Charging device

Abstract

To disclose a charging device in which unbalanced voltage can be suppressed.SOLUTION: A charging device [127] includes a plurality of converter units [116], a matrix switch [120] having input ports to which the plurality of converter units are connected and output ports to which a plurality of power storage devices are connected, and a control unit [128] that controls output currents from the converter units and the matrix switch. The converter units each include a converter cell [108] having an AC / DC conversion circuit [109] and a DC / DC conversion circuit [112] connected to the AC / DC conversion circuit via a capacitor. A plurality of AC input terminals of the AC / DC conversion circuits are connected in series with each other. The control unit reduces the output currents from the converter units to a prescribed value, and then, reconfigures a connection state between the input ports and the output ports in the matrix switch.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a charging device that supplies charging power to a power storage device such as a storage battery. [Background technology]

[0002] In recent years, as the capacity of charging devices for electric vehicles has increased, charging devices equipped with medium- and high-voltage isolated AC / DC converters are beginning to be used. In the following, "electric vehicle" will be abbreviated as "EV."

[0003] 2. Description of the Related Art The technology described in Patent Document 1 is known as a conventional technology relating to a charging device equipped with a medium- to high-voltage isolated AC / DC converter.

[0004] In the technology described in Patent Document 1, the AC inputs of multiple converter cells, each of which is an isolated AC / DC converter, are connected in series with each other. The series-connected AC inputs are then directly connected to a high-voltage AC power supply system without going through a transformer.

[0005] Each converter cell includes an AC / DC conversion circuit having an AC input, a smoothing capacitor connected to the DC side of the AC / DC conversion circuit, a DC / AC conversion circuit whose AC side is connected to the DC side of the AC / DC conversion circuit, a high-frequency transformer whose primary winding is connected to the AC side of the DC / AC conversion circuit, and an AC / DC conversion circuit whose AC side is connected to the secondary winding of the high-frequency transformer and has a DC output.

[0006] The DC outputs of the multiple converter cells are connected to multiple input ports of a switch. In the switch, switches are connected in a matrix between the multiple input ports and multiple output ports. Therefore, by operating the switches, the DC output of each converter cell is connected to an arbitrary output port. Each converter cell supplies DC power to a storage battery of an electric vehicle, which is a load connected to the output port, to charge the storage battery. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2019 / 234988 Summary of the Invention [Problem to be solved by the invention]

[0008] In the above-mentioned conventional technology, when the load connection state of the multiple output ports changes, an imbalance occurs in the DC voltages of the multiple smoothing capacitors, which may cause the circuit to fail.

[0009] Therefore, the present invention provides a charging device that can suppress voltage imbalance even if the load connection state changes. [Means for solving the problem]

[0010] In order to solve the above problems, a charging device according to the present invention charges a plurality of power storage devices, and includes a plurality of converter units that input AC power and output DC power, a matrix switch having a plurality of input ports to which the plurality of outputs of the plurality of converter units are connected and a plurality of output ports to which the plurality of power storage devices are connected, and a control unit that controls the output current of the plurality of converter units and controls a plurality of switches in the matrix switch. Each of the plurality of converter units includes a converter cell having an AC / DC conversion circuit that inputs AC power and a DC / DC conversion circuit that is connected to the AC / DC conversion circuit via a capacitor and outputs DC power. A plurality of AC input terminals of the plurality of AC / DC conversion circuits are connected in series with each other. When connecting the power storage device to the output port or when disconnecting the power storage device from the output port, the control unit reduces the output current of the plurality of converter units to a predetermined value, and then the control unit reconfigures the connection state between the plurality of input ports and the plurality of output ports in the matrix switch. Effect of the Invention

[0011] According to the present invention, voltage imbalance can be suppressed.

