Vehicle charging system

Abstract

To be able to perform an efficient charging without a surplus power produced.SOLUTION: A vehicle charging system comprises: multiple chargers for charging a vehicle; and a charge control device for controlling the charging current of each of the multiple chargers. The charge control device comprises: one or more slave control units for controlling the charging current of one or more chargers among the multiple chargers; and a master control unit for controlling the one or more slave control units. The master control unit transmits difference information indicating difference between a first value based on a value of the charging current used for the charging of the vehicle by the multiple chargers and a reference value based on a maximum value of the current usable for the charging of the vehicle by the multiple chargers, to each of the one or more slave control units. The slave control unit controls the charging current of the chargers controlled by the slave control unit among the multiple chargers on the basis of the difference information received from the master control unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle charging system.

Background Art

[0002] A vehicle charging system that simultaneously charges a plurality of vehicles such as an EV or a PHV is known (Patent Document 1). In the vehicle charging system described in Patent Document 1, the charging control unit that controls the charging current of the charger has a control master unit and a control slave unit. One control slave unit is installed for each charger. The control slave unit individually controls the charging current of the charger. The control slave unit controls the charging current so that the power received from the commercial power supply does not exceed the reference value based on the difference information output by the control master unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the vehicle charging system described in Patent Document 1, when performing simple proportional control assuming that there are no vehicles waiting to be charged, as the maximum current value of each charger, a value obtained by dividing the main breaker capacity (for example, 100 A) by the number of chargers (for example, 6 units) (in this example, 16 A) is set. This is because the main breaker does not trip when the chargers are fully operating. However, in the vehicle charging system described in Patent Document 1, if there are chargers that are not charging among all the chargers, a surplus will occur with respect to the main breaker capacity. For example, when 5 out of 6 chargers are charging vehicles, the total charging current is 80 A, resulting in a surplus of 20 A with respect to the main breaker capacity of 100 A. It is required to prevent the occurrence of a surplus and perform efficient charging.

[0005] This invention has been made in view of the above points, and provides a vehicle charging system that prevents excess capacity from being generated and enables efficient charging. [Means for solving the problem]

[0006] The present invention has been made to solve the above problems, and one aspect of the present invention is a vehicle charging system comprising a plurality of chargers for charging a vehicle, and a charging control device for controlling the charging current of each of the plurality of chargers, wherein the charging control device comprises one or more control slave units for controlling the charging current of one or more of the plurality of chargers, and a control master unit for controlling the one or more control slave units, wherein the control master unit transmits to each of the one or more control slave units difference information indicating the difference between a first value based on the value of the charging current used by the plurality of chargers to charge the vehicle and a reference value based on the maximum value of the current that the plurality of chargers can use to charge the vehicle, and the control slave unit controls the charging current of the charger controlled by the control slave unit among the plurality of chargers based on the difference information received from the control master unit The charging current values ​​of each of the chargers controlled by the control unit among the plurality of chargers are to be the same. To control.

[0007] Furthermore, in one aspect of the present invention, in the above-described vehicle charging system, the control master unit transmits to each of the one or more control slave units located below the monitoring point a difference information indicating the difference between a first value based on the value of the charging current used for charging the vehicle by one or more chargers located below the monitoring point among the plurality of chargers, and a reference value based on the maximum value of the current that can be used for charging the vehicle by one or more chargers located below the monitoring point among the plurality of chargers.

[0008] Furthermore, in one aspect of the present invention, in the above-described vehicle charging system, each of the one or more control units controls the charging current of the charger controlled by the control unit among the plurality of chargers such that the sum of the charging currents of the chargers controlled by the control unit among the plurality of chargers is less than or equal to the maximum current that the plurality of chargers can use to charge the vehicle.

[0009] Furthermore, in one aspect of the present invention, in the above-described vehicle charging system, the control slave unit controls the charging current of the charger controlled by the control slave unit among the plurality of chargers based on the difference information received from the control master unit and a current reference value for the charging current of one of the plurality of chargers.

[0010] Furthermore, in one aspect of the present invention, in the above-described vehicle charging system, the current reference value is the maximum value of the charging current charged by one of the plurality of chargers.

[0012] Furthermore, in one aspect of the present invention, in the above-described vehicle charging system, the control slave unit controls the charging current of the charger controlled by the control slave unit among the plurality of chargers based on the difference information received from the control master unit and the priority order among the plurality of chargers controlled by the control slave unit.

[0013] Furthermore, in one aspect of the present invention, in the above-mentioned vehicle charging system, The aforementioned one or more control slave units are multiple, The aforementioned multiple The control slave units communicate with each other. [Effects of the Invention]

[0014] According to the present invention, it is possible to prevent excess power from being generated and to perform efficient charging. [Brief explanation of the drawing]

[0015] [Figure 1] This figure shows an example of the configuration of a vehicle charging system according to the first embodiment of the present invention. [Figure 2]It is a diagram showing an example of the functional configuration of the control master unit according to the first embodiment of the present invention. [Figure 3] It is a diagram showing an example of the functional configuration of the control slave unit according to the first embodiment of the present invention. [Figure 4] It is a diagram showing an example of the charge control process by the control slave unit according to the first embodiment of the present invention. [Figure 5] It is a diagram showing an example of the configuration of the vehicle charging system according to the first modification of the first embodiment of the present invention. [Figure 6] It is a diagram showing an example of the configuration of the vehicle charging system according to the second modification of the first embodiment of the present invention. [Figure 7] It is a diagram showing an example of the configuration of the vehicle charging system according to the second embodiment of the present invention.

Mode for Carrying Out the Invention

[0016] (First Embodiment) Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings. In the following description, when a plurality of values are equal to each other or the same, etc., it also includes the case where the plurality of values are approximately equal or approximately the same. When the plurality of values are approximately equal or approximately the same, a difference of about the minimum unit when changing the value is allowed among the plurality of values. The minimum unit is, for example, the minimum current setting value described later. Also, since current and power are related by a predetermined voltage, in the following description, there may be cases where current and power are described without distinction.

[0017] FIG. 1 is a diagram showing an example of the configuration of the vehicle charging system 1 according to the present embodiment. The vehicle charging system 1 includes a control master unit 2, one or more control slave units 3, a plurality of chargers 4, one or more main breakers 5, one or more branch breakers 6, and one or more inlet boards 7.

[0018] In the example shown in FIG. 1, two control slave units, namely control slave unit 31 and control slave unit 32, are provided as the control slave unit 3. Let the number of control slave units 3 provided in the vehicle charging system 1 be the number of slave units N1. In the example shown in FIG. 1, the number of slave units N1 is 2. Note that the number of slave units N1 may be 1 or a number of 3 or more.

