JP2001287572A - Railway dc power source facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the disadvantage of the suppression of the voltage fluctuation of a feeder by the serial connection of only a current control circuit 4 and a DC power accumulating circuit 5A having a cell structure of secondary batteries or electric double-layer capacitors in parallel to a rectifier 1, or the necessity of a high voltage for the circuit 5A, resulting in the larger size thereof, and poor facility efficiency. SOLUTION: A semiconductor power converting device 6 generates a fixed voltage corresponding to the rated voltage of the feeder as the bias voltage applied to the DC power accumulating circuit 5A, whereby the number of serially connected cells necessary for the DC power accumulating circuit 5A is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC power supply system for railways, and more particularly to an energy storage device installed for the purpose of measures against voltage drop, peak cut, regenerative power and the like.

[0002]

2. Description of the Related Art Electric railway power supply equipment is mainly powered by electric vehicles, and therefore is required to have a power supply capability unique to other general distribution system loads.

(1) Capable of following a sudden load change. In other words, electric vehicles, which are loads on electric railways, have a plurality of randomly changing operating states such as acceleration, constant speed, deceleration, and stop, and the sum of these changes suddenly. Equipment that can supply power with good responsiveness is required.

(2) A stable power supply is possible for a long time. That is, electric vehicles include those that operate non-stop over long distances, such as limited express trains, and require a stable power supply capability over the operation time.

(3) It is desired to level the load. That is, a sudden load change involves a sudden change in the load as viewed from the substation. In addition, the number of electric vehicles to be driven is large during the morning and evening rush hours, and is reduced during the off hours during the day. For these load changes, load leveling is required from the substation side in order to improve power conversion efficiency and the like.

[0006] To meet the above requirements, a method of providing an energy storage device has been proposed. For example, a test using a storage battery facility as an energy storage device has been performed at Nakajima Station on the JR Kabe Line for five years since 1979, and a report has been published.

As another method, in a DC feeding system, a system has been proposed in which regenerative power from an electric vehicle is regenerated as DC power in an energy storage device provided on the feeder line side (for example, Japanese Patent Application Laid-Open No. 11-91415). No.). This energy storage device is configured as shown in FIG. In supplying DC power to the feeder line from the rectifier (or forward converter) 1 and further supplying power to the electric vehicle 3 from the trolley wire via the switch 2, a current control circuit (step-up / step-down chopper) 4 is provided on the DC side of the rectifier 1. An energy storage device including a DC power storage device (a secondary battery or an electric double layer capacitor) 5 is provided. When the electric vehicle is in a regenerative state, the DC power storage device 5 is charged through the current control circuit 4, and the electric vehicle is charged. In the power running state, the DC power storage device 5 is discharged through the current control circuit 4.

[0008]

As described above, the feeding voltage of a DC railroad fluctuates greatly with respect to a rated voltage of 1500 V due to a sudden load change and a peak time period peculiar to an electric vehicle. In response to the voltage fluctuation, the energy storage device discharges and charges the lowest voltage from 900 V to the highest voltage 18.
Suppress to about 00V.

The voltage suppressing operation by this energy storage device is as shown in FIG. 5. When the feeder line voltage exceeds the upper limit value 1800 V of the control voltage, the current control circuit 4 performs the step-down charging operation, and Overvoltage is suppressed by starting charging the DC power storage device 5, and the current control circuit 4 performs a boost discharge operation when the feeder line voltage falls below the lower limit value 900V of the control voltage, and discharges from the device 5 to the feeder side. To suppress the undervoltage.

Therefore, in order to obtain a compensation voltage range of 900 V (1800-900), an energy storage device having a high rated voltage including a bias voltage of 900 V is required.

The bias divided voltage of the DC power storage device 5 is actually set to a lower voltage (for example, a rated voltage of 600 V) by the step-up / step-down ratio of the current control circuit 4.

Here, the storage battery or electric double layer capacitor serving as the power storage means of the energy storage device has a voltage per unit cell of about 2 V, and has a DC
In order to apply the voltage to 0 V, a configuration is adopted in which 750 to 800 cells are connected in series, and further, cells connected in series are connected in parallel according to the current capacity.

