JP6343577B2 - Cross current detection circuit, auxiliary power supply device, and auxiliary power supply system - Google Patents

Description

  The present invention relates to a cross current detection circuit, an auxiliary power supply device, and an auxiliary power supply system used in a railway vehicle.

  In an auxiliary power supply system that connects railcar auxiliary power supplies in parallel and supplies power to a common load, if the voltage and phase of the three-phase mains voltage output from each auxiliary power supply is unbalanced, A current that flows only between the power supply devices (hereinafter referred to as “cross current”) is generated. Thus, it is known that parallel synchronous operation by an auxiliary power supply device can be realized by detecting the cross current and controlling the cross current to be minimum (see, for example, Patent Documents 1 and 2).

  FIG. 3 is a diagram showing a configuration example of such a conventional auxiliary power supply system. The auxiliary power supply system 2 includes auxiliary power supply devices 10 connected in parallel. Each auxiliary power supply device 10 includes an inverter 11, a control unit 12, a main line current detection unit 13, a cross current detection circuit 20, and a contactor (3phMK: 3 Phase Motor Contactor) 30. The cross current detection circuit 20 detects the cross current and outputs it to the control unit 12. The control unit 12 controls the voltage and phase output from the inverter 11 so that the cross current is minimized. The control unit 12 connects and releases the auxiliary power supply 10 and the mains voltage by turning on and releasing (releasing) the main contact of the contactor (3phMK: 3 Phase Motor Contactor) 30. In addition, the cross current detection circuit 20 is turned on and opened using the auxiliary contact of the contactor 30.

JP-A-8-214553 JP 2002-64938 A

  However, since the main contact and the auxiliary contact of the contactor 30 are mechanically delayed from receiving the input command from the control unit 12 to being actually input, even if there is no abnormality in the main line at the time of the input command, When the contactor 30 is inserted into the main line, an abnormality may occur in the main line. In this case, an overcurrent flows to the auxiliary power supply 10 at the same time when the main contact of the contactor 30 is turned on. Further, since the cross current detection circuit 20 uses the auxiliary contact of the contactor 30, the auxiliary contact is also turned on simultaneously with the turning on of the main contact, and an overcurrent flows through the cross current detection circuit 20. In particular, since the cross current detection circuit 20 is a control circuit, it is vulnerable to a large current and breaks down when a large current flows. If the cross current detection circuit 20 fails, the auxiliary power supply 10 cannot be operated in parallel.

  An object of the present invention made in view of such circumstances is a cross current detection circuit, an auxiliary power supply device, and an auxiliary power supply capable of preventing an overcurrent from flowing to the cross current detection circuit due to a mechanical delay of the contactor. To provide a system.

In order to solve the above-described problem, the cross current detection circuit according to the present invention is provided between the inverters connected in parallel when the power is supplied to the load through the load contactor by the inverter connected in parallel. A cross current detection circuit for detecting a cross current, comprising: a cross current detection unit that detects the cross current and outputs the cross current to a control unit that controls the inverter; and a cross current detection contactor that protects the cross current detection circuit. the cross flow detection contactors after the load contactor is turned on, by the control unit, the abnormal trunk connecting between the load contactor an output terminal of the inverter has not occurred When it is determined, it is thrown based on a throwing command from the control unit.

In order to solve the above problems, an auxiliary power supply according to the present invention is an auxiliary power supply that is connected in parallel and supplies power to a load, and is connected in parallel to an inverter that converts DC power into AC power. A cross current detection circuit that detects a cross current that flows only between the inverters, a control unit that controls a voltage and phase output from the inverter based on the cross current detected by the cross current detection circuit, the inverter, A load contactor connected in series with a load, and the control unit connects the output terminal of the inverter and the load contactor after the load contactor is inserted. When no abnormality occurs in the main line , a closing command is output to the cross current detection contactor of the cross current detection circuit.

Moreover, in order to solve the said subject, the auxiliary power supply system which concerns on this invention is an auxiliary power supply system which supplies electric power to load with the inverter connected in parallel, Comprising: The some inverter which converts direct-current power into alternating current power, and A cross current detection circuit that detects a cross current that flows only between the inverters connected in parallel; a load contactor connected in series between each inverter and the load; and the cross current detection circuit And a control unit for controlling the voltage and phase output from each inverter based on the cross current, and the control unit, after the load contactor is inserted, the output terminal of the inverter and the load When there is no abnormality in the main line connecting to the contactor, a closing command is output to the crossflow detection contactor that protects the crossflow detection circuit.

  According to the present invention, it is possible to prevent an overcurrent from flowing to the cross current detection circuit due to the mechanical delay of the contactor.