[0019] The control slave unit 3 controls the charging current of one or more of the plurality of chargers 4. Here, let the number of chargers 4 controlled by the i-th control slave unit 3 be the number of chargers Mi. In the example shown in FIG. 1, the number of chargers Mi is equal among one or more control slave units 3. For example, the control slave unit 31 is the first control slave unit. The control slave unit 31 controls three chargers, namely charger 411, charger 412, and charger 413. Therefore, the number of chargers M1 is 3. The control slave unit 32 is the second control slave unit. The control slave unit 32 controls three chargers, namely charger 421, charger 422, and charger 423. Therefore, the number of chargers M2 is 3. Note that the number of chargers M2 may be 1 or a number of 3 or more. Also, the number of chargers M2 may be different among one or more control slave units 3.

[0020] The control slave unit 3 and the charger 4 communicate with each other by wireless communication. Note that the control slave unit 3 and the charger 4 may be connected by a cable, and the control slave unit 3 may communicate with the charger 4 by wired communication.

[0021] The charger 4 charges the vehicle 8. The charger 4 charges the vehicle 8 in a state where the charger � and the vehicle 8 are connected by a charging cable. The vehicle 8 is an electric vehicle such as an EV (Electric Vehicle) or a PHV (Plug-in Hybrid Vehicle).

[0022] Vehicles 811, 812, 813, and 821 are each an example of the vehicle 8. In the example shown in FIG. 1, the charger 411 is charging the vehicle 811. The charger 412 is charging the vehicle 812. The charger 413 is charging the vehicle 813. The charger 421 is charging the vehicle 821.

[0023] The master control unit 2 controls one or more slave control units 3. The master control unit 2 communicates with each of the slave control units 3. In the example shown in Figure 1, the master control unit 2 controls slave control unit 31 and slave control unit 32. The master control unit 2 obtains power received information from the power meter 10. Power received information indicates the power received from the grid. Power received from the grid is supplied via the commercial power supply 11. The power meter 10 measures this power received. The power meter 10 is, for example, a smart meter. The master control unit 2 and the power meter 10 communicate, for example, by wireless communication. Alternatively, the master control unit 2 and the power meter 10 may be connected by a cable, and the master control unit 2 and the power meter 10 may communicate by wired communication.

[0024] One or more control units 3, multiple chargers 4, one or more main breakers 5, and one or more branch breakers 6 are each installed in a predetermined number in each of one or more service entrance panels 7. One branch breaker 6 is installed for each charger 4. One main breaker 5 is installed for each of the multiple chargers 4 installed in one service entrance panel 7. In one service entrance panel 7, the main breaker 5 and the multiple chargers 4 are connected by power lines via multiple branch breakers 6.

[0025] In the example shown in Figure 1, there are two service entrance panels 7, namely service entrance panel 71 and service entrance panel 72. Service entrance panel 71 houses a control unit 31, chargers 411, 412, 413, a main breaker 51, branch breakers 611, 612, and 613. The main breaker 51 is connected by power lines to each of the chargers 411, 412, and 413, and to each of the branch breakers 611, 612, and 613.

[0026] The service entrance panel 72 is equipped with a control unit 32, chargers 421, 422, 423, a main breaker 52, branch breakers 621, 622, and 623. The main breaker 52 is connected by power lines to chargers 421, 422, and 423, respectively, and to branch breakers 621, 622, and 623, respectively.

[0027] The transformer 9 converts the high-voltage power received from the commercial power source 11 into low-voltage power. The power converted by the transformer 9 is supplied to multiple chargers 4 and general loads 12. General load 12 is the load of various electrical equipment such as lighting.

[0028] Here, we will briefly explain the charging control by the vehicle charging system 1. In this embodiment, the maximum value of the current that the charger 4 can use to charge the vehicle 8 is called the maximum available charging value. The maximum available charging value is a current value set so that the received power does not exceed a set maximum power such as a demand value. The maximum available charging value changes each time depending on the power supplied to the general load 12.

[0029] In the example in Figure 1, the maximum current that can be supplied from transformer 9 is assumed to be 200A. The maximum current used by the general load 12 is assumed to be 100A. In this case, the maximum usable charge capacity in the example in Figure 1 is 100A, which is the difference between the maximum current that can be supplied from transformer 9 and the maximum current used by the general load 12. In other words, in the example in Figure 1, the maximum usable charge capacity is 100A regardless of the value of the current used by the general load 12.

[0030] In the vehicle charging system 1, the current that can be used by multiple chargers 4 (the maximum usable charging current of 100A) is controlled to be used as little as possible without any waste, and the charging current values ​​of each of the multiple chargers 4 are controlled to be the same (referred to as apportionment control, equalization charging control, etc.).

[0031] Here, the maximum charging current of a single charger 4 is called the maximum current setting value. In other words, the maximum current setting value is the current value that can be supplied to one vehicle 8. In this embodiment, the maximum current setting value is set to 30A. The maximum current setting value is a value determined by the performance of the charger 4. The maximum current setting value is equal among multiple chargers 4. The control unit 3 sets the charging current value of the charger 4 to the maximum current setting value (30A) at the start of charging in order to avoid leaving any unused current.

[0032] The current value that each of the multiple main breakers 5 allows is set to be greater than or equal to the larger of the sum of the maximum current settings of the one or more chargers 4 installed in the same service entrance panel 7 as the main breaker 5, and the maximum usable charge value. This is to ensure that the power supply amount is equal to the maximum usable charge value, while also addressing any imbalances in that supply.

[0033] In the example shown in Figure 1, the sum of the maximum current settings for chargers 411, 412, and 413 installed in the service entrance panel 71 where the main breaker 51 is installed is 90A, which is 30A for three units. On the other hand, as mentioned above, the maximum usable current for charging is 100A. Therefore, in the example shown in Figure 1, the current values ​​allowed by the main breaker 51 and the current values ​​allowed by the main breaker 52 are set to 100A, which is the maximum usable current for charging.

[0034] One control unit 3 sets the maximum total charging current of the multiple chargers 4 controlled by that control unit 3 to a current value allowed by the main breaker 52. In the example in Figure 1, control unit 31 sets the maximum total charging current of charger 411, charger 412, and charger 413 to 100A. Control unit 32 sets the maximum total charging current of charger 421, charger 422, and charger 423 to 100A.

[0035] Here, we assume that chargers 411, 412, and 413 are each charging using their maximum current setting of 30A. In other words, we assume that a total of 90A is being used as the charging current by the three chargers controlled by the control slave unit 31. Furthermore, we assume that charger 421, controlled by the control slave unit 32, has started charging using its maximum current setting of 30A.

[0036] In this case, the sum of the charging currents of charger 411, charger 412, charger 413, and charger 421 is 120A. As mentioned above, in the example in Figure 1, the maximum usable charging current is 100A. Therefore, in this case, the multiple chargers 4 are using a current that exceeds the limit by 20A for charging.