Therefore, even if the DC power storage device 5 needs only a voltage lowered by the step-up / step-down ratio by the current control circuit 4, a large number of battery cells including the voltage are connected in series in order to secure a bias divided voltage. In this case, there is a problem that the device becomes large and the equipment efficiency is low.

SUMMARY OF THE INVENTION An object of the present invention is to provide a DC power supply for electric railways capable of reducing the size of an energy storage device and improving the efficiency of the equipment.

[0015]

In order to solve the above-mentioned problems, the present invention provides a semiconductor power converter in which a bias voltage required for a DC power storage device of an energy storage device is provided in series with the device. It is designed to bear the burden, and is characterized by the following configuration.

A rectifier or a forward converter that supplies DC power to the feeder is provided in parallel, and is stored in the DC power storage device by charging from the wire in response to a change in load, and is supplied from the DC power storage device to the feeder. In a direct current power supply facility for railways provided with an energy storage device for discharging power, the DC power storage device is configured by a cell with a secondary battery or an electric double layer capacitor, and a rated voltage corresponding to a voltage fluctuation range of a feeder line. And a semiconductor power converter connected in series with the DC power storage circuit and generating a constant voltage corresponding to a bias applied to the DC power storage circuit.

Further, the semiconductor power conversion device may include a step-up / step-down chopper for generating a constant voltage using a DC output of the rectifier or the forward converter as a power supply, or a constant voltage using an AC power supply of the rectifier or the forward converter as a power supply. And a constant-voltage DC power supply.

[0018]

FIG. 1 is a diagram showing a main circuit configuration of an energy storage device, which is an electric power supply system according to an embodiment of the present invention. 4 differs from FIG. 4 in that a DC power storage circuit 5A and a semiconductor power conversion device 6 connected in series to the DC power storage circuit 5A to generate a constant voltage are provided.

The power conversion device 6 sets the generated constant voltage to a voltage close to or close to the bias voltage required for the conventional DC power storage device 5. The power conversion device 6 obtains a power supply necessary for generating a constant voltage from a DC output of the rectifier 1 or an AC power supply of the rectifier 1.

With the above configuration, the semiconductor power converter 6 bears the bias voltage required for the DC power storage device 5, so that the rated voltage of the DC power storage circuit 5A is higher than that of the conventional DC power storage circuit 5A. A lower voltage with less minutes is sufficient.

For example, in the power supply configuration having the voltage fluctuation range shown in FIG. 5, when the energy storage device has a bias of 900 V to suppress the line voltage, the DC power storage circuit 5A responds to the conventional 1800V charge / discharge operation. On the other hand, it is made possible to respond to the charge / discharge operation for 900 V, and the semiconductor power converter 6 generates a constant voltage of 900 V.

As a result, the DC power storage circuit 5A only needs to have a rated voltage that is half that of the conventional DC power storage circuit, and the number of cell configuration stages can be reduced by half, so that the device can be reduced in size and the equipment efficiency can be improved.

The semiconductor power converter 6 can be realized by a chopper system or a constant-voltage DC power supply using an external power supply.

FIG. 2 shows a main circuit configuration of the step-up / step-down chopper system. The step-up / step-down chopper 6A is configured by connecting semiconductor switches SW1 and SW2 represented by IGBTs in series, providing flywheel diodes D1 and D2 in anti-parallel to these switches SW1 and SW2 to form upper and lower arms. A connection is made to the electric double layer capacitor (or power capacitor) C0 via the DC reactor L.

The capacity of the capacitor C0 is for generating a constant voltage, and the necessary charge / discharge current is borne by the step-up / step-down chopper 6A. For this reason, the capacitor C0 needs to be a high-voltage, small-current capacitor, that is, a small-sized capacitor.

With this configuration, the capacitor C0 is controlled to a constant voltage (bias divided voltage) by step-down charging from the feeder line to the electric double layer capacitor C0 or boosting discharge from the capacitor C0 to the feeder line side.

