JP2010110099A - Protection device for automobile power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To protect a power converter from an overvoltage when an overvoltage due to an induced voltage of a motor is applied to an automobile power converter. <P>SOLUTION: A power conversion system includes a power converter, which is configured of a semiconductor device and converts DC power into AC power or converts AC power into DC power, a power supply for supplying power to the power converter, a power circuit-breaker for cutting off power, and a motor operated by the power converter. A protection device for an automobile power converter is configured so that a limiting resistor and a relay are installed in series between DC-side bus-bars. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a protection device for an automotive power conversion device that performs power conversion between DC power and AC power.

  The electric drive system for automobiles is composed of an electric motor for driving a vehicle, a power conversion device for controlling the electric motor, a switchgear having a circuit breaker for shutting off the power supply in an emergency, and a power source by a secondary battery such as a lithium ion battery. . A conventional protection device for a power conversion device is a vehicle power conversion device, which describes overvoltage protection from the overhead line side.

JP-A-8-126101

  An electric drive system for an automobile is composed of an electric motor for driving a vehicle, a power conversion device for controlling the electric motor, a shut-off device having a shut-off device for shutting off the power in an emergency, and a power source using a secondary battery such as a lithium ion battery. . In such a system, the shut-off device may operate during regenerative operation due to a system abnormality, and may be disconnected from the power source. In this case, the induced voltage of the electric motor is applied to the power converter by stopping the power converter. Normally, in order to prevent short-circuit failure in the power converter, set the motor induced voltage to be lower than the rated voltage of the power converter, etc., or set the power converter rated higher than the motor induced voltage. There is a restriction of setting the voltage.

  The present invention has been made to solve the above-described problems. In the electric drive system for automobiles, an abnormality such as a short circuit failure does not occur even in a power converter having a rated voltage lower than the induced voltage of the motor. It is providing the protection device of the power converter device for motor vehicles which can be used.

  A protection device for an automotive power conversion device according to the present invention is a power conversion device comprising a semiconductor element and a smoothing capacitor connected to a DC bus, and a current limiting resistor connected to the DC bus in parallel with the smoothing capacitor. And a component for controlling the current such as a relay, and the operation of the component for controlling the current causes the current to flow between the DC buses via the limiting resistor, thereby suppressing the voltage on the DC side.

  The present invention prevents damage to a power conversion device due to overvoltage with a minimum configuration of overvoltage applied by an induced voltage of an electric motor when disconnected from a power source by a shut-off device when an electric drive system for an automobile is abnormal. Can do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, the same reference numerals are given to those having the same function.

  First, the configuration of a system including a power conversion device will be described with reference to FIG. FIG. 1 is an example of an electric drive system for an automobile including a power converter to which the present invention is applied. The electric motor 1 is connected to the power converter 2 by an AC bus 1a. The power converter 2 is connected to a power source 4 such as a lithium ion battery through a shut-off device 3 by DC buses 2a and 2b. The power converter 2 includes a smoothing capacitor 22 connected between the semiconductor element (A) 21 and the DC buses 2a and 2b, and a limiting resistor 23 connected in parallel to the smoothing capacitor 22 to the DC buses 2a and 2b. And a relay 24 connected in series with the limiting resistor 23. In addition, voltage detecting means 25 connected to the DC buses 2a and 2b and relay driving means 26 connected to the voltage detecting means 25 are provided.