[0037] The master control unit 2 transmits differential information to the slave control units 31 and 32, respectively. Here, differential information refers to information indicating the difference between a first value based on the value of the charging current used by the multiple chargers 4 to charge the vehicle 8, and a reference value based on the maximum usable charging value (i.e., the maximum current that the multiple chargers 4 can use to charge the vehicle 8).

[0038] The difference information is calculated based on the monitoring points. The monitoring points are locations in the vehicle charging system 1 that monitor whether the first value exceeds a reference value based on the difference information on the power lines. In the example in Figure 1, monitoring point P0 and monitoring point P1 are shown as monitoring points.

[0039] Monitoring point P0 corresponds to the power receiving point for high-voltage power reception. Monitoring point P0 is a location for monitoring whether the first value exceeds the demand value. At monitoring point P0, the power meter 10 measures the value of the current used by the power equipment downstream (also called lower side) of monitoring point P0. The power meter 10 transmits the measured value of the current to the control master unit 2.

[0040] Monitoring point P1 is a location for monitoring whether the first value exceeds an upper limit set to be less than the capacity of transformer 9. Monitoring point P1 can be located anywhere between transformer 9 and each load. In the example shown in Figure 1, monitoring point P1 is downstream of transformer 9 and upstream (also called upstream) of one or more main breakers 5 and branch points to general loads 12. At monitoring point P1, a current transformer (not shown) measures the value of the current used by the power equipment downstream of monitoring point P1. The current transformer transmits the measured value of the current to the control master unit 2. Other examples of monitoring points will be discussed later.

[0041] The first value is the value of the current used by the power equipment downstream (also called lower side) of the monitoring point P1. This current includes the charging current used by multiple chargers 4 to charge the vehicle 8. For example, the first value is the value of the charging current used by multiple chargers 4 to charge the vehicle 8. Alternatively, the first value may be the value obtained by adding the value of the charging current used by multiple chargers 4 to the value of the current used by the general load 12.

[0042] The reference value based on the maximum usable charge value is the maximum current usable by the power equipment downstream of the monitoring point. As described above, in this embodiment, differential information is calculated based on the monitoring point P1, so the reference value based on the maximum usable charge value is the maximum current usable by the power equipment downstream of the monitoring point P1. As an example, the reference value based on the maximum usable charge value is the maximum usable charge value itself. As described above, in this embodiment, the difference information is, for example, information that shows the difference between the value of the charging current used by one or more chargers 4 to charge the vehicle 8 and the maximum value of the charger that can be used for charging.

[0043] The difference information is calculated by the master control unit 2. In this embodiment, the master control unit 2 calculates two types of difference information: difference information for monitoring point P0 and difference information for monitoring point P1. The master control unit 2 transmits the difference information indicating the larger of the two calculated types of difference information to each of the one or more slave control units 3.

[0044] The master control unit 2 may also transmit the two calculated difference information to each of the one or more slave control units 3. In this case, each of the one or more slave control units 3 controls the charging current based on the difference information that indicates the larger of the two difference information received from the master control unit 2.

[0045] By calculating the difference information, the control master unit 2 monitors the value of the charging current being used at monitoring point P1 relative to the maximum available charging value. Monitoring the received power relative to the maximum available charging value means determining whether the value of the charging current being used is equal to or less than the maximum available charging value, or less than the maximum available charging value. By monitoring the value of the charging current being used relative to the maximum available charging value, control is performed so that the value of the charging current being used is less than or equal to the maximum available charging value and as close to the maximum available charging value as possible. In other words, control is performed so that the available power surplus is as small as possible.

[0046] When the control slave unit 3 receives differential information from the control master unit 2, it performs proportional control based on the differential information indicating an excess of the charging current value. In order to perform proportional control, the control slave unit 3 reduces the charging current of one or more chargers 4 controlled by the control slave unit 3 by the minimum current setting value. The minimum current setting value is the smallest unit in which the control slave unit 3 controls the charging current of the charger 4. The minimum current setting value is equal among one or more control slave units 3.

[0047] In the example in Figure 1, for simplicity of explanation, the minimum current setting value is set to 1A. Note that the minimum current setting value is set according to the performance of the charger 4. The minimum current setting value is, for example, the minimum charging current that the charger 4 can charge.

[0048] In the example shown in Figure 1, the control unit 31 reduces the charging current of charger 411, charger 412, and charger 413 by the minimum current setting value (1A). The control unit 32 reduces the charging current of charger 421 by the minimum current setting value (1A). As a result, the charging currents of charger 411, charger 412, charger 413, and charger 421 are each reduced from 30A by 1A to 29A. Consequently, the sum of the charging currents of charger 411, charger 412, charger 413, and charger 421 is 116A. Therefore, the multiple chargers 4 are using a current that exceeds the limit by 16A for charging.

[0049] The master control unit 2 receives a signal from the energy meter 10 indicating that the power is exceeding 16A. The master control unit 2 transmits differential information indicating that the charging current value is exceeding the limit to each of the slave control units 31 and 32. When the slave control unit 3 receives the differential information from the master control unit 2, it reduces the charging current of one or more chargers 4 controlled by the slave control unit 3 by the minimum current setting value.

[0050] In the vehicle charging system 1, the above process is repeated. After the above process is performed 5 times, the charging current of charger 411, charger 412, charger 413, and charger 421 each decrease by 5A from the initial 30A to 25A. As a result, the sum of the charging currents of charger 411, charger 412, and charger 413 becomes 75A, and the charging current of charger 421 becomes 25A. In other words, the sum of the charging currents of charger 411, charger 412, charger 413, and charger 421 becomes 100A. Therefore, the multiple chargers 4 are using the maximum usable charging current of 100A for charging.

[0051] As described above, in the vehicle charging system 1, if the sum of the charging current values ​​used by the multiple chargers 4 exceeds the maximum usable charging value, the control master unit 2 transmits differential information indicating that the charging current value has been exceeded to each of the one or more control slave units 3 in one direction. Each of the one or more control slave units 3 reduces the charging current value of one or more chargers 4 by the minimum current setting value based on the differential information indicating that the charging current value has been exceeded. In the vehicle charging system 1, these processes are repeated until the sum of the charging current values ​​used by the multiple chargers 4 equals the maximum usable charging value.

[0052] On the other hand, in the vehicle charging system 1, if the sum of the charging current values ​​used by the multiple chargers 4 falls below the maximum usable charging limit, the control master unit 2 transmits differential information indicating that there is excess usable current to each of the one or more control slave units 3 in one direction. Each of the one or more control slave units 3 increases the charging current value of each of the one or more chargers 4 by the minimum current setting value based on the differential information indicating that there is excess usable current. In the vehicle charging system 1, these processes are repeated until the sum of the charging current values ​​used by the multiple chargers 4 equals the maximum usable charging limit.

