JPH11178201A - Electric vehicle controlling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of quickly removing the arc non-extinguishing state of a thyristor arising from the dynamic current caused by the residual magnetic flux of an induction motor in an electric vehicle controlling device, making use of the thyristor for an overvoltage protective device of an inverter device. SOLUTION: A brake resistance contactor 3 and a brake resistance 4 are connected in parallel via a filter reactor 5 to an overvoltage suppressing resistance 14 and an overvoltage suppressing thyristor 15 connected parallel to an inverter 9. A controlling means 16 is provided which is capable of controlling the brake resistance contactor 3 arbitrarily, thus closing it based on predetermined conditions when overvoltage is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle having an inverter, and more particularly to an electric vehicle control device for performing protection during regenerative braking.

[0002]

2. Description of the Related Art In recent years, an inverter control device using a large-capacity self-extinguishing semiconductor has been generally used as an electric vehicle control device.

[0003] An induction motor is connected to the inverter device, and during braking, it is possible to convert the electric power generated by the induction motor into a DC current and regenerate the electric power to the overhead wire connected via a disconnector.

[0004] However, when a load that consumes electric power is not sufficiently present in the overhead line, regenerative electric power is not absorbed, so that the filter capacitor voltage of the inverter device increases. At this time, in order to protect the device from an overvoltage condition, a method is used in which a thyristor connected in parallel is ignited and the charge of the filter capacitor is discharged instantaneously via a resistor.

Here, the inverter device is stopped during discharge of the filter capacitor. However, since a residual magnetic flux exists in the motor, the motor generates a voltage, and the current passes through the free wheel diode to filter the filter capacitor. Continue to flow in the discharge circuit of. If this current is equal to or greater than the thyristor protection current, the thyristor does not extinguish. During this time, the inverter cannot be restarted.

Conventionally, as disclosed in JP-A-1-50701,
A GTO thyristor with a large holding current is used.
As in JP-A-62-71404, a method of inserting a contactor in series and opening a circuit after discharging has been used.

[0007] Here, the GTO thyristor is more expensive than a normal thyristor, and the method of connecting the contactors in series has the drawback that an extra device is required.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inexpensive and simple electric vehicle control device which can be operated at an early stage after an overvoltage suppressing operation.

[0009]

Even when the regenerative power cannot be absorbed by the overhead line, a large-capacity resistor may be provided on the upper side of the vehicle, and a power generation braking method may be adopted in which the resistor consumes power. In particular, it is often used for routes where regenerative load such as undesired line pressure cannot be expected, or for deceleration braking for long-time braking in a long gradient section.

As a method of switching from regenerative braking to power generation braking, there are a chopper device using a large-capacity semiconductor, a method of sequentially conducting thyristors, and the like, but a method of connecting a brake resistor using a contactor as an inexpensive method. There is.

Normally, when the filter capacitor voltage exceeds a certain value, the contactor for the brake resistor is turned on to switch to the active braking.

However, if the filter capacitor voltage rises sharply due to a sudden change in the overhead wire, etc., an overvoltage suppression device using a semiconductor is used in order to instantaneously discharge the charge of the filter capacitor. When a thyristor is used for the overvoltage suppression device, the problems described in the above-described related art occur.

Here, when the operation of the overvoltage suppressing device is operated, the predetermined discharge time is passed, and the thyristor is kept conducting by the continuation current, the contactor for the brake resistor is turned on and the brake resistor is connected. Thus, the path of the current generated by the residual magnetic flux of the motor is divided into the first overvoltage suppression resistor, the path of the overvoltage suppression device, and the second filter reactor.
Brake resistor contactor-diverts to two of the brake resistors.

The resistance value of the brake resistor is selected to be low to allow a large current to flow so that a sufficient braking force can be obtained, whereas the overvoltage suppression resistance value is determined by the current capacity of the semiconductor and the resistance to the overhead line. There is a restriction as a resistance value from cooperation.

Therefore, normally, the resistance value of the brake resistor is smaller than that of the overvoltage suppression resistor. As described above, the subsequent flow is divided into two paths, and the division ratio is smaller in the overvoltage suppression device in the first path.

Thus, the continuity of the overvoltage suppressing device is reduced, the thyristor current is reduced to the holding current of the thyristor at an early stage, and the thyristor is extinguished, so that the inverter can be restarted.

[0017]

FIG. 1 shows an embodiment of the present invention.
14 is an overvoltage suppressing resistor, and 15 is an overvoltage suppressing thyristor. The brake resistor contactor 3 and the brake resistor 4 are connected in parallel via the filter reactor 5. The contactor 3 for the brake resistor is controlled by means 16 capable of arbitrarily controlling opening and closing. When the filter capacitor voltage is in an overvoltage state and the overvoltage suppression thyristor is operated, when a predetermined discharge time has elapsed and the vehicle speed is higher than a certain speed, the brake resistor contactor 3 is turned on. Here, the determination as to whether the vehicle speed is equal to or higher than a certain speed is to determine whether or not the electric motor generates electric power by the residual magnetic flux.

If the speed is sufficiently low, this phenomenon does not occur, so that the unnecessary operation of the contactor is restricted. The vehicle speed is determined by the rotor frequency at which the rotor speed of the induction motor is detected. The speed of the judgment value is arbitrarily set for each application product. Also, contactor 3 for brake resistor
When turning on, make sure that the circuit is in the open state and then turn on. FIG. 2 is an embodiment of a block diagram which realizes the input logic.

[0019]

According to the present invention, by controlling the contactor for the brake resistor in a coordinated manner, the continuity flowing through the overvoltage suppression thyristor after the overvoltage suppression operation of the filter capacitor is reduced, and the holding current is reduced to the holding current earlier. Is extinguished, the operation of the inverter can be restarted, and a highly reliable electric vehicle control device can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an electric vehicle control device according to an embodiment of the present invention.

FIG. 2 is a control block diagram according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pantograph, 2 ... Disconnector, 3 ... Contactor for brake resistance, 4 ... Brake resistor, 5 ... Filter reactor,
6 ... Main semiconductor, 7 ... Freewheel diode, 9 ... Inverter, 10 ... Induction motor, 11 ... Rotation detector, 12
... Inverter control device, 13 ... Overvoltage detector, 14 ... Overvoltage suppression resistor, 15 ... Overvoltage suppression thyristor, 1
6 ... cutoff controller.

Claims (1)

[Claims] 1. A filter circuit having a capacitor connected to an overhead line via a disconnector, a power converter supplied with power from the overhead line via the filter circuit, and a power converter connected to the power converter. An electric motor that regenerates the generated power during braking, a thyristor and a resistor connected in parallel to the capacitor of the filter circuit, a contactor connected in parallel to the filter circuit, and a resistor that consumes the generated power. An electric vehicle control device having a function of arbitrarily opening and closing the contactor.