GB2540660A

GB2540660A - Auxiliary power supply system and operation method for the same

Info

Publication number: GB2540660A
Application number: GB1608993.0A
Authority: GB
Inventors: Muraoka Kazufumi; Kawamoto Takehiro; Yamaguchi Satoshi; Kogure Hiroshi
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2015-06-01
Filing date: 2016-05-23
Publication date: 2017-01-25
Anticipated expiration: 2036-05-23
Also published as: DE102016209442B4; GB2540660B; GB201608993D0; CN106183816A; JP6397799B2; JP2016226187A; CN106183816B; DE102016209442A1

Abstract

An auxiliary power supply system, particularly mounted on a plurality of railway vehicles, includes a plurality of auxiliary power supplies 31, 32 including an inverter 4 for converting power received from an overhead line 1 into AC power. Vehicle connection joint boxes 111 to 113 are placed at positions joining vehicles between the output lines 91 to 95 and an electromagnetic contactor 12 is provided between the output lines. The auxiliary power supply includes a control device for controlling the inverter and the electromagnetic contactor. The control device opens the electromagnetic contactor when detecting an abnormal state of an input or output of the inverter equal to or more than a predetermined number of times within a predetermined time. The abnormal state of the input or output of the inverter may be an imbalance of AC output phase current, an overvoltage at the AC output voltage, an overvoltage at a filter capacitor of the inverter and/or an overload of an AC output current.

Description

TITLE OF THE INVENTION

AUXILIARY POWER SUPPLY SYSTEM AND OPERATION METHOD FOR THE

SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an auxiliary power supply for supplying power to an electronic component for a vehicle (load) mounted on a vehicle, and especially, to a system in which the plurality of auxiliary power supplies is operated in parallel. 2. Description of the Related Art

In order to ensure redundancy to stop due to a failure and the like, the plurality of auxiliary power supplies (APS) for supplying power to the electronic component for the vehicle mounted on the vehicle is operated in parallel. Even when the single auxiliary power supply is stopped to be protected, system down is prevented by continuously operating other auxiliary power supplies. When the plurality of auxiliary power supplies is operated in parallel, an output line connected to the load is pulled between the auxiliary power supplies. Therefore, when the auxiliary power supply has detected the protection and has been stopped due to the pulled line, all the APSs operated in parallel are stopped for protection, and there is a possibility that the system down occurs. As a solution to this problem, the following proposal has been made. JP-2006-304435-A discloses a solution at the time when an output line of a power supply for a vehicle corresponding to the auxiliary power supply is grounded. When a controller of the power supply for a vehicle detects an overcurrent and stops the operation of the power supply for a vehicle, an opening contactor provided in the output line is opened. After that, when the power supply for a vehicle is restarted, the power supply for a vehicle including a grounding section in a supply section detects the overcurrent again and locks out the power supply, and other power supplies for a vehicle are continuously operated. Accordingly, the system down is prevented.

SUMMARY OF THE INVENTION

Generally, since the loads connected to the output lines are arranged across a plurality of vehicles, the output line is connected with a vehicle connection joint box provided at the end of the vehicle. Incorrect connection of the output line due to a work error in the vehicle connection joint box generates a contact failure and the like, and the parallel operation fails because of a change of a resistance value of the output line. Then, there is a possibility that the system down occurs.

In a parallel operation protection device of the power supply for a vehicle disclosed in JP-2006-304435-A, when the output lines are correctly connected in the joint box, the opening contactor cannot be opened without generation of the overcurrent, and all the power supplies for a vehicle operated in parallel are stopped for the protection. There is a possibility that the system down occurs . A purpose of the present invention is to provide an auxiliary power supply system which prevents system down by separating an auxiliary power supply in an abnormal state even when a connection failure and the like occurs in a vehicle connection joint box connected between output lines of the auxiliary power supplies.

The present invention is an auxiliary power supply system which includes a plurality of auxiliary power supplies including an inverter for converting power received from an overhead line into AC power, a vehicle connection joint box for connecting output lines when the output line from the auxiliary power supply joints vehicles, and an electromagnetic contactor provided between the output lines. The auxiliary power supply includes a control device for controlling the inverter and the electromagnetic contactor. The control device opens the electromagnetic contactor when detecting an abnormal state of a state quantity according to an input or output of the inverter equal to or more than a predetermined number of times within a predetermined time.