[0012] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing the configuration of an electric vehicle charging device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram showing an example of an AC / DC conversion circuit. [Diagram 3] FIG. 3 is a circuit diagram showing another example of the AC / DC conversion circuit. [Figure 4] FIG. 4 is a circuit diagram showing an example of a DC / DC conversion circuit. [Diagram 5] FIG. 5 is a block diagram showing the configuration of the control unit. [Figure 6] FIG. 6 is a flow chart showing the operation of the control unit. [Figure 7] FIG. 7 is a time chart showing the transition of the operation modes (I, II, III) of the control unit

[0128] . [Figure 8] FIG. 8 is a circuit diagram showing an example of a connection state of input / output ports in the matrix switch

[0120] when a storage battery mounted in an EV

[0124] is charged. [Figure 9] FIG. 9 is a circuit diagram showing an example of reconfiguration of the connection state of the input / output ports in the matrix switch

[0120] when charging a storage battery mounted in an EV

[0124] . [Figure 10] FIG. 10 is a circuit diagram showing an example of a connection state of input / output ports in the matrix switch

[0120] when discharging a storage battery mounted in an EV

[0124] . [Figure 11]FIG. 11 is a circuit diagram showing an example of reconfiguration of the connection state of the input / output ports in the matrix switch

[0120] when discharging a storage battery mounted in the EV

[0124] . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same reference numbers indicate the same components or components having similar functions.

[0015] FIG. 1 is a block diagram showing the configuration of a charging device for an electric vehicle according to one embodiment of the present invention.

[0016] The charging device

[0127] has a plurality (m units) of converter units 116 that receive three-phase AC power from a three-phase, four-wire AC power source

[0100] via a three-phase reactor

[0102] . "m" is an integer of 2 or more. Each converter unit 116 has three phases (i.e., three units) of converter cells

[0108] that receive single-phase AC power from one phase of the AC power source

[0100] . Each converter cell

[0108] is composed of an AC / DC conversion circuit

[0109] that converts the single-phase AC power into DC power, and a DC / DC conversion circuit

[0112] that converts the DC power output by the AC / DC conversion circuit

[0109] into DC power of a different voltage. The DC output terminal of the AC / DC conversion circuit

[0109] and the DC input terminal of the DC / DC conversion circuit

[0112] are connected by DC buses [110, 111].

[0017] In a plurality (m units) of converter units

[0116] , the AC inputs of one phase of the three-phase (three units) converter cells

[0108] included in each converter unit

[0116] are connected in series with each other. That is, the AC input terminals [103, 104] of the plurality (m units) of AC / DC conversion circuits

[0109] are connected in series with each other. One end and the other end

[0106] of the series connection of the AC input terminals are connected to one phase (e.g., U-phase) of the AC power source

[0100] and the neutral point N of the AC power source

[0100] , respectively. This allows the input of the converter cell

[0108] to be directly connected to the high-voltage (e.g., 6.6 kV or 11 kV) AC power source

[0100] without going through a transformer.

[0018] The DC outputs of the three-phase (three units) converter cells

[0108] of each converter unit

[0116] are connected in parallel to each other. That is, the DC output terminals [113, 114] of the three-phase (three units) DC / DC conversion circuits

[0112] are connected in parallel. This forms the DC output of each converter unit

[0116] .

[0019] The matrix switch

[0120] has multiple (m) input ports and multiple (n) output ports. The matrix switch

[0120] has m×n switches arranged in a matrix of m rows and n columns between the multiple (m) input ports and the multiple (n) output ports. Each DC output of the multiple (m) converter units

[0116] is connected to a different input port among the multiple (m) input ports via a DC bus

[0115] . By operating these switches, each input port is electrically connected to an arbitrary output port.

[0020] In addition, electromagnetic or electronic switches are used as switches in the matrix switch

[0120] .

[0021] Each of the multiple (n) output ports of the matrix switch

[0120] is electrically connected to an EV charging port

[0122] (charging stand) via a connection cable

[0121] . An EV

[0124] is connected to each of the multiple (n) EV charging ports

[0122] (charging stand) via a charging cable

[0125] .

[0022] When the matrix switch

[0120] is operated to connect the DC output of any one of the multiple (m units) converter units

[0116] , the DC power output from the converter unit

[0116] is charged to the storage battery mounted on the EV

[0124] . By controlling the multiple switches in the matrix switch

[0120] , the DC output of the converter unit

[0116] is connected to the EV or disconnected from the EV. In addition, by controlling the opening and closing of the matrix switch

[0120] , the DC outputs of multiple (e.g., two) converter units

[0116] can be connected to one EV in the case of high-speed charging, etc.