[0053] As described above, in the vehicle charging system 1, when a charger 4 starts charging, the control unit 3 controls the charging current value of each of the one or more chargers 4 so that the charging current value of one of the chargers 4 becomes the maximum current setting value. In addition, in the vehicle charging system 1, for one or more chargers 4 whose charging current is controlled by a certain control unit 3, when another charger 4 is already charging and a new charger 4 starts charging, the newly starting charger 4 starts charging with a charging current value that is the same as the current charging current value of the other charger 4 that is charging.

[0054] For example, if charger 421 is charging at 25A, and charger 422 starts charging, the charging current value of charger 422 will start charging at the same value as the charging current value of charger 421, which is 25A. Due to the above control, the charging current values ​​become equal among one or more chargers 4 controlled by a certain control slave unit 3.

[0055] When the control slave unit 3 increases or decreases the charging current based on differential information received from the control master unit 2, the control slave unit 3 increases or decreases the charging current by a predetermined amount in a single control operation. The predetermined amount of change is, for example, the minimum current setting value. The minimum current setting value is the same among one or more chargers 4, regardless of which control slave unit 3 is controlling which charger.

[0056] When the charging current is controlled to increase based on differential information, if the charging current value of a certain charger 4 exceeds the maximum current setting value, the charging current value of that charger 4 is controlled to become the maximum current setting value. The maximum current setting value becomes the current reference value, which is the reference value of the charging current among one or more chargers 4.

[0057] In this case, if there is a difference in charging current values ​​among one or more chargers 4 controlled by one or more control slave units 3, and the charging current is increased or decreased based only on the difference information, the charging current will increase or decrease by a predetermined amount, so the difference in charging current values ​​among one or more chargers 4 controlled by one or more control slave units 3 will not change. In the vehicle charging system 1, because the control is based on the current reference value described above, the variation in charging current among one or more chargers 4 controlled by one or more control slave units 3 will be smaller compared to the case where the control is not based on a current reference value.

[0058] The control provided by the vehicle charging system 1 described above is independent of the number of slave units N1 or the number of chargers Mi. Therefore, in the vehicle charging system 1, even when the number of chargers 4 controlled by each of the one or more control slave units 3, the number of chargers 4 currently charging, or the charging current value being used are not shared, the system can increase or decrease the total charging current value while keeping the charging current value equal among one or more chargers 4. In other words, the vehicle charging system 1 can perform proportional control over one or more chargers 4 without bidirectional communication between one or more control slave units 3.

[0059] Furthermore, the vehicle charging system 1 performs control at a sufficient speed. Therefore, it is assumed that a new vehicle 8 will not be connected to the charger 4 and charging will not start again during the control process.

[0060] In this embodiment, the current reference value is, for example, the maximum current setting value. Therefore, the difference between the sum of the charging currents of one or more chargers 4 and the maximum usable charging value is smaller than when the current reference value is not set to the maximum current setting value. In other words, by setting the current reference value to the maximum current setting value, the remaining charge current of one or more chargers 4 relative to the maximum usable charging value can be reduced.

[0061] Note that the current reference value is not limited to the maximum current setting value. The current reference value may be a predetermined value other than the maximum current setting value. This predetermined value is smaller than the maximum current setting value. When the current reference value is a predetermined value, the current reference value is supplied from the control master unit 2 to each of the one or more control slave units 3 before the vehicle charging system 1 starts control. In this way, the current reference value is shared among the one or more control slave units 3.

[0062] Furthermore, when the control slave unit 3 increases or decreases the charging current of the charger 4 by a predetermined amount based on the differential information, this predetermined amount of change may be other than the minimum current setting value. The predetermined amount of change may be supplied from the control master unit 2 to each of the one or more control slave units 3. When the predetermined amount of change is supplied from the control master unit 2 to each of the one or more control slave units 3, the control master unit 2 will, for example, supply the predetermined amount of change to each of the one or more control slave units 3 when the vehicle charging system 1 starts the charging control processing. In another example, the control master unit 2 may supply each of the one or more control slave units 3 with a predetermined amount of change corresponding to the differential value indicated by the differential information each time it transmits differential information to each of the one or more control slave units 3.

[0063] Now, referring to Figures 2 and 3, the functional configurations of the master control unit 2 and the slave control unit 3 will be explained. Figure 2 shows an example of the functional configuration of the control master unit 2 according to this embodiment. The control master unit 2 comprises a master unit measurement unit 200, a master unit control unit 210, a master unit communication unit 220, and a master unit storage unit 230.

[0064] The master unit measurement unit 200 acquires power received information from the power meter 10. The control master unit 2 and the power meter 10 are connected by a communication line. The master unit measurement unit 200 acquires power received information from the power meter 10 via the communication line.

[0065] The master control unit 210 controls the entire control master unit 2. The master control unit 210 includes a CPU (Central Processing Unit).

[0066] The master unit communication unit 220 communicates with the control slave unit 3. For example, the master unit communication unit 220 communicates with the control slave unit 3 via wireless communication.

[0067] The master unit memory unit 230 stores various types of information used by the master unit control unit 210 for control. This information includes the maximum usable charge limit.

[0068] Figure 3 shows an example of the functional configuration of the control slave unit 3 according to this embodiment. Control slave units 31 and 32 have the same functional configuration. Control slave unit 3 comprises a slave unit first signal unit 300, a slave unit control unit 310, a slave unit second communication unit 320, and a slave unit storage unit 330.

[0069] The first signal unit 300 of the slave unit communicates with the master control unit 2. For example, the first signal unit 300 of the slave unit communicates with the master control unit 2 by wireless communication. The slave unit control unit 310 controls the entire control slave unit 3. The slave unit control unit 310 includes a CPU.

[0070] The second communication unit 320 consists of one or more second communication units. In the example shown in Figure 3, the second communication unit 320 consists of a second communication unit 321, a second communication unit 322, and a second communication unit 323. The second communication unit 320 communicates with the charger 4 via wireless communication.

[0071] The second communication unit 320 transmits a control signal to the charger 4 to control the charging current of the charger 4. The second communication unit 321 transmits a control signal to the charger 411. The second communication unit 322 transmits a control signal to the charger 412. The second communication unit 323 transmits a control signal to the charger 413. These control signals are generated by the control unit 310.

[0072] The slave unit storage unit 330 stores various types of information used by the slave unit control unit 310 for control. This information includes differential information and current reference values. The differential information is updated each time it is acquired from the control master unit 2. In this embodiment, the maximum current setting value is stored in advance as the current reference value.

[0073] Alternatively, the master control unit 2 and the slave control unit 3 may communicate via wired communication. In that case, the master control unit 2 and the slave control unit 3 are connected by a communication line.

[0074] Next, referring to Figure 4, the details of the charging control by the vehicle charging system 1 will be explained, focusing on the control by the control slave unit 3. Figure 4 is a diagram showing an example of the charging control process by the control slave unit 3 according to this embodiment. The charging control process shown in Figure 4 is executed by a slave unit control unit 310 provided in each of the one or more control slave units 3.