According to the present invention, an unstable state such as unbalance of an output current and fluctuation of an output voltage caused by the generation of the connection failure in the vehicle connection joint box and the change of the load of the auxiliary power supply is quickly detected, and the auxiliary power supply in an abnormal state is separated from a parallel operation system. According to this, the auxiliary power supply, which supplies power to a section where a connection failure of the vehicle connection joint box does not occur, can be continuously operated, and system down can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a block diagram of a parallel operation system of an auxiliary power supply according to a basic embodiment of the present invention;

Fig. 2 is a diagram of a control flowchart by a contactor opening command creating unit in Fig. 1;

Fig. 3 is a block diagram of a parallel operation system of an auxiliary power supply a according to a first embodiment;

Fig. 4 is a diagram of a control flowchart by a contactor opening command creating unit according to the first embodiment;

Fig. 5 is a block diagram of a parallel operation system of an auxiliary power supply according to a second embodiment;

Fig. 6 is a diagram of a control flowchart by a contactor opening command creating unit according to the second embodiment;

Fig. 7 is a block diagram of a parallel operation system of an auxiliary power supply according to a third embodiment;

Fig. 8 is a diagram of a control flowchart by a contactor opening command creating unit according to the third embodiment;

Fig. 9 is a block diagram of a parallel operation system of an auxiliary power supply according to a fourth embodiment; and

Fig. 10 is a diagram of a control flowchart by a contactor opening command creating unit according to the fourth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, a basic embodiment is described with reference to the drawings as an embodiment of the present invention. Subsequently, first to fourth embodiments are described. In each drawing and embodiment, same or similar components are denoted with the same reference numerals, and overlapped description will be omitted.

Fig. 1 is a block diagram of a parallel operation system of an auxiliary power supply according to the basic embodiment of the present invention.

First, a basic structure of the parallel operation system of the auxiliary power supply is described. Power is taken in auxiliary power supplies 31 and 32 from an overhead line 1 via a collector 2. The auxiliary power supplies 31 and 32 convert the taken power into a three-phase AC power by an inverter 4 and supply the three-phase AC power to loads 101 to 104 connected to output lines 91 to 95. Vehicle connection joint boxes 111 to 113 are placed at positions joining vehicles between the output lines 91 to 95. The vehicle connection joint boxes 111 to 113 respectively connect the output lines 91 and 92, 93 and 94, and 94 and 95. An opening contactor 12 is provided between the output lines 92 and 93. When a contactor opening circuit 121 included in the opening contactor 12 receives an opening command of a contactor output from a control device 8 of each of the auxiliary power supplies 31 and 32, the contactor opening circuit 121 opens an electromagnetic contactor 122. Also, the control device 8 has a function for creating the opening command to the opening contactor 12. In addition, the control device 8 includes a function for controlling an entire system including the control of the plurality of inverters 4 respectively mounted on a plurality of railway vehicles and a protection function for stopping and restarting the system when an abnormality occurs in the inverter 4. In Fig. 1, details of the function for controlling the entire system including the control of the inverter 4 in the control device 8 and the protection function for stopping and restarting the system when the abnormality of the inverter 4 is detected are not shown.

Here, the minimum unit to be the basic structure of the parallel operation system of the auxiliary power supply according to the present invention includes two auxiliary power supplies, two loads, a single vehicle connection joint box, and a single opening contactor. In Fig. 1, the minimum unit includes the auxiliary power supplies 31 and 32, the loads 101 and 104, the vehicle connection joint box 111, and the opening contactor 12. The output lines 91 and 92 are provided on the side of the auxiliary power supply 31, and the output line 93 is provided on the side of the auxiliary power supply 32. The loads 102 and 103, and the vehicle connection joint boxes 112 and 113 other than the above are surrounded by boxes indicated by dotted lines, and the reference numbers of the components including the output lines 94 and 95 on the side of the auxiliary power supply 32 are placed between parentheses.

Next, a processing mode of the control device 8 for creating the opening command to the opening contactor 12 is described. The control device 8 generates an abnormality detecting signal from state guantities (for example, voltage or current) of the auxiliary power supplies 31 and 32 by using an abnormal state detecting unit 81 and outputs it to the contactor opening command creating unit 82. The contactor opening command creating unit 82 creates the opening command to the opening contactor 12 based on the abnormality detecting signal. As the state quantities of the auxiliary power supplies 31 and 32, a detection signal of the voltage or the current from the DC input side to the AC output side of the inverter 4 is used. A specific state quantity is described in the first to fourth embodiments.