  Next, the operation will be described. In FIG. 1, when the shut-off device 3 is closed, electric power is supplied to the power conversion device 2, an alternating current is generated by switching control of the semiconductor element (A) 21, and the electric motor 1 connected by the alternating current bus 1 a. The power running state is controlled. When the electric motor 1 is rotated, the alternating current generated by the electric motor 1 is supplied to the power conversion device via the alternating current bus 1a, rectified by the semiconductor element (A) 21 and converted into direct current, and the interruption device 3 It will be in the regenerative state where the power supply 4 is charged via the. Here, in the regenerative state, when the shut-off device 3 is opened due to a system abnormality, the voltage between the DC buses 2a and 2b is increased by the induced voltage of the electric motor 1. The voltage between the DC buses 2a and 2b is monitored by the voltage detecting means 25, and an operation signal is sent to the relay driving means 26 by a voltage equal to or higher than a threshold value. By this operation signal, the relay driving means 26 is activated, the relay 24 is closed, and a current flows between the DC buses 2a and 2b via the limiting resistor 23. This current suppresses the voltage between the DC buses 2a and 2b.

  With reference to FIG. 2, another embodiment of the present invention will be described. FIG. 2 shows a configuration in which a semiconductor element (B) 27 is connected instead of the relay 24.

  The operation of the semiconductor element (B) 27 will be described. As in the first embodiment, when the shut-off device 3 is opened due to a system abnormality in the regenerative state, the voltage between the DC buses 2a and 2b is increased by the induced voltage of the electric motor 1. The voltage between the DC buses 2a and 2b is monitored by the voltage detecting means 25, and an operation signal is sent to the semiconductor element driving means 28 by a voltage equal to or higher than a threshold value. With this operation signal, a gate signal is input to the semiconductor element (B) 27 from the semiconductor element driving means 28, and a current flows to the semiconductor element (B) 27 through the limiting resistor 23. This current suppresses the voltage between the DC buses 2a and 2b.

  It is also possible to control the current flowing through the semiconductor element (B) 27 and to flow a current according to the voltage level.

  FIG. 3 illustrates another embodiment of the present invention. FIG. 3 differs from the second embodiment in that means for operating the semiconductor element (B) 27 is changed. The semiconductor element driving means 28 is connected to the DC buses 2a and 2b, and generates a control voltage for the semiconductor element (B) 27 using the voltage between the DC buses 2a and 2b. The semiconductor element driving means 28 divides the voltage between the DC buses 2a and 2b and outputs the control voltage of the semiconductor element 29, so that the current of the semiconductor element (B) 27 corresponds to the voltage between the DC buses 2a and 2b. Can be controlled.

1 is a first embodiment in which the present invention is applied to an electric drive device for an automobile. It is the 2nd Example which applied this invention to the electric drive device for motor vehicles. It is the 3rd Example which applied this invention to the electric drive device for motor vehicles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 1a AC bus 2 Power converters 2a and 2b DC bus 3 Breaker 4 Power supply 21 Semiconductor element (A)
22 smoothing capacitor 23 limiting resistor 24 relay 25 voltage detecting means 26 relay driving means 27 semiconductor element (B)
28 Semiconductor element driving means

Claims (6)

  A power converter configured by a semiconductor element to convert DC power to AC power or convert AC power to DC power, a power supply for supplying power to the power converter, a power breaker for cutting power, and the power A protective device for an automotive power converter, wherein a limiting resistor and a relay are installed in series between the DC buses in a power conversion system including an electric motor that operates with the converter.   The protection device for a power conversion device according to claim 1, further comprising a voltage detection means and a voltage determination means between the DC side buses, wherein the relay is opened and closed by a set voltage. apparatus.   The power conversion system according to claim 1, wherein the relay closing operation is performed in synchronization with the power breaker opening operation.   A power converter configured by a semiconductor element to convert DC power to AC power or convert AC power to DC power, a power supply for supplying power to the power converter, a power breaker for cutting power, and the power A protection device for an automotive power conversion device, wherein a limiting resistor and a semiconductor element for controlling current are installed in series in a power conversion system including an electric motor that operates with the conversion device.   5. The protection device for a power conversion device according to claim 4, further comprising a voltage detection means and a voltage determination means between the DC side buses, wherein the relay is opened and closed by the set voltage.   5. The protection device for a power conversion device for an automobile according to claim 4, wherein the operating voltage of the semiconductor element for controlling the current is varied using a DC voltage.

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