[0023] The control unit

[0128] generates drive signals

[0130] for the matrix switch

[0120] and each converter cell

[0108] for controlling the opening and closing of the matrix switch

[0120] and for controlling the DC output power of each converter cell

[0108] based on voltage and current information

[0129] in the charging equipment

[0127] , a voltage or current reference value

[0131] , and EV side information

[0133] from multiple (n) EV charging ports

[0122] (charging stations), i.e., a charging port group

[0132] .

[0024] In this embodiment, the voltage and current information

[0129] is the DC bus voltage

[0117] connecting the AC / DC conversion circuit

[0109] and the DC / DC conversion circuit

[0112] in each converter cell

[0108] , and the voltage and current

[0118] at the DC output

[0115] of each converter unit

[0116] . The voltage and current information

[0129] is detected by a voltage sensor and a current sensor, respectively.

[0025] In this embodiment, the EV side information

[0133] includes SOC information

[0123] related to the state of charge (SOC) of the EV storage battery, user setting information such as charging speed (low speed, medium speed, fast speed), and EV connection information related to connection / disconnection of the EV to the EV charging port (charging stand)

[0122] . The SOC information

[0123] is transmitted to the control unit

[0128] via a communication line provided in the charging cable

[0125] and the EV charging port (charging stand)

[0122] . The user setting information is set by operating a switch device or button of the EV charging port (charging stand)

[0122] . The EV connection information is detected by the EV charging port (charging stand)

[0122] . The user setting information and the EV connection information are transmitted to the control unit

[0128] by the EV charging port (charging stand)

[0122] .

[0026] FIG. 2 is a circuit diagram showing an example of an AC / DC conversion circuit.

[0027] As shown in Fig. 2, the AC / DC conversion circuit

[0109] is composed of a single-phase full-bridge circuit using a semiconductor device

[0200] in which a semiconductor switching element (IGBT in Fig. 2) and a diode are connected in anti-parallel, and a DC link capacitor

[0201] connected in parallel to the single-phase full-bridge circuit. The series connection point of the two semiconductor devices

[0200] in each half-bridge circuit is the AC input [103, 104]. The parallel connection point of the two half-bridge circuits and the DC link capacitor

[0201] is connected to the DC bus [110, 111] as a DC output.

[0028] The AC power input to the AC input terminals [103, 104] is rectified by the diodes and converted to DC power. The DC power charges the DC link capacitor

[0201] and is output to the DC bus [110, 111].

[0029] The AC / DC conversion circuit

[0109] can convert DC power input to the DC buses [110, 111] into AC power using semiconductor switching elements and output it from the AC inputs [103, 104]. In other words, the AC / DC conversion circuit

[0109] can operate as a bidirectional power conversion circuit.

[0030] FIG. 3 is a circuit diagram showing another example of the AC / DC conversion circuit.

[0031] As shown in Fig. 3, the AC / DC conversion circuit

[0109] is composed of a half-bridge circuit using a semiconductor device

[0200] in which a semiconductor switching element (IGBT in Fig. 3) and a diode are connected in anti-parallel, and a series-connected circuit of DC link capacitors [201, 202] connected in parallel. The series-connected point of the two semiconductor devices

[0200] in the half-bridge circuit and the series-connected point of the two DC link capacitors

[0201] are respectively defined as AC inputs [103, 104]. Both ends of the half-bridge circuit, i.e., both ends of the series-connected circuit of the DC link capacitors [201, 202], are connected to the DC bus [201, 202] as DC.

[0032] The AC power input to the AC inputs [103, 104] is rectified by diodes and converted to DC power, which alternately charges the DC link capacitors [201, 202] depending on the polarity of the AC input voltage.

[0033] The AC / DC conversion circuit

[0109] shown in Fig. 3 can convert DC power input to the DC output terminals [110, 111] into AC power and output it from the AC input terminals [103, 104] by using semiconductor switching elements. In other words, the AC / DC conversion circuit

[0109] can operate as a bidirectional power conversion circuit.

[0034] FIG. 4 is a circuit diagram showing an example of a DC / DC conversion circuit.