Fig. 2 is a diagram of a control flowchart by the contactor opening command creating unit 82 in Fig. 1. The control flowchart indicates a flow of the basic control to create a contactor opening command from an abnormal state detecting signal based on the state quantities of the auxiliary power supplies 31 and 32 (specifically, the inverter 4). Also, the control flowcharts in the first to fourth embodiments to be described are common to the control flowchart of the basic embodiment. A difference between the control flowcharts in the first to fourth embodiments and that of the basic embodiment is that the abnormality detecting signal is changed to be a state quantity employed in each of the first to fourth embodiments .

The contactor opening command creating unit 82 (referred to as "command creating unit" below) starts processing in step S001. The command creating unit determines in step S002 whether an elapsed time from the detection of the previous abnormality detecting signal is equal to or longer than a predetermined time. When the elapsed time is equal to or longer than the predetermined time (Yes), the command creating unit clears the elapsed time to zero and clears a count value of an abnormality detection counter, which counts the number of times of generation of the abnormality detecting signal, to zero in step S003. On the other hand, when the elapsed time is shorter than the predetermined time (No), the command creating unit continues to measure the elapsed time in step S008 .

Here, the predetermined time is set to be one to three minutes. That is, a state in which the abnormal detection continues for a long time is an obvious abnormal state, and it is necessary to operate the protection function for stopping or restarting the auxiliary power supply. When the predetermined time is set to be too long, a time when the auxiliary power supply does not work becomes long, and this is not a preferable state. Also, since it takes equal to or longer than 30 seconds to restart the auxiliary power supply, it is not preferable that the predetermined time be set to be too short. When placing emphasis on shortening the time when the auxiliary power supply does not work, the best predetermined time is one minute. Also, the predetermined time is commonly considered in the first to fourth embodiments.

After that, the command creating unit determines in step S004 whether the abnormality detecting signal is ON. When the abnormality detecting signal is OFF (No), the procedure proceeds to step S009, and the command creating unit ends the processing. On the other hand, when the abnormality detecting signal is ON (Yes), the command creating unit counts up the abnormality detection counter in step S005. In step S005, when the abnormality detecting signal is not turned to be OFF during the control flowchart after the abnormality detecting signal has been ON and the command creating unit has counted up, the command creating unit does not count up the abnormality detection counter. That is, the abnormality detection counter counts an unstable state such that the abnormality detecting signal is continued to be ON/OFF. In the obvious abnormal state such that the abnormality detecting signal is continued to be ON, the protection function for stopping or restarting the system is operated.

Next, the command creating unit determines in step S006 whether the count value of the abnormality detection counter is equal to or more than the predetermined number of times. When the count value is less than the predetermined number of times (No), the procedure proceeds to step S009, and the command creating unit ends the processing. When the count value is equal to or more than the predetermined number of times (Yes), the command creating unit turns ON the opening command to the opening contactor in step S007 and ends the processing in step S009. In the control flow, it is assumed that an initial state of the opening command to the opening contactor is OFF and that ON state is continued until a control power supply is turned to be OFF when the opening command is turned to be ON once.

Here, the predetermined number of times is set to be twice or three times. The predetermined number of times is an indication to determine the unstable state such that the abnormality detecting signal is continuously turned to be ON/OFF. In order to make the unstable state be kept in a short time, the minimum number of times of reproduction (intermittent) is desired. In consideration of this point, the best predetermined number of times is twice. Also, the predetermined number of times is commonly considered in the first to fourth embodiments.

Also, the contactor opening command creating unit may be realized by hardware by designing a part of or all of the contactor opening command creating unit by using an integrated circuit which is employed as a component of the control device 8 and may be realized by software by interpreting and executing a program for realizing each function by a processor (which is not shown) included in the control device 8. The information such as the program can be stored in a recording device such as a memory, a hard disk, and an SSD or recording media such as an IC card, an SD card, and a DVD.

The description returns to Fig. 1, and a processing mode after the opening command has been turned to be ON is described. The opening command output from the contactor opening command creating unit 82 in the control device 8 is input to the opening contactor 12. The input method may be transmission via a metal line and transmission performed by using a control information processor which is not shown. The opening commands from all the auxiliary power supplies are input to the opening contactor 12. In the opening contactor 12, the contactor opening circuit 121 receives the opening commands from the auxiliary power supplies 31 and 32 and opens the electromagnetic contactor 122. The contactor opening circuit 121 can be designed so that the electromagnetic contactor 122 is opened when receiving the opening commands from both the auxiliary power supplies 31 and 32 and the electromagnetic contactor 122 is opened when receiving the opening command from either one of the auxiliary power supplies. The processing mode after the opening command has been turned to be ON is commonly used in the first to fourth embodiments.

