Charging device, charging system and control device

Abstract

To provide a charger capable of sufficiently utilizing rated power of a power source supply unit.SOLUTION: A charger 1001 comprises: a plurality of DC power supply units that are connectable to storage batteries 4 mounted on a plurality of vehicles and output a charging current Ic not exceeding a rated current Icn to the storage batteries 4; a plurality of changeover switches for changing over connection states between the plurality of DC power supply units and the storage batteries 4; and a control section 2 that determines DC current and the number UN of DC power supply units that maximize the total value of the charging current Ic output from the DC power supply units within a range of maximum charging currents Icmax respectively input from the vehicles, creates a DC current instruction for instructing the DC power supply units to output DC current and a changeover operation instruction for instructing a changeover operation of the changeover switch so that the number UN of DC power supply units, and the storage batteries 4 are connected, and outputs the instructions.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a charging device, a charging system, and a control device for vehicles such as electric automobiles and electric motorcycles. [Background technology]

[0002] In recent years, vehicles such as electric cars and electric motorcycles that run using electric motors that use electricity stored in storage batteries as an energy source have become widespread, and as a result, demand for charging equipment to charge these vehicles has increased. Charging the storage batteries of these vehicles takes longer than refueling vehicles that run using gasoline-fueled internal combustion engines, so technologies for charging them in a short period of time are being considered.

[0003] For example, Patent Document 1 discloses a charging device that supplies charging power from multiple power supply units to multiple electric vehicles in accordance with charging power command values transmitted from the electric vehicles.The device also discloses a scheme to improve the operating rate by switching the connection of the power supply unit from the electric vehicle being charged to another electric vehicle when the charging rate of the electric vehicle increases and surplus power is generated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-061880 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a problem in that the rated power of the power supply units cannot be fully utilized by simply distributing the charging power of a plurality of power supply units to the storage batteries of a plurality of vehicles.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to fully utilize the rated power of a power supply unit. [Means for solving the problem]

[0007] A charging device according to the present disclosure includes a plurality of DC power supply units connectable to storage batteries mounted on a plurality of vehicles and outputting a charging current not exceeding a rated current to the storage batteries; a plurality of changeover switches for switching the connection state between the plurality of DC power supply units and the storage batteries; and a control unit that determines the DC current and the number of DC power supply units that maximizes the total value of the charging current output from the DC power supply units within the range of the maximum charging current input from each vehicle, generates a DC current command that commands the DC power supply units to output a DC current, and a changeover operation command that commands the changeover switch to change over so that the plurality of DC power supply units and the storage batteries are connected, and outputs them. The control unit determines the number of vehicles according to the set charging priority of the vehicles, and when a variable determined by the maximum charging current input from the vehicle with the high charging priority is less than a threshold, operates a changeover switch to switch the connection of the DC power supply unit from the storage battery of the vehicle with the high charging priority to the storage battery of the vehicle with the low charging priority, and when the variable is equal to or greater than the threshold, operates the changeover switch to continue the connection of the DC power supply unit to the storage battery of the vehicle with the high charging priority. . In addition, a charging device according to the present disclosure includes a plurality of DC power supply units connectable to storage batteries mounted on a plurality of vehicles and outputting a charging current to the storage batteries that does not exceed a rated current; a plurality of changeover switches that switch the connection state between the plurality of DC power supply units and the storage batteries; and a control unit that determines the DC current and number of DC power supply units that will maximize the total value of the charging current output from the DC power supply units within the range of the maximum charging current input from each vehicle, generates a DC current command that instructs the DC power supply units to output a DC current, and a changeover operation command that instructs the changeover switch to perform a changeover operation so that the plurality of DC power supply units and the storage batteries are connected, and outputs them, wherein the control unit determines the number of units according to the set charging priority of the vehicles, and, in the case where the storage batteries are in a connection state where they are electrically connected to each other, changes the set connection priority of the DC power supply units, and determines the connection state between the plurality of DC power supply units and the storage batteries according to the changed connection priority. In addition, a charging device according to the present disclosure includes a plurality of DC power supply units connectable to storage batteries mounted on a plurality of vehicles and outputting a charging current to the storage batteries that does not exceed a rated current; a plurality of changeover switches that switch the connection state between the plurality of DC power supply units and the storage batteries; and a control unit that determines the DC current and number of DC power supply units that will maximize the total value of the charging current output from the DC power supply units within the range of the maximum charging current input from each vehicle, generates a DC current command that instructs the DC power supply units to output a DC current, and a changeover operation command that instructs the changeover switch to perform a changeover operation so that the plurality of DC power supply units and the storage batteries are connected, and outputs them. The control unit determines the number of vehicles according to the set charging priority of the vehicles, and, if it is not possible to switch the connection of the DC power supply units from the vehicle with the Nth highest charging priority (N is an integer greater than or equal to 1) to the vehicle with the N+1th highest charging priority, operates the changeover switch to switch the connection of the DC power supply units to the vehicle with the N+3th highest charging priority.

[0008] The charging system according to the present disclosure is a charging system that supplies power from an external power source to charge storage batteries installed in multiple vehicles, and includes a charging device according to the present disclosure and an external control device that is connected to the charging device via an interface and transmits external information to the charging device.

[0009] The control device according to the present disclosure includes a data input unit that inputs the maximum charging current of each of a plurality of vehicles, and a control unit that controls the charging current so that the total value of the charging current output from the DC power supply units connected to the storage batteries mounted on the plurality of vehicles is maximized within the range of the maximum charging current. , according to the set charging priority of the vehicle. a DC power supply unit number determination unit that determines the number of DC power supply units; a DC current output determination unit that determines the DC current output of the DC power supply units so as to maximize the total value; a DC current command generation unit that generates a DC current command in accordance with the DC current output determined by the DC current output determination unit; an operation command generation unit that determines a connection state between the DC power supply units and the storage battery and generates an operation command to establish the connection state; a DC current command output unit that outputs the DC current command to the DC power supply units; and an operation command output unit that outputs the operation command to a changeover switch. The DC current command generation unit generates an operation command to switch the connection of the DC power supply unit from the storage battery of the vehicle with the high charging priority to the storage battery of the vehicle with the low charging priority when a variable determined by the maximum charging current input from the vehicle with the high charging priority is less than a threshold value, and generates an operation command to continue the connection of the DC power supply unit to the storage battery of the vehicle with the high charging priority when the variable is equal to or greater than the threshold value.It is characterized by the following. [Effects of the Invention]

