JP2019118226A - Power storage device - Google Patents

Abstract

To provide a power storage device capable of suppressing an increase in size of the device.SOLUTION: The power storage device includes: a circuit breaker connected to a DC power supply; a first power conversion circuit provided downstream of the circuit breaker; a first storage battery provided downstream of the first power conversion circuit; a second power conversion circuit provided downstream of the first storage battery; a second storage battery provided downstream of the second power conversion circuit; and a control panel for controlling the circuit breaker, the first power conversion circuit, and the second power conversion circuit with first power supplied from the first storage battery through the second power conversion circuit and second power supplied from the second storage battery. Further, the second power conversion circuit includes: a DC-AC conversion circuit provided on the first storage battery side; an AC-DC conversion circuit provided on the second storage battery side; and an isolation transformer provided between the DC-AC conversion circuit and the AC-DC conversion circuit.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a power storage device.

  In a direct current feeding system which is a power supply system of a direct current electric railway, a load fluctuation is severe, so that a fluctuation of a wire overhead voltage becomes large. Therefore, there is a case where a power storage device for absorbing the surplus regenerative power of the vehicle is installed. In this case, by utilizing the power stored in the power storage device, it is possible to suppress the fluctuation of the overhead wire voltage.

JP 2014-30343 A

  The above power storage device includes devices such as a circuit breaker, a converter, and a storage battery, and a control panel that controls the devices. The control power source required for the operation of the control panel is covered by a storage battery other than the storage battery for storing the regenerative power. Therefore, if the storage battery for the control power supply needs to be increased due to the above-mentioned equipment, the storage battery has a large capacity, and as a result, there is a concern that the entire power storage device may become large.

  Then, the embodiment of the present invention aims to provide a power storage device capable of suppressing an increase in the size of the device.

  The power storage device according to one embodiment includes a circuit breaker connected to a DC power supply, a first power conversion circuit provided downstream of the circuit breaker, and a first storage battery provided downstream of the first power conversion circuit. A second power conversion circuit provided downstream of the first storage battery, a second storage battery provided downstream of the second power conversion circuit, and first power supplied from the first storage battery via the second power conversion circuit And a control panel for controlling the circuit breaker, the first power conversion circuit, and the second power conversion circuit with the second power supplied from the second storage battery. Further, the second power conversion circuit is provided between the DC-AC conversion circuit provided on the first storage battery side, the AC-DC conversion circuit provided on the second storage battery side, the DC-AC conversion circuit, and the AC-DC conversion circuit. And an insulating transformer provided.

FIG. 1 is a circuit diagram showing a configuration of a power storage device 1 according to a first embodiment. It is a circuit diagram showing the composition of the 1st power conversion circuit. It is a circuit diagram which shows the structure of a 2nd power inverter circuit. It is a circuit diagram showing composition of an EMC filter. It is a circuit diagram which shows the structure of the electrical storage apparatus which concerns on 2nd Embodiment. It is a circuit diagram which shows the structure of the electrical storage apparatus which concerns on 3rd Embodiment. It is a circuit diagram which shows the structure of the electrical storage apparatus which concerns on 4th Embodiment. It is a circuit diagram which shows the modification of a 2nd power inverter circuit.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. This embodiment does not limit the present invention.

First Embodiment
FIG. 1 is a circuit diagram showing a configuration of the power storage device 1 according to the first embodiment. Power storage device 1 includes circuit breaker 10, first power conversion circuit 20, first storage battery 30, second power conversion circuit 40, second storage battery 50, control panel 60, and contactors 70 to 75. A converter cooling fan 80, a battery cooling fan 81, and an EMC (Electro Magnetic Compatibility) filter 90 are provided.

  Circuit breaker 10 is connected to DC power supply 100. When the circuit breaker 10 is in a closed state (on state), DC power is input from the DC power supply 100 to the first power conversion circuit 20. On the other hand, when the circuit breaker 10 is in the open state (off state), the input of the DC power is cut off. In the present embodiment, the DC power supply 100 is configured of a feeder wire, a rail, and a diode rectifier. The power of the DC power supply 100 corresponds to the regenerative power generated by the electric railway. However, the direct current power supply 100 is not limited to the electric railway because it may be connected to a direct current transmission line. The first power conversion circuit 20 is provided downstream of the circuit breaker 10.