When a contact failure due to poor maintenance and a contact failure during traveling are generated in the vehicle connection joint box, and for example in a state where output line intermittently repeats a cut-off state and a connection state, the load of the auxiliary power supply is changed. Then, a case where an output current from the inverter goes into an unbalanced state or an overload state or a case where a DC side voltage and an AC side output voltage of the inverter go into an unstable state occurs. By using the parallel operation system of the auxiliary power supply according to the basic embodiment of the present invention, the abnormal state as described above can be quickly detected, and the abnormal auxiliary power supply can be opened (separated). Accordingly, system down can be prevented.

Next, as a specific content of the abnormal state detected by the abnormal state detecting unit 81, in an order of an occurrence frequency, unbalance of an AC output phase current, an overvoltage of a filter capacitor voltage in the inverter as the DC side voltage or an overvoltage of an AC output voltage as an AC side voltage, and an overload state in which the AC output current increases can be exemplified. In the first to fourth embodiments below, an object of the abnormality detecting signal in the basic embodiment of the present invention includes the above states according to the order of the occurrence frequency.

In the description on the parallel operation system of the auxiliary power supply according to the first to fourth embodiments below, description on common parts in the system structure of the basic embodiment and the control flowchart by the contactor opening command creating unit are omitted, and differences are mainly described. In each system structure of the first to fourth embodiments, regardless of the minimum unit of the basic structure, it is assumed that the structure include the loads 102 and 103, the vehicle connection joint boxes 112 and 113, and the output lines 94 and 95 accompanying with them (surrounded by boxes indicated by solid lines in the drawings), Also, when the numbers of components are equal to or more than those of the minimum unit, the numbers of the auxiliary power supplies, the opening contactors, the loads, and the vehicle connection joint boxes can be appropriately increased and reduced.

First embodiment

Fig. 3 is a block diagram of a parallel operation system of an auxiliary power supply according to a first embodiment of the present invention.

In the first embodiment, an AC output current of an inverter 4 is employed as a state quantity to detect an abnormal state in the basic embodiment described above. Therefore, in the first embodiment, an AC current sensor (CT) 5 is provided in a rear stage (AC output side) of the inverter 4 as an abnormality detection unit and an AC output phase current unbalance protection detecting unit 801 is provided in a control device 8 as the abnormal state detecting unit in the basic embodiment. That is, the control device 8 includes the AC output phase current unbalance protection detecting unit 801 and a contactor opening command creating unit 802. A processing mode for creating an opening command to an opening contactor 12 by the control device 8 is described below. The AC output phase current unbalance protection detecting unit 801 compares an AC output phase current input from the AC current sensor (CT) 5 with an AC output phase current unbalanced protection detecting set value and creates a PUD signal indicating whether unbalance of the AC output phase current over a protection level has been detected. Next, the contactor opening command creating unit 802 creates the opening command to the opening contactor 12 by using the PUD signal.

Fig. 4 is a diagram of a control flowchart by the contactor opening command creating unit 802 in Fig. 3. As described above, a processing content of each step in the control flowchart is similar to that in the control flowchart (Fig. 2) according to the basic embodiment. Therefore, the processing content of each step is omitted below. The PUD signal indicating whether the unbalance of the output phase current over the protection level has been detected is employed as the abnormality detecting signal, and a PUD counter counts the number of times of generation of the PUD signals. An ON/OFF state of the PUD signal is determined, and an ON state of the opening command to the opening contactor is determined from a count up value of the PUD counter.

Also, a processing mode after the opening command has been turned to be ON is similar to that of the basic embodiment described above.

As described above, the control device 8 according to the first embodiment determines whether the AC output phase current unbalance protection detecting unit 801 has detected the unbalance of the AC output phase current over the protection level from the AC output phase current and outputs the opening command to open the opening contactor 12 when the contactor opening command creating unit 802 has detected the unbalance of the AC output phase current over the protection level more than the predetermined number of times (twice or three times, twice is the best) within the predetermined time (one to three minutes, one minute is the best).

