JP7122875B2 - charging device - Google Patents

Description

The present invention relates to a charging device that supplies charging power to a power storage device such as a storage battery.

In recent years, while environmental problems and energy resource problems have been attracting attention, vehicles such as electric vehicles, hybrid vehicles, and plug-in hybrid vehicles (hereinafter collectively referred to as "electric vehicles") that run using power from storage batteries as a driving source are becoming popular. It is becoming popular.

With the spread of electric vehicles, there are issues with charging equipment, such as shortening charging time, securing installation sites, and improving operating rates. In particular, it is difficult to secure installation sites in urban areas. For example, an existing parking lot can be considered as the installation location, but the space that can be used as a charging space, including the installation space for the charging device and the work space, is limited.

On the other hand, a conventional technique described in Patent Document 1 is known. In this prior art, a switch is provided between a plurality of rectifiers (AC/DC converters) and a plurality of charging stations. With this switch, each charging station is connected to the number of rectifiers corresponding to the charging menu (rest, medium speed, low speed). As a result, it is possible to improve the operation rate while suppressing an increase in the size of the charging device.

JP 2012-70479 A

In the prior art described above, sufficient consideration is not always given to the configuration and operation of the switch. For example, during the switching operation, there is a risk that a large potential difference will be applied to the terminals of the switch or that a large rush current will flow, making it difficult to obtain practically sufficient reliability as a charging device.

Accordingly, the present invention provides a charging device capable of improving reliability.

In order to solve the above problems, a charging device according to the present invention charges a plurality of power storage devices of a plurality of electric vehicles, and includes a plurality of converter cells that output DC power, and a plurality of power storage devices of the plurality of converter cells. a switch having a plurality of input ports to which outputs are connected and a plurality of output ports to which a plurality of power storage devices are connected; A control device that, when connected, adjusts the output voltage of a converter cell connected to one of a plurality of input ports according to the voltage of a power storage device that is connected to one of the plurality of output ports; and a plurality of electric vehicles. and a plurality of charging connectors connected to the plurality of output ports of the switch via a plurality of repeaters, wherein the switch includes each of the plurality of input ports and the plurality of output ports. has a switch part consisting of a plurality of switches connected between the , a high frequency transformer, a primary side power converter connected to the primary side of the high frequency transformer, and a secondary side power converter connected to the secondary side of the high frequency transformer and having an output connected to an output port. The repeater relays a signal line between the electric vehicle and the control device, the repeater constitutes a charging station, and the control device is based on information transmitted from the electric vehicle via the signal line controls the converter cell, controls the switch based on a request sent from the charging station via the signal line, and the switch is connected to the high potential side of the pair of secondary terminals of the converter cell. a first switch and a second switch to which the low potential side of the pair of secondary terminals of the converter cell is connected; It is installed above the repeater of

ADVANTAGE OF THE INVENTION According to this invention, the reliability of a charging device can be improved.

1 shows a schematic configuration of a charging device that is an embodiment of the present invention; 2 shows an example of a switching operation of a switch in the charging device of FIG. 1; 4 is a circuit diagram showing the configuration of a switch; FIG. 4 shows the operating state of the switch in the switch. 4 shows the operating state of the switch in the switch. 4 shows the operating state of the switch in the switch. 4 shows a configuration of a modification of the switch. 4 is a flow chart showing processing operations in the arithmetic unit of the central controller; 7 is a flowchart showing an example of converter voltage processing in FIG. 6; 3 is a functional block diagram showing the configuration of a central controller; FIG. 1 shows an example of a circuit configuration of a charging device; 3 shows another example of the circuit configuration of the charging device. The connection configuration of a switch and a repeater is shown. The connection configuration of a switch and a repeater is shown. An example of the installation form of the charging device of this embodiment is shown. 4 shows a modification of the circuit configuration of the AC/DC converter in the converter cell. 4 shows a modification of the circuit configuration of the DC/DC converter section. 4 shows a modification of the circuit configuration of the DC/DC converter section. 4 shows a modification of the circuit configuration of the DC/DC converter section.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same reference numbers denote the same components or components with similar functions.

FIG. 1 shows a schematic configuration of a charging device that is one embodiment of the present invention. Note that the charging device of the present embodiment supplies electric power to the electric vehicle to replenish the energy stored in the storage battery.

As shown in FIG. 1, the charging device charges a storage battery mounted on an electric vehicle with electric power received from an AC or DC power supply system 23 via a power conversion circuit. Here, the power conversion circuit includes converter cells 20-1 to 20-M (M: natural number) for converting received power into DC power for charging, a switch 21, and repeaters 30-1 to 30-M. , charging connectors 31-1 to 31-M. The power conversion operations of converter cells 20-1 to 20-M and the switching operations of switch 21 are controlled by central controller 22. FIG.

Switch 21 connects each converter cell to an arbitrary repeater among repeaters 30-1 to 30-M. In FIG. 1, the switch 21 connects the converter cells 20-1 to 20-M and the repeaters 30-1 to 30-M on a one-to-one basis. In this case, the charging device can simultaneously charge up to M electric vehicles 32-1 to 32-M.

