JPH02106101A - Controller for electric vehicle - Google Patents

Abstract

PURPOSE:To enable maintenance/inspection of a main circuit only through switching operation by arranging a discharge circuit comprising a switching element in parallel with a capacitor and providing a firing command for the switching element synchronously with a command for electrically isolating the main circuit from a stringing. CONSTITUTION:A discharge resistor 9 and a switching element 10 are connected in series to form a discharge circuit which is then connected in parallel with a capacitor 6. Furthermore, a pantograph control circuit 11 and a pantograph lowering switch 11A arranged on the operating table of an electric vehicle are provided. When the main circuit is isolated electrically from an AC stringing 1 by throwing in the pantograph lowering switch 11A, for example, the switching element 10 is turned ON synchronously and the capacitor 6 is discharged through the discharge resistor 6. By such an arrangement, the main circuit can be brought into a state where there is no possibility of electric shock resulting in safe maintenance/inspection of the main circuit.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a control device for an electric vehicle.

[Conventional technology]

Figure 2 shows, for example, IEEJ Technical Report (Part ■) 251
Main circuit of an AC electric car using a conventional voltage-type power converter shown in Table 4.6, page 26 of “AC motor drive/inverter control system for electric cars” (issued on June 1, 1986) This is what is shown. In the figure, 1 is an AC overhead line, 2 is
is a pantograph, 3 is an AC breaker, 4 is a main transformer (step-down transformer), and 5 is an overhead line side conversion device (in this example, a PWM converter, which is used to remove high-order harmonics generated on the overhead line side). multiplexed). 6 is a smoothing capacitor, 7 is a motor side power conversion device (VVVF inverse conversion device)
, 8 is an induction motor.

In this configuration, the AC overhead line 1 is transmitted through the pantograph 2.
AC voltage is applied to the main transformer 4 via the AC circuit breaker 3 . This alternating current voltage is converted into a constant voltage direct current by a PWM converter 5, and a capacitor 6 is charged by this direct current. The power converter 7 is a capacitor 6
The voltage is converted into alternating current with variable voltage and variable frequency and is supplied to the induction motor 8.

[Problem to be solved by the invention]

As described above, since the capacitor 6 is provided, when performing maintenance and inspection of the PWM converter 5 or the inverter 7, it is necessary to discharge the charge of the capacitor 6 to prevent electric shock. Since the conventional main circuit described above is not provided with a discharge circuit, after disconnecting it from the high voltage side by opening the AC circuit breaker 3, etc. In this case, either wait for the natural discharge due to the voltage dividing resistor, or separately
There is a problem in that the above-mentioned inspection operation cannot be started promptly because it is necessary to connect a discharge resistor to form a discharge circuit.

This invention was made to solve the above problem.
An object of the present invention is to provide a control device for an electric vehicle that can place the main circuit in a safe state where it can be maintained and inspected with a single switch operation during maintenance and inspection of the main circuit.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a discharge circuit having a discharge resistor and a switching element connected in series with the discharge resistor in parallel to the capacitor, and the ignition command to the switching element is transmitted to the main circuit from the overhead wire. It is designed so that it can be given in synchronization with the command to separate the target.

[Effect]

In this invention, for example, when an operation is performed to electrically disconnect the main circuit from the AC overhead wire, such as by turning on a pantograph lowering switch, the switching element is synchronously turned off.
NL, the charge on the capacitor is discharged through the discharge resistor.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 9 is a discharge resistor, and 10 is a switching element (Sirisk in this example). Both are connected in series to form a discharge circuit, and are connected in parallel to the capacitor 6. Reference numeral 11 indicates a pantograph control circuit, and IIA indicates a switch for lowering the pantograph located in the driver's cab of the electric vehicle. Since the other configurations are the same as those of the conventional device, the same components are denoted by the same reference numerals.

In this configuration, the pantograph control circuit 11 is controlled by the driver using a pantograph lowering switch II located in the cab.
When A is turned on, a pantograph lowering command A is generated,
In response to this command A, the pantograph 2 descends and separates from the AC overhead wire 1. The pantograph control circuit 11 also
When the switch IIA is turned on, an ignition command signal (discharge command signal) B is sent to the thyristor 12.

Therefore, when performing maintenance and inspection of the PWM converter 5 or inverter 7, the pantograph lowering switch 11
When A is turned on, the main transformer 4 is electrically disconnected from the AC overhead line 1, the thyristor 12 is made conductive, and the accumulated charge in the capacitor 6 is discharged through the discharge resistor 9.

Note that the ignition command B may be synchronized with the command for opening the AC circuit breaker 3, and may also be synchronized with the low voltage test command (generally,
It may also be synchronized with the empty notch command).

Further, in the above embodiments, an AC electric vehicle has been described, but the present invention can be applied to obtain a similar effect when the power conversion device is a chopper device and the electric vehicle driving electric motor is a DC motor. Can be done.

〔Effect of the invention〕

As explained above, in this invention, the capacitor can be discharged by disconnecting the main circuit from the high voltage side, so the main circuit can be quickly placed in a state where there is no risk of electric shock, compared to the conventional method. The safety of maintenance and inspection of the main circuit can be improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional electric vehicle control device. In the figure, 1 overhead wire, 2 pantograph, 3 AC circuit breaker, 5 forward conversion device, 6 capacitor 7 reverse conversion device,
8 induction motor, 9 discharge resistor, 10 switching element, 11 pantograph control circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] The main circuit includes a forward converter that converts alternating current taken in from the overhead line through the pantograph and circuit breaker into direct current, a capacitor inserted between the positive and negative electrodes of this forward converter, and a power converter that uses the voltage of this capacitor as direct current input. Prepare,
In a control device for an AC electric vehicle that controls a motor for driving an electric vehicle using the output of the power conversion device, a discharge circuit having a discharge resistor and a switching element connected in series thereto is provided in parallel with the capacitor, A control device for an electric vehicle, characterized in that an ignition command to the element is given in synchronization with a command to electrically disconnect the main circuit from the AC overhead wire.