[0075] When the vehicle charging system 1 starts operating, the power to the master control unit 2 and the one or more slave control units 3 are turned on. The charging control process shown in Figure 4 is repeatedly executed by the slave unit control unit 310 while the power to the master control unit 2 and the one or more slave control units 3 are turned on. The repetition period is, for example, 1 second.

[0076] Step S10: The slave unit control 310 determines whether or not differential information has been received. Here, the slave unit control 310 determines whether or not the slave unit first signal unit 300 has received differential information from the control master unit 2. If the slave unit control 310 determines that differential information has been received (Step S10; YES), it executes the process in Step S20. On the other hand, if the slave unit control 310 determines that differential information has not been received (Step S10; NO), it executes the process in Step S10 again.

[0077] Step S20: The slave unit control 310 determines whether the difference value indicated by the received difference information is not nearly zero. The difference value indicated by the difference information is the difference between the power received from the grid at monitoring point P1 and the maximum usable charge value. In other words, the slave unit control 310 determines whether the power received and the maximum usable charge value are nearly equal. If the slave unit control 310 determines that the difference value is not nearly zero (Step S20; YES), it executes the process in Step S30. On the other hand, if the slave unit control 310 determines that the difference value is nearly zero (Step S20; NO), it terminates the charge control process.

[0078] Step S30: The slave unit control 310 determines whether the difference value is greater than 0. If the slave unit control 310 determines that the difference value is greater than 0 (Step S30; YES), it executes the process in Step S40. On the other hand, if the slave unit control 310 determines that the difference value is less than 0 (Step S30; NO), it executes the process in Step S70.

[0079] Step S40: The slave unit control 310 calculates the reduction current value. The slave unit control 310 calculates the minimum current setting value as the reduction current value. After that, the slave unit control 310 executes the process of step S50.

[0080] Step S50: The slave unit control unit 310 subtracts the reduction current value from the current charging current value to set the charging current value. As described above, when the charger 4 starts charging, the control slave unit 3 controls the charging current value of each of the one or more chargers 4 so that the charging current value of one of the chargers 4 becomes the maximum current setting value. Also, for one or more chargers 4 whose charging current is controlled by a certain control slave unit 3, when another charger 4 is already charging and a new charger 4 starts charging, the newly starting charger 4 starts charging with a charging current value that is the same as the current charging current value of the other charger 4 that is charging.

[0081] Furthermore, the sub-unit control unit 310 does not subtract the reduction current value from the current charging current value if the current charging current value is equal to the minimum current setting value. As mentioned above, the current reference value may be any predetermined value other than the maximum current setting value, as long as it is smaller than the maximum current setting value. Subsequently, the slave unit control unit 310 executes the process of step S60.

[0082] Step S60: The slave unit control unit 310 controls the charger 4 based on the set charging current value. The slave unit control unit 310 controls the charger 4 via the slave unit second communication unit 320. The slave unit control unit 310 controls each of the one or more chargers 4 so that the charging current value of one of the chargers 4 becomes the set charging current value. After that, the slave unit control unit 310 executes the process of step S10 again.

[0083] Step S70: The slave unit control unit 310 calculates the increased current value. The slave unit control unit 310 calculates the minimum current setting value as the increased current value. After that, the slave unit control unit 310 executes the process of step S80.

[0084] Step S80: The slave unit control 310 adds the increased current value to the current charging current value to set the charging current value. However, if the current charging current value is equal to the maximum current setting value, the slave unit control 310 does not add the increased current value to the current charging current value. As mentioned above, the maximum current setting value is an example of a current reference value. Therefore, one or more control slave units 3 each control the charging current of the charger 4 controlled by the control slave unit 3 among the multiple chargers 4 so that the sum of the charging currents of the chargers 4 controlled by the control slave unit 3 among the multiple chargers 4 is less than or equal to the maximum current that the multiple chargers 4 can use to charge the vehicle 8 (maximum usable charging value). After that, the slave unit control 310 executes the process of step S60. With this, the slave unit control unit 310 terminates the charging control process.

[0085] As described above, the control slave unit 3 controls the charging current of the charger controlled by the control slave unit 3 among the multiple chargers 4, based on the differential information received from the control master unit 2 and the current reference value for the charging current of one of the multiple chargers 4.

[0086] As described above, in this embodiment, the control slave unit 3 controls the charging current values ​​of each of the chargers controlled by the control slave unit 3 among the multiple chargers 4, based on the difference information received from the control master unit 2 and the current reference value for the charging current of one of the multiple chargers 4.

[0087] Furthermore, if the control slave unit 3 receives difference information indicating a difference value that is not nearly zero for the first time after receiving difference information indicating a difference value that is nearly zero, the control slave unit 3 may set the charging current value of one or more chargers 4 controlled by the control slave unit 3 to be equal to the reset reference value. This control also resets the charging current to the reset reference value, thereby suppressing variations in charging current among the control slave units 3. Furthermore, if the control unit 3 receives a difference less than zero when each of the chargers 4 is charging at its maximum current setting, it determines that it cannot increase the output any further. In that case, the control unit 3 may reset the charging current to a reset reference value by considering the difference value to be approximately zero.

[0088] As a reset reference value, for example, a value is set such that even if each of the multiple chargers 4 provided in the vehicle charging system 1 charges with a charging current equal to the reset reference value, the maximum usable charging current will not exceed the maximum usable charging current of 100A. In the example in Figure 1, the reset reference value is set such that even if the six chargers from charger 411 to charger 423 charge with a charging current equal to the reset reference value, the maximum usable charging current will not exceed the maximum usable charging current of 100A. In that case, for example, 16A, which is the value obtained by dividing 100A by six chargers, is set as the reset reference value.

[0089] In this embodiment, the control slave unit 3 may control the charging current of the charger 4 controlled by the control slave unit 3 among the multiple chargers 4 based on the differential information received from the control master unit 2, the current reference value for the charging current of one of the multiple chargers 4, and the priority order among the multiple chargers 4 controlled by the control slave unit 3. For example, the control slave unit 3 may set the priority order to the order in which the vehicles 8 were connected to the charger 4 (the order in which charging began). In another example, the control slave unit 3 may set the priority order based on an index (SOC: State Of Charge) representing the charge rate or charge state of the vehicle 8 connected to the charger 4. In that case, the control slave unit 3 will set the priority order so that vehicles 8 with lower SOCs have a higher priority.

[0090] In this embodiment, the first value is the value of the charging current used by the multiple chargers 4 to charge the vehicle 8, and the reference value based on the maximum usable charging value is the maximum usable charging value itself. Therefore, it was determined whether the difference value indicated by the difference information is approximately not zero. If the first value is the sum of the value of the charging current used by the multiple chargers 4 to charge the vehicle 8 and the value of the current used by the general load 12, it may be determined whether the difference value indicated by the difference information is approximately equal to the value of the current used by the general load 12. In that case, the value of the current used by the general load 12, measured by the current transformer, is transmitted from the master control unit 2 to each of the one or more slave control units 3 along with the difference information.