Charging connectors 31-1 to 31-M are connected to charging ports of electric vehicles 32-1 to 32-M, respectively. Also, charging connectors 31-1 to 31-M are connected to repeaters 30-1 to 30-M via charging cables, respectively.

The power system 23 side inputs of a plurality of (M) converter cells 20-1 to 20-M are connected in series with each other. As a result, the converter cells 20-1 to 20-M are directly connected to the high voltage (for example, 6.6 kV, 11 kV, etc.) power supply system 23 without a transformer. Since no transformer is used in the power receiving unit of the charging device in this way, the size of the charging device including the power receiving unit can be reduced. Further, as will be described later (FIGS. 9 and 10), each converter cell includes a power conversion circuit (for example, SST (Solid State Transformer)) including a semiconductor switching element and a high frequency transformer. Thereby, each converter cell can be miniaturized.

As the power supply system 23, for example, a commercial AC power supply, a photovoltaic power generation system, a wind power generation system, a DC power distribution system, or the like is used.

Electric power from power supply system 23 is received by M converter cells 20-1 to 20-M. As described above, since the inputs of the power supply system 23 side of the converter cells 20-1 to 20-M are connected in series, the voltage of the power supply system is divided by each converter cell. Therefore, power from power supply system 23 is shared by each converter cell. Electric power shared by converter cells 20-1 to 20-M is input to switch 21 via converter cells 20-1 to 20-M.

Switch 21 has M input ports 21-x1 to 21-xM to which the charging DC power output from converter cells 20-1 to 20-M are input, respectively. Further, the switch 21 has M output ports 21-y1 to 21-yM for outputting power input to the input ports 21-x1 to 21-xM. By operating the switch 21, each of the input ports 21-x1 to 21-xM is connected to an arbitrary output port among the output ports 21-y1 to 21-yM. That is, each power input to the input ports 21-x1 to 21-xM can be output from any of the output ports 21-y1 to 21-yM. The internal configuration of the switch 21 will be described later (FIGS. 3-5).

The charging power output from the output ports 21-y1 to 21-yM is supplied to electric vehicles 32-1 to 32-M via repeaters 30-1 to 30-M, respectively. Relays 30-1 to 30-M relay power lines for supplying power for charging between switch 21 and electric vehicles 32-1 to 32-M. Therefore, the charging connectors 31-1 to 31-M are connected to the output ports 21-y1 to 21-yM of the switch 21 by the power lines via the repeaters 30-1 to 30-M, respectively. . Further, repeaters 30-1 to 30-M relay vehicle communication line signal lines 33 between central controller 22 and electric vehicles 32-1 to 32-M.

Each of repeaters 30-1 to 30-M constitutes a so-called charging station. Although not shown, each of the relays 30-1 to 30-M has a charging time, a charging fee, and a remaining capacity of the storage battery in order to improve the convenience of the user or operator as a charging stand. You may provide the indicator which displays information, such as.

Charging connectors 31-1 to 31-M are connected to the repeaters 30-1 to 30-M, respectively. When charging storage batteries mounted on electric vehicles, the charging connectors 31-1 to 31-M are connected to charging ports of the electric vehicles 32-1 to 32-M, respectively.

The electric vehicles 32-1 to 32-M receive electric power from charging devices via charging connectors 31-1 to 31-M. Also, the electric vehicles 32-1 to 32-M transmit and receive various information to and from the central controller 22 in the charging device via the vehicle communication line signal line 33. FIG. For example, via the vehicle communication line signal line 33, charging control command information such as the state of charge of the storage battery mounted on the electric vehicle, charging voltage, charging power, and charging current is transmitted from the electric vehicle to the central controller 22. be. Also, a request from the charging device side is transmitted from the central controller 22 to the electric vehicle via the vehicle communication line signal line 33 .

The central controller 22 receives various information obtained via the vehicle communication line signal line 33, information regarding the operating state of each converter cell obtained via the converter control signal line 35, and information obtained via the sensor signal line 36. Based on the information about the input voltage and input current from the power supply system 23, a control command for each converter cell, switch 21 and each repeater is created. Control commands for each converter cell, switch and repeater are transmitted via converter control signal line 35, switch control signal line 34 and vehicle communication line signal line 33, respectively.

The input voltage and input current from power supply system 23 are detected by voltage sensor 24a and current sensor 24b, respectively.

FIG. 2 shows an example of the switching operation of the switching device 21 in the charging device of FIG. It is assumed that the state of the switch 21 has changed from the state shown in FIG. 1 to the state shown in FIG.

As shown in FIG. 2, charging of electric vehicle 32-2 using repeater 30-2 to which converter cell 20-2 is connected is completed, and repeater 30-2 is not used. Here, since quick charging is requested for the electric vehicle 32-1, the switch 21 changes the connection destination of the input port 21-x2 to which the converter cell 20-2 is connected to the electric vehicle 32-1. switch to the output port 21-1 connected to the repeater 30-1 used for charging the storage battery mounted on the . As a result, the storage battery mounted on the electric vehicle 32-1 is charged by the two converter cells (20-1 and 20-2), thereby shortening the charging time.