[0010] According to the present disclosure, the rated power of the power supply unit can be fully utilized. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an example of a schematic configuration of a charging device according to a first embodiment. [Figure 2] 1 is a block diagram showing an example of a schematic configuration of a charging system according to a first embodiment. [Figure 3] 4 is a flowchart showing an example of the operation of the charging device according to the first embodiment. [Figure 4] 4 is a flowchart showing an example of the operation of the charging device according to the first embodiment. [Figure 5] FIG. 3 is a diagram illustrating an example of the operation of the charging device according to the first embodiment. [Figure 6] FIG. 3 is a diagram illustrating an example of the operation of the charging device according to the first embodiment. [Figure 7] FIG. 3 is a diagram illustrating an example of the operation of the charging device according to the first embodiment. [Figure 8] 1 is a block diagram showing an example of a schematic configuration of a control device according to a first embodiment. [Figure 9] FIG. 3 is a diagram illustrating an example of the operation of the charging device according to the first embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of a schematic configuration of a charging device according to a second embodiment. [Figure 11] FIG. 10 is a diagram illustrating an example of the operation of the charging device according to the second embodiment. [Figure 12] FIG. 10 is a diagram illustrating an example of the operation of the charging device according to the second embodiment. [Figure 13] FIG. 10 is a diagram illustrating an example of the operation of the charging device according to the second embodiment. [Figure 14] FIG. 10 is a diagram illustrating an example of the operation of the charging device according to the second embodiment. [Figure 15]FIG. 11 is a block diagram showing an example of a schematic configuration of a charging device according to a third embodiment. [Figure 16] FIG. 10 is a diagram illustrating an example of the operation of the charging device according to the third embodiment. [Figure 17] FIG. 10 is a diagram illustrating an example of the operation of the charging device according to the third embodiment. [Figure 18] FIG. 10 is a diagram illustrating an example of the operation of the charging device according to the third embodiment. [Figure 19] FIG. 10 is a block diagram showing an example of a schematic configuration of a charging device according to a fourth embodiment. [Figure 20] 10 is a flowchart showing an example of the operation of the charging device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The charging device according to the present disclosure will be described with reference to the drawings. In the drawings, DC power supply units are given reference numerals, but when referring to any DC power supply unit, particularly when multiple DC power supply units are not distinguished, the unit may be referred to as a DC power supply unit without the reference numeral. Also, while selector switches are given reference numerals, when referring to any selector switch, particularly when multiple selector switches are not distinguished, the unit may be referred to as a selector switch without the reference numeral. Also, while electric vehicles are given reference numerals, when referring to any electric vehicle, particularly when multiple electric vehicles are not distinguished, the unit may be referred to as an electric vehicle.

[0013] Embodiment 1 A charging device 1001 according to this embodiment will be described with reference to FIGS. In FIG. 1, a charging device 1001 is connected to a power source 1 and storage batteries 4 mounted on two electric vehicles, and the charging device 1001 is equipped with two DC power supply units, three selector switches, a control unit 2, and an interface circuit 3.

[0014] The two DC power supply units each convert the power supplied from the power source 1, adjust the charging current Ic in accordance with a DC current command input from a control unit 2 (described later), and charge the storage battery 4. Two DC power supply units connected in parallel may be used to charge one storage battery 4. The DC power supply units acquire information such as input / output status using sensors such as a voltage sensor and a current sensor (not shown), and output the information to the control unit 2. The DC power supply unit is composed of, for example, an AC / DC converter, a DC / DC converter, or a combination of these.

[0015] The three changeover switches change the connection state between the DC power supply units and the storage batteries 4 between a current-permitted state and a current-cut state in response to an operation command input from the control unit 2, and supply the charging current Ic supplied from the DC power supply units to the storage batteries 4. By operating the changeover switches, one storage battery 4 can be charged using two DC power supply units, and two DC power supply units can also be connected one-to-one to two storage batteries 4, allowing them to be charged individually.

[0016] For example, when the selector switches 12A and 12C are turned on, the storage battery 4 of the electric vehicle 13A can be charged from the DC power supply units 11A and 11B connected in parallel. That is, it is possible to charge one storage battery 4 with the power of two DC power supply units. When the selector switch 12C is turned off and the selector switches 12A and 12B are turned on, it is possible to charge the storage battery 4 of the electric vehicle 13A from the DC power supply unit 11A, and the storage battery 4 of the electric vehicle 13B from the DC power supply unit 11B. That is, it is possible to charge each storage battery 4 with the power of one DC power supply unit.

[0017] The changeover switch is configured, for example, by a relay switch, etc. If the storage batteries 4 are directly connected to each other, there is a risk that the storage batteries 4 may break down due to cross currents between the storage batteries 4. Therefore, it is desirable to install a safety mechanism such as an interlock mechanism so that the storage batteries 4 are not directly connected to each other in the event that an erroneous operation command is input from the control unit 2.

[0018] The control unit 2 performs overall control of the charging device 1001. For example, it outputs a DC current command generated based on the charging current command acquired from each electric vehicle to the DC power supply unit, and controls the magnitude of the charging current Ic output by the DC power supply unit. It also outputs an operation command to the selector switch and determines whether to open or close the selector switch. The control unit 2 is configured by a microcomputer including, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile memory, and the like.

[0019] The power supply 1 is an AC or DC power supply and supplies power to the DC power supply unit. Of the DC power supply constituted by an AC power supply and an AC / DC converter, the AC / DC converter may be included in charging device 1001 .

[0020] The interface circuit 3 is a circuit that connects the charging device 1001 to the external control device 21 shown in Fig. 2. For example, the interface circuit 3 communicates with the external control device 21, such as a sequencer, a user interface, or an energy management system, acquires information about various command values and various setting values, and outputs the acquired information to the control unit 2. In other words, some of the command functions performed by the control unit 2 may be provided to the external control device 21. The interface circuit 3 may be installed inside the charging device 1001 or outside the charging device 1001. As shown in Fig. 2, the charging device 1001, the interface circuit 3, and the external control device 21 form a charging system 2001.

[0021] The electric vehicle runs using an electric motor that uses electricity stored in a storage battery 4 as an energy source. The electric vehicle is a plug-in vehicle that can be charged by a charging device 1001. Plug-in vehicles include, for example, plug-in hybrid vehicles.

[0022] The storage battery 4 stores the charging power Wc supplied from the charging device 1001, and the stored power is used to drive the electric motor of an electric vehicle (not shown). The storage battery 4 and the charging device 1001 are connected via a power plug and power line provided on the electric vehicle, and the charging device 1001 inputs information about the storage battery 4 via the power plug and power line. The storage battery 4 is configured, for example, by a lithium-ion battery, and the power plug is configured, for example, by CHAdeMO, Combo, or other charging standards for electric vehicles.