As the abnormal state, there is a state where the contact failure occurs in any one of vehicle connection joint boxes 111, 112, and 113. For example, in a condition where the output line intermittently repeats a cut-off state and a connection state, the vehicle connection joint box has a large resistance. Then, loads of the respective auxiliary power supplies are uneven, and the AC output phase current goes into the unbalanced state. In this case, the auxiliary power supply is individually operated by opening the opening contactor 12. According to this, since the auxiliary power supply, which supplies power to a section where a connection failure of the vehicle connection joint box does not occur, can be continuously operated, system down can be prevented.

Second embodiment

Fig. 5 is a block diagram of a parallel operation system of an auxiliary power supply according to a second embodiment of the present invention.

In the second embodiment, a filter capacitor voltage of an inverter 4 is employed as a state quantity to detect an abnormal state in the basic embodiment described above. Therefore, in the second embodiment, a DC voltage sensor (PT) 6 for detecting voltages of both ends of a filter capacitor (not shown) in the inverter 4 is provided as an abnormality detection unit, and a filter capacitor overvoltage protection detecting unit 803 is provided in a control device 8 as the abnormal state detecting unit in the basic embodiment. That is, the control device 8 includes the filter capacitor overvoltage protection detecting unit 803 and a contactor opening command creating unit 804. A processing mode for creating an opening command to an opening contactor 12 by the control device 8 is described below. The filter capacitor overvoltage protection detecting unit 803 compares the filter capacitor voltage input from the DC voltage sensor (PT) 6 with a filter capacitor overvoltage protection detecting set value and creates an information OVD signal indicating whether the filter capacitor overvoltage over a protection level has been detected. Next, the contactor opening command creating unit 804 creates the opening command to the opening contactor 12 by using the OVD signal.

Fig. 6 is a diagram of a control flowchart by the contactor opening command creating unit 804 in Fig. 5. As described above, a processing content of each step in the control flowchart is similar to that in the control flowchart (Fig. 2) according to the basic embodiment. Therefore, the processing content of each step is omitted below. The OVD signal indicating whether the filter capacitor overvoltage over the protection level has been detected is employed as the abnormality detecting signal, and an OVD counter counts the number of times of generation of the OVD signals. An ON/OFF state of the OVD signal is determined, and an ON state of the opening command to the opening contactor is determined from a count up value of the OVD counter.

As described above, the control device 8 according to the second embodiment determines whether the filter capacitor overvoltage protection detecting unit 803 has detected the filter capacitor overvoltage over the protection level from the filter capacitor voltage and opens the opening contactor 12 when the contactor opening command creating unit 804 has detected the filter capacitor overvoltage over the protection level equal to or more than the predetermined number of times (twice or three times, twice is the best) within the predetermined time (one to three minutes, one minute is the best).

As described above, in a state where a contact failure occurs in any one of vehicle connection joint boxes 111, 112, and 113 and an output line intermittently repeats a cut-off state and a connection state, a load of the auxiliary power supply is changed, and the filter capacitor voltage becomes unstable. Accordingly, the auxiliary power supply cannot be operated in parallel. In this case, the auxiliary power supply is individually operated by opening the opening contactor 12. According to this, since the auxiliary power supply, which supplies power to a section where a connection failure of a joint box does not occur, can be continuously operated, system down can be prevented.

Third embodiment

Fig. 7 is a block diagram of a parallel operation system of an auxiliary power supply according to a third embodiment of the present invention.

In the third embodiment, an AC output voltage of an inverter 4 is employed as a state quantity to detect an abnormal state in the basic embodiment described above. Therefore, in the third embodiment, an AC voltage sensor (PT) 7 for detecting an AC output voltage in a rear stage (AC output side) of the inverter 4 is provided as an abnormality detection unit, and an AC output overvoltage protection detecting unit 805 is provided in a control device 8 as the abnormal state detecting unit in the basic embodiment. That is, the control device 8 includes the AC output overvoltage protection detecting unit 805 and a contactor opening command creating unit 806. A processing mode for creating an opening command to an opening contactor 12 by the control device 8 is described below. The AC output overvoltage protection detecting unit 805 compares the AC output voltage input from the AC voltage sensor (PT) 7 with an AC output overvoltage protection detecting set value and creates an ACOVD signal indicating whether an AC output overvoltage over a protection level has been detected. Next, the contactor opening command creating unit 806 creates the opening command to the opening contactor 12 by using the ACOVD signal.