Switch 21 may be operated for load leveling of each converter cell in addition to rapid charging.

Next, the configuration and operation of the switch 21 will be specifically described.

FIG. 3 is a circuit diagram showing the configuration of the switch 21. As shown in FIG.

As shown in FIG. 3, the switch 21 includes M input ports 21-x1 to 21-xM serving as connection terminals to which M (M: a natural number equal to or greater than 2) converter cells are connected, and M input ports 21-x1 to 21-xM. It has M output ports 21-y1 to 21-yM serving as connection terminals to which repeaters are connected. In this embodiment, the converter cells 20-1 to 20-M (FIG. 1) are connected to the input ports 21-x1 to 21-xM, respectively, and the repeaters 30-1 to 30-M (FIG. 1) , are connected to output ports 21-y1 to 21-yM, respectively. That is, M converter cells are connected to M input ports one-to-one, and M repeaters are connected to M output ports one-to-one.

Further, the switch 21 includes M ² switches connected in a matrix of M rows and M columns between the input ports 21-x1 to 21-xM and the output ports 21-y1 to 21-yM. 21-s11 to 21-sMM. As a result, the output power of the converter cell connected to the input port is transferred from an arbitrary input port among the input ports 21-x1 to 21-xM to an arbitrary output port among the output ports 21-y1 to 21-yM. can send That is, the output power of any one of the converter cells 20-1 to 20-M (FIG. 1) can be sent to any one of the repeaters 30-1 to 30-M (FIG. 1). can be done.

Each switch may be either a mechanical switch or an electronic switch. For example, mechanical relays, semiconductor relays, semiconductor valves, semiconductor switches, etc. can be applied as switches. Moreover, each switch may incorporate a snubber circuit or the like that absorbs a surge accompanying the switching operation.

4a, 4b and 4c show the operating states of the switches 21-s11 to 21-sMM in the switch 21. FIG.

The operating state of the switches 21-s11 to 21-sMM shown in FIG. 4a corresponds to the operating state of the switch 21 in FIG.

As shown in FIG. 4a, among the switches 21-s11 to 21-sMM, the switches 21-skk (k=1 to M) are closed and the other switches are opened. As a result, as shown in FIG. 1, the input ports 21-x1 to 21-xM are connected to the output ports 21-y1 to 21-yM, respectively.

The operating state of the switches 21-s11 to 21-sMM shown in FIG. 4b corresponds to the transition state from the operating state of the switch 21 in FIG. 1 to the operating state of the switch 21 in FIG.

As shown in FIG. 4b, the switch 21-s22 connected between the input port 21-x2 and the output port 21-y2 is opened to finish charging the storage battery mounted on the electric vehicle 32-2. be.

The operating state of the switches 21-s11 to 21-sMM shown in FIG. 4c corresponds to the operating state of the switch 21 in FIG.

As shown in FIG. 4c, a switch connected between the input port 21-x2 and the output port 21-y1 so as to connect the input port 21-x2 to the output port 21-y1 according to the demand for fast charging. 21-s21 is turned on.

FIG. 5 shows a configuration of a modification of the switch in this embodiment.

As shown in FIG. 5, in this modification, the number of input ports differs from the number of output ports. For this reason, the switch 21 is arranged between the input ports 21-x1 to 21-xM and the output ports 21-y1 to 21-yN (M, N: a natural number of 2 or more, M≠N), so to speak, M rows. It has M×N switches 21-s11 to 21-sMN connected in a matrix of N columns. This modification is used, for example, when the number of converter cells (M) is made larger than the number of repeaters (N) to give redundancy to the number of converter cells and improve the reliability of the charging device. Applies.

Each switch in the switch described above is controlled to be closed and opened by a control command transmitted from the central controller 22 (FIG. 1) via the switching control signal line 34 (FIG. 1). Therefore, the configuration and operation of the central controller 22 will be described below.

FIG. 8 is a functional block diagram showing the configuration of the central controller 22. As shown in FIG.

As shown in FIG. 8, the central controller 22 executes a predetermined program to create a control command for the converter cells 20-1 to 20-M, the switch 21, etc., and a communication unit 22e with an external device. and interfaces (33-36). A converter control signal line 35, a switching control signal line 34, and a vehicle communication signal line 33 are connected to the converter communication transmitting/receiving end 22a, the switching command transmitting end 22b, the vehicle communication transmitting/receiving end 22c, and the sensor signal receiving end 22d, which are communication interfaces, respectively. and sensor signal line 36 are connected. Note that the arithmetic unit 22e is configured by an arithmetic processing device such as a microcomputer, FPGA, or ASIC.

