JP2016068741A - Electric power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power conversion device which supplies electric power to a feeder line when an electric power supply is lost and, thereby, can retreat a train on the feeder line to a nearest station.SOLUTION: An electric power conversion device which is provided on a facility for supplying DC electric power to a feeder line via a diode rectifier from an electric power supply in order to supply and recover electric power upon acceleration/deceleration of a train upon the feeder line includes: a DC/DC electric power converter which connects a DC circuit of the feeder line side to both ends of a vertical arm by means of a switching element provided with a reverse parallel diode and connects an electric power storage device side DC circuit between connection points of the vertical arm by means of the switching element and a lower arm; and a smoothing capacitor installed in parallel to the DC circuit of the feeder line side. Therein, a series circuit of an electric power storage device and a step-up reactor is disposed on the electric power storage device side DC circuit and, when an electric power supply is lost, the electric power storage device side DC circuit is connected to the DC/DC electric power converter to charge the smoothing capacitor and, subsequently, the DC circuit of the feeder line side is connected to the feeder line to start firing of the switching element.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power converter used for a feeder, and more particularly to a power converter suitable for supplying power to a feeder when the power of the feeder is lost.

  In the wake of the Great East Japan Earthquake, the loss of infrastructure functions during large-scale power outages has become a social concern. Similar countermeasures for large-scale power outages are also required in the field of electric railways. Specifically, when power is lost in feeders for electric railways, power supply from feeders proceeds. There is a need to transport trains from emergency stops to the nearest station.

  However, in this case, since the power source itself is lost, a power source for supplying power to the train is required instead. As an alternative power source in this case, it is conceivable to apply a power storage type regenerative power absorbing device that stores regenerative power at the time of stopping of the train on the feeder and supplies power when the train is accelerated.

  Regarding a power storage type regenerative power absorbing device, for example, Patent Document 1 proposes a device that uses a power storage element and stabilizes a wire voltage.

  Moreover, although it is not a power storage type regenerative power absorption device, Patent Document 2 discloses a method for initial charging using a chopper device that intermittently controls current and controls a conduction rate for a power converter device for general use. Has been.

Japanese Patent No. 4432675 JP 2013-027095 A

  The power storage type regenerative power absorption device of Patent Document 1 can contribute to stabilization of feeder voltage. However, it cannot function in the scene of power loss that should be dealt with in the present invention.

  The facility of Patent Document 1 is based on the premise that a feeder voltage is maintained from a power source by a diode rectifier, and a smoothing capacitor provided in the input circuit of the power converter is naturally discharged during a power failure. If the power is turned on to start operation in this state, an excessive inrush current flows through the smoothing capacitor and the diode, which may damage the smoothing capacitor and the diode.

  About patent document 2, the idea of carrying out initial charge using a chopper device is worth considering. However, in Patent Document 2, a system is configured by separately preparing equipment for initial charging and originally adding to the equipment, and it is inevitable that the entire system including the initial charging apparatus is enlarged. Also, when using a chopper device, the switching element must have a high withstand voltage because of its large transformation ratio. For this reason, the switching element is enlarged, and the system including the initial charging device is enlarged in a double sense. In addition, the circuit configuration becomes complicated.

  In view of the above, an object of the present invention is to provide a power converter capable of supplying power to a feeder line when the power source is lost and retracting a train on the conductor to the nearest station.

  From the above, in the present invention, a power converter for supplying and collecting electric power at the time of acceleration / deceleration of a train on a feeder is provided in a facility for supplying DC power to a feeder via a diode rectifier from a power source. In this power converter, a DC circuit on the feeder side is connected to both ends of the upper and lower arms of the switching element having antiparallel diodes, and power is connected between the connection point of the upper and lower arms by the switching element and the lower arm. A DC / DC power converter that connects the DC circuit on the storage device side and a smoothing capacitor installed in parallel on the DC circuit on the feeder side, and a series circuit of the power storage device and the boosting reactor are provided on the DC circuit on the power storage device side When the power source is lost, the power storage device side DC circuit is connected to the DC / DC power converter to charge the smoothing capacitor, and then the feeder side DC circuit is connected to the feeder. Connected, characterized by starting the ignition of the switching element.