[0091] (First variation) Next, with reference to Figure 5, a first modified example of this embodiment will be described. In the first modified example, a case will be described in which, when surplus power is generated by the current value used by the general load 12, this surplus power is used to charge the vehicle 8.

[0092] Figure 5 shows an example of the configuration of a vehicle charging system 1A according to a first modified example of this embodiment. Comparing the vehicle charging system 1A with the vehicle charging system 1, the difference is that the vehicle charging system 1A has a control master unit 2A and one or more control slave units 3A (control slave unit 31A, control slave unit 32A) instead of a control master unit 2 and one or more control slave units 3, respectively.

[0093] In the vehicle charging system 1A, the current used by the general load 12 is less than the maximum current used by the general load 12. For example, suppose the current used by the general load 12 is 80A, compared to a maximum of 100A.

[0094] The control master unit 2A changes the maximum usable charge value according to the current value used by the general load 12. In the example shown in Figure 5, since the general load 12 is using a current of 80A, the maximum usable charge value is set to 120A, which is obtained by subtracting 80A from 200A.

[0095] The master control unit 2A transmits differential information to each of the one or more slave control units 3A, indicating the difference in the current available for charging the vehicle 8 relative to the maximum chargeable value, which is changed according to the current value used by the general load 12. Based on the differential information received from the master control unit 2A, the slave control unit 3A performs the same control as the slave control unit 3 in the embodiment described above.

[0096] For example, suppose chargers 411, 412, and 413 are each charging using their maximum current setting of 30A as the charging current. Furthermore, suppose that charger 421 is controlled by the control slave unit 32 and starts charging using its maximum current setting of 30A as the charging current.

[0097] In this case, the sum of the charging currents of charger 411, charger 412, charger 413, and charger 421 is 120A. As mentioned above, the maximum usable charging current is changed to 120A in accordance with the fact that the general load 12 is using a current of 80A. Therefore, in this case, the multiple chargers 4 are using the maximum usable charging current for charging. In this case, the control slave unit 3A does not change the charging current value. In the vehicle charging system 1A, the surplus capacity (20A) of the transformer 9, generated according to the current value used by the general load 12, can be used to charge the vehicle 8.

[0098] (Second variation) Next, a second modification of this embodiment will be described. In the second modification, a case where there are multiple monitoring points for the control master unit will be described.

[0099] Figure 6 shows an example of the configuration of a vehicle charging system 1B according to a second modified example of this embodiment. The vehicle charging system 1B comprises a master control unit 2B, a slave control unit 31B, a slave control unit 32B, a slave control unit 33B, a slave control unit 34B, a charger panel 71B, a charger panel 72B, a charger panel 73B, a charger panel 74B, a light panel 75B, a light panel 76B, a light panel 77B, a transformer 91B, and a transformer 92B.

[0100] The control slave unit 31B is installed on the charger panel 71B along with three chargers and three branch circuit breakers. The control slave unit 32B is installed on the charger panel 72B along with three chargers and three branch circuit breakers. The control slave unit 33B is installed on the charger panel 73B along with three chargers and three branch circuit breakers. The control slave unit 34B is installed on the charger panel 74B along with three chargers and three branch circuit breakers.

[0101] Lighting panel 75B is equipped with one main breaker and four branch breakers. Lighting panel 76B is equipped with one main breaker and four branch breakers. Lighting panel 77B is equipped with one main breaker and four branch breakers.

[0102] Transformer 91B converts the power received at high voltage into low voltage power and supplies it to the lighting panels 75B and 76B. Transformer 92B converts the power received at high voltage into low voltage power and supplies it to the lighting panel 77B.

[0103] Current is supplied to the charger panels 71B, 72B, 73B, and 74B via the light panel 75B.

[0104] As shown in Figure 6, on the power line, monitoring point P2 is located below monitoring point P20. On the power line, monitoring point P21 is located below monitoring point P2. Monitoring points P211 and P212 are located below monitoring point P21. The control master unit 2B monitors five monitoring points: monitoring points P20, P2, P21, P211, and P212. In the vehicle charging system 1B, the remaining capacity below each of these monitoring points P20, P2, P21, P211, and P212 is monitored. In other words, these five monitoring points control the system so that the remaining capacity below each of the monitoring points is minimized (the remaining capacity is used up).

[0105] The control master unit 2B controls the power equipment at monitoring point P20 so that the total current used by the power equipment included in the monitored equipment G0 is less than or equal to the maximum usable current set for the power equipment included in the monitored equipment G0, and so that it approaches that maximum value. Monitoring point P20 is the location on the power line where an energy meter (not shown in Figure 6) is installed, and this location is the power receiving point for high-voltage power reception. The maximum value is the demand value. In other words, the maximum value corresponds to the contracted power. The power equipment included in the monitored equipment G0 consists of various loads installed in the lighting panel 77B, various loads installed in the lighting panel 76B, and chargers included in the monitored equipment G1 (chargers installed in charger panels 71B, 72B, 73B, and 74B, respectively).

[0106] The control master unit 2B controls the power equipment at monitoring point P2 so that the total current used by the power equipment included in the monitored G2 is less than or equal to the maximum usable current set for the power equipment included in the monitored G2, and approaches that maximum value. Monitoring point P2 is the location on the power line where the transformer 91B is installed, and this location is the power receiving point for low-voltage power reception. The maximum value is the transformer capacity of the transformer 91B. The power equipment included in the monitored G2 consists of various loads installed in the lighting panel 76B and the chargers included in the monitored G1 (chargers installed in charger panels 71B, 72B, 73B, and 74B, respectively).

[0107] The control master unit 2B controls the monitoring point P21 so that the total charging current used by the chargers included in the monitored target G1 (chargers installed in charger panels 71B, 72B, 73B, and 74B) is less than or equal to the maximum usable charging current set for the chargers included in the monitored target G1, and so that it approaches the maximum usable charging current. Monitoring point P21 is the location on the power line where the main breaker of the lighting panel 75B is installed. The maximum usable charging current is the rated value of the main breaker of the lighting panel 75B.

[0108] The control master unit 2B controls the monitoring point P211 so that the total charging current used by the chargers included in the monitored G11 (chargers installed in charger panels 71B and 72B respectively) is less than or equal to the maximum usable charging current set for the chargers included in the monitored G11, and so that it approaches the maximum usable charging current. The monitoring point P211 is a location on the power line that is above the point where the power line branches to charger panels 71B and 72B, and below the lighting panel 75B. The maximum usable charging current is the sum of the rated value of the main breaker installed in charger panel 71B and the rated value of the main breaker installed in charger panel 72B.