  FIG. 2 is a circuit diagram showing a configuration of the first power conversion circuit 20. As shown in FIG. The first power conversion circuit 20 is a DC / DC converter circuit that boosts and lowers a DC voltage. Specifically, the switching elements 20a and 20b and the diodes 20c and 20d constitute a so-called half bridge circuit. For each switching element, for example, a semiconductor device such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) made of silicon carbide (SiC) can be used. An inductor 20 e is connected to the output end of the first power conversion circuit 20.

  By the switching operation of the switching elements 20a and 20b, the DC voltage input from the DC power supply 100 is stepped up and down. A contactor 70 is provided between the first power conversion circuit 20 and the first storage battery 30, and when the contactor 70 is in the on state, the DC voltage boosted / boosted by the first power conversion circuit 20 is It is supplied to the first storage battery 30.

  Contactors 71 and 72 are connected to both ends of the first storage battery 30, respectively. When the contactors 71 and 72 are in the on state, the first storage battery 30 performs charging and discharging. A second power conversion circuit 40 is provided downstream of the first storage battery 30.

  FIG. 3 is a circuit diagram showing a configuration of second power conversion circuit 40. Referring to FIG. As shown in FIG. 3, the second power conversion circuit 40 includes a chopper circuit 41, a DC / AC conversion circuit 42, an AC / DC conversion circuit 43, and an insulating transformer 44.

  In the chopper circuit 41, the switching elements 41a and 41b and the diodes 41c and 41d constitute a half bridge circuit. Further, an inductor 41 f and a direct current capacitor 41 e are provided at the front stage of this half bridge circuit. Furthermore, an inductor 41g is provided at the subsequent stage of this half bridge circuit.

  The direct current to alternating current conversion circuit 42 is a resonant inverter circuit provided at the rear stage of the chopper circuit 41. In this resonant inverter circuit, the switching elements 42a and 42b and the diodes 42c and 42d form a half bridge circuit. Similar to the switching element of the chopper circuit 41, a semiconductor device such as an IGBT or a MOSFET can be used as a switching element of the DC-AC conversion circuit 42. A direct current capacitor 42g is provided at the front stage of the half bridge circuit, and resonance capacitors 42e and 42f are connected in series at the rear stage.

  The AC-DC converter circuit 43 is provided at the subsequent stage of the DC-AC converter circuit 42. In the AC-DC converter circuit 43, four diodes 43a to 43d constitute a diode bridge circuit. In addition, a DC capacitor 43e is provided at the rear stage of the diode bridge circuit.

  The insulating transformer 44 is provided between the DC-AC conversion circuit 42 and the AC-DC conversion circuit 43. The insulating transformer 44 transforms the AC voltage input from the DC-AC conversion circuit 42 into a predetermined voltage, and outputs the voltage to the AC-DC conversion circuit 43.

  In the second power conversion circuit 40 configured as described above, the switching elements 41a and 41b of the chopper circuit 41 perform switching operation, whereby the output voltage of the DC-AC conversion circuit 42 can be controlled and adjusted. As a result, the output voltage of the alternating current direct current conversion circuit 43 can also be controlled. The direct current voltage output from the alternating current direct current conversion circuit 43 is supplied to the second storage battery 50.

  Returning to FIG. 1, the second storage battery 50 is a power supply for achieving uninterruption of the control panel 60, and is a secondary battery such as a lead storage battery or a nickel hydrogen battery, for example. The rated voltage of the second storage battery 50 is lower than the rated voltage of the first storage battery 30. Contactors 74 and 75 are connected to both ends of the second storage battery 50. When the contactors 74 and 75 are in the on state, the second storage battery 50 performs charging and discharging. A control panel 60 is provided downstream of the second storage battery 50.

  Control panel 60 is controlled by a plurality of controls supplied with power (first power) supplied from first storage battery 30 via second power conversion circuit 40 or power (second power) supplied from second storage battery 50. Circuits 61 to 64 are included.