Arithmetic unit 22e acquires, via converter communication transmitting/receiving end 22a, information about the operating state of each converter cell, which is transmitted from each converter cell via converter control signal line 35. FIG. The computing unit 22e also receives information (voltage, power, current, capacity) about the storage battery and its charging state transmitted from the electric vehicle via the vehicle communication signal line 33, and charging control command information ( charging voltage, charging power, charging current), and a request for quick charging transmitted from the electric vehicle or relay (charging station) via the vehicle communication signal line 33 is obtained via the vehicle communication transmitting/receiving end 22c. Further, the computing unit 22e receives information about the input voltage and input current from the power supply system transmitted from the voltage sensor 24a and the current sensor 24b (FIG. 1) via the sensor signal line 36 via the sensor signal receiving end 22d. get.

The calculation unit 22e creates a control command for the switch 21 based on the acquired information, and sends it to the switching control signal line 34 via the switching command transmission end 22b. Based on the acquired information, the calculation unit 22e also creates a control command for each converter cell and sends it to the converter control signal line 35 via the converter communication transmitting/receiving end 22a.

FIG. 6 is a flow chart showing the processing operation in the computing section 22e of the central controller 22. As shown in FIG.

When the processing unit 22e starts processing (step F0), first, based on acquired information such as a request for quick charging, information on completion of charging, and a request for load equalization of the converter cells, the open/close state of the switch is determined. is changed (step F1). If changed (YES in step F1), the process proceeds to step F2, and if not changed (NO in step F1), step F1 is executed again.

In step F1, when determining to change the open/closed state of the switch, the computing unit 22e further determines whether or not a request such as quick charging can be met based on the performance specifications and operating state of the charging device. You can judge. If yes, go to step F2, otherwise step F1 is executed again.

In step F2, the calculation unit 22e determines whether there is a switch to be opened based on the acquired information. Here, an open switcher means a switcher section that is not connected to any output port and is open among the switcher sections connected to each input port in the switcher 21 . That is, in the present embodiment, the switching unit to be opened is a switching unit composed of a plurality of switches (for example, switches 21-s11 to 21-s1M in FIG. 3) connected to one input port, It is a switch part in which all the switches are open. As a result of the determination, if there is a switch to be opened (YES in step F2), then step F3 is executed, and if there is no switch to be opened (NO in step F2), then step F4 is executed.

In step F3, the calculation unit 22e creates a control command to open the switch unit determined to be opened, and transmits the control command to the switch unit 21. FIG. As a result, the switching section is opened. After executing step F3, next step F4 is executed.

In step F4, the calculation unit 22e determines whether there is a switch to be turned on based on the acquired information. Here, the switching unit to be turned on means a switching unit connected to one of the output ports among the switching units connected to the respective input ports in the switching unit 21 . That is, in the present embodiment, the switching unit to be turned on is a switching unit composed of a plurality of switches (for example, switches 21-s11 to 21-s1M in FIG. 3) connected to one input port, It is a switch part in which any one of the switches is open. As a result of the determination, if there is a switch to be turned on (YES in step F4), then step F6 is executed, and if there is no switch to be turned on (NO in step F4), the calculation unit 22e ends the process (step F8).

In step F6, the calculation unit 22e determines whether the difference between the input-side voltage and the output-side voltage of the switch of the switching unit determined to be turned on in step F4 is within a predetermined value, based on the acquired information. As a result of the determination, if it is within the predetermined value (YES in step F6), then step F7 is executed, and if it exceeds the predetermined value (NO in step F6), then step F5 is executed. Information about the voltage on the input side of the switch is acquired based on information about the output voltage of the converter cell transmitted from the converter cell via the converter control signal line 35, for example. Information about the voltage on the output side of the switch is acquired based on information about the voltage of the storage battery transmitted from the electric vehicle 32-2 via the vehicle communication signal line 33, for example.

At step F5, the calculation unit 22e executes a converter voltage control process. That is, the calculation unit 22e creates a control command for the converter cell connected to the switch determined to be turned on so as to reduce the difference between the input side voltage and the output side voltage, and transmits the control command to this converter cell. This adjusts the output voltage of the converter cell. After step F5 is executed, step F6 is executed again. Therefore, steps F6 and F5 are repeatedly executed until the difference between the input side voltage and the output side voltage is within a predetermined value.

In step F7, the calculation unit 22e creates a control command for closing the switch unit (switch) determined to be closed, and transmits the control command to the switch 21. FIG. As a result, the switch section is turned on in a state in which the difference between the input side voltage and the output side voltage is within a predetermined value. As a result, it is possible to prevent an excessive rush current from flowing through the charging device and the storage battery. When step F7 is executed, the calculation unit 22e terminates a series of processes.

Note that the calculation unit 22e repeatedly executes the series of processes shown in FIG. 6 while the charging device is in operation.

As a specific example of the processing shown in FIG. 6, the operating state of the switch 21 transitions from the state shown in FIG. 1 to the state shown in FIG. A case of transitioning in the order of the states in FIG. 4c will be described. 1, 2, 4a to 4c, and 8 will be referred to in the following description.

First, in step F1, the operating state of the switch 21 transitions from the state shown in FIG. 1 to the state shown in FIG. Next, step F2 is executed.