[0023] The operation of the control unit 2 in this embodiment will be described with reference to Fig. 3. The flowchart consisting of the steps shown below is repeatedly executed every time a predetermined condition is met.

[0024] In step S101, the control unit 2 receives information from the electric vehicles, the external control device 21, etc., and updates the information. Here, the number of connected electric vehicles, the charging priority, and the maximum charging current Icmax are set. The maximum charging current Icmax is, for example, a maximum charging current command or a charging current upper limit value sent from the electric vehicle. Then, in step S102, the charging priority N is initialized to N=1 (N is an integer equal to or greater than 1). Then, in step S103, the control unit 2 determines whether the Nth priority electric vehicle (EV) can be charged. If the electric vehicle (EV) can be charged (step S103: YES), the control unit 2 proceeds to step S104, and if the electric vehicle (EV) cannot be charged (step S103: NO), the control unit 2 proceeds to step S108. Then, in step S104, the number U of DC power supply units to be connected to the N-th priority electric vehicle is calculated. N (U N is an integer greater than or equal to 1). Then, in step S105, a DC power supply unit is installed in the electric vehicle with the Nth priority. N The control unit 2 determines whether or not a U N If the unit can be connected (step S105: YES), the process proceeds to step S106. N If the machine cannot be connected (step S105: NO), the process proceeds to step S107. Then, in step S106, a DC power supply unit to be connected to the electric vehicle with the Nth priority is selected, and a DC current command to be output to each DC power supply unit is determined. Then, in step S107, the number of connected DC power supply units is increased to the maximum possible number. N DC power supply units are selected to serve as the power supply units, and DC current commands for each DC power supply unit are determined. Then, in step S108, the control unit 2 determines whether the value of the charging priority N is greater than the number of electric vehicles connected to the charging device 1001. If the value is greater than the number of connected vehicles (step S108: YES), the control unit 2 proceeds to step S110, and if the value is less than the number of connected vehicles (step S108: NO), the control unit 2 proceeds to step S109. Then, in step S109, N is incremented, and the process proceeds to step S103. By repeating the processing of steps S103 to S107, the allocation of DC power supply units to all electric vehicles to be charged is determined. Then, in step S110, the connection state of the changeover switch is determined based on the allocation of the DC power supply units determined in step S106, and the determined connection state is compared with the current connection state to determine whether or not a change in the connection state of the changeover switch is necessary. If a change is necessary (step S110: YES), the control unit 2 proceeds to step S111, and if a change is not necessary (step S110: NO), the control unit 2 proceeds to step S112. Then, in step S111, an operation command is generated to establish the connection state determined in step S106. In step S112, the DC current command determined in steps S106 and S107 is generated, and the DC current command and the operation command generated in step S111 are output to the DC power supply unit and the changeover switch. In this way, the operation of charging device 1001 is determined by steps S101 to S112.

[0025] The charging priority of the electric vehicles in step S101 may be set individually by the user, or if not set by the user, may be set according to a predefined rule. For example, the predefined rule may determine the charging priority according to the order in which the electric vehicles are connected to the charging device 1001.

[0026] If the electric vehicle cannot be charged in step S103, for example, the electric vehicle is fully charged or has a malfunction.

[0027] In step S110, it is determined whether or not the connection state of the changeover switch needs to be changed by comparing it with the current connection state, but the current connection state may be saved in a memory unit each time, or the connection state may be measured each time by a sensor.

[0028] 4, the control unit 2 determines the number U of DC power supply units in step S104. N The procedure for determining this will be described below.

[0029] In step S141, the number U of DC power supply units is N Initialize as =1. Then, in step S142, the maximum charging current Icmax is substituted into a temporary variable Itmp. Then, in step S143, the number of DC power supply units U N If it is less than the total number of units (step S143: YES), the control unit 2 proceeds to step S144, and if it is equal to or greater than the total number (step S143: NO), the control unit 2 ends the process. Then, in step S144, Itmp=Itmp-Icn (Formula 1) Substitute the temporary variable Itmp and the rated current Icn of the DC power supply unit into the right-hand side of the equation to determine Itmp on the left-hand side. Then, in step S145, it is determined whether Itmp on the left side of step S144 is smaller than the charging current threshold value Icth. If Itmp is smaller than the charging current threshold value Icth (step S145: YES), control unit 2 ends the process, and if Itmp is equal to or greater than the charging current threshold value Icth (step S145: NO), control unit 2 proceeds to step S146. Then, in step S146, the number U N Then, 1 is added to the value, and the process proceeds to step S143. Then, in step S143, the number of DC power supply units U N If the number is less than the total number of DC power supply units (step S143: YES), the control unit 2 proceeds to step S144. Then, in step S144, the temporary variable Itmp substituted into the right side of the formula 1 is the number U N The left-hand side of Itmp is updated to Itmp calculated in the above equation, and the rated current Icn of the DC power supply unit is substituted to determine Itmp on the left-hand side. After that, repeat the same process until the number of DC power supply units U N is determined.

[0030] The number U of DC power supply units in step S141 N is determined according to the maximum charging current Icmax, for example, the maximum charging current Icmax, the charging current threshold Icth, the rated current Icn, etc. The charging current threshold Icth is set in the range from zero to the maximum charging current Icmax, and may be changed via the interface circuit 3 during operation. When the charging current threshold Icth is set to zero, in step S143, the number U NThe process in step S145 proceeds to step S146 until U becomes larger than the total number of DC power supply units. N For example, if the user wishes to minimize the charging time of the electric vehicle with the highest priority, the charging current threshold Icth is set to zero. If the charging current threshold Icth is set to a value equal to the rated current Icn, and the difference between the maximum charging current Icmax and the rated current Icn becomes smaller than the charging current threshold Icth in step S145, N is not incremented and the processing ends. Therefore, if you want to reduce the charging time for all electric vehicles, the charging current threshold Icth is set to the rated current Icn.

[0031] In step S105 shown in FIG. N When determining whether or not two electric vehicles can be connected, DC power supply units that have already been determined to be connected to electric vehicles with higher charging priority are not used in the determination, and a determination is made so that electric vehicles are not directly electrically connected to each other, including settings that have already been determined to be connected.

[0032] In the selection of a DC power supply unit in step S107, if all DC power supply units have already been selected for other electric vehicles, a setting is made such that no DC power supply unit is selected. Furthermore, the DC current command is determined so that the sum of the DC current commands of one or more selected DC power supply units is as equal to the maximum charging current Icmax of the electric vehicle as possible.

