JPH0311905A - Control device of ac electric rolling stock - Google Patents

Abstract

PURPOSE:To allow both converter on a power source side and inverter on a load side to be reoperated immediately by being equipped with a detection means to detect that the voltage of a smoothing capacitor exceeds the predetermined overvoltage set value and a reset voltage detection means to detect that the above voltage falls short of the reset voltage set value. CONSTITUTION:An AC electric rolling stock is equipped with an over-voltage detection means 20 to command a power switch 5 to open, a converter 6 on a power source side and an inverter 11 on a load side to stop operation, and overvoltage inhibition circuits 8 and 9 to start operation when the voltage of a smoothing capacitor exceeds the predetermined overvoltage set value, while it is equipped with a reset voltage detection means 20 to command the power switch to close, the converter 6 on the power source side and the inverter 11 on the load side to restart the operation and the overvoltage inhibition circuits 8 and 9 to stop the operation when the voltage of the smoothing capacitor 7 falls short of the reset voltage set value determined lower than this voltage set value. No power running and braking running of the AC electric rolling stock will thereby be prevented if the time of stop is shortened when the converter 6 on the power source side and the inverter on the load side are stopped so as to dissolve the overvoltage.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes a power supply side converter and a load side converter,
The present invention relates to a control device B for an AC electric car that runs by driving an AC motor with AC power supplied from an overhead wire.

[Conventional technology]

FIG. 3 is a circuit diagram showing a conventional example of an AC electric vehicle that is equipped with a power supply side converter and a load side converter and is driven by an AC motor by AC power supply.

As shown in FIG. 3, AC power supplied from the overhead wire l is converted into DC power at a predetermined voltage by a converter 6 as a power supply side converter via a power switch 5, and then as a load side converter. The inverter 11 converts the AC power into AC power of a desired voltage and frequency, and the induction motor 12 is operated at a variable speed. Therefore, the AC electric car driven by the induction motor 12 can freely change its running speed. .

Does converter 6 control this converter 6? The converter control circuit 13 for
An inverter control n circuit 14 is also attached to each of the inverter control circuits 14 for controlling this. In addition, a so-called DC intermediate circuit that connects the DC side of the converter 6 and the DC side of the inverter 11 includes a smoothing capacitor 7 for smoothing the power flowing through the DC intermediate circuit, and a resistor and overvoltage suppressing thyristor 9. There are provided an overvoltage suppression circuit connected in series with the DC intermediate circuit and a DC voltage detector 10 for detecting the DC intermediate circuit voltage.

(Problem to be Solved by the Invention) If the DC intermediate circuit voltage increases for some reason while the AC electric vehicle having the configuration shown in FIG. Detection circuit 1
5 detects that the preset overvoltage setting value has been exceeded, the overvoltage detection circuit 15 sends an open signal to the power switch 5 and also outputs a converter control signal. ■Circuit 1
3 and inverter control line 14, the power switch 5 is shut off, and the converter 6 and inverter 11 stop their power conversion operations. At the same time, a signal is sent from the overvoltage detection circuit 15 to the one-shot gate signal generation circuit 16, so that a firing signal is applied to the gate of the overvoltage suppression thyristor 9, and the overvoltage suppression thyristor 9 is turned on.

As a result, the charge stored in the smoothing capacitor 7 is
Since the overvoltage suppression thyristor 9 converts heat into heat and is consumed in the resistor 8, the overvoltage condition is resolved.
The operation of this overvoltage suppression circuit is as follows:
This continues until the I charge becomes zero.

Therefore, if the DC intermediate circuit voltage becomes an overvoltage, the DC intermediate circuit voltage will be reduced to zero, so in order to restart, the smoothing capacitor 7 must first be charged to a predetermined voltage. There was an inconvenience that it took a long time.

Furthermore, if the DC intermediate circuit voltage becomes overvoltage during regenerative braking operation to decelerate a running AC electric vehicle, converter 6 and inverter 11 both stop their operation, making regenerative braking operation impossible and causing the AC electric vehicle to decelerate. The car has other braking mechanisms,
For example, since the air brake must be applied, there is also the disadvantage that the electric brake cannot be used effectively.

FIG. 4 is an operation waveform diagram showing the operation of each part of the conventional circuit shown in FIG. 3, in which FIG. 4 (C) shows the operation of the power switch 5, FIG. 4 (D) shows the operation of the overvoltage suppression thyristor 9, and FIG.
E) shows the operation of the converter 6 and inverter 11, respectively.

As shown in Fig. 4, when the DC intermediate circuit voltage reaches the overvoltage setting value ■1 at time T1, the overvoltage suppression thyristor 9 turns on and reduces the DC intermediate circuit voltage to zero, so this voltage is It can be seen that it takes a long time to restart the converter 6 and inverter 11 after the value is returned to .

Therefore, an object of the present invention is to generate an overvoltage in the DC intermediate circuit and eliminate this overvoltage (by shortening the stop time when stopping the power supply side conversion means and the load side converter stage, The purpose is to ensure that the vehicle does not interfere with slow driving or braking.

[Means to solve the problem]

In order to achieve the above object, the control device of the present invention includes:
It consists of a power supply side converter that converts AC power supplied from overhead lines into DC power via a power switch, a smoothing capacitor that smoothes this DC power, and a series connection of an overvoltage suppression switch element and a resistor. An overvoltage suppression circuit connected in parallel to the smoothing capacitor of the lever, a load-side converter that converts the smoothed DC power into AC power of a desired voltage and frequency, and an AC power output from the load-side converter to generate electricity. In an AC electric vehicle configured with an AC motor that drives the vehicle, if the voltage of the smoothing capacitor exceeds a predetermined overvoltage setting value, the power supply switch is opened and the power supply side converter and load side converter are connected. an overvoltage detection means for instructing the stop of operation of the overvoltage suppressing circuit and the start of operation of the overvoltage suppression circuit; , a return voltage detection means for instructing restart of operation of the power supply side converter and load side converter and stop of operation of the overvoltage suppression circuit.