In step F2, the calculation unit 22e determines that the switch 21-s22, which is closed as shown in FIG. 4a in the switch state of FIG. It is determined that there is a switch to be opened (YES in step F2), and then step F3 is executed.

In step F3, the calculation unit 22e creates a control command to open the switch 21-s22 and transmits it to the switch 21 via the switch command transmission end 22b. As a result, the switch 21-s22 is opened, and the state of the switch 21 becomes the state shown in FIG. 4b. After executing step F3, the calculation unit 22e next executes step F4.

In step F4, the computing unit 22e is in a standby state in which it can be connected to the relay 30-1 in addition to the converter cell 20-1 in response to information such as a quick charge request from the electric vehicle 32-1 or the relay 30-1. The converter cell 20-2 whose charging operation has been completed and whose input port 21-x2 is open is selected as the converter cell for the second cell. Then, in order to connect the converter cell 20-2 to the repeater 30-1, the operation unit 22e turns on the switch 21-s21, which connects the input port 21-x2 to the output port 21y1. It is determined that there is a switch (Yes in step F4), and then step F6 is executed.

In step F6, the calculation unit 22e determines the difference between the voltage of the input side of the switch 21-s21, that is, the input port 21-x2, and the voltage of the output side of the switch 21-s21, that is, the voltage of the output port 21-y1, that is, the open It is determined whether the potential difference between the input port 21-x2 and the output port 21-y1 is within a predetermined value. This predetermined value is set so that the rush current that flows into the storage battery or the charging device when the switch 21-s21 is turned on is within the allowable value. The information about the voltage on the input side of the switch 21-s21 is acquired based on the information about the output voltage of the converter cell 20-2 transmitted from the converter cell 20-2 via the converter control signal line 35, for example. be. Information about the voltage on the output side of the switch 21-s21 is acquired based on information about the voltage of the storage battery transmitted from the electric vehicle 32-2 via the vehicle communication signal line 33, for example.

Normally, before charging is started, the amount of electricity stored in the storage battery of the electric vehicle is low, so the voltage of the storage battery and the output voltage of the charging device are different. This example is such a normal state, and in step S6, the calculation unit 22e determines that the difference between the input side voltage of the switch 21-s21 and the output side voltage of the switch 21-s21 is not within a predetermined value. (NO in step F6), and then step F5 is executed.

In step F5, the calculation unit 22e reduces the difference between the input side voltage of the switch 21-s21 and the output side voltage of the switch 21-s21, that is, the output voltage of the converter cell 20-2 and the electric vehicle 32- A control command for converter cell 20-2 is created and transmitted to converter cell 20-2 via converter control signal line 35 so as to reduce the difference from the voltage of No. 1 storage battery. After executing step F5, the calculation unit 22e executes step F6 again.

After re-executing step F6, the calculation unit 22e increases the output voltage of the converter cell 20-2 so that the difference between the input side voltage of the switch 21-s21 and the output side voltage of the switch 21-s21 is reduced in step F5. Since it is adjusted, it is determined that the difference between the input side voltage of the switch 21-s21 and the output side voltage of the switch 21-s21 is within a predetermined value (YES in step F6), and then step F7 is executed. do.

In step F7, the calculation unit 22e creates a control command for closing the switch 21-s21 and transmits it to the switch 21 via the switching control signal line . As a result, the difference between the input side voltage of the switch 21-s21 and the output side voltage of the switch 21-s21 is within a predetermined value, that is, the output voltage of the converter cell 20-2 and the storage battery of the electric vehicle 32-1. The switch 21-s21 is turned on in a state where the difference from the voltage of is small. Therefore, it is possible to prevent an excessive rush current from flowing through the converter cell 20-2 and the storage battery of the electric vehicle 32-1. At this time, the switch 21 is in the state shown in FIG. 4c.

FIG. 7 is a flow chart showing an example of converter voltage processing (step F5) in FIG. In this example, each converter cell includes a so-called LLC type DC/DC converter section, as will be described later (see FIG. 9). Note that in the case of the LLC system, the higher the operating frequency, the lower the output voltage.

In step F5 of FIG. 6, the calculation unit 22e calculates the difference between the input side voltage and the output side voltage of the switch (21-s21) to be closed, that is, the output voltage of the converter cell (20-2) and the storage battery, as described above. When it is determined that the difference in voltage (installed in the electric vehicle 32-1) exceeds a predetermined value (NO in step F6), the converter voltage processing of FIG. 7 is started (step F5-0).

First, in step F5-1, the calculation unit 22e determines whether the input side voltage is higher than the output side voltage in the switch. If the calculation unit 22e determines that the input side voltage is higher (YES in step F5-1), then it executes step F5-2, and if it determines that the input side voltage is not higher (step F5-1 NO), then step F5-3 is executed.