Fig. 8 is a diagram of a control flowchart by the contactor opening command creating unit 806 in Fig. 7. As described above, a processing content of each step in the control flowchart is similar to that in the control flowchart (Fig. 2) according to the basic embodiment. Therefore, the processing content of each step is omitted below. The ACOVD signal indicating whether the AC output overvoltage over the protection level has been detected is employed as an abnormality detecting signal, and an ACOVD counter counts the number of times of generation of the ACOVD signals. An ON/OFF state of the ACOVD signal is determined, and an ON state of the opening command to the opening contactor is determined from a count up value of the ACOVD counter.

As described above, the control device 8 according to the third embodiment determines whether the AC output overvoltage protection detecting unit 805 has detected the AC output overvoltage over the protection level from the AC output voltage and outputs the opening command to open the opening contactor 12 when the contactor opening command creating unit 806 has detected the AC output overvoltage over the protection level more than the predetermined number of times (twice or three times, twice is the best) within the predetermined time (one to three minutes, one minute is the best).

As described above, in a state where a contact failure occurs in any one of vehicle connection joint boxes 111, 112, and 113 and an output line intermittently repeats a cut-off state and a connection state, a load of the auxiliary power supply is changed, and the AC output voltage becomes unstable. Accordingly, the auxiliary power supplies cannot be operated in parallel. In this case, the auxiliary power supply is individually operated by opening the opening contactor 12. According to this, since the auxiliary power supply, which supplies power to a section where a connection failure of a joint box does not occur, can be continuously operated, system down can be prevented.

Fourth embodiment

Fig. 9 is a block diagram of a parallel operation system of an auxiliary power supply according to a fourth embodiment of the present invention.

In the fourth embodiment, an AC output current of an inverter 4 is employed as a state quantity to detect an abnormal state in the basic embodiment described above similarly to the first embodiment. Therefore, in the fourth embodiment, an AC current sensor (CT) 5 is provided in a rear stage (AC output side) of the inverter 4 as an abnormality detection unit, and an overload protection detecting unit 807 is provided in a control device 8 as the abnormal state detecting unit in the basic embodiment.

That is, the control device 8 includes the overload protection detecting unit 807 and a contactor opening command creating unit 808. A processing mode for creating an opening command to an opening contactor 12 by the control device 8 is described below. The overload protection detecting unit 807 compares the AC output current input from the AC current sensor (CT) 5 with an overload protection detecting set value and creates an ACOCD signal indicating whether an overload state (overcurrent state) over a protection level has been detected. Next, the contactor opening command creating unit 808 creates the opening command to the opening contactor 12 by using the ACOCD signals.

Fig. 10 is a diagram of a control flowchart by the contactor opening command creating unit 808 in Fig. 9. As described above, a processing content of each step in the control flowchart is similar to that in the control flowchart (Fig. 2) according to the basic embodiment. Therefore, the processing content of each step is omitted below. The ACOCD signal indicating whether the overload state over the protection level has been detected is employed as an abnormality detecting signal, and an ACOCD counter counts the number of times of generation of the ACOCD signal. An ON/OFF state of the ACOCD signal is determined, and an ON state of the opening command to the opening contactor is determined from a count up value of the ACOCD counter.

As described above, the control device 8 according to the fourth embodiment determines whether the overload protection detecting unit 807 has detected the overload state over the protection level from the AC output current and outputs the opening command to open the opening contactor 12 when the contactor opening command creating unit 808 has detected the overload state over the protection level equal to or more than the predetermined number of times (twice or three times, twice is the best) within the predetermined time (one to three minutes, one minute is the best).

As described above, a contact failure occurs in any one of vehicle connection joint boxes 111, 112, and 113, and the vehicle connection joint box has a large resistance. Also, loads of the auxiliary power supplies are uneven, and a state where the loads are concentrated to the single auxiliary power supply (overload state) occurs. In this case, the auxiliary power supply is individually operated by opening the opening contactor 12, and the load to supply the power is limited. According to this, since the auxiliary power supply, which supplies power to a section where a connection failure of a joint box does not occur, can be continuously operated, system down can be prevented.

The first to fourth embodiments have been described based on the basic embodiment of the present invention above. However, the structure of each embodiment is an example, and the present invention can be appropriately changed without departing from the technical ideas of the present invention.