  The control circuit 61 is a circuit breaker control circuit that controls the circuit breaker 10. Specifically, control circuit 61 includes, for example, an excitation circuit for driving circuit breaker 10 and the like.

  The control circuit 62 is a first power conversion control circuit that controls the first power conversion circuit 20. Specifically, the control circuit 62 controls the switching operation of the switching elements 20 a and 20 b of the first power conversion circuit 20. The control circuit 62 also supplies power to the converter cooling fan 80 to control its operation. Furthermore, the control circuit 62 also controls the operation of the contactor 70.

  Control circuit 63 controls the charge / discharge operation of first storage battery 30. Specifically, the control circuit 63 monitors the voltage, current, temperature, state of charge, and the like of the first storage battery 30, and controls the operation of the contactor 71 and the contactor 72. Further, the control circuit 53 supplies power to the battery cooling fan 81 to control its operation.

  The control circuit 64 is a second power conversion control circuit that controls the second power conversion circuit 40. In the present embodiment, the control circuit 64 also controls the charge and discharge operation of the second storage battery 50. Specifically, the control circuit 64 controls the switching operation of each switching element of the chopper circuit 41 and the DC / AC conversion circuit 42 and the operation of the contactors 73 to 75.

  The converter cooling fan 80 cools the first power conversion circuit 20 which generates heat by the switching operation of the switching elements 20a and 20b. In addition, the battery cooling fan 81 cools the first storage battery 30 which generates heat in the charge and discharge operation.

  The EMC filter 90 is provided between the first storage battery 30 and the second power conversion circuit 40. The EMC filter 90 is also provided between the second storage battery 50 and the control panel 60. Here, the circuit configuration of the EMC filter 90 will be described.

  FIG. 4 is a circuit diagram showing the configuration of the EMC filter 90. As shown in FIG. In the EMC filter 90 shown in FIG. 4, a pair of coils 90 a and 90 b are provided in the high potential side power transmission path and the low potential side power transmission path. A capacitor 90c and a capacitor 90c are connected in series between the coil 90a and the coil 90b. Furthermore, the neutral point of the capacitor 90c and the capacitor 90c is grounded. According to this EMC filter 90, electromagnetic wave noise can be reduced.

  Hereinafter, the operation of the power storage device 1 according to the present embodiment will be described. Here, the operation in the stop state of power storage device 1 and the operation at the time of startup will be described.

  First, the operation in the stop state will be described. When power storage device 1 is in the stop state, circuit breaker 10 is in the off state. Further, the contactor 70 to the contactor 75 are also in the off state. Furthermore, the switching operation of the first power conversion circuit 20, the chopper circuit 41, and the DC-AC conversion circuit 42 is stopped. At this time, power is not supplied to each control circuit of the control board 60.

  Here, when the contactor 74 and the contactor 75 are manually switched from the off state to the on state, the discharge of the second storage battery 50 starts to supply DC power to each control circuit of the control panel 60. As a result, power storage device 1 is activated.

  Next, the operation at startup will be described. First, the control circuit 63 switches the contactor 71 and the contactor 72 from the off state to the on state by the DC power supplied from the second storage battery 50.

  Subsequently, the control circuit 64 switches the contactor 73 from the off state to the on state. As a result, the discharge of the first storage battery 30 applies a voltage to the DC-AC conversion circuit 42. Subsequently, the control circuit 64 controls the DC-AC conversion circuit 42 and the AC-DC conversion circuit 43. Thereby, the power supply from the power of the first storage battery 30 to the second storage battery 50 and the control circuits 61 to 64 is started. At this time, the control circuit 64 sets the output voltage of the AC-DC conversion circuit 43 so that the power of the second storage battery 50 is not supplied to each control device or the power supply amount of the second storage battery 50 is reduced. The setting of the output voltage may be set by the transformation ratio of the insulating transformer 44. Each control circuit of the control panel 60 is supplied with power from the first storage battery 30 by such setting of the output voltage.