In step F5-2, the calculation unit 22e creates a control command to raise the switching frequency of the AC/DC converter 12 (see FIG. 9) described later, that is, the operating frequency of the converter cell (20-2) by a predetermined amount, and converts the converter control signal It is transmitted via line 35 to the converter cell (20-2). As a result, the input side voltage, that is, the output voltage of the converter cell (20-2) decreases, and the difference between the input side voltage and the output side voltage of the switch (21-s21) decreases.

Further, in step F5-3, the calculation unit 22e creates a control command to lower the switching frequency of the AC/DC converter 12 (see FIG. 9) described later, that is, the operating frequency of the converter cell (20-2) by a predetermined amount. It is transmitted to the converter cell (20-2) via the control signal line 35. FIG. As a result, the input side voltage, that is, the output voltage of the converter cell (20-2) increases, and the difference between the input side voltage and the output side voltage of the switch (21-s21) decreases.

In steps F5-2 and F5-3, the amount of increase/decrease in the switching frequency (the above-mentioned “predetermined amount”) is determined by the difference between the input side voltage and the output side voltage according to the frequency characteristics of the output voltage of the LLC type converter cell. It is appropriately set so that it can be reduced. In steps F5-2 and F5-3, the amount of increase/decrease in the switching frequency may be the same or different.

After executing step F5-2 or step F5-3, the calculation unit 22e ends the series of converter voltage processing (step F5-4), and executes step F6 in the above-described processing of FIG. 6 again.

In the example of FIG. 7, the output voltage is adjusted by frequency-controlling the LLC type converter cell. may apply.

Next, the circuit configuration of this embodiment will be described.

FIG. 9 shows an example of the circuit configuration of the charging device of this embodiment.

The M converter cells 20-1 to 20-M have a pair of primary side terminals (25, 26) and a pair of secondary side terminals ((27-1, 28-1) to (27-M, 28 -M)), AC/DC converter 11 (first AC/DC converter (primary side converter)), AC/DC converter 12 (second AC/DC converter (primary side converter)), AC/DC converter 13 (third AC/DC converter (secondary converter)), a high frequency transformer 15, a smoothing capacitor 17, and smoothing capacitors 18-1 to 18-M.

At the input of the charging device, the primary terminals 25 and 26 of the converter cells 20-1 to 20-M are connected in series with each other, and the power of the power supply system 23 is received at such an input. . Further, among the pair of secondary terminals of the converter cells 20-1 to 20-M, the secondary terminals (27-1 to 27-M) on the high potential side are connected to the switch 21, and the secondary terminals on the low potential side are connected to the switch 21. Secondary terminals (28-1 to 28-M) are connected to the switch 21'. Thereby, each potential on the secondary side of the converter cells 20-1 to 20-M can be made independent.

Note that filter reactors 19a and 19b are inserted between the AC input portion of the AC/DC converter 11 and the pair of primary side terminals (25, 26).

Both the switch 21 and the switch 21' have the configuration shown in FIG. 3 or 5 above. Corresponding input ports (eg, 21-x1 and 21'-x1) are connected to the respective input ports, and the corresponding switches of the switches 21 and 21' are interlocked to turn on the switches 21 and 21'. Any of the corresponding output ports ((21-y1, 21'-y1) to (21-yN, 21'-yN) including the case where N=M) (eg, 21-y1 and 21'-y1) connected to

The AC/DC converter 11 on the primary side converts AC power received from the power supply system 23 (FIG. 1) into DC power. The AC/DC converter 12 on the primary side converts the DC power output from the AC/DC converter 11 into AC power. The high-frequency transformer 15 steps up or steps down the AC power output from the AC/DC converter 12 and transmits it to the secondary side. The AC/DC converter 13 on the secondary side converts the AC power output from the secondary winding 15b of the high frequency transformer 15 into DC power. The DC power output by the AC/DC converter 13 is used for charging the storage battery mounted on the electric vehicle.

The high-frequency transformer 15 has a capacitor connected in series with the primary winding 15a, and this capacitor and the inductance on the primary side of the high-frequency transformer 15 constitute a resonance circuit. That is, the AC/DC converter 12, the high-frequency transformer 15, and the AC/DC converter 13 form a so-called LLC type DC/DC converter. Therefore, as described above, by adjusting the switching frequency of the switching element in the AC/DC converter 12 that converts DC power into AC power, the output voltage of the AC/DC converter 13, that is, the output voltage of the converter cell can be adjusted. Also, the LLC method can reduce the power loss of the converter cell without increasing the circuit scale.

A leakage inductance of the high-frequency transformer may be used as the inductance on the primary side of the high-frequency transformer 15 . In this case, a high frequency transformer designed to intentionally generate leakage inductance may be used.

High-frequency transformers are no different from general transformers in terms of the structure in which windings are applied to a magnetic core. A low-loss magnetic material is used.

Each of the AC/DC converters 11 to 13 has four switching elements connected in an H-bridge configuration and diodes, ie, FWDs (Free Wheeling Diodes) connected in anti-parallel to these switching elements. In addition, in this embodiment, the switching element is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Note that other semiconductor switching elements such as IGBTs (Insulated Gate Bipolar Transistors) may be applied instead of MOSFETs.