[0033] When multiple DC power supply units are connected to a single electric vehicle, the method of allocating DC current commands is determined according to predefined rules. For example, if two DC power supply units with a rated current Icn of 75 A are connected to one electric vehicle and the maximum charging current Icmax is 100 A, a DC current command of 50 A will be issued to each DC power supply unit, a DC current command of 75 A will be issued to one DC power supply unit and a DC current command of 25 A will be issued to the other DC power supply unit, etc.

[0034] In addition, if the selection of DC power supply units for all electric vehicles has been completed but there are DC power supply units that have not been allocated to electric vehicles, the number of units U N Alternatively, the number of DC power supply units may be increased one by one in order from N=1, and a process may be performed in which as many DC power supply units as possible perform charging operations. Furthermore, if the number of DC power supply units required to supply sufficient charging current Ic to all electric vehicles is less than the number of installed electric vehicles, there will be DC power supply units that are not allocated to electric vehicles.

[0035] An operation of charging two electric vehicles using two DC power supply units will be described using Figure 5. Assume that electric vehicle 13A (first priority electric vehicle) and electric vehicle 13B (second priority electric vehicle) with a low SoC (State of Charge) and a maximum charging current command of 150 A are connected to charging device 1001, and DC power supply unit 11A and DC power supply unit 11B are installed. The rated current Icn of DC power supply unit 11A and DC power supply unit 11B is both set to 75 A, and the charging current threshold Icth is set to 75 A, which is equal to the rated current Icn.

[0036] In step S101 shown in FIG. 3, the number of connected electric vehicles is two, electric vehicle 13A is the first-priority electric vehicle, electric vehicle 13B is the second-priority electric vehicle, and the maximum charging current Icmax is set to 150 A based on the SoC. Then, in step S102, N is initialized as N=1. Then, in step S103, if the first-priority electric vehicle 13A is chargeable (step S103: YES), the process proceeds to step S104. Then, in step S104, the number U of DC power supply units to be connected to the first-priority electric vehicle 13A is determined. N is calculated. That is, in step S141 shown in FIG. 4, the number U of DC power supply units N In step S142, the maximum charging current Icmax (150 A) is substituted into the temporary variable Itmp, and in step S143, the number of DC power supply units U N Since (1 unit) is less than the total number of DC power supply units (2 units) (step S143: YES), processing proceeds to step S144, where the temporary variable Itmp (150A) and the rated current Icn (75A) of the DC power supply unit are substituted into the right-hand side of equation 1, and Itmp on the left-hand side is determined to be 75A. In step S145, since Itmp (75A) on the left side of step S144 is not greater than the charging current threshold Icth (75A) (step S145: NO), the process proceeds to step S146. N Add 1 to U N = 2 and the process proceeds to step S143. Then, in step S143, the number of DC power supply units U N (2 units) becomes equal to or greater than the total number of DC power supply units (2 units) (step S143: NO), and the process ends. Then, in step S105 of FIG. 3, the number U of DC power supply units is installed in the electric vehicle 13A with first priority. N Since (two devices) can be connected (step S105: YES), the process proceeds to step S106. Then, in step S106, the DC power supply unit 11A and the DC power supply unit 11B to be connected to the electric vehicle 13A with the first priority are selected, and the respective DC current commands are determined. Then, in step S108, since the value of the charging priority N(1) is smaller than the number of electric vehicles (2) connected to the charging device 1001 (step S108: NO), the process proceeds to step S109, N is incremented to N=2, and the process proceeds to step S103. Here, the same process is performed on the electric vehicle 13B with second priority, but since the determination in step S105 is NO, the process proceeds to step S107. Then, in step S107, since DC power supply unit 11A and DC power supply unit 11B have already been selected for electric vehicle 13A, which has the first priority, processing is performed so that no DC power supply unit is selected for electric vehicle 13B, which has the second priority.

[0037] As shown in FIG. 5, when charging starts, two DC power supply units are provided to the first-priority electric vehicle 13A, the selector switch 12A and the selector switch 12C shown in FIG. 6 are in the energization permission state, and the selector switch 12B is in the energization cut-off state, and a charging current Ic of 150 A in total, which is the rated current Icn (75 A), is output to the storage battery 4 mounted on the first-priority electric vehicle 13A.

[0038] As charging progresses, when the maximum charging current Icmax of the first-priority electric vehicle 13A falls below 150A, the maximum charging current Icmax of the electric vehicle 13A is updated to less than 150A in step S101 shown in FIG. Then, in step S104, that is, step S145 in FIG. 4, Itmp on the left side of step S144 becomes smaller than the charging current threshold Icth (75 A) (step S145: YES), so the number of units U N On the other hand, the maximum charging current Icmax input from the electric vehicle 13B is 150 A, so the number of vehicles U N There will be two units. Then, by performing the processes of steps S105 and S106, the DC power supply unit 11A continues to be selected for the electric vehicle 13A having the first priority, but in S110 it is determined that switching of the selector switch is necessary, and at the time of operation switching in Fig. 5, the selector switch is operated in S111. That is, as shown in Fig. 7, selector switches 12A and 12B are in the energization permission state, and selector switch 12C is in the energization cut-off state, so that the DC power supply unit 11A, which outputs 75 A as the rated current Icn, outputs 75 A as the charging current Ic to the storage battery 4 mounted on the electric vehicle 13A having the first priority, and the DC power supply unit 11B, which outputs 75 A as the rated current Icn, outputs 75 A as the charging current Ic to the storage battery 4 mounted on the electric vehicle 13B having the second priority. Here, if the maximum charging current Icmax is below 75 A, the value of the charging current Ic is also adjusted according to the value of the maximum charging current Icmax.

[0039] In this way, charging apparatus 1001 of this embodiment controls the DC power supply units connected to each electric vehicle to operate at the rated current Icn within the range of the maximum charging current Icmax input from each electric vehicle, so that it is possible to charge a plurality of electric vehicles in a state in which the total charging current Ic of the plurality of DC power supply units is always close to the total value of the rated current Icn. In other words, it is possible to fully utilize the rated power of the DC power supply units, and as a result, it is possible to reduce the total charging time for all connected vehicles.