  After the control circuit 64 starts the switching operation of the second power conversion circuit 40, the control circuit 62 switches the contactor 70 from the off state to the on state. Subsequently, the control circuit 62 starts the switching operation of the first power conversion circuit 20. Thereafter, when the input voltage of the first power conversion circuit 20 approaches or becomes equal to the voltage value of the DC power supply 100, the control circuit 61 switches the contactor 7 from the off state to the on state. As a result, first storage battery 30 is charged with DC power of DC power supply 100.

  In the power storage device 1 according to the present embodiment described above, the control circuit 62 may require a large control power supply in order to cover the drive power of the switching elements of the first power conversion circuit 20. In addition, since the inrush current flows into the control circuit 61 when driving the contactor 7, the load of the control power supply may increase. In these cases, if it is necessary for the second storage battery 50 to have a separate control power supply to the control panel 60, the second storage battery 50 needs to be reinforced. In this case, since the capacity of the second storage battery 50 is increased, there is a concern that the entire apparatus may be enlarged.

  However, in the present embodiment, it is possible to supply power to the control panel 60 also from the first storage battery 30 having a larger capacity than the second storage battery 50 by the insulating transformer 44. Therefore, the increase of the second storage battery 50 can be minimized. Therefore, it is possible to suppress an increase in the size of the entire power storage device.

  Further, in the present embodiment, the power supply can be continued from the first storage battery 30 to the second storage battery 50. Therefore, even if the power from the rectifier is not supplied to the overhead wire due to a power failure in the DC electric railway, the operation time of the emergency travel storage function can be maximized. That is, the control panel 60 can receive power supply from the first storage battery 30 with priority. Therefore, it is possible to avoid the situation where power storage device 1 is stopped due to the loss of control power due to the exhaustion of second storage battery 50.

  If the control power is lost before the storage device 1 stops, for example, if the contactor 7 is a machine-held circuit breaker, the closed state is maintained and voltage is continuously applied to the first power conversion circuit 20. . At this time, since the power supply to the control board 60 is already cut off, the control circuit 62 can not operate. Therefore, when one switching element of the first power conversion circuit 20 is in the on state, the negative bias can not be applied to the gate of the other switching element. In this case, there is a possibility that the switching element may be broken due to the erroneous turning on of the switching element. However, according to the present embodiment, it is also possible to safely stop the power storage device 1 while avoiding such element destruction.

Second Embodiment
FIG. 5 is a circuit diagram showing a configuration of a power storage device according to a second embodiment. The same code | symbol is attached | subjected to the component similar to 1st Embodiment mentioned above, and detailed description is abbreviate | omitted. As shown in FIG. 5, the power storage device 2 according to the present embodiment additionally includes a detection circuit 45 and a contactor 76 in addition to the components of the power storage device 1 according to the first embodiment.

  The detection circuit 45 detects the output current of the AC / DC conversion circuit 43. The detection circuit 45 only needs to detect voltage abnormality or current abnormality of the second power conversion circuit 40. Therefore, the detection circuit 45 may be installed at a position where it can detect the input voltage of the DC-AC conversion circuit 42, the input current of the DC-AC conversion circuit 42, or the output voltage of the AC-DC conversion circuit 43.

  The contactor 76 is provided between the AC / DC conversion circuit 43 and the second storage battery 50. The contactor 76 opens and closes in accordance with the control of the control circuit 64. When the contactor 76 is closed, the power supply to the second storage battery 50 and the control panel 60 is maintained. On the contrary, when the contactor 76 is opened, the power supply is cut off.

  Here, an operation of power storage device 2 when a voltage abnormality or a current abnormality occurs in second power conversion circuit 40 will be described.

  When the detection value of the detection circuit 45 exceeds a predetermined threshold value, the control circuit 64 determines that an abnormality has occurred in the second power conversion circuit 40. In this case, the control circuit 64 stops the switching operation of each switching element of the second power conversion circuit 40, and turns off the contactors 73 and 76. Thereby, the input / output of the power to the second power conversion circuit 40 can be cut off.