[0109] The control master unit 2B controls the monitoring point P212 so that the total charging current used by the chargers included in the monitored G12 (chargers installed in charger panels 73B and 74B respectively) is less than or equal to the maximum usable charging current set for the chargers included in the monitored G12, and so that it approaches the maximum usable charging current. The monitoring point P212 is a location on the power line that is above the point where the power line branches to charger panels 73B and 74B, and below the lighting panel 75B. The maximum usable charging current is the sum of the rated value of the main breaker installed in charger panel 73B and the rated value of the main breaker installed in charger panel 74B.

[0110] Each of the control slave units 31B, 32B, 33B, and 34B controls the chargers to be controlled so that the sum of the charging currents of the multiple chargers to be controlled is less than or equal to the maximum usable charging value and approaches the maximum usable charging value, similar to the embodiment described above. In addition, each of the control slave units 31B, 32B, 33B, and 34B performs proportional control, similar to the embodiment described above.

[0111] The master control unit 2B transmits to each of the multiple monitoring points (monitoring point P20, monitoring point P2, monitoring point P21, monitoring point P211, and monitoring point P212) a difference information indicating the difference between a first value, which is based on the value of the charging current used for charging the vehicle by one or more chargers located lower than a certain monitoring point among the multiple chargers, and a reference value, which is based on the maximum value of the current that can be used for charging the vehicle by one or more chargers located lower than the monitoring point among the multiple chargers. This difference information is transmitted to each of the one or more control slave units (control slave unit 31B, control slave unit 32B, control slave unit 33B, and control slave unit 34B) located lower than the monitoring point in question.

[0112] In the embodiments and modifications described above, an example was given in which one or more control slave units 3 do not communicate with each other, but this is not the only example. One or more control slave units 3 may communicate with each other (bidirectional communication).

[0113] When one or more control slave units 3 communicate with each other, the control slave units 3 may set a priority order for the charging sequence of one or more chargers 4. The priority order is set, as described above, for example, based on the order in which charging is started or on an indicator such as SOC.

[0114] Furthermore, when one or more control units 3 communicate with each other, the current charging current value of one charger 4 may be set as the current reference value. In the vehicle charging system 1, proportional control is performed, so the current charging current value is equal among one or more chargers 4 that have already started charging. When one or more control units 3 communicate with each other, the current charging current value of one charger 4 can be shared among the one or more control units 3. If a charger 4 has just started charging, the charging current value of this charger 4 is set to the same value as the charging current value of a charger 4 that has already started charging.

[0115] Furthermore, when one or more control units 3 communicate with each other, the total number of chargers 4 that have already started charging can be shared among the one or more control units 3. Therefore, when one or more control units 3 communicate with each other, the control units 3 may change the charging current of each charger 4 that has already started charging by a value obtained by dividing the difference value indicated by the difference information by the total number of chargers 4 that have already started charging. Proportional control is also possible in this way.

[0116] As described above, the vehicle charging system 1 according to this embodiment includes a plurality of chargers 4 for charging a vehicle 8, and a charging control device (in this embodiment, a master control unit 2 and one or more slave control units 3) that controls the charging current of each of the plurality of chargers 4. The charging control device (in this embodiment, a master control unit 2 and one or more slave control units 3) comprises one or more slave control units 3 and a master control unit 2. One or more slave control units 3 control the charging current of one or more chargers among a plurality of chargers 4. The master control unit 2 controls one or more slave control units 3 (in this embodiment, slave control units 31 and 32). The master control unit 2 transmits to one or more slave control units 3 (in this embodiment, slave control units 31 and 32) differential information indicating the difference between a first value based on the value of the charging current used by the multiple chargers 4 to charge the vehicle 8 (in this embodiment, the value of the charging current used by the multiple chargers 4 to charge the vehicle 8 itself) and a reference value based on the maximum value of the current that the multiple chargers 4 can use to charge the vehicle 8 (in this embodiment, the maximum usable charging value). The control slave unit 3 controls the charging current of the charger controlled by the control slave unit 3 among the multiple chargers 4 based on the differential information received from the control master unit 2.

[0117] With this configuration, the vehicle charging system 1 according to this embodiment can perform proportional control based on differential information and a current reference value, thereby preventing excess capacity from being generated and enabling efficient charging.

[0118] (Second Embodiment) A second embodiment of the present invention will be described in detail below with reference to the drawings. In the first embodiment described above, the case in which the vehicle charging system 1 is monitored by the control master unit 2 for both monitoring point P0 and monitoring point P1 was explained. In this embodiment, the case in which monitoring point P1 is not provided and monitoring is performed by the control master unit will be explained. The vehicle charging system according to this embodiment is referred to as vehicle charging system 1C.

[0119] Figure 7 shows an example of the configuration of the vehicle charging system 1C according to this embodiment. Comparing the vehicle charging system 1C with the vehicle charging system 1, the vehicle charging system 1C is equipped with two transformers, transformer 91C and transformer 92C, and there is no monitoring point downstream of transformer 91C and transformer 92C. In addition, the vehicle charging system 1C differs in that it is equipped with a control master unit 2C and one or more control slave units 3C (control slave unit 31C, control slave unit 32C) instead of a control master unit 2 and one or more control slave units 3.

[0120] In the vehicle charging system 1C, simple proportional control and monitoring of multiple chargers 4 are performed by one or more control slave units 3C based on differential information transmitted from the control master unit 2C. This differential information is differential information for monitoring point P0. Because simple proportional control and monitoring of multiple chargers 4 are performed, in the vehicle charging system 1C, when the charger 4 charges at the maximum current setting value of 30A, one or more control slave units 3C control the system so as not to exceed the upper limit of the current allowed by the main breaker 5. Therefore, in the vehicle charging system 1C, charging is performed without leaving any reserve capacity.

[0121] Here, monitoring at monitoring point P0 alone does not allow the control master unit 2C to obtain the sum of the maximum usable charging values ​​for one or more chargers 4 controlled by the control slave unit 31C and the maximum usable charging values ​​for one or more chargers 4 controlled by the control slave unit 32C. Therefore, in the vehicle charging system 1C, the current value that can be used by one or more chargers 4 controlled by the control slave unit 3C is set to a value smaller than the sum of the maximum current setting values ​​(30A) of each of the three chargers 4 (90A). In the example shown in Figure 7, the current value that each of the multiple main breakers 5 allows is set to 50A, which is a value smaller than 90A. The control unit 3C controls the total current of the three chargers 4 so that it does not exceed the upper limit. For this reason, the maximum current setting value for each of the three chargers 4 is set to 30A.

[0122] The master control unit 2C obtains the value of the current used by the power equipment downstream of monitoring point P0 from the energy meter 10. The master control unit 2C calculates difference information showing the difference between the value of the current used by the power equipment downstream of monitoring point P0 and the demand value. The master control unit 2C transmits the calculated difference information to one or more slave control units 3C.