[0040] As described above, the charging device 1001 of this embodiment includes a plurality of DC power supply units that can be connected to the storage batteries 4 mounted on a plurality of vehicles and that output a charging current Ic that does not exceed the rated current Icn to the storage batteries 4, a plurality of changeover switches that switch the connection state between the plurality of DC power supply units and the storage batteries 4, a DC current command that determines the number of DC power supply units and the DC current that maximizes the total value of the charging current Ic output from the DC power supply units within the range of the maximum charging current Icmax input from each vehicle, and commands the DC power supply units to output a DC current, and a number of DC power supply units and the storage batteries 4 to be connected. and a control unit 2 that outputs a switching operation command to instruct a changeover switch to switch the connection of the DC power supply unit from the storage battery 4 of the vehicle with the higher charging priority to the storage battery 4 of the vehicle with the lower charging priority. The control unit 2 determines the number of vehicles according to the set charging priority of the vehicles. When a variable determined by the maximum charging current Icmax input from the vehicle with the higher charging priority is less than a threshold, the control unit 2 operates the changeover switch to switch the connection of the DC power supply unit from the storage battery 4 of the vehicle with the higher charging priority to the storage battery 4 of the vehicle with the lower charging priority. When the variable is equal to or greater than the threshold, the control unit 2 operates the changeover switch to continue the connection of the DC power supply unit to the storage battery 4 of the vehicle with the higher charging priority. Here, the variable is the difference between the maximum charging current Icmax and the total value of the rated current Icn for the number of DC power supply units connected to the electric vehicles, and the threshold is the rated current Icn. In this way, multiple electric vehicles can be charged while the total charging current Ic of the multiple DC power supply units is always close to the total value of the rated current Icn. In other words, the rated power of the DC power supply units can be fully utilized.

[0041] In the present embodiment, an example has been shown in which control unit 2 comprehensively controls charging device 1001. However, as shown in FIG. 8 , a control device 3001 including a data input unit 31, a DC power supply unit number determination unit 32, a DC current output determination unit 33, a DC current command generation unit 34, an operation command generation unit 35, a DC current command output unit 36, and an operation command output unit 37 may comprehensively control charging device 1001. As shown in FIG. 8, a data input unit 31 inputs the maximum charging current Icmax of each of a plurality of electric vehicles, and a number U of DC power supply units is selected so that the total value of the charging current Ic output from the DC power supply units connected to the storage batteries 4 mounted on the plurality of vehicles is maximized within the range of the maximum charging current Icmax. N a DC power supply unit number determination unit 32 that determines the number of DC power supply units to be connected to the storage battery 4, a DC current output determination unit 33 that determines the DC current output of the DC power supply units so that the total value is maximized, a DC current command generation unit 34 that generates a DC current command in accordance with the DC current output determined by the DC current output determination unit 33, an operation command generation unit 35 that determines the connection state between the DC power supply units and the storage battery 4 and generates an operation command to establish the connection state, a DC current command output unit 36 that outputs the DC current command to the DC power supply units, and an operation command output unit 37 that outputs the operation command to the change-over switch.

[0042] Furthermore, in the present embodiment, an example has been shown in which the maximum charging current commands of electric vehicles 13A and 13B in a low SoC state are the same value, but as shown in FIG. 9, the maximum charging current commands may be different values, such as 150 A for electric vehicle 13A with first priority and 130 A for electric vehicle 13B with second priority.

[0043] Furthermore, in this embodiment, an example has been shown in which the maximum charging current command and the maximum charging current Icmax are the same, but the maximum charging current Icmax may be set to be lower than the maximum charging current command.

[0044] Furthermore, in this embodiment, the DC power supply unit 11A and the DC power supply unit 11B have the same rated current Icn, but the rated currents Icn may have different values.

[0045] Furthermore, in this embodiment, an example has been shown in which changeover switches 12A, 12B, and 12C are arranged as shown in FIG. 1, but the arrangement of the changeover switches may be changed as long as the electric vehicles are not electrically connected to each other.

[0046] Embodiment 2 Charging device 1002 according to this embodiment will be described with reference to FIGS. In the first embodiment, a configuration in which two DC power supply units are installed in charging device 1001 and two electric vehicles are connected thereto has been described, but in this embodiment, three DC power supply units are installed in charging device 1002 and three electric vehicles are connected thereto, which is different from the first embodiment. The other configurations are the same as those in the first embodiment, and the same reference numerals are used to designate the same or equivalent parts as those in the first embodiment.

[0047] In FIG. 10, a charging device 1002 is connected to a power source 1 and storage batteries 4 mounted on three electric vehicles, and the charging device 1002 includes three DC power supply units, six changeover switches, a control unit 2, and an interface circuit 3.

[0048] Six selector switches are provided to accommodate an increase in the number of DC power supply units and the number of electric vehicles connected. By operating the selector switches, one storage battery 4 can be charged using three or two DC power supply units, and three DC power supply units and three storage batteries 4 can also be connected one-to-one to charge them individually.

[0049] In this embodiment, in steps S106 and S107 shown in FIG. 3, the number U of DC power supply units is determined based on the preset connection priority. N, and the selection of DC power supply units, and the DC current command to each DC power supply unit are determined. The connection priority is arbitrarily set by a user, equipment manager, designer, etc., for reasons such as reducing wiring loss in the charging path and preventing direct connection of storage batteries 4, and is input to the control unit 2 from the interface circuit 3. It may also be arbitrarily set within the control unit 2. The connection priority can be exceptionally changed to select a DC power supply unit. For example, when determining the DC power supply unit for an electric vehicle with Nth priority, the connection priority of the electric vehicle with Nth priority is changed to the lowest for the changeover switches connected between the DC power supply units corresponding to the electric vehicle with N+1th priority.

[0050] The operation of the charging device 1002 in this embodiment will be described using Figures 10 to 14. In Figure 10, it is assumed that electric vehicle 23A (electric vehicle with first priority), electric vehicle 23B (electric vehicle with second priority), and electric vehicle 23C (electric vehicle with third priority), each with a low SoC and a maximum charging current Icmax of 150 A, are connected to the charging device 1002, and DC power supply units 21A, 21B, and 21C are installed. The rated current Icn of the DC power supply units is set to 50 A, and the charging current threshold Icth is set to 50 A, which is equal to the rated current Icn. The connection priority of electric vehicle 23A is set in the order of DC power supply unit 21A → DC power supply unit 21B → DC power supply unit 21C, the connection priority of electric vehicle 23B is set in the order of DC power supply unit 21B → DC power supply unit 21A → DC power supply unit 21C, and the connection priority of electric vehicle 23C is set in the order of DC power supply unit 21C → DC power supply unit 21B → DC power supply unit 21A.