[Effect]

The present invention provides a means for detecting that the voltage of a DC intermediate circuit that connects a power supply side conversion means and a load side conversion means of an AC electric vehicle exceeds a predetermined overvoltage setting value; The system is equipped with a reset voltage detection means that detects when the reset voltage has fallen below the reset voltage set value set at the lower side. If this is detected, the operation of this overvoltage suppression circuit is stopped, and the power supply side conversion means and the load side conversion means are immediately restarted.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

In this FIG. 1, AC power supplied from an overhead wire 1 is taken into an AC electric car by a pantograph 2, and is transferred to a transformer 3.
is applied to The AC power insulated and transformed to a desired voltage by the transformer 3 passes through the AC reactor 4 and the power switch 5, and is converted into power by the converter 6 as a power supply side converter and the inverter 11 as a load side converter. AC power of variable voltage and variable frequency is supplied to the induction motor 12 that drives the electric car.

A DC intermediate circuit that connects the DC sides of the converter 6 and the inverter 11 includes a smoothing capacitor 7, an overvoltage suppression circuit configured by a series connection of a resistor and an overvoltage suppression circuit 9, and a DC voltage detector 10. A converter control circuit 13 is attached to the converter 6, and an inverter control circuit 14 is attached to the inverter 11.

In the present invention, an overvoltage control system is provided for controlling the operation stoppage of the overvoltage suppression circuit, the operation stoppage of the converter 6, the operation stoppage of the inverter 11, and the opening/closing of the power switch 5.
A return voltage detection circuit 20 is provided.

That is, when it is detected that the DC intermediate circuit voltage has increased and exceeded the overvoltage setting value, the power switch 5 is turned on, the converter 6 is stopped, the inverter 11 is stopped, and the overvoltage suppression thyristor 9 is turned on. is commanded by the overvoltage/return voltage detection circuit 20, and as a result, when the DC intermediate circuit voltage decreases to the reset voltage setting value, the source switch 5 is closed, the converter 6 starts operating, and the inverter 1 is closed.
The overvoltage/return voltage detection circuit 20 receives a signal that commands the start of operation of the overvoltage/return voltage detection circuit 20 and the overvoltage suppression thyristor 9 to turn off.
is output from.

In FIG. 1, overvoltage detection and recovery voltage detection are performed by a common overvoltage/release voltage detection circuit 20, but this can be done by using, for example, a comparator with appropriate hysteresis. This is because it is possible to achieve this, and it is of course possible to use a circuit configuration that separately performs overvoltage detection and recovery voltage detection.

FIG. 2 is an operation waveform diagram showing the operation of each part of the embodiment circuit shown in FIG. 1, in which FIG. The output of the voltage detection circuit 20, FIG. 2(c) shows the operation of the power switch 5, FIG. 2(d) shows the operation of the overvoltage suppression thyristor 9,
E) shows the operation of the converter 6 and inverter 11, respectively.

As shown in Fig. 2, the period from time T when the DC intermediate circuit voltage reaches the overvoltage set value vl to time T2 when it drops to the reset voltage set value 2, which is set near the rated voltage. Converter 6 and inverter 11 only for a short time
You can see that it has stopped.

[Effects of the Invention] According to the present invention, if the DC intermediate circuit voltage that connects the power supply side converter and load side converter of an AC electric vehicle becomes an overvoltage of a predetermined value or more, the double converter is switched off. The DC intermediate circuit stops and the smoothing capacitor in the DC intermediate circuit is discharged to lower its voltage by discharging the electric charge, but this discharge stops when the voltage drops to the return voltage, which is set near the rated voltage of the DC intermediate circuit. make it stop. As a result, the converters on the power supply side and the load side can be restarted immediately, so that the period during which the converters are stopped can be limited to a short period of time.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is an operation waveform diagram showing the operation of each part of the embodiment circuit shown in Fig. 1, and Fig. 3 is a diagram showing the operation of each part of the embodiment circuit shown in Fig. 1. AC 2i equipped with a load-side converter and driven by an AC motor using AC power supply
FIG. 4 is a circuit diagram showing a conventional example of an electric vehicle. FIG. 4 is an operation waveform diagram showing the operation of each part of the conventional example circuit shown in FIG.

Claims (1)

[Claims] 1) Consists of a power supply side converter that converts AC power supplied from the overhead line into DC power via a power switch, a smoothing capacitor that smoothes this DC power, and a series connection of an overvoltage suppression switch element and a resistor. An overvoltage suppression circuit connected in parallel to the smoothing capacitor of the lever, a load-side converter that converts the smoothed DC power into AC power of a desired voltage and frequency, and an AC power output from the load-side converter to generate electricity. In an AC electric car that is composed of an AC motor that drives the car, if the voltage of the smoothing capacitor exceeds a predetermined overvoltage setting value, the power switch is opened and the power supply side converter and load side converter are opened. overvoltage detection means for instructing to stop the operation and to start the operation of the overvoltage suppression circuit; and when the voltage of the smoothing capacitor falls below a reset voltage setting value that is set lower than the overvoltage setting value, closing the power switch; A control device for an AC electric vehicle, comprising a return voltage detection means for instructing restart of operation of a power supply side converter and a load side converter and stop of operation of an overvoltage suppression circuit.