The step-down charging of the electric double layer capacitor C0 by the step-up / step-down chopper 6A is performed by switches SW1 and SW
Switch SW with respect to the DC voltage applied across
1 is operated as a chopper, and the switch SW
1 through the reactor L through the electric double layer capacitor C0
During the off period, the charging current is supplied to the electric double layer capacitor C0 through the path of the electric double layer capacitor C0 → diode D2.

The step-up discharge from the electric double layer capacitor C0 through the step-up / step-down chopper 6A causes the switch SW2 to perform a chopper operation, and a short-circuit current flows from the electric double layer capacitor C0 to the reactor L during the on-period thereof. During the off-period, the current energy flows from the reactor L through the diode D1 and is discharged to the electric wire side.

The capacitor C and the reactor DCL provided on the high voltage side of the step-up / step-down chopper 6A generate harmonics (harmonics due to chopper operation) included in the charge / discharge current from the electric double layer capacitor C0 through the step-up / step-down chopper 6A. It is for suppressing.

FIG. 3 is a main circuit configuration diagram when the semiconductor power converter 6 is a constant-voltage DC power supply. The constant-voltage DC power supply 6B enables exchange of AC power between the AC power supply of the rectifier 1 and the AC power supply by interposing an AC circuit breaker CB and a step-down transformer TR therebetween.

A forward / inverse converter CON is provided on the secondary side of the step-down transformer TR. The DC output of the converter CON charges and discharges the electric double layer capacitor C0 to a constant voltage. That is, when the voltage of the capacitor C0 is about to decrease, the converter CON performs a forward conversion operation to control the capacitor C0 to a constant voltage. When the voltage of the capacitor C0 is about to rise, the converter CON performs an inverse conversion operation to control the capacitor C0 to a constant voltage.

The semiconductor power conversion device 6 has an input / output current capacity equivalent to the charge / discharge current capacity required for the DC power storage circuit 5A, so that the conventional energy storage device 5 has Voltage fluctuation can be suppressed with a response almost equal to the response. At this time, even if the semiconductor power conversion device 6 having the current capacity is configured,
The configuration provided with the device 6 can be downsized compared to the cell configuration corresponding to the bias component of the conventional DC power storage device 5.

[0033]

As described above, according to the present invention, the bias voltage required for the DC power storage device is borne by the semiconductor power conversion device provided in series with the DC power storage device. Miniaturization and facility efficiency can be improved.

[Brief description of the drawings]

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

FIG. 2 is a circuit example of a step-up / step-down chopper according to the embodiment;

FIG. 3 is a circuit example of a constant-voltage DC power supply according to the embodiment.

FIG. 4 is a configuration example of a DC power supply system for railways.

FIG. 5 is a diagram showing a voltage suppression range by the energy storage device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rectifier 4 current control circuit 5 DC power storage device 5A DC power storage circuit 6 semiconductor power conversion device 6A step-up / step-down chopper 6B constant voltage DC power supply

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G003 AA01 BA03 CA12 DA16 FA06 GA01 GB03 GB06 5H006 AA06 AA07 BB05 CA01 CA07 CA08 CA12 CB00 CC04 CC08 DA04 DB01 FA04

Claims (2)

[Claims] 1. A rectifier or a forward converter that supplies DC power to a feeder line, and is provided in parallel with a rectifier or a forward converter. The charge from the feeder line accumulates in the DC power storage device and responds to the feeder line from the DC power storage device in response to a change in load. In a DC power supply facility for railways provided with an energy storage device for discharging DC power, the DC power storage device is composed of a secondary battery or an electric double layer capacitor, and has a rating corresponding to a voltage fluctuation range of a feeder line. A DC power storage circuit having a voltage, and a semiconductor power converter that is connected in series with the DC power storage circuit and generates a constant voltage as a bias applied to the DC power storage circuit. DC power supply equipment. 2. The step-up / step-down chopper for generating a constant voltage by using a DC output of the rectifier or the forward converter as a power supply, or a constant voltage by using an AC power supply of the rectifier or the forward converter as a power supply. The DC power supply for railways according to claim 1, wherein the DC power supply is a constant voltage DC power supply.