[0051] In step S104, the number U of DC power supply units to be connected to the electric vehicle 23A with the first priority, the electric vehicle 23B with the second priority, and the electric vehicle 23C with the third priority is determined. NThe number of power supply units is determined to be three for each of the electric vehicles 23A and 23B. Then, in step S106, the DC power supply unit 21A, the DC power supply unit 21B, and the DC power supply unit 21C to be connected to the electric vehicle 23A with the first priority are selected, and the DC current commands for each are determined. Therefore, the determination in step S105 for the electric vehicle 23B with the second priority and the electric vehicle 23C with the third priority is NO, and the process proceeds to step S107. Then, in step S107, the DC power supply unit 21A, the DC power supply unit 21B, and the DC power supply unit 21C have already been selected for the electric vehicle 23A with the first priority, so the process does not select DC power supply units for the electric vehicle 23B with the second priority and the electric vehicle 23C with the third priority.

[0052] Therefore, during the period from the start of charging to operation switching A as shown in FIG. 11, as shown in FIG. 12, selector switches 22A, 22D, and 22F are in a current-permitting state, and selector switches 22B, 22C, and 22E are in a current-blocking state, and a charging current Ic150A is output to storage battery 4 mounted on first-priority electric vehicle 23A by DC power supply unit 21A, DC power supply unit 21B, and DC power supply unit 21C, which output a rated current Icn of 50A.

[0053] Here, as charging progresses, when the maximum charging current Icmax of the first-priority electric vehicle 23A falls below 150A, the number U of DC power supply units connected to the first-priority electric vehicle 23A is N In steps S141 to S146, the number of DC power supply units U is determined to be two. If the maximum charging current Icmax of the first-priority electric vehicle 23A is 120 A, then in step S141, N (1 unit), and in step S142, the maximum charging current Icmax (120 A) is substituted into a temporary variable Itmp. Then, in step S143, the number of DC power supply units U N It is determined that (1 unit) is less than the total number of DC power supply units (2 units) (step S143: YES), and the process proceeds to step S144. Then, in step S144, the temporary variable Itmp (120 A) and the rated current Icn (50 A) of the DC power supply unit are substituted into the right-hand side, and Itmp (70 A) on the left-hand side is determined. Then, in step S145, Itmp (70 A) is greater than the charging current threshold Icth (50 A) (step S145: NO), and therefore the process proceeds to step S146. Then, in step S146, the number U N Then, 1 is added to the value, and the process proceeds to step S143. Then, in step S143, the number of DC power supply units U N Since (2 units) is less than the total number of DC power supply units (3 units) (step S143: YES), processing proceeds to step S144, the temporary variable Itmp on the right-hand side is updated to Itmp (70A), the rated current Icn (50A) of the DC power supply unit is substituted, and Itmp (20A) on the left-hand side is determined. Then, in step S145, Itmp (20 A) becomes smaller than the charging current threshold Icth (50 A) (step S145: YES), and the process ends. On the other hand, the maximum charging current Icmax input from electric vehicle 23B and electric vehicle 23C remains at 150 A. N There will be three units.

[0054] Then, in step 106, if the DC power supply units to be connected to electric vehicle 23A, which has the first priority, are selected based on the connection priority of electric vehicle 23A and are DC power supply unit 21A and DC power supply unit 21B, then in step 107, DC power supply unit 21C is selected for electric vehicle 23B, which has the second priority. In this case, there is a risk that the storage batteries 4 mounted on electric vehicle 23A, which has the first priority, and electric vehicle 23B, which has the second priority, will be connected. To prevent this, the DC power supply unit 21B corresponding to electric vehicle 23B, which has the second priority, is ranked lowest in the connection priority of electric vehicle 23A, which has the first priority. Specifically, by performing a process in which the connection priority of electric vehicle 23A, which has first priority, is changed from DC power supply unit 21A → DC power supply unit 21B → DC power supply unit 21C to DC power supply unit 21A → DC power supply unit 21C → DC power supply unit 21B, in step S106, DC power supply unit 21A and DC power supply unit 21C to be connected to electric vehicle 23A, which has first priority, can be selected, and in step S107, DC power supply unit 21B to be connected to electric vehicle 23B, which has second priority, can be selected.

[0055] As described above, during the period from operation changeover A to operation changeover B shown in Fig. 11, the selector switches 22A, 22B, and 22F are in a current-permitting state, and the selector switches 22C, 22D, and 22E are in a current-blocking state, as shown in Fig. 13. Then, the DC power supply units 21A and 21C, which output a rated current Icn of 50 A, output a charging current Ic of 100 A to the storage battery 4 mounted on the electric vehicle 23A having the first priority, and the DC power supply unit 21B, which outputs a rated current Icn of 50 A, outputs a charging current Ic of 50 A to the storage battery 4 mounted on the electric vehicle 23B having the second priority.

[0056] Here, as charging progresses, if the maximum charging current Icmax of the first-priority electric vehicle 23A falls below 100 A, the maximum charging current Icmax of the first-priority electric vehicle 23A is set to be less than 100 A in step S101, and therefore the number U NOn the other hand, the maximum charging current Icmax input from the electric vehicles 23B and 23C remains at 150 A, so the number of vehicles U N There will be three units. In this process, even if a DC power supply unit is selected based on the connection priority, the storage batteries 4 are not directly connected to each other, and therefore a DC power supply unit to be connected to the electric vehicle is selected based on the connection priority. In steps 106 and 107, the DC power supply unit 21A to be connected to the electric vehicle 23A with the first priority and the DC power supply unit 21B and DC power supply unit 21C to be connected to the electric vehicle 23B with the second priority are selected.

[0057] In this way, after operation switching B in FIG. 11, the connection state becomes as shown in FIG. 14, i.e., selector switches 22A, 22B, and 22E are in the energization permission state, and selector switches 22C, 22D, and 22F are in the energization cut-off state, and a charging current Ic of 50 A is output from DC power supply unit 21A, which outputs a rated current Icn of 50 A, to storage battery 4 mounted on first-priority electric vehicle 23A, and a charging current Ic of 100 A is output from DC power supply unit 21B and DC power supply unit 21C, which output a rated current Icn of 50 A, to storage battery 4 mounted on second-priority electric vehicle 23B.

[0058] As described above, the charging device 1002 in this embodiment can set connection priorities for DC power supply units compatible with electric vehicles and can change the connection priority order as needed, which has the effect of making full use of the rated power of the DC power supply units and preventing direct connection between storage batteries 4. Since there is no need to wait for connection of an electric vehicle to a DC power supply unit, the operating rate of the charging device 1002 can be improved.

[0059] Embodiment 3 Charging device 1003 in this embodiment will be described with reference to FIGS. In the first embodiment, a configuration was described in which the number of DC power supply units and the number of connected electric vehicles were equal, but in this embodiment, the number of connected electric vehicles is greater than the number of DC power supply units, which is different from the first embodiment. The rest of the configuration is the same as in the first embodiment, and the same reference numerals are used to designate the same or equivalent parts as in the first embodiment.

