the power generation capacity is significantly higher than the current capacity at the time of starting, set the inverter module to the current capacity at the time of power generation and the current capacity of the diode 22. The inverter module will be larger than necessary. Alternatively, there is also a method of using an inverter module having a capacity equivalent to that of an electric motor and externally connecting a large-capacity diode in parallel with the diode 22, but this also increases the size of the power control device, and the inverter module It is difficult to balance with the external diode so that the generated current exceeding the capacity does not flow into the internal diode 22.

Therefore, by setting the current capacity of the diode in a general inverter module to a capacity determined by the output current during power generation, regardless of the current capacity of the switching element 21 or more, a low cost and simple power consumption is achieved. Made the control device possible. As described above, according to the present invention, in the power control device for converting the electric power of the generator and the electric power generation, when the current capacity during power generation becomes larger than the current capacity during electric power generation, the current capacity of the diode of the inverter module is changed. It is possible to convert the power in one inverter module and reduce the overshoot amount when the switching element is turned on and off, which is generated by the diode, by making the size determined by the output during power generation.

In the above-described embodiment, an example in which the generator and the electric motor are integrated is explained, but the present invention is not limited to this, and the generator and the electric motor are separately configured and The same operation and effect can be obtained even if the power is controlled by one power control device. However, in this case, a configuration such as a switching device is required so that the generator and the electric motor do not act simultaneously. Further, the power control device having the configuration of the present invention can be applied not only to a hybrid vehicle but also to a generator of a general gasoline vehicle.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of a power control device and a generator motor according to the present invention.

FIG. 2 is a schematic configuration diagram of a hybrid vehicle including the power control device of the present invention.

[Explanation of symbols]

 1 Generator Motor 2 Power Control Device 3 Battery 4 Inverter 5 Motor 6 Reducer 7 Drive Wheel 21 Switching Element 22 Diode 23 Capacitor 24 Control Circuit

Claims (3)

[Claims] 1. A battery that supplies electric power to a traveling motor, a generator that charges the battery, an engine that drives the generator, a starter motor that starts the engine, and a control device that controls the generator. Wherein the control device comprises a plurality of pairs of switching elements connected in series between the positive and negative terminals of the battery, and a diode connected in antiparallel to the switching elements, and a connection point of the switching elements connected in series. The generator is controlled as an electric motor by the intermittent control of the switching element, while rectifying the alternating current of the generator by the diode connected in anti-parallel, the current capacity of the diode, the switching element An electric power control device for a vehicle, wherein the electric power control device is larger than the current capacity of the electric power control device. 2. The starter motor controls the generator as an electric motor.
The vehicle power control device described. 3. A power control device for a vehicle, comprising: a rotating electric machine connected to an engine; a control device for controlling the rotating electric machine; and a battery for charging and discharging electric power between the rotating electric machine. The control device includes a plurality of switching elements, a control circuit that operates the rotating electric machine as an electric motor by performing a switching operation of the switching elements, and is connected in inverse parallel to each of the switching elements, and the rotating electric machine is rotationally driven by the engine. And a diode configured to rectify the AC power generated in the rotating electric machine to charge the battery when being operated, and a current capacity of the diode is set to be larger than a current capacity of the switching element. Vehicle power control device.