JPS62265043A - Electric power changing device for electric railroad - Google Patents

Abstract

PURPOSE:To provide possibility of changing over a PWM control device into a diode rectifier device by furnishing a switch to switch the connection of the secondary winding of a transformer from No.1 output terminal into No.2 output terminal. CONSTITUTION:A transformer 3 for PWM converter has terminals with different voltages between output-1 and output-2. When any failure has occurred in a PWM control device 7 or a GTO thyristor element 5, an AC shutoff device 2 and a DC shutoff device 9 are opened. At the same time, a changeover control device 13 opens SW1 and changes over SW2 from output 1 into output 2. A lock command is sent to said PWM control device 7, and GATE signals to said GTO thyristor 5 are all locked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a power conversion device for a substation for a railway that supplies DC power to electric cars.

(Prior Art) A typical example of a conventional PWM power conversion device is shown in FIG. In FIG. 2, the PWM converter includes a CTO thyristor arm 5, a diode arm 6, a PVM control device 7, a smoothing capacitor 8, a reactor 4, and a PWM converter transformer 3.
It is connected to a three-phase AC power source 1 via an AC breaker 2 and to an electric vehicle load 10 via a DC breaker 9.

This PWM converter converts three-phase AC power into DC power when the electric car load 10 is in a running state, and supplies the electric car load to the electric car load, and when the electric car load 10 is in a regenerative state, It converts the regenerated DC power generated from the vehicle load into three-phase AC power and returns it to the three-phase AC power source.

At this time, the PWM control device 7 sends a gate signal to the GTO thyristor so that the DC output voltage of the PWM converter w7 becomes approximately constant and the waveform of the input current becomes approximately a sine wave at the input power factor 'vl. give.

However, if the PWM control device fails and no gate signal is output, or if it begins to output unnecessary gate signals, or if the GTO thyristor element fails, the PWM converter will not be able to operate normally. As a result, the above functions cannot be satisfied.

As a result, it is no longer possible to supply electric power to the load of the electric vehicle, which hinders the operation of the electric vehicle, and in the worst case scenario, causes serious social problems such as the electric vehicle becoming unable to operate.

[Problems to be Solved by the Invention] In a PWM power conversion device, when the PWM control device or the GTO thyristor element fails, serious problems as described above occur. To avoid this, the following method has traditionally been used:

■ In case of a PWM control device failure, use a PWM controller with exactly the same rating.
An M power conversion device will be provided as a standby device.

- In preparation for GTO thyristor element failure, increase the number of GTO thyristor elements connected in series so that even if one GTO thyristor element fails, the operation of the PWM converter will not be affected.

However, the PWM power converter is very expensive and has a large external size, and if method (2) is adopted, the equipment cost will be enormous and at the same time it will require a large installation space, which is extremely uneconomical.

Furthermore, the method (2) is also uneconomical because the unit price of the GTO thyristor element is high and the number of GTO thyristor elements is large to increase the number of elements connected in series, leading to a significant increase in the price of the PWM power converter.

[Structure of the invention]

(Means and effects for solving the problem) The PWM power converter has the function of supplying power to the train load and at the same time absorbing regenerated power from the train load. This is to enable effective regenerative braking.

However, for safety reasons, trains always have mechanical brakes to prevent problems even if the electric regenerative brake does not operate, and for normal train operation, There is no need for the regeneration function of the PWM power converter, and as long as the minimum running power can be supplied, there will be no problem with train operation.

The present invention has focused on this point, and in order to solve the above problems, a diode and a control switch are made anti-parallel and connected to the secondary winding of the transformer and the DC output side, thereby converting AC power to DC power. The first output terminal and this first A second output terminal that outputs a higher voltage than the output terminal is provided, and a switch that disconnects the control switches connected in antiparallel on the AC side, and a second output terminal that connects the secondary winding of the transformer to the first output terminal. A switch is provided to switch from the output terminal to the second output terminal, and under normal conditions, the control switch is connected in anti-parallel with the diode, and the secondary winding of the transformer is connected to the first output terminal to operate the electric vehicle. In addition to supplying electricity to
For example, it is possible to return the regenerated power from the electric vehicle and output the control switch and the control signal for this control switch.If a failure occurs in the PWM control section, the control switch can be disconnected on the AC side and the , the secondary winding of the transformer is reconnected to the second output terminal to maintain the supply of power necessary for operation of the electric vehicle.