[0060] In FIG. 15, a charging device 1003 is connected to a power source 1 and storage batteries 4 mounted on four electric vehicles, and the charging device 1003 includes two DC power supply units, five changeover switches, a control unit 2, and an interface circuit 3.

[0061] The operation of the charging device 1003 in this embodiment will be described. In Fig. 16, it is assumed that an electric vehicle 33A (electric vehicle with first priority), an electric vehicle 33B (electric vehicle with second priority), an electric vehicle 33C (electric vehicle with third priority), and an electric vehicle 33D (electric vehicle with fourth priority), each with a low SoC and a maximum charging current Icmax of 150 A, are connected to the charging device 1003, and a DC power supply unit 31A and a DC power supply unit 31B are installed. The rated current Icn of the DC power supply units is set to 75 A, and the charging current threshold Icth is set to 75 A, which is equal to the rated current Icn. The connection priority of the electric vehicle 33A is set in the order of DC power supply unit 31A → DC power supply unit 31B, and the connection priority of the electric vehicle 33B is set in the order of DC power supply unit 31B → DC power supply unit 31A.

[0062] In step S104, the number U of DC power supply units to be connected to the first priority electric vehicle 33A, the second priority electric vehicle 33B, the third priority electric vehicle 33C, and the fourth priority electric vehicle 33D is determined. NIn step S107, the DC power supply unit 31A and the DC power supply unit 31B are selected to be connected to the electric vehicle 33A with the first priority, and the DC current commands for each are determined. Therefore, the determination in step S105 is NO for the electric vehicle 33B with the second priority, the electric vehicle 33C with the third priority, and the electric vehicle 33D with the fourth priority, and the process proceeds to step S107. Then, in step S107, the DC power supply unit 31A and the DC power supply unit 31B have already been selected for the electric vehicle 33A with the first priority, and therefore the process is processed so that no DC power supply units are selected for the electric vehicle 33B with the second priority, the electric vehicle 33C with the third priority, and the electric vehicle 33D with the fourth priority.

[0063] 16, the connection state is as shown in FIG. 17, that is, the selector switches 32A and 32E are in the energization permission state, and the selector switches 32B, 32C, and 32D are in the energization cut-off state. Then, the DC power supply units 31A and 31B, which output a rated current Icn of 50 A, output a charging current Ic of 150 A to the storage battery 4 mounted on the first-priority electric vehicle 33A.

[0064] Here, as charging progresses, if the maximum charging current Icmax of the first-priority electric vehicle 33A falls below 150 A, in step S101, the maximum charging current Icmax of the first-priority electric vehicle 33A is set to be less than 150 A, and therefore the number U N On the other hand, the maximum charging current Icmax input from electric vehicle 33B, electric vehicle 33C, and electric vehicle 33D remains at 150 A, so the number of vehicles U N There will be two units. Then, steps S105 and S106 are performed, thereby continuing to select the DC power supply unit 31A with the highest connection priority for the electric vehicle 33A with first priority. Then, steps S108, S109, and S103 to S106 are performed, and in S107, the number of connected DC power supply units is reduced to the maximum possible number. NDC power supply units are selected so that there are two (two) DC power supply units, and a DC current command for each DC power supply unit is determined. When DC power supply unit 31B with a high connection priority is selected for electric vehicle 33B with second priority, DC power supply unit 31A is connected to electric vehicle 33A with first priority, and DC power supply unit 31B is connected to electric vehicle 33B with second priority, and the storage batteries 4 are connected, so it is determined that connection is impossible. Therefore, no DC power supply unit is allocated to electric vehicle 33B with second priority, and DC power supply unit 31B is selected for electric vehicle 33C with third priority.

[0065] 16, the connection state becomes that of FIG. 18, i.e., the selector switches 32A and 32C are in the energization permission state, and the selector switches 32C, 32B, 32D, and 32E are in the energization cut-off state. Then, the DC power supply unit 31A, which outputs 75 A, which is the rated current Icn, outputs 75 A, which is the charging current Ic, to the storage battery 4 mounted on the electric vehicle 33A, which has first priority, and the DC power supply unit 31B, which outputs 75 A, which is the rated current Icn, outputs 75 A, which is the charging current Ic, to the storage battery 4 mounted on the electric vehicle 33C, which has third priority. Furthermore, if the maximum charging current Icmax is less than 75 A, the value of the charging current Ic is also adjusted according to the value of the maximum charging current Icmax.

[0066] Therefore, the charging device 1003 of this embodiment can fully utilize the rated power of the DC power supply unit, and also prevents the storage batteries 4 from being connected to each other, eliminating the need to have the electric vehicle stand by without being connected to the DC power supply unit, thereby improving the operating rate of the charging device 1003.

[0067] Embodiment 4 The charging device 1004 according to this embodiment will be described with reference to FIGS. This embodiment differs from the first embodiment in that the control unit 2 is connected to an external control device 21 via an interface circuit 3, and processing related to calculation of charging power Wc and limiting a DC current command is added to the control unit 2. The other configurations are the same as those of the first embodiment, and the same reference numerals are used to designate the same or corresponding parts to those of the first embodiment.

[0068] In FIG. 19, a charging device 1004 is connected to a power source 1 and storage batteries 4 mounted on two electric vehicles, and the charging device 1004 includes two DC power supply units, three changeover switches, a control unit 2, and an interface circuit 3.

[0069] The external control device 21 is connected to the control unit 2 via the interface circuit 3. The external control device 21 monitors the operating state of the charging device 1004, updates the charging priority, and outputs the power limit value. The input power limit value is generated based on information such as the received power of the power receiving unit of the electric vehicle to which the charging device 1004 is connected, the contracted power, etc.

[0070] The operation of charging device 1004 in this embodiment will be described with reference to Fig. 20. The processes other than step S401 are the same as those in embodiment 1, and the same reference numerals are used for the same or corresponding processes as those in embodiment 1.

[0071] In step S401 shown in FIG. 20, the control unit 2 calculates the charging power Wc and limits the DC current command. The charging power Wc is calculated from the DC current command determined in steps S106 and S107 and the battery voltage that is initially input or measured. In step S401, if the calculated charging power Wc exceeds the power limit value, the DC current command is limited so that the charging power Wc is equal to or less than the power limit value. This is particularly necessary when the power supply from the power source becomes unstable or when operations such as peak cutting and peak shifting are required. The process of limiting the DC current command limits the DC current command of the DC power supply unit allocated to the electric vehicle with the lowest charging priority when, for example, multiple electric vehicles are connected to the charging device 1004. Specifically, when two DC power supply units are allocated to the electric vehicle with the first priority and two DC power supply units are allocated to the electric vehicle with the second priority, for example, the DC current command of each of the two DC power supply units connected to the electric vehicle with the second priority is reduced equally so that it is equal to or below the power limit value.