[0035] As shown in FIG. 4, the DC / DC conversion circuit

[0112] is an isolated type and has a DC / AC conversion circuit

[0300] and an AC / DC conversion circuit

[0400] connected to the DC / AC conversion circuit

[0300] via a high-frequency transformer

[0310] .

[0036] The DC / AC conversion circuit

[0300] consists of a single-phase full-bridge circuit that uses a semiconductor device

[0301] in which a semiconductor switching element (IGBT in FIG. 4) and a diode are connected in inverse parallel, and a primary side capacitor

[0311] that is connected in parallel to the single-phase full-bridge circuit.

[0037] The parallel connection point of the two half-bridge circuits and the primary side capacitor

[0311] is connected to the DC bus [110, 111] as a DC input. The series connection point of the two semiconductor devices

[0301] in each half-bridge circuit is connected to the primary winding

[0305] of the high frequency transformer

[0310] via the reactor

[0303] as an AC output.

[0038] The AC / DC conversion circuit

[0400] consists of a single-phase full-bridge circuit that uses a semiconductor device

[0312] in which a semiconductor switching element (IGBT in Figure 4) and a diode are connected in inverse parallel, and a secondary side capacitor

[0313] that is connected in parallel to the single-phase full-bridge circuit.

[0039] The series connection point of the two semiconductor devices

[0312] in each half-bridge circuit is connected to the secondary winding

[0308] of the high-frequency transformer

[0310] as an AC input. The parallel connection point of the two half-bridge circuits and the primary side capacitor

[0201] is connected to the DC bus [113, 114] as a DC output.

[0040] The DC / AC conversion circuit

[0300] converts the DC power input from the DC bus [110, 111] into AC power using semiconductor switching elements and outputs it to the primary winding

[0305] of the high frequency transformer

[0310] . The high frequency transformer

[0310] steps down or steps up the AC voltage received by the primary winding

[0305] and outputs it to the secondary winding

[0308] .

[0041] The AC power input to the AC input terminals [103, 104] is rectified by the diodes and converted to DC power. The DC power charges the DC link capacitor

[0201] and is output to the DC bus [110, 111].

[0042] The AC / DC converter circuit

[0400] rectifies the AC power input from the secondary winding

[0308] using diodes and converts it into DC power. The DC power charges the secondary capacitor

[0313] and is output to the DC buses [110, 111].

[0043] The AC / DC conversion circuit

[0400] can convert the DC power input from the DC bus [110, 111] into AC power using semiconductor switching elements. The DC / AC conversion circuit

[0300] can convert the AC power input from the AC / DC conversion circuit

[0400] via the high-frequency transformer

[0310] into DC power using diodes. In other words, the DC / DC conversion circuit

[0112] can operate as a bidirectional power conversion circuit.

[0044] FIG. 5 is a block diagram showing the configuration of the control unit.

[0045] As shown in FIG. 5, it consists of a first control unit

[0401] and a second control unit

[0402] .

[0046] The first control unit

[0401] creates an output current command

[0400] for the converter cell

[0128] and a matrix switch control command

[0403] for setting the open / closed state (ON, OFF) of each switch in the matrix switch

[0120] based on the voltage or current reference value

[0131] and the EV side information

[0133] (SOC, user setting information).

[0047] The second control unit

[0402] generates a drive signal

[0130] for the converter cell

[0108] and the matrix switch

[0120] based on the output current command

[0400] and the output current command

[0400] generated by the first control unit

[0401] , and on the voltage and current information

[0129] in the charging device

[0127] . For example, the drive signal

[0130] is an on / off drive signal for the switch in the matrix switch

[0120] , and a gate drive signal for the semiconductor switching element in the converter cell

[0108] .

[0048] 6 is a flow chart showing the operation of the control unit 0128. The control unit 0128 has a computer system such as a microcomputer, and the computer system executes a predetermined program to perform control operations.

[0049] In step S0, the control unit

[0128] starts a control operation.

[0050] Next, in step S1, the control unit

[0128] checks the connection status of EVs at a plurality (n units) of EV charging ports

[0122] (charging stations) based on the EV side information

[0133] .

[0051] Next, in step S2, the control unit

[0128] confirms or calculates the charging power required by the EV connected to the EV charging port

[0122] (charging station) based on the EV side information

[0133] .