Also, as the abnormality detecting signal, the unbalance of the AC output phase current from the AC output current is employed in the first embodiment, the filter capacitor overvoltage from the filter capacitor voltage is employed in the second embodiment, the AC output overvoltage from the AC output voltage is employed in the third embodiment, and the overload state from the AC output current is employed in the fourth embodiment, and the contactor opening command is created. However, without limiting the abnormality detecting signal to one kind, the opening command may be turned to be ON when two or more abnormality detecting signals are combined and an logical add (OR) of them and an logical add (OR) of count up according to each abnormal signal are obtained, and the count value (total value) of them is equal to or more than the predetermined number of times. At this time, when two kinds are combined, there is a possibility that the abnormal state can be more quickly and accurately detected in a case where the current and voltage are combined than a case where the currents are combined and where the voltages are combined.

Claims

What is claimed is:

1. An auxiliary power supply system comprising: a plurality of auxiliary power supplies configured to include an inverter for converting power received from an overhead line into AC power; a vehicle connection joint box configured to connect an output line when the output line from the auxiliary power supply joints vehicles; and an electromagnetic contactor configured to be provided between the output lines of the auxiliary power supplies, wherein the auxiliary power supply includes a control device for controlling the inverter and the electromagnetic contactor, and the control device opens the electromagnetic contactor when detecting an abnormal state of a state quantity according to an input or output of the inverter equal to or more than the predetermined number of times within a predetermined time.

2. The auxiliary power supply system according to claim 1, wherein the abnormal state of the state quantity according to the input or output of the inverter is a state where unbalance of an AC output phase current exceeds a protection level.

3. The auxiliary power supply system according to claim 1, wherein the abnormal state of the state quantity according to the input or output of the inverter is an overvoltage state where a filter capacitor voltage of the inverter exceeds a protection level.

4. The auxiliary power supply system according to claim 1, wherein the abnormal state of the state quantity according to the input or output of the inverter is an overvoltage state where an AC output voltage exceeds a protection level.

5. The auxiliary power supply system according to claim 1, wherein the abnormal state of the state quantity according to the input or output of the inverter is an overload state where an AC output current exceeds a protection level.

6. The auxiliary power supply system, wherein when detections of at least two or more abnormal states according to claim 2 are combined and the number of times of the detections of all the abnormal states is equal to or more than the predetermined number of times within the predetermined time, the electromagnetic contactor is opened.

7. The auxiliary power supply system according to claim 1, wherein the predetermined time is one to three minutes, and the best predetermined time is one minute, and the predetermined number of times is twice or three times, and the best predetermined number of times is twice.

8. An operation method for an auxiliary power supply system, comprising: counting the number of times of detection of the abnormal state by detecting whether a state quantity according to an input or output of an inverter is an abnormal state within a predetermined time; and opening an electromagnetic contactor when the number of times of the detection within the predetermined time is equal to or more than a predetermined number of times, wherein the auxiliary power supply system includes a plurality of auxiliary power supplies including the inverter for converting power received from an overhead line into AC power, a vehicle connection joint box connecting the output line when the output line from the auxiliary power supply joints vehicles, and the electromagnetic contactor provided between the output lines of the auxiliary power supplies.

9. The operation method for an auxiliary power supply system according to claim 8, wherein the abnormal state of the state quantity according to the input or output of the inverter is a state where unbalance of an AC output phase current exceeds a protection level.

10. The operation method for an auxiliary power supply system according to claim 8, wherein the abnormal state of the state quantity according to the input or output of the inverter is an overvoltage state where a filter capacitor voltage of the inverter exceeds a protection level.

11. The operation method for an auxiliary power supply system according to claim 8, wherein the abnormal state of the state quantity according to the input or output of the inverter is an overvoltage state where an AC output voltage exceeds a protection level.

12. The operation method for an auxiliary power supply system according to claim 8, wherein the abnormal state of the state quantity according to the input or output of the inverter is an overload state where an AC output current exceeds a protection level.

13. The operation method for an auxiliary power supply system, wherein when detections of at least two or more abnormal states according to claim 9 are combined and the number of times of the detections of all the abnormal states is equal to or more than the predetermined number of times within the predetermined time, the electromagnetic contactor is opened.

14. The operation method for an auxiliary power supply system according to claim 8, wherein the predetermined time is one to three minutes, and the best predetermined time is one minute, and the predetermined number of times is twice or three times, and the best predetermined number of times is twice.