  Further, the control circuit 64 outputs the result of the abnormality determination to the other control circuits 61 to 63. As a result, the control circuit 61 turns off the circuit breaker 10. Further, the control circuit 62 stops the switching operation of the switching elements 20 a and 20 b of the first power conversion circuit 20. As a result, since the switching elements 20a and 20b do not need to be cooled, the control circuit 62 stops the power supply to the converter cooling fan 80. Further, the control circuit 63 turns the contactors 71 and 72 off. As a result, since the first storage battery 30 does not need to be cooled, the control circuit 63 stops the power supply to the battery cooling fan 81.

  According to the embodiment described above, when voltage abnormality or current abnormality occurs in the second power conversion circuit 40, the abnormality is detected by the detection circuit 45, and the control circuit 64 operates the second power conversion circuit 40. Stop. Therefore, the device can be safely shut down.

Third Embodiment
FIG. 6 is a circuit diagram showing a configuration of a power storage device according to a third embodiment. The same code | symbol is attached | subjected to the component similar to 1st Embodiment mentioned above, and detailed description is abbreviate | omitted. As shown in FIG. 6, the power storage device 3 according to the present embodiment newly includes a current limiting circuit 51 in addition to the components of the power storage device 1 according to the first embodiment. The current limiting circuit 51 may be provided in the power storage device 2 described in the second embodiment.

  The current limiting circuit 51 is provided between the AC / DC conversion circuit 43 of the second power conversion circuit 40 and the second storage battery 50. In the present embodiment, the current limiting circuit 51 includes a resistor 51a and a diode 51b.

  The diode 51 b is connected in antiparallel to the resistor 51 a. In other words, the anode of the diode 51 b is connected to the second storage battery 50, and the cathode is connected to the AC-DC converter circuit 43.

  In the current limiting circuit 51, the charging current is supplied to the second storage battery 50 via the resistor 51a. On the other hand, the discharge current is supplied to the control board 60 via the diode 51b.

  According to the present embodiment described above, only the charging current to the second storage battery 50 can be limited by the current limiting circuit 51. Thereby, the second storage battery 50 can be safely charged, and the power of the second storage battery 50 can be effectively used.

Fourth Embodiment
FIG. 7 is a circuit diagram showing a configuration of a power storage device according to a fourth embodiment. The same code | symbol is attached | subjected to the component similar to 1st Embodiment mentioned above, and detailed description is abbreviate | omitted.

  As shown in FIG. 7, in the power storage device 4 according to the present embodiment, a plurality of post-stage components of the first storage battery 30 such as the second power conversion circuit 40 and the second storage battery 50 exist. These subsequent parts are connected in parallel to one first storage battery 30.

  Further, the control circuit 64 collectively controls the plurality of second power conversion circuits 40 and the plurality of second storage batteries 50. When the power storage device 4 starts up, the control circuit 64 simultaneously controls the plurality of second power conversion circuits 40 and the plurality of second storage batteries 50. After that, for example, when the second power conversion circuit 40 or the second storage battery 50 breaks down, the control circuit 64 separates the broken downstream part from the remaining downstream parts. From this point on, the power supply to the control board 60 is covered only with normal rear stage parts.

  According to the present embodiment described above, the plurality of second power conversion circuits 40 and the plurality of second storage batteries 50 are redundantly provided. Therefore, the reliability of the device can be improved.

  In the present embodiment, the number of the first power conversion circuit 20 and the number of the first storage battery 30 are one. However, these numbers are not limited to one, and there may be a plurality of first power conversion circuits 20 and a plurality of first storage batteries 30.

(Modification)
FIG. 8 is a circuit diagram showing a modification of the second power conversion circuit. The second power conversion circuit 140 shown in FIG. 8 includes a DC / AC conversion circuit 142 and an AC / DC conversion circuit 143.

  In the DC-AC conversion circuit 142, the switching elements 142a and 142b and the diodes 142c and 142d constitute a half bridge circuit. The switching elements 142e and 142f and the diodes 142g and 142h constitute another half bridge circuit. That is, the DC-AC conversion circuit 142 constitutes an inverter circuit in which these half bridge circuits are connected in parallel. A DC capacitor 142i is provided at the front stage of this inverter circuit.

  On the other hand, the AC-DC conversion circuit 143 also configures an inverter circuit including switching elements 143a, 143b, 143e and 143f and diodes 143c, 143d, 143g and 143h, similarly to the DC-AC conversion circuit 142. A DC capacitor 143i is provided on the output side of the inverter circuit.