  When power is lost, power can be supplied to the feeder and the train on the conductor can be evacuated to the nearest station.

The figure which shows an example of the whole structure of the feeder electric power feeding equipment with which the power converter device of this invention is applied. The figure which shows each part voltage of FIG. 1, the opening / closing state of each part contactor, etc. The figure which shows the initial stage charge process sequence of the power converter device of this invention.

  Hereinafter, the present invention will be described with reference to the drawings.

  An example of the overall configuration of a feeder power supply facility to which the power conversion device of the present invention is applied will be described with reference to FIG. In FIG. 1, G is a power source, CB is a circuit breaker, Tr is a transformer, and Re is a diode rectifier. Normally, this flow supplies DC power between the feeder 7 and the rail 8, and the train 12 Driving with electric power. In addition, since the state which has lost the power supply is assumed in this invention, the circuit breaker CB is in an open state.

  A regenerative power absorbing device 20 that is a power conversion device of the present invention stores regenerative power at the time of deceleration of a train on a feeder, and is appropriately disposed at various places on the feeder for the purpose of supplying power in a scene such as acceleration of a train. Has been. A regenerative power absorbing device 20 shown in FIG. 1 includes a power storage device (storage battery such as lithium) 1, contactors 2 and 6, a boosting reactor 3, a DC / DC power converter 4, a smoothing capacitor 5, a controller 10, and a voltage detector. 11 or the like.

  The DC / DC power converter 4 is composed of a switching element Sw such as a MOS semiconductor element provided with an antiparallel diode D, and connects a feeder DC circuit DC1 to both ends of the upper and lower arms of the switching element Sw. The power storage device side DC circuit DC2 is connected between the connection point of the upper and lower arms and the lower arm. The step-up reactor 3 and the smoothing capacitor 5 constitute a smoothing circuit.

  Further, the DC / DC power converter 4 receives the ignition signal S1 from the controller, and the ignition timing of the switching element Sw is controlled. The terminal voltage of the DC / DC power converter 4 with respect to the voltage on the feeder side By adjusting the power direction, the direction of electric power is determined as electric power supply in the train acceleration direction and electric power recovery in the train deceleration direction.

  In the state where the power source is lost, the contactors 2 and 6 are in an open state, and the DC / DC power converter 4 is in a non-conductive state. It is assumed that sufficient electric power is stored for evacuation.

  Further, since the voltage Vc of the smoothing capacitor is about twice the voltage of the power storage device at the time of initial charging, the power storage device is configured such that (overvoltage judgment value of the voltage Vc)> (voltage of the power storage device × 2). . Further, it is assumed that the antiparallel diode D of the DC / DC power converter 4 has a current tolerance greater than the current flowing in the circuit during initial charging.

  FIG. 2 shows each part voltage in FIG. 1, the open / close state of each contactor, and the like. From above, (a) is the terminal voltage of the smoothing capacitor 5, (b) is the initial charging current, (c) is the open / closed state of the contactor 2, (d) is the open / closed state of the contactor 6, and (e) is the switching element (eg, IGBT). ) On and off states, respectively.

  In the terminal voltage Vc of the smoothing capacitor 5 in FIG. 2 (a), the time t1 means the power supply loss time, and as a result, the terminal voltage Vc of the smoothing capacitor 5 is reduced to be lower than the judgment value 1 at the time t2. Accordingly, the contactors 2 and 6 are in the off state. At approximately the same time, the switching element (e) (eg, IGBT) is also turned off.

  The voltage detector 11 detects the voltage Vc of the smoothing capacitor 5. The controller 10 compares the voltage Vc of the smoothing capacitor 5 with the determination value, and outputs ON / OFF commands for the contactors 2 and 6.

  From this state, in the present invention, by performing the initial charging process according to the procedure shown in FIG. FIG. 3 is a diagram showing an initial charging process procedure of the power conversion device of the present invention. The process of FIG. 3 is a summary of instructions from the controller 10 of FIG.