[0052] Next, in step S3, the control unit

[0128] sets a connection configuration between the multiple (m) input ports (on the converter unit

[0116] side) and the multiple (n) output ports (on the EV charging port

[0122] side) in the matrix switch based on the EV-side information

[0133] . That is, the control unit

[0128] creates a matrix switch control command

[0403] using the first control unit

[0401] (FIG. 2).

[0053] Next, in step S4, the control unit

[0128] determines the range of charging current for each EV, i.e., the maximum value (I ref_max ), minimum(I ref_min ) and the mean (I ref_avg (=(I ref_max +I ref_min ) / 2)).

[0054] Next, in step S6, the control unit

[0128] determines a charging current user setting value (I ref_user ) is within the range of the charging current calculated in step S4 (I ref_min ≦I ref_user ≦I ref_max In addition, the control unit 0128 determines whether the charging current user setting value (I ref_user ) is extracted from the relationship between the user setting information and the charging current user setting value, which is stored in advance (step S5).

[0055] The control unit

[0128] determines the charging current user-set value (I ref_user ) is within the range of the charging current calculated in step S4 (I ref_min ≦I ref_user ≦Iref_max If it is determined that the charging current is a user-set value (I ref_user ) is within the range of the charging current calculated in step S4 (I ref_min ≦I ref_user ≦I ref_max ), (No in step S6), then step S8 is executed.

[0056] In step S7, the control unit 0128 sets the value of the charging current to the charging current user-set value (I ref_user )

[0057] In step S8, the control unit

[0128] calculates the value of the charging current as an average value (I ref_avg (=(I ref_max +I ref_min ) / 2)).

[0058] Next, in step S9, the control unit

[0128] sets a charging current command value for the converter cell

[0108] in response to steps S7 and S8. That is, the control unit

[0128] generates an output current command

[0400] (FIG. 2) using the first control unit

[0401] (FIG. 2).

[0059] Next, in step S10, the control unit

[0128] determines whether or not there is a request for EV disconnection, charging termination, or additional connection of another EV based on the EV side information

[0133] . If the control unit

[0128] determines that there is a request (Yes in step S10), it then executes step S11. If the control unit

[0128] determines that there is no request (No in step S10), it executes steps S4 and onward again.

[0060] In step S11, the control unit

[0128] changes the output current command

[0400] (FIG. 2) so as to reduce the output current of each of the multiple (m units) converter units

[0116] used by the charging device

[0127] . At this time, the control unit

[0128] controls the multiple (three-phase) converter cells

[0108] connected in parallel in each converter unit

[0116] so as to reduce the output current of each converter cell

[0108] .

[0061] According to the study by the inventors, it is preferable that the changed output current command is set so that the voltage imbalance of the DC bus [110, 111] to which the capacitors (201, 202 in Figs. 2 and 3, 311 in Fig. 4) are connected is less than 30% of the reference value of the DC bus voltage (e.g., AC power supply voltage / m). For example, the voltage ripple of the high voltage capacitors (201, 202 in Figs. 2 and 3, 311 in Fig. 4) is kept less than 30% of the reference value. The changed output current command may be a predetermined value that is zero or close to zero.

[0062] Next, in step S12, the control unit

[0128] reconfigures the connection configuration between multiple (m) input ports (on the converter unit

[0116] side) and multiple (n) output ports (on the EV charging port

[0122] side) in the matrix switch in response to a new connection or disconnection of an EV.

[0063] Next, in step S13, the control unit

[0128] executes step S1 and subsequent steps again after a predetermined delay time. The delay time is set to the time (e.g., 1 μsec or more) required for the transient fluctuations in voltage and current in the converter unit

[0116] and converter cell

[0108] caused by the new connection or disconnection of an EV to subside.

[0064] Modes I, II, and III in FIG. 6 will be described later.

[0065] FIG. 7 is a time chart showing the transition of the operation modes (I, II, III) of the control unit

[0128] .

[0066] Mode I corresponds to the operations of steps S0 to S9 in the flowchart of Fig. 6. That is, mode I is an operation for setting a charge current command value to each converter cell

[0108] immediately after the start of operation.