  In the present modification, the control circuit 64 controls the switching operation of each switching element of the DC-AC conversion circuit 142 and the AC-DC conversion circuit 143. An IGBT or MOSFET can be used for each switching element. Since each switching element performs a hard switching operation, it is desirable to use a wide band gap semiconductor such as a MOSFET made of SiC. In this case, the loss of each switching element can be reduced to miniaturize the device.

  Further, according to the present modification, the DC-AC conversion circuit 142 and the AC-DC conversion circuit 143 are each configured by an inverter circuit. Therefore, voltage control can be performed without installing a chopper circuit at the front stage of the DC-AC conversion circuit 142. As described above, since the chopper circuit is not required, it is possible to suppress an increase in the size of the entire apparatus.

  While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

DESCRIPTION OF SYMBOLS 10 Circuit breaker 10 1st power conversion circuit 20, 30 1st storage battery, 40 2nd power conversion circuit, 41 chopper circuit, 42 direct current alternating current conversion circuit, 43 alternating current direct current conversion circuit, 44 insulation type transformer, 45 detection circuit, 50 Second storage battery, 51 current limiting circuit, 51a resistor, 51b diode, 60 control panel, 61 to 64 control circuit, 80 converter cooling fan, 81 battery cooling fan, 90 EMC filter

Claims (10)

Circuit breaker connected to DC power supply,
A first power conversion circuit provided downstream of the circuit breaker;
A first storage battery provided at a stage subsequent to the first power conversion circuit;
A second power conversion circuit provided downstream of the first storage battery,
A second storage battery provided at a subsequent stage of the second power conversion circuit;
The first power supplied from the first storage battery through the second power conversion circuit and the second power supplied from the second storage battery, the circuit breaker, the first power conversion circuit, and the second power And a control panel for controlling the conversion circuit,
The second power conversion circuit includes a DC-AC conversion circuit provided on the first storage battery side, an AC-DC conversion circuit provided on the second storage battery side, the DC-AC conversion circuit, and the AC-DC conversion circuit. A storage battery provided between the two. The control panel includes a shutoff control circuit that controls the circuit breaker, a first power conversion control circuit that controls the first power conversion circuit, and a second power conversion control circuit that controls the second power conversion circuit. Including
The first power conversion control circuit and the second power conversion control circuit operate so that the first power is supplied to the interruption control circuit before the circuit breaker is turned on. Power storage device.   The first power conversion control circuit and the second power conversion control circuit operate so that the first power is supplied to the cutoff control circuit when the first power conversion circuit is driven. Power storage device. It further comprises at least one of a battery cooling fan for cooling the first storage battery and a converter cooling fan for cooling the first power conversion circuit,
The power storage device according to claim 2 or 3, wherein the first power conversion control circuit and the second power conversion circuit operate such that the battery cooling fan or the converter cooling fan performs a rotational operation with the first power. . It further comprises a detection circuit for detecting voltage abnormality or current abnormality in the second power conversion circuit,
The power storage device according to any one of claims 1 to 4, wherein the control panel controls the circuit breaker, the first power conversion circuit, and the second power conversion circuit based on a detection result of the detection circuit. .   The power storage device according to any one of claims 1 to 5, further comprising a current limiting circuit provided between the second power conversion circuit and the second storage battery.   The power storage device according to claim 6, wherein the current limiting circuit includes a resistor and a diode connected in antiparallel to the resistor.   The power storage device according to any one of claims 1 to 7, wherein the plurality of second power conversion circuits and the plurality of second storage batteries are connected in parallel at a stage subsequent to one first storage battery. The second power conversion circuit has a chopper circuit at a front stage of the DC-AC conversion circuit,
The power storage device according to any one of claims 1 to 8, wherein the DC-AC conversion circuit is configured of a resonant inverter circuit including at least two switching elements.   The electricity storage according to any one of claims 1 to 9, further comprising an EMC filter respectively provided between said first storage battery and said second power conversion circuit, and between said second storage battery and said control panel. apparatus.

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