JPH0339300Y2 - - Google Patents

Description

[Detailed explanation of the idea] A. Industrial application field The present invention relates to a power supply device for a DC electric railway.

B. Summary of the invention The present invention is a DC type equipped with a forward converter that converts AC power to DC and supplies the DC power to the overhead contact line, and an inverse converter that converts the DC regenerative power generated in the overhead contact line to AC. In an electric railway power supply system, a battery is attached to the inverter, and a switching circuit is inserted in the electric line connecting the battery to the overhead contact line, so that when an electric car located under the overhead contact line performs regenerative braking, The generated electric power is charged to the battery and regenerated by the reverse converter, and when the electric vehicle is running, the DC output of the forward converter is supplied to the overhead contact line, and the charging energy of the battery is transferred to the reverse converter. By regenerating the regenerative power to the AC power source side, the regenerative power generated during regenerative braking of an electric vehicle can be regenerated without waste without increasing the power capacity of the inverter.

C. PRIOR TECHNOLOGY In recent years, an increasing number of direct current electric railway lines have adopted regenerative braking vehicles in their electric cars to save energy by returning regenerative energy during regenerative braking to the power source. A power supply device for a DC electric railway employing regenerative braking for electric cars as described above is shown, for example, as shown in FIG. In FIG. 2, one end of the transformer 1 is connected to a commercial frequency power source (not shown). The other end of the transformer 1 is connected to the overhead contact line 3 via a forward converter 2 configured by, for example, bridge-connecting thyristors. One end of an inverter 4 configured by bridge-connecting thyristors, for example, is connected to the overhead contact line 3. Inverse converter 4
The other end is connected to a commercial frequency power source (not shown) via a transformer 5. 6 is an electric vehicle capable of regenerative braking, and 7 is a rail. In the device configured as described above, AC power led from a commercial frequency power source (not shown) via the transformer 1 is converted to DC power by the forward converter 2,
The DC power is supplied via the overhead contact line 3 to the electric vehicle 6 during power running. Further, assume that the electric car 6 that is running performs regenerative braking in order to stop at a station (not shown), for example. In this case, the regenerated energy generated in the electric car 6 is converted into AC power by the inverter 4, and then regenerated to a commercial frequency power source (not shown) via the converter 5.

D. Problems to be Solved by the Invention In the device configured as described above, the current mode flowing during power running and regenerative braking of the electric vehicle 6 is shown in FIG. In FIG. 3, the region from time t ₀ to time t ₁ shows the current waveform during power running of the electric vehicle 6, and the region from time t ₁ to time t ₂ represents the current waveform during regenerative braking of the electric vehicle 6. Shows the current waveform. Immediately after the electric vehicle 6 starts regenerative braking at time _t1 , the peak value of the regenerative current becomes very large, and a large amount of electric power is generated. In order to wastelessly regenerate the large electric power generated immediately after the start of regenerative braking to the commercial frequency power supply side, the inverter 4 needs to have a large capacity. This results in poor economic efficiency and an increase in equipment area.
Therefore, considering issues such as economic efficiency, equipment area, and utilization rate of the inverter, if the capacity of the inverter 4 is set to a level that allows normal operation, the problem occurs immediately after starting regenerative braking. This makes it impossible to regenerate the large amount of regenerative energy that is generated, and it becomes impossible to use electric power effectively.

The present invention has been devised in view of the above points, and provides a DC electric railway power supply device that can wastelessly regenerate regenerative power generated during regenerative braking without increasing the power capacity of the inverter. The purpose is to

E. Means for Solving Problems The present invention consists of a forward converter that converts AC power to DC and supplies the DC power to the overhead contact line, and an inverse converter that converts the DC regenerative power generated in the overhead contact line to AC. , a battery attached to this inverter and an electric line connecting this battery and the above-mentioned overhead contact line are inserted, and the electric power generated in the overhead contact line is guided to the battery when the overhead contact line voltage exceeds a predetermined value, and the electric power generated in the overhead contact line is connected to the battery. The present invention is characterized in that it includes a switching circuit that guides the charge stored in the battery to the DC input side of the inverter when is below a predetermined value.

F Effect In the device configured as above, among the electric power generated when an electric car under the overhead contact line performs regenerative braking, a large amount of energy immediately after the start of regenerative braking is charged to the battery by the switching circuit. The amount of power that can be regenerated by the inverter is regenerated to the AC power supply side by the inverter. During power running of the electric vehicle, DC output power of the forward converter is supplied. At this time, if the overhead line voltage is below a predetermined value, the charging energy of the battery is guided to the inverter via the switching circuit and returned to the AC power source. In this way, it is possible to charge the battery with a large amount of energy immediately after the start of regenerative braking of the electric vehicle, so that the power capacity of the inverter can be suppressed to a level that allows normal operation.

G. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the same parts as in FIG. 2 are designated with the same reference numerals. In Figure 1, the second
The difference from the diagram is that the DC input side of the inverter 4 is connected to the overhead contact line 3 via the cathode and anode of the diode 11, and the diode 1 is connected to the overhead contact line 3.
Battery 13 via the anode and cathode of 2
A thyristor 16 of the polarity shown in the figure is inserted into the electric line connecting the positive terminal of the battery 13 and the diode 12 and the common connection point 15 of the inverter 4 and the diode 11, Voltage relay 1 via DC transformer 17
8 are connected, and the other parts have the same configuration. Here, the thyristor 16 is turned on when the secondary voltage of the DC transformer 17 (voltage proportional to the voltage of the overhead contact line 3) becomes equal to or less than the set value of the voltage relay 18. Further, the capacity of the inverter 4 is set to a level that allows normal operation. Further, the thyristor 16 is in an off state when the secondary voltage of the DC transformer 17 (voltage proportional to the voltage of the overhead contact line 3) is equal to or higher than the set value of the voltage relay 18.

When the electric car 6 currently running under the overhead contact line 3 performs regenerative braking, regenerative power is generated. At this time, immediately after the start of regenerative braking, a peak current i ₂ with a large rise occurs, and this peak current i ₂ flows into the battery 13 via the contact wire 3 and the diode 12 as indicated by the broken arrow, and charges the battery 13. . Moreover, if the regenerative current flowing from the electric car 6 has a current value i ₁ that can be absorbed by the inverter 4,
The regenerated current i ₁ flows into the inverter 4 via the overhead contact line 3 as indicated by the solid arrow, and is regenerated to the commercial frequency power source (not shown) by the inverse conversion operation. Next, when the electric vehicle 6 performs a power running operation, power running power is supplied from the forward converter 2. At this time, when a voltage drop occurs in the overhead contact line 3 and the secondary voltage of the DC transformer 17 becomes lower than the set voltage of the voltage relay 18, an on-gate signal is supplied from a control circuit (not shown) to the gate of the thyristor 16, and the thyristor 16 is turned on. Becomes conductive. This causes the battery 13 to pass through the thyristor 16 to the inverter 4 as shown by the dashed arrow.
A current _i3 flows into the input side of. The DC power generated by the current i ₃ is converted into AC by the inverter 4 and returned to the commercial frequency power source (not shown). The current i ₃ flowing from the battery 13 to the inverter 4 includes the electric power due to the peak current i ₂ stored in the battery 13 during the regenerative braking described above, and the large electric power generated immediately after regenerative braking is It can be returned to the commercial frequency power source and used effectively.

The switching circuit is not limited to the diodes 11, 12 and the thyristor 16 as in the embodiment, but may be composed of other elements having the same function.

By repeating the above-described operations during power running and regenerative operation, regenerated power during regenerative braking of the electric vehicle 6 can be effectively utilized. Further, since the battery 13 is provided, the capacity of the inverter 4 does not have to be large enough to cope with the large amount of power generated immediately after the start of regenerative braking, resulting in a significant cost reduction.

E. Effects of the invention As described above, according to the invention, the following effects can be obtained. That is, (1) Since a battery is attached to the inverter, there is no need to increase the power capacity of the inverter, and costs can be reduced.

(2) Since the switching circuit is provided, charging energy of the battery can be supplied to the input side of the inverter when the overhead line voltage is at the desired set voltage.

(3) Regenerative power generated by electric vehicles can be used effectively without waste.

(4) Electric vehicles no longer need to use air brakes and can effectively utilize regenerative braking.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing one embodiment of the present invention;
The figure is a circuit diagram showing an example of a conventional power supply device, and FIG. 3 is a current waveform diagram for explaining the operation of FIG. 2. 2...forward converter, 3...telephone line, 4...inverse converter, 6...electric car, 11, 12...diode,
13...Battery, 16...Thyristor, 17
...DC transformer, 18...voltage relay.

Claims (1)

[Scope of utility model registration request] a forward converter that converts AC power to DC and supplies the DC power to the overhead contact line; an inverse converter that converts the DC regenerated power generated in the overhead contact line to AC; a battery attached to the inverse converter; It is inserted into the electric line connecting the battery and the above-mentioned contact line, and when the contact line voltage is above a predetermined value, the electric power generated in the contact line is conducted to the battery, and when the contact line voltage is below the predetermined value, the charge in the battery is transferred to the above-mentioned reverse. A power supply device for a DC electric railway, comprising a switching circuit that leads to the DC input side of a converter.