[0067] Mode II corresponds to the operations of steps S10 to S13 in the flowchart of Fig. 6. That is, operation mode II is an operation in which, when changing the connection state of the EV, the output current command value of each converter cell

[0108] is set to a minimum level, and then the connection state of the input / output ports in the matrix switch

[0200] is reconfigured.

[0068] Mode III corresponds to the operations of steps S1 to S19 in the flowchart of Fig. 6. That is, operation mode I is an operation for setting a charge current command value to each converter cell

[0108] after the start of operation.

[0069] 7, at the start of operation (t0), the control unit

[0128] first operates in operation mode I. When a request for a change in the connection state of the EV is received (t1), the operation mode transitions to mode II.

[0070] In mode II, a predetermined delay time is set as shown in Fig. 6 (step S13). Therefore, the time width of mode II is a constant value including the delay time.

[0071] When mode II ends (t2), the operation mode transitions to mode III. After that (after t3), the operation mode alternates between mode II and mode III.

[0072] During the period t0-t1, the EVs connected to EV charging ports 1-m start charging and the battery voltage rises. At time t1 (start of mode II), EV charging port 1 receives a command from the control unit

[0128] to stop EV charging at EV charging port 1. Therefore, the control unit

[0128] sends a reference current command to all converter units

[0116] to zero for safe EV disconnection. During t1-t2, all converter currents decrease to zero. After the currents become zero, the EV is disconnected from EV charging port 1, but the other ports remain connected. Thus, the EV voltage is reflected to the connected ports during t2-t3. During this time interval, the converter unit

[0116] connected to EV charging port 1 is reconnected with one of the other available ports to which the EV is still connected by the matrix switch

[0120] . During t3-t4, the converter units of EV charging port m and the other ports start charging. Note that the voltage and current waveforms of the EV charging port

[0122] are shown.

[0073] Next, an example of reconfiguration of the connection state of input / output ports in the matrix switch will be described.

[0074] FIG. 8 is a circuit diagram showing an example of a connection state of input / output ports in a matrix switch

[0120] when charging a storage battery mounted on an EV. In the figure, the power transmission path is indicated by arrows. Note that the configuration of the matrix switch

[0120] shown in FIG. 8 described below is the same as that of the matrix switches

[0120] shown in FIGS. 9 to 11.

[0075] The matrix switch

[0120] has a plurality of (m×n) switches [700(1,1) to 700(m,n)] arranged in a matrix of m rows and n columns. The matrix switch

[0120] has a plurality of (m) input ports [115(1) to 115(m)] to which a plurality of (m) DC outputs

[0115] of a plurality of (m) converter units

[0116] are electrically connected. The matrix switch

[0120] also has a plurality of (m) input ports [115(1) to 115(m)] to which a plurality of (m) DC outputs

[0115] of a plurality of (units) converter units

[0116] are electrically connected. The matrix switch

[0120] also has a plurality of (n) output ports [121(1) to 121(n)] to which a plurality of (n) connection cables

[0121] are electrically connected.

[0076] In the matrix switch

[0120] , the input ports [115(1)-115(m)] are connected to the buses [701(1)-701(m)], and the output ports [121(1)-121(n)] are connected to the buses [702(1)-702(n)]. The switches [700(m,n)] are connected between the buses [701(m)] and [702(n)].

[0077] As shown in FIG. 8, n EVs

[0124] are connected to output ports 121(1), 121(2), and 121(n).

[0078] The output power of the converter unit

[0116] connected to the input port 115(1) is transmitted to the EV

[0124] connected to the output port 121(1) via the route of the bus [701(1)] → switch [700(1,1)] → bus [702(1)]. This charges the storage battery installed in the EV

[0124] connected to the output port 121(1).

[0079] The output power of the converter unit

[0116] connected to the input port 115(2) is transmitted to the EV

[0124] connected to the output port 121(2) via the route of the bus [701(2)] → switch [700(2,2)] → bus [702(2)]. This charges the storage battery installed in the EV

[0124] connected to the output port 121(2).

[0080] The output power of the converter unit

[0116] connected to the input port 115(m) is transmitted to the EV

[0124] connected to the output port 121(n) via the route of the bus [701(m)] → switch [700(m,n)] → bus [702(n)]. This charges the storage battery installed in the EV

[0124] connected to the output port 121(n).