Here, since the AC/DC converters 11 and 13 have switching elements, in addition to the rectification operation by the diodes, the switching elements can improve the power factor on the AC side and reduce harmonics. Since the AC/DC converters 11 to 13 are provided with switching elements connected in an H-bridge configuration, they are capable of bi-directional power conversion. Therefore, the charging device of this embodiment can supply the power stored in the storage battery mounted on the electric vehicle to the power supply system 23 (FIG. 1).

The high frequency transformer 15 transmits power at a predetermined frequency between the primary winding 15a and the secondary winding 15b. A high frequency current flows between the AC/DC converters 12 and 13 and the high frequency transformer 15 . Here, a high frequency is a frequency of 100 Hz or higher. Preferably, frequencies above 1 kHz or above 10 kHz are employed. As a result, the size of the converter cell can be reduced.

FIG. 10 shows another example of the circuit configuration of the charging device of this embodiment.

As shown in FIG. 10, in this circuit configuration example, unlike the circuit configuration example shown in FIG. 9, the secondary output terminals of the converter cells 20-1 to 20-M are connected to a common potential portion. As a result, of the pair of secondary terminals of the converter cells 20-1 to 20-M, only the secondary terminal on the high potential side is connected to the switch. Therefore, the size of the charging device can be reduced.

Figures 11a and 11b show the connection configuration of the switch and the repeater. 11a and 11b, respectively, the circuit configurations shown in FIGS. 9 and 10 are applied.

As shown in FIG. 11a, when the circuit configuration shown in FIG. 9 is applied, the high potential side terminal and the low potential side terminal of the relays 30-1 to 30-N are connected to the output port of the switch 21 and the switch 21, respectively. connected to the output port of the device 21'. Thereby, a plurality of electric vehicles can be insulated from each other and charged.

Further, as shown in FIG. 11b, when the circuit configuration shown in FIG. 9 is applied, only the high potential side terminals of the high potential side terminals and the low potential side terminals of the repeaters 30-1 to 30-N are switched. 21, and the low potential side terminal is connected to the same common potential section as the converter cell.

In this embodiment, the central controller 22 equalizes the input voltages of the converter cells 20-1 to 20-M (the voltages of the terminals 25 and 26 of the converter cells) in addition to controlling the switches and the like described above. , the converter cells 20-1 to 20-M may be controlled. In this case, the central controller 22 controls the voltage value of the power supply system 23 detected by the voltage sensor 24a (FIG. 1) and the voltage value of the converter cell 20 detected by a voltage sensor (not shown) provided on the input side of each converter cell. Control is performed based on the input voltage value from -1 to 20-M. For example, the input voltage value of converter cells 20-1 to 20-M is controlled to be 1/M of the voltage value of power supply system . According to this control, since the inputs of the converter cells 20-1 to 20-M on the side of the power supply system 23 are connected in series, the same current flows to the input side of each converter cell. can be equalized. This equalizes the power burden of each converter cell, thereby improving the reliability of the charging device.

FIG. 12 shows an example of the installation form of the charging device of this embodiment.

As shown in FIG. 12, four repeaters 30-1 to 30-4 (charging stations) are installed in a parking space of a parking lot within a building. In the figure, the charging connector 31-2 connected to the repeater 30-2 is attached to the charging port of the parked electric vehicle 32-2, and the electric vehicle 32-2 is being charged. Switch 21 and converter cells 20-1 to 20-4 are individually housed in a housing and installed in a gap in the ceiling.

In this embodiment, the power receiving unit does not require a transformer, and each converter cell can be downsized, so that the main circuit unit of the charging device can be installed in a narrow space. Therefore, in the parking lot, the charging device can be installed without damaging the parking space. In addition, in this embodiment, since various charging menus such as normal charging and quick charging can be handled, the usability for electric vehicle users is improved.

FIG. 13 shows a modification of the circuit configuration of the AC/DC converter in the converter cell.

In this modification, an AC/DC converter that converts AC power to DC power, for example, the AC _/ DC converter ₁₃ in FIG. be. As a result, the size of the converter cell can be reduced.

In FIG. 13, the rectifying elements D ₁ to D ₄ are semiconductor diodes, but the semiconductor material is not limited to Si, and wide-gap semiconductors such as SiC and GaN may be used.

14a-14c show variants of the circuit configuration of the DC/DC converter part in the main circuit of the converter cell.

14a, similar to the circuit configuration of FIGS. and the secondary winding 15b of the high frequency transformer.

In the modification of FIG. 14b, between the AC/DC converter 12 and the primary winding 15a, and between the AC/DC converter 13 and the secondary winding 15b, between the AC/DC converter 13 and the secondary winding 15b A capacitor 52 is inserted only between them.

In the modification of FIG. 14c, no capacitors are inserted between the AC/DC converter 12 and the primary winding 15a and between the AC/DC converter 13 and the secondary winding 15b.

Further, the high-frequency transformer 15 applied to each of the above-described embodiments may be designed to intentionally generate leakage inductance.