(Example) Examples of the present invention will be described above with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In Figure 1, 1
10 are the same as those in Fig. 2 mentioned above, so their explanation will be omitted. However, the PWM converter transformer 3 has a voltage tap on the secondary side, so that outputs 1 and 2 can have different voltages. Use one with terminals.

Output 1 is the voltage when operating as a PWM converter, for example, in the case of a DC 1500 V feeding circuit, the voltage is 700 V.
The value shall be approximately.

Further, the output 2 is a voltage when the PWM converter is operated as a simple diode rectifier, and has a value of about 1200V in the case of a DC 1500V feeding circuit.

In FIG. 1, 11 is a switch such as a disconnector or circuit breaker (hereinafter referred to as a switchgear) that can disconnect between the GTO thyristor arms and the diode arm, and hereinafter referred to as SW.
It is called I.

Reference numeral 12 denotes a switching device such as a disconnector or circuit breaker capable of switching output 1 and output 2 of the three-phase AC power supply, and is hereinafter referred to as SW2.

Reference numeral 13 is a switching control device, which controls switching devices 11 and 12 (S
The combination of WI and 5W2) has the following effects.

During normal operation as a PWM power converter, SW1 is in the on state, SW2 is connected to the output 1 side, and the circuit configuration is exactly the same as the state shown in FIG. 2.

Here, if a failure of the PWM control device or a failure of the GTO thyristor element occurs, the AC circuit breaker 2 and the DC circuit breaker 9 are opened to protect the device, but at the same time, the switching control device 13 uses this failure information to protect the device. At the same time as SW1 is opened, SW2 is switched from the output 1 side to the output 2 side. Also P
A lock command is sent to the WM control device 7 to lock all gate signals to the GTO thyristors.

By doing so, the GTO thyristor and the PWM control device can stop their functions and become a simple diode rectifier consisting of only the diode arm 6.

When the AC circuit breaker 2 and the DC circuit breaker 9 are turned on, the three-phase AC power supplied from the three-phase AC power supply 1 via the output 2 is converted to DC by the diode rectifier and supplies power to the electric load 10. can do.

Here, the supply of DC power is stopped until the PWM power converter operation is switched to the diode rectifier operation, but the time required for this switch is short and there is little impact on train operation.

Although the operation of the PWM power converter device having a three-phase bridge configuration has been described above, the exact same idea can be applied to a PWM power converter device having a six-phase bridge configuration.

〔Effect of the invention〕

As explained above, according to the present invention, the rectifier that normally operates as a P%1M power converter can be easily switched to a 7-diode rectifier, and the PWM power converter, which was conventionally considered necessary, can be easily switched. Spare aircraft or GT
To provide an economical and reliable PWM power conversion device for electric railways that does not require an increase in the number of O-thyristor elements, is simple and inexpensive, saves space, and does not hinder train operation.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a power conversion device for electric railways according to the present invention, and FIG. 2 is a schematic configuration diagram of a conventional PVM power conversion device. 1... Three-phase AC power supply 2... AC breaker 3.
...PvM converter transformer 4...Reactor 5.
...GTO thyristor arm 6...Diode arm 7...PvM control device 8...Smoothing capacitor 9...DC breaker 10...Train load 11...Switching device! 12...Switching device 13...Switching control device Agent Patent attorney Noriyuki Chika Yudo Hirofumi Mitsumata

Claims (1)

[Claims] For electric railways, which connects a diode and a control switch in inverse parallel to the secondary winding of a transformer and the DC output side to convert AC power to DC power and reversely convert DC power to AC power. In the power conversion device, the control switch is connected in antiparallel to a first output terminal provided on the secondary winding of the transformer and a second output terminal that outputs a higher voltage than the first output terminal. 1. A power converter for electric railways, comprising: a switch that disconnects the transformer on the alternating current side; and a switch that switches the connection of the secondary winding of the transformer from a first output terminal to a second output terminal.