[0081] 9 is a circuit diagram showing an example of reconfiguration of the connection state of the input / output ports in the matrix switch

[0120] when charging a storage battery mounted on an EV. In the figure, the power transmission path is indicated by an arrow.

[0082] The connection state in the matrix switch transitions from the connection state shown in FIG. 8 to the connection state shown in FIG.

[0083] In the connection state of Fig. 8, when there is a request to disconnect the EV

[0124] connected to the output port 121(n), the output current command value of the converter cell

[0108] is reduced as described above. Then, the connection state of the matrix switch is reconfigured and transitions to the connection state of Fig. 9. This makes it possible to suppress the magnitude of the voltage imbalance of the DC buses [110, 111].

[0084] As shown in Fig. 9, of the three EVs

[0124] , the EV

[0124] connected to the output port [121(n)] in Fig. 8 is disconnected from the output port 121(n). At this time, the switch [700(m,n)] is turned off.

[0085] When the switch [700(m,n)] is turned off, power transmission to the EV

[0124] connected to the output port [121(n)] is cut off. At this time, a voltage imbalance may occur in the DC buses [110,11], but the magnitude of the voltage imbalance is suppressed because the output current of each converter cell

[0116] is reduced.

[0086] In this embodiment, by turning on the switch [700(m,2)], the output power of the converter unit

[0116] connected to the input port [115(m)] is charged to the EV

[0124] that remains connected to the output port [121(2)]. In other words, the transmission of the output power of the converter unit

[0116] connected to the input port [115(m)] continues. This prevents the occurrence of a voltage imbalance in the DC bus [110,11] that would occur if the EV

[0124] were disconnected from the output port 121(n).

[0087] 10 is a circuit diagram showing an example of a connection state of input / output ports in a matrix switch when discharging a storage battery mounted in an EV. In the figure, the arrows indicate the power transmission paths.

[0088] Since both the AC / DC conversion circuit

[0109] and the DC / DC conversion circuit

[0112] are bidirectional power conversion circuits, they are capable of charging and discharging the storage battery installed in the EV

[0124] .

[0089] As shown in FIG. 10, three EVs

[0124] are connected to output ports 121(1), 121(2), and 121(n).

[0090] The stored power of the EV

[0124] connected to output port 121(1) is transmitted to the converter unit

[0116] connected to input port 115(1) via the route of bus [702(1)] → switch [700(1,1)] → bus [701(1)]. This causes the storage battery installed in the EV

[0124] connected to output port 121(1) to be discharged.

[0091] The stored power of the EV

[0124] connected to the output port 121(2) is transmitted to the converter unit

[0116] connected to the input port 115(2) via the bus [702(2)] → switch [700(2,2)] → bus [701(2)]. This causes the storage battery installed in the EV

[0124] connected to the output port 121(2) to be discharged.

[0092] The stored power of the EV

[0124] connected to the output port 121(n) is transmitted to the converter unit

[0116] connected to the input port 115(m) via the bus [702(n)] → switch [700(m,n)] → bus [701(m)]. This charges the storage battery installed in the EV

[0124] connected to the output port 121(n).

[0093] 11 is a circuit diagram showing an example of reconfiguration of the connection state of the input / output ports in the matrix switch

[0120] when discharging a storage battery mounted in an EV. In the figure, the power transmission path is indicated by an arrow.

[0094] The connection state in the matrix switch transitions from the connection state shown in FIG. 10 to the connection state shown in FIG.

[0095] In the connection state of Fig. 10, when there is a request to disconnect the EV

[0124] connected to the output port 121(n), the output current command value of the converter cell

[0108] is reduced as described above. Then, the connection state of the matrix switch is reconfigured and transitions to the connection state of Fig. 10. This makes it possible to suppress the magnitude of the voltage imbalance of the DC buses [110, 111].

[0096] As shown in Fig. 11, of the three EVs

[0124] , the EV

[0124] connected to the output port [121(n)] in Fig. 10 is disconnected from the output port 121(n). At this time, the switch [700(m,n)] is turned off.