It is a figure which shows the structural example of the auxiliary power supply system which concerns on one Embodiment of this invention. It is a time chart which shows the difference in operation of the conventional auxiliary power supply system and the auxiliary power supply system concerning one embodiment of the present invention. It is a figure which shows the structural example of the conventional auxiliary power supply system.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration example of an auxiliary power supply system according to an embodiment of the present invention. The auxiliary power supply system 1 includes a plurality of auxiliary power supply devices 10 connected in parallel. In the example shown in FIG. 1, the auxiliary power supply system 1 includes two auxiliary power supply apparatuses 10 (10-1 and 10-2) connected in parallel, but three or more auxiliary power supply apparatuses 10 may be connected in parallel. Is possible.

  Each auxiliary power supply device 10 includes an inverter 11, a control unit 12, a main line current detection unit 13, a cross current detection circuit 20, and a load contactor 50.

  The load 40 is a device such as a fluorescent lamp or an air conditioner in the vehicle, a storage battery, or the like.

  The inverter 11 converts the DC power collected from the overhead wire into three-phase AC power and supplies the load 40 via the load contactor 50.

  The main line current detection unit 13 detects the main line current and outputs it to the control unit 12. For example, a current transformer (CT) can be used as the main line current detection unit 13.

  Each cross current detection circuit 20 includes cross current detection units 21 and 22, a resistor 23, and a cross current detection contactor 24.

  The cross current detection units 21 and 22 detect a cross current that flows only between the inverters 11 (auxiliary power supply device 10) connected in parallel without flowing to the load 40, and output the detected cross current to the control unit 12. As the cross current detection unit 21, for example, a current transformer (CT) can be used.

  The control unit 12 controls the voltage and phase output from the inverter 11 so that the cross current approaches 0 based on the cross current detected by the cross current detection units 21 and 22.

  Further, the control unit 12 outputs an input or release command to the load contactor 50 and the cross current detection contactor 24. The charging command to the load contactor 50 and the cross current detection contactor 24 is not performed at the same time, but after the load contactor 50 is actually input, the main line abnormality is detected from the current value detected by the main line current detection unit 13. It is determined whether or not it has occurred, and when a trunk line abnormality has not occurred, a closing command is output to the crossflow detection contactor 24. Here, the trunk line abnormality means that an overcurrent such as a short-circuit current flows through the load 40.

  Since a predetermined mechanical delay time (for example, about 150 ms) is generated from when the input command is output to the load contactor 50 until the load contactor 50 is actually input, for example, the control unit 12 loads After outputting the input command to the contactor 50, it is determined whether a main line abnormality has occurred after waiting for a predetermined mechanical delay time to elapse.

  The cross current detection contactor 24 is connected between the output lines of the inverters 11. By introducing the cross current detection contactor 24, the cross current detection circuit 20 can detect the cross current, and when a trunk line abnormality occurs, the cross current detection circuit 20 is opened by opening the cross current detection contactor 24. Can be protected from the main line. Since the cross current detection contactor 24 uses only the main contact without using the auxiliary contact, in this specification, the introduction of the cross current detection contactor 24 refers to the main contact of the cross current detection contactor 24. Means input. The resistor 23 is a resistor that can withstand a large current that flows instantaneously when the cross current detection contactor 24 is opened.

  The load contactor 50 is connected in series between the inverter 11 and the load 40. The load contactor 50 receives an input command from the control unit 12 when the inverter 11 is connected to the load 40. That is, the control unit 12 issues a loading command to the load contactor 50 to connect the inverter 11 to the load 40. Since the load contactor 50 uses only the main contact without using the auxiliary contact, in this specification, the loading of the load contactor 50 means the loading of the main contact of the load contactor 50. To do.

  FIG. 2 is a time chart showing the difference in operation between the conventional auxiliary power system and the auxiliary power system according to the present invention. 2A shows the operation of the conventional auxiliary power supply system 2 shown in FIG. 3, and FIG. 2B shows the operation of the auxiliary power supply system 1 according to the present invention shown in FIG. In FIG. 2, regarding “trunk line abnormality”, the presence of trunk line abnormality is indicated at a high level, and the absence of trunk line abnormality is indicated at a low level. In addition, regarding the “command to the contactor”, the closing command is shown at a high level and the opening command is shown at a low level. In addition, regarding the “contactor operation”, the closing operation is shown at a high level and the opening operation is shown at a low level.

  First, the operation of the conventional auxiliary power supply system 2 shown in FIG. 3 will be described with reference to FIG. A mechanical delay occurs between the main contact and the auxiliary contact of the contactor 30 until the actual contact is received after receiving the input command. Therefore, when the control unit 12 outputs a closing command to the contactor 30 at time t1, the main contact and the auxiliary contact of the contactor 30 are charged at time t3 after a mechanical delay time from the closing command. Then, as shown in FIG. 2A, when there is no trunk line abnormality at time t1 when the control unit 12 outputs the input command to the contactor 30, and when a trunk line abnormality occurs at the time t2 immediately after that, the contactor 30 While it is turned on, overcurrent flows through the cross current detection circuit 20.