  In FIG. 3, in the first process step S101 of this determination process, the occurrence of a power failure is detected. That is, the loss of the power supply G is detected by, for example, opening the circuit breaker CB or decreasing the terminal voltage Vc of the smoothing capacitor 5. This time corresponds to t1 in FIG. If a power failure occurs at time t1 while the regenerative power absorber 20 is in operation, the voltage Vc of the smoothing capacitor 5 decreases after the power failure occurs. At time t2, the controller 10 determines that the voltage Vc is equal to or less than the determination value 1, and gives an OFF signal to the contactor 2 and the contactor 6.

  In the next processing step S102, it is confirmed whether or not there is an operation start command. It is possible to start the next initial charging process immediately under the condition of a voltage drop, but after confirming the current status of each train and making the emergency evacuation process known to various parts of the site, upon the agreement of all members It is desirable to set the operation start command. The time when this operation start command is issued is t5.

  In the next processing step S103, it is confirmed that the capacitor voltage Vc is sufficiently lowered (determination value 2 or less) in the state where the operation start is instructed. This confirmation time is t3.

  In the processing step S104, when the controller 10 determines that the voltage Vc is equal to or less than the determination value 2 at the time t3, it gives an ON signal to the contactor 2. When the contactor 2 is turned on, a circuit extending from the power storage device 1 to the contactor 2 to the anti-parallel diode D of the upper arm of the DC / DC power converter 4 to the smoothing capacitor 5 to the power storage device 1 is formed. The smoothing capacitor 5 is initially charged by LC resonance of the boost reactor 3. This initial charging current is shown in FIG. 2B, and the initial charging current flows only during the half-wave period in which the circuit is formed.

  In process step S105, completion of initial charging is detected. This time is t4. In processing step S106, the controller 10 gives an ON signal to the contactor 6, and in processing step S107, for example, gives an ignition signal to the IGBT as the switching element SW from time t6. drive.

  In this way, if a circuit is formed through the antiparallel diode D in the switching element Sw of the DC / DC power converter 4 and the LC resonance by the smoothing capacitor 5 and the step-up reactor 3 is used, the size of the initial charging device can be increased. By avoiding complication, the smoothing capacitor can be initially charged even during a power failure. This enables emergency evacuation of the train on the feeder to the nearest station.

DESCRIPTION OF SYMBOLS 1 ... Electric power storage device 2, 6 ... Contactor 3 ... Boosting reactor 4 ... DC / DC power converter 5 ... Smoothing capacitor 7 ... Feed wire 8 ... Rail 10 ... Controller 11 ... Voltage detector

Claims (4)

A power converter for supplying and recovering power at the time of acceleration / deceleration of a train on a feeder, provided in a facility for supplying DC power to the feeder via a diode rectifier from a power source,
In the power converter, a DC circuit on the feeder line side is connected to both ends of an upper and lower arm by a switching element provided with an antiparallel diode, and a power storage device side is connected between the connection point of the upper and lower arm by the switching element and the lower arm. A DC / DC power converter for connecting a DC circuit, and a smoothing capacitor installed in parallel to the DC circuit on the feeder side, and a series circuit of a power storage device and a boosting reactor in the DC circuit on the power storage device side,
In the lost state of the power source, connect the DC circuit to the DC / DC power converter and charge the smoothing capacitor, and then connect the DC circuit on the feeder side to the feeder line, A power conversion device which starts ignition of a switching element. The power conversion device according to claim 1,
The DC circuit on the power storage device side is connected to the DC / DC power converter via a first contactor, and the DC circuit on the feeder side is connected to the feeder via a second contactor. The power converter characterized by this. The power conversion device according to claim 1 or 2, wherein
When connecting the DC circuit of the power storage device side to the DC / DC power converter, it is necessary to confirm that the terminal voltage of the smoothing capacitor is not more than a predetermined value. It is a power converter device of any one of Claims 1-3, Comprising:
When connecting the power storage device side DC circuit to the DC / DC power converter, it is necessary to confirm that there is an operation start command.

Images