[0097] When the switch [700(m,n)] is turned off, power transmission from the EV

[0124] connected to the output port [121(n)] is cut off. At this time, a voltage imbalance may occur in the DC buses [110,11], but the magnitude of the voltage imbalance is suppressed because the output current of each converter cell

[0108] is reduced.

[0098] In this embodiment, by turning on the switch [700(m,2)], the stored power of the EV

[0124] that remains connected to the output port [121(2)] is discharged to the converter cell

[0108] connected to the input port [115(m)]. In other words, the transmission of power to the converter cell

[0108] connected to the input port [115(m)] continues. This prevents the voltage imbalance of the DC bus [110,11] that occurs when the EV

[0124] is disconnected from the output port 121(n).

[0099] It is to be understood that the present invention is not limited to the specific construction and arrangement of parts illustrated in the accompanying drawings, because the present invention may be implemented in other ways and may be practiced or carried out in various ways. It is also to be understood that the words and terms used herein are for the purpose of description and not of limitation.

[0100] For example, the power storage device installed in an EV may be a capacitor instead of a storage battery.

[0101] For example, the semiconductor switching elements constituting the AC / DC conversion circuit

[0109] and the DC / DC conversion circuit

[0112] are not limited to IGBTs, but may be MOSFETs, junction bipolar transistors, etc. Also, the semiconductor material constituting the semiconductor switching elements and diodes is not limited to Si, but may be wide-gap semiconductors such as SiC and GaN. [Explanation of symbols]

[0102] 100 AC power supply 102 Three-phase reactor 103,104 AC input terminal 108 Converter Cell 109 AC / DC conversion circuit 110,111 DC Bus 112 DC / DC conversion circuit 113,114 DC output terminal 115 DC Bus 120 Matrix Switch 121 Connection cable 122 EV charging port (charging station) 124EV 125 Charging cable 127 Charging device 128 Control Unit 129 Voltage and Current Information 130 Drive signal 131 Voltage or current reference value 133 EV side information 310 High Frequency Transformer 300 DC / AC conversion circuit 400 AC / DC conversion circuit

Claims

1. In a charging device that charges a plurality of power storage devices, A plurality of converter units that receive AC power and output DC power; a matrix switch having a plurality of input ports to which a plurality of outputs of the plurality of converter units are connected and a plurality of output ports to which the plurality of power storage devices are connected; a control unit that controls output currents of the converter units and controls a plurality of switches in the matrix switch; Equipped with Each of the plurality of converter units is a converter cell including an AC / DC conversion circuit that receives the AC power and a DC / DC conversion circuit that is connected to the AC / DC conversion circuit via a capacitor and outputs the DC power; The AC input terminals of the AC / DC conversion circuits are connected in series with each other, A charging device characterized in that when the storage device is connected to the output port or when the storage device is disconnected from the output port, the control unit reduces the output current of the multiple converter units to a predetermined value, and then the control unit reconfigures the connection state between the multiple input ports and the multiple output ports in the matrix switch.

2. 2. The charging device according to claim 1, A charging device characterized in that the control unit sets output current commands for the multiple converter units after reconfiguring the connection state between the multiple input ports and the multiple output ports in the matrix switch.

3. 2. The charging device according to claim 1, A charging device characterized in that the ripple of the voltage of the capacitor is kept below 30% of the reference value of the voltage.

4. 2. The charging device according to claim 1, A charging device, characterized in that the predetermined value of the output current can be reduced to zero.

5. 2. The charging device according to claim 1, A charging device characterized in that the control unit sets output current commands for the multiple converter units a predetermined delay time after reconfiguring the connection state between the multiple input ports and the multiple output ports in the matrix switch.

6. 6. The charging device according to claim 5, The charging device according to claim 1, wherein the predetermined delay time is 1 μsec or more.

7. 2. The charging device according to claim 1, A charging device, wherein each of a plurality of converter units includes a plurality of the converter cells whose DC outputs are connected in parallel to each other.

8. 2. The charging device according to claim 1, A charging device capable of setting a charging speed for the power storage device.

9. 2. The charging device according to claim 1, The charging device according to claim 1, wherein the AC / DC conversion circuit and the DC / DC conversion circuit are bidirectional power conversion circuits.

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