  When the control unit 12 detects a trunk line abnormality, it outputs an opening command to the contactor 30 at time t4, and the main contact and auxiliary contact of the contactor 30 are opened at time t5 after the mechanical delay time. Thereafter, when the trunk line abnormality is resolved at time t6, and the controller 12 detects the elimination of the trunk line abnormality, the control unit 12 outputs the input command to the contactor 30 again at time t7, and at time t8 after the mechanical delay time, the control unit 12 The main contact and auxiliary contact are turned on again.

  Next, the operation of the auxiliary power supply system 1 according to the present invention shown in FIG. 1 will be described with reference to FIG. As with the contactor 30, the load contactor 50 and the cross current detection contactor 24 have a mechanical delay from when they are input to when they are actually input. Therefore, when the control unit 12 outputs the input command to the load contactor 50 at time t1, the load contactor 50 is input at time t3 after a mechanical delay time from the input command. In the auxiliary power supply system 1, the control unit 12 determines whether or not a trunk line abnormality has occurred after the load contactor 50 is turned on, and if a trunk line abnormality has not occurred, the cross current detection contactor A closing command is output to 24. As shown in FIG. 2B, when a trunk line abnormality occurs at time t2 between time t1 at which a loading command is output to the load contactor 50 and time t3 at which the load contactor 50 is loaded. The control unit 12 does not output a closing command to the cross current detection contactor 24. Therefore, it is possible to prevent an overcurrent from flowing through the cross current detection circuit 20.

  When the control unit 12 detects a trunk line abnormality, it outputs an opening command to the load contactor 50 at time t4, and the load contactor 50 is opened at time t5 after the mechanical delay time. Thereafter, when the trunk line abnormality is resolved at time t6, and the controller 12 detects the elimination of the trunk line abnormality, the control unit 12 outputs the input command to the load contactor 50 again at time t7, and the load unit is activated at time t8 after the mechanical delay time. The contactor 50 is turned on again. Then, after the time t8 when the load contactor 50 is turned on, the control unit 12 confirms that no trunk line abnormality has occurred, and at time t9, outputs a closing command to the cross current detection contactor 24, and mechanically The cross current detection contactor 24 is turned on at time t10 after the delay time.

  As described above, the cross current detection circuit 20 protects the cross current detection circuits 20 and 22 that detect the cross current that flows only between the inverters 11 connected in parallel and outputs the cross current to the control unit 12. And a crossflow detection contactor 24. The auxiliary power supply device 10 converts the voltage and phase output from the inverter 11 based on the cross current detected by the inverter 11 that converts DC power into AC power, the cross current detection circuit 20 that detects cross current, and the cross current detection circuit 20. The control unit 12 outputs a closing command to the cross current detection contactor 24 when no trunk line abnormality has occurred after the load contactor 50 is turned on. With this configuration, it is possible to prevent an overcurrent from flowing to the cross current detection circuit 20 due to a mechanical delay of the contactor with a simple configuration in which the cross current detection contactor 24 is added.

  Although the above embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, a plurality of constituent blocks described in the embodiments can be combined into one, or one constituent block can be divided.

DESCRIPTION OF SYMBOLS 1 Auxiliary power supply system 10-1, 10-2 Auxiliary power supply device 11 Inverter 12 Control part 13 Trunk current detection part 20 Cross current detection circuit 21, 22 Cross current detection part 23 Resistance 24 Cross current detection contactor 40 Load 50 Load contactor

Claims (3)

A cross current detection circuit that detects a cross current that flows only between inverters connected in parallel when power is supplied to a load via a load contactor by an inverter connected in parallel,
A cross current detection unit that detects the cross current and outputs to the control unit that controls the inverter; and
A cross current detection contactor for protecting the cross current detection circuit,
The cross flow detection contactors determined after the load contactor is turned on, by the control unit, abnormal trunk connecting between the load contactor an output terminal of the inverter has not occurred When this is done, the cross current detection circuit is turned on based on a turn command from the control section. An auxiliary power supply device connected in parallel and supplying power to a load,
An inverter that converts DC power to AC power;
A cross current detection circuit that detects a cross current that flows only between the inverters connected in parallel;
Based on the cross current detected by the cross current detection circuit, a control unit for controlling the voltage and phase output from the inverter;
A load contactor connected in series between the inverter and the load,
Wherein, after said load contactor is turned on, when an abnormality in the main line connecting between the load contactor an output terminal of the inverter does not occur, lateral flow detection of the cross current detecting circuit Auxiliary power supply device that outputs a closing command to the contactor for use. An auxiliary power supply system that supplies power to a load by an inverter connected in parallel,
A plurality of inverters for converting DC power to AC power;
A cross current detection circuit that detects a cross current that flows only between the inverters connected in parallel;
A load contactor connected in series between each inverter and the load;
A controller that controls the voltage and phase output from each inverter based on the cross current detected by the cross current detection circuit;
Wherein, after the load contactor is turned on, when an abnormality in the main line connecting between the load contactor an output terminal of the inverter has not occurred, to protect the cross current detecting circuit An auxiliary power supply system that outputs a closing command to a contactor for detecting a cross current.

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