In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Moreover, it is possible to add, delete, or replace a part of the configuration of the embodiment with another configuration.

For example, a power storage device mounted on an electric vehicle may be a capacitor as well as a storage battery.

In addition to MOSFETs and IGBTs, vacuum tube elements such as junction bipolar transistors, thyristors, GTOs (Gate Turn-Off Thyristors), IEGTs (Injection Enhanced Gate Transistors), and thyratrons are used as switching elements that make up the main circuit of the converter cell. may apply. Moreover, the semiconductor material forming the switching element is not limited to Si, and may be a wide-gap semiconductor such as SiC or GaN.

Further, vacuum tube elements such as mercury rectifiers may be applied in addition to semiconductor diodes as the rectifying elements forming the main circuit of the converter cell. Moreover, the semiconductor material forming the rectifying element is not limited to Si, and may be a wide-gap semiconductor such as SiC or GaN.

11, 12, 13 AC/DC converter 15 High frequency transformer 15a Primary winding 15b Secondary winding 17, 18-1 to 18-M Smoothing capacitors 19a to 19b Filter reactors 20-1 to 20-M Converter cells 21, 21' Switches 21-x1 to 21-xM, 21'-x1 to 21'-xM Input ports 21-y1 to 21-yM, 21-yN Output ports 21'-y1 to 21'-yM, 21'-yN Output ports 21-s11 to 21-sMN Switch 22 Central controller 22a Converter communication transmitting/receiving end 22b Switching command transmitting end 22c Vehicle communication transmitting/receiving end 22d Sensor signal receiving end 22e Operation unit 23 Power supply system 24a Voltage sensor 24b Current sensors 25, 26 Primary side Terminals 27, 28 Secondary side terminals 30-1 to 30-M Repeaters 31-1 to 31-M Charging connectors 32-1 to 32-M Electric vehicle 33 Vehicle communication signal line 34 Switching control signal line 35 Converter control signal line 36 sensor signal line

Claims (6)

In a charging device that charges a plurality of power storage devices of a plurality of electric vehicles,
a plurality of converter cells that output DC power;
a switch having a plurality of input ports to which the plurality of outputs of the plurality of converter cells are connected, and a plurality of output ports to which the plurality of power storage devices are connected;
When the switch connects one of the plurality of input ports to one of the plurality of output ports, the power storage device connected to one of the plurality of output ports changes the a control device that adjusts the output voltage of the converter cell connected to one of a plurality of input ports;
a plurality of charging connectors connected to the plurality of electric vehicles and connected to the plurality of output ports of the switch via a plurality of repeaters;
with
The switcher has a switcher section composed of a plurality of switches connected between each of the plurality of input ports and the plurality of output ports, and the switcher section, when turned on, switches between the plurality of input ports and the plurality of output ports. one of the switches is closed and the other is open,
The converter cell is
a high frequency transformer;
a primary side power converter connected to the primary side of the high frequency transformer;
a secondary side power converter connected to the secondary side of the high frequency transformer and having an output connected to the output port;
with
The repeater relays a signal line between the electric vehicle and the control device,
The repeater constitutes a charging station,
The control device controls the converter cell based on information transmitted from the electric vehicle via the signal line, and operates the switch based on a request transmitted from the charging station via the signal line. control and
The switch is
a first switch to which a high potential side of a pair of secondary terminals of the converter cell is connected;
a second switch to which a low potential side of the pair of secondary terminals of the converter cell is connected;
When,
has
The charging device , wherein the plurality of converter cells and the switch are installed above the plurality of repeaters arranged side by side . In the charging device according to claim 1,
A charging device, wherein the output voltage of the converter cell is adjusted so as to reduce a difference between the output voltage of the converter cell and the voltage of the power storage device. In the charging device according to claim 1,
The control device reduces the output voltage of the converter cell when the output voltage of the converter cell is higher than the voltage of the power storage device, and reduces the output voltage of the converter cell when the output voltage of the converter cell is lower than the voltage of the power storage device. A charging device characterized by increasing the output voltage of a converter cell. In the charging device according to claim 1,
A charging device according to claim 1, wherein a primary winding of said high-frequency transformer and a capacitor connected in series with said primary winding constitute a resonance circuit. In the charging device according to claim 1,
The control device increases the operating frequency of the converter cell when the output voltage of the converter cell is higher than the voltage of the power storage device, and increases the operating frequency of the converter cell when the output voltage of the converter cell is lower than the voltage of the power storage device. A charging device characterized by reducing the operating frequency of a converter cell. In the charging device according to claim 1,
The control device controls closing and opening of the switching unit,
The control device is
When it is determined that there is the switching unit to be turned on,
The output voltage of the converter cell connected to the input port connected to the switch section determined to be turned on, and the power storage connected to the output port connected to the switch section determined to be turned on. adjusting the output voltage of the converter cell connected to the input port connected to the switch unit determined to be turned on so as to reduce the voltage difference of the device;
Next, the charging device is characterized in that the switching unit determined to be turned on is turned on.

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