[0123] For example, suppose chargers 411, 412, and 413 are each charging using their maximum current setting of 30A. Also, suppose chargers 421 and 422 are each charging using their maximum current setting of 30A.

[0124] In this case, the value of the current used by the power equipment downstream of monitoring point P0 is the sum of the charging currents of chargers 411, 412, and 413, which is 90A; the sum of the charging currents of chargers 421 and 422, which is 60A; and the current used by the general load 12, which is 100A, totaling 250A. The master control unit 2C transmits differential information to the slave control units 31C and 32C respectively, indicating that the current exceeds the demand value of 200A by a difference of 50A.

[0125] The control slave unit 31C determines that there is no surplus power in the received power because the difference information received from the control master unit 2C is greater than 0. At this point, the sum of the charging currents of charger 411, charger 412, and charger 413 is 90A. This sum exceeds the upper limit of usable current, which is 50A, by 40A. The control slave unit 31C divides the upper limit among the three chargers 411, 412, and 413 and causes them to charge at the same charging current value. Therefore, the control slave unit 31C controls the charging current of one charger 4 to decrease by 14A. As a result, the charging currents of charger 411, charger 412, and charger 413 each become 16A. The sum of the charging currents of charger 412 and charger 413 becomes 48A, which is approximately 50A.

[0126] The control slave unit 32C determines that there is no surplus power because the difference information received from the control master unit 2C is greater than 0. At this point, the sum of the charging currents of charger 421 and charger 422 is 60A. This sum exceeds the upper limit of usable current, which is 50A, by 10A. The control slave unit 32C divides the upper limit between charger 421 and charger 422 and causes both charger 421 and charger 422 to charge at the same charging current value. Therefore, the control slave unit 32C controls the charging current of one charger 4 to decrease by 5A. As a result, the charging current of charger 421 and charger 422 become 25A each. The sum of the charging currents of charger 421 and charger 422 becomes 50A.

[0127] If the difference information is greater than 0, each of the one or more control slave units 3C determines that there is no surplus power in the received power. If the difference information is greater than 0, each of the one or more control slave units 3C reduces the charging current value of each of the one or more chargers 4 controlled by the control slave unit 3C by a value obtained by dividing the difference in the total charging current of the one or more chargers 4 controlled by the control slave unit 3C that exceeds the upper limit of current allowed by the main breaker 5 by the number of chargers 4 controlled by the control slave unit 3C.

[0128] On the other hand, if the difference information is less than 0, each of the one or more control slave units 3C determines that there is surplus power in the received power. If the difference information is less than 0, each of the one or more control slave units 3C increases the charging current value of each of the one or more chargers 4 controlled by the control slave unit 3C by a value obtained by dividing the difference in the total charging current of the one or more chargers 4 controlled by the control slave unit 3C that is less than the upper limit of current allowed by the main breaker 5 by the number of chargers 4 controlled by the control slave unit 3C.

[0129] As described above, each of the one or more control slave units 3C controls the chargers 4 controlled by the control slave unit 3C so that the sum of the charging currents of the one or more chargers 4 controlled by the control slave unit 3C does not exceed the upper limit of the current allowed by the main breaker 5, and so that the charging current values ​​of the one or more chargers 4 controlled by the control slave unit 3C are the same, based on the differential information received from the master control unit 2C.

[0130] In the vehicle charging system 1C, the control described above ensures that the total charging current of one or more chargers 4 is 100A. Therefore, in the vehicle charging system 1C, charging is performed without any surplus power, using the 100A current value that all of the one or more chargers 4 can utilize.

[0131] Furthermore, each component of the device in the above embodiment may be implemented by dedicated hardware, or it may be implemented by memory and a microprocessor.

[0132] Furthermore, each component of each device may consist of memory and a CPU (Central Processing Unit), and its functions may be realized by loading a program into memory and executing it to realize the functions of each component of each device.

[0133] Alternatively, programs for realizing the functions of each part of each device may be recorded on a computer-readable recording medium, and the programs recorded on this recording medium may be loaded into a computer system and executed to perform processing by the parts of the control unit. The term "computer system" here includes hardware such as the operating system and peripheral devices.

[0134] Furthermore, "computer system" shall also include the homepage provisioning environment (or display environment) if a WWW system is being used. Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. In addition, "computer-readable recording media" also includes those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs over networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside computer systems that act as servers or clients in such cases. Moreover, the above-mentioned programs may be for the purpose of realizing some of the functions described above, and may also be able to realize the above-mentioned functions in combination with programs already recorded in the computer system.

[0135] Although one embodiment of this invention has been described in detail above with reference to the drawings, the specific configuration is not limited to that described above, and various design changes can be made without departing from the spirit of this invention. [Explanation of Symbols]

[0136] 1...Vehicle charging system, 2...Control master unit, 3, 31, 32...Control slave units, 4...Charger, 8...Vehicle

Claims

1. Multiple chargers for charging vehicles, A charging control device that controls the charging current of each of the aforementioned multiple chargers, A vehicle charging system comprising, The charging control device is One or more control units that control the charging current of one or more chargers among the plurality of chargers, A control master unit that controls the one or more control slave units, Equipped with, The control master unit transmits to each of the one or more control slave units difference information indicating the difference between a first value based on the value of the charging current used by the plurality of chargers to charge the vehicle and a reference value based on the maximum value of the current that the plurality of chargers can use to charge the vehicle. The control slave unit controls the charging current of the charger controlled by the control slave unit among the plurality of chargers based on the difference information received from the control master unit, such that the charging current values ​​of each charger controlled by the control slave unit are the same. Vehicle charging system.

2. The control master unit transmits to each of the one or more control slave units located below the monitoring point a difference information indicating the difference between a first value, which is based on the value of the charging current used by one or more chargers located below the monitoring point among the multiple chargers for charging the vehicle, and a reference value, which is based on the maximum value of the current that one or more chargers located below the monitoring point among the multiple chargers can use to charge the vehicle. The vehicle charging system according to claim 1.

3. Each of the one or more control units controls the charging current of the charger it controls among the plurality of chargers so that the sum of the charging currents of the chargers it controls among the plurality of chargers is less than or equal to the maximum current that the plurality of chargers can use to charge the vehicle. The vehicle charging system according to claim 1.

4. The control slave unit controls the charging current of the charger controlled by the control slave unit among the multiple chargers, based on the difference information received from the control master unit and a current reference value for the charging current of one of the multiple chargers. The vehicle charging system according to claim 1.

5. The current reference value is the maximum charging current provided by one of the chargers included in the plurality of chargers. The vehicle charging system according to claim 4.

6. The control slave unit controls the charging current of the charger controlled by the control slave unit among the multiple chargers based on the difference information received from the control master unit and the priority order among the multiple chargers controlled by the control slave unit. The vehicle charging system according to claim 1.

7. The one or more control slave units are a plurality, The aforementioned multiple control slave units communicate with each other. The vehicle charging system according to claim 1.

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