[0072] The operation of charging device 1004 in this embodiment will be described using Figure 19. In Figure 19, it is assumed that electric vehicle 43A (electric vehicle with first priority) and electric vehicle 43B (electric vehicle with second priority) with a low state of charge, maximum charging current Icmax of 150 A, and storage battery voltage of 250 to 350 V are connected to charging device 1004, and DC power supply unit 41A and DC power supply unit 41A2 are installed. The rated current Icn of the DC power supply unit is set to 75 A, the charging current threshold Icth is set to 75 A, which is equal to the rated current Icn, and the input power limit value is set to 30 kW assuming daytime peak shaving.

[0073] In step S104, the number U of DC power supply units to be connected to the first priority electric vehicle 43A and the second priority electric vehicle 43B is determined. N It is determined that there are two of each of the electric vehicle 43A with first priority. However, in step S106, the DC power supply unit 41A and the DC power supply unit 41B to be connected to the electric vehicle 43A with first priority are selected, and their respective DC current commands are determined. Therefore, in step S107, the DC power supply unit 41A and the DC power supply unit 41B have already been selected for the electric vehicle 43A with first priority, so processing is performed to set up so that no DC power supply unit is selected for the electric vehicle 43B with second priority. Therefore, in step S106, it is provisionally set that the DC power supply unit 41A and the DC power supply unit 41B outputting the rated current Icn of 75 A will output the charging current Ic of 150 A to the storage battery 4 mounted on the first priority electric vehicle 43A.

[0074] After the processes of steps S108 to S111, in step S401, the charging power Wc is calculated based on the DC current command and the storage battery voltage acquired from the storage battery 4. Specifically, when the storage battery voltage is 250 V and the total DC current command of the DC power supply unit is 150 A, the charging power Wc is 37.5 kW, which exceeds the set input power limit value. Therefore, the DC current command is limited so that the input power limit value is not exceeded. Specifically, the total DC current command is set to 120 A, and the charging power Wc is limited to 30.0 kW. In step S112, the DC current command determined in step S401 is output.

[0075] As described above, in addition to the effects of the first embodiment, charging device 1004 of the present embodiment can limit the DC current command for each electric vehicle and each DC power supply unit, so that it is possible to determine which electric vehicle is to be charged first and charge it without any restrictions. Furthermore, even when the power supply becomes unstable or when peak cutting or peak shifting is required, the load on the power system can be reduced and the rated power of the DC power supply unit can be fully utilized, and as a result, the total charging time for all connected vehicles can be reduced. In the first to fourth embodiments, examples of charging devices 1001, 1002, 1003, 1004, charging system 2001, and control device 3001 that charge the storage battery 4 of an electric vehicle are described, but they can also be used to charge other vehicles that require charging, such as electric bicycles and electric boards.

[0076] In addition to the above, the embodiments can be freely combined, any of the components of the embodiments can be modified, or any of the components of the embodiments can be omitted. [Explanation of symbols]

[0077] 1 power supply, 2 control unit, 3 interface circuit, 4 storage battery, 21 external control device, 1001, 1002, 1003, 1004 charging device, 2001 charging system, 3001 control device

Claims

1. a plurality of DC power supply units connectable to storage batteries mounted on a plurality of vehicles and outputting a charging current not exceeding a rated current to the storage batteries; a plurality of changeover switches that change the connection states of the plurality of DC power supply units and the storage battery; determining a DC current and the number of DC power supply units that maximizes the total value of the charging currents output from the DC power supply units within a range of the maximum charging currents input from the vehicles; a control unit that generates and outputs a DC current command that commands the DC power supply unit to output the DC current and a switching operation command that commands the selector switch to perform a switching operation so that the DC power supply units and the storage battery are connected in the number; Equipped with the control unit determines the number of vehicles according to the set charging priority of the vehicles, and when a variable determined by the maximum charging current input from the vehicle with the high charging priority is less than a threshold, operates the selector switch to switch the connection of the DC power supply unit from the storage battery of the vehicle with the high charging priority to the storage battery of the vehicle with the low charging priority, and when the variable is equal to or greater than the threshold, operates the selector switch to continue the connection of the DC power supply unit to the storage battery of the vehicle with the high charging priority.

2. 2. The charging device according to claim 1, wherein the variable is a difference between the maximum charging current and the total value of the rated currents of the number of devices.

3. 2. The charging device according to claim 1, wherein the threshold value is the rated current.

4. A plurality of DC power supply units connectable to storage batteries mounted on a plurality of vehicles and outputting a charging current not exceeding a rated current to the storage batteries; a plurality of changeover switches that change the connection states of the plurality of DC power supply units and the storage battery; determining a DC current and the number of DC power supply units that maximizes the total value of the charging currents output from the DC power supply units within a range of the maximum charging currents input from the vehicles; a control unit that generates and outputs a DC current command that commands the DC power supply unit to output the DC current and a switching operation command that commands the selector switch to perform a switching operation so that the DC power supply units and the storage battery are connected in the number; Equipped with the control unit determines the number of vehicles in accordance with a set charging priority of the vehicles, and in the case of the connection state in which the storage batteries are electrically connected to each other, changes the set connection priority of the DC power supply units, and determines the connection state between the plurality of DC power supply units and the storage batteries in accordance with the changed connection priority.

5. A plurality of DC power supply units connectable to storage batteries mounted on a plurality of vehicles and outputting a charging current not exceeding a rated current to the storage batteries; a plurality of changeover switches that change the connection states of the plurality of DC power supply units and the storage battery; determining a DC current and the number of DC power supply units that maximizes the total value of the charging currents output from the DC power supply units within a range of the maximum charging currents input from the vehicles; a control unit that generates and outputs a DC current command that commands the DC power supply unit to output the DC current and a switching operation command that commands the selector switch to perform a switching operation so that the DC power supply units and the storage battery are connected in the number; Equipped with The control unit determines the number of vehicles according to the set charging priority of the vehicles, and if it is not possible to switch the connection of the DC power supply unit from the vehicle with the Nth highest charging priority (N is an integer greater than or equal to 1) to the vehicle with the N+1th highest charging priority, operates the changeover switch to switch the connection of the DC power supply unit to the vehicle with the N+3rd highest charging priority.

6. 6. The charging device according to claim 1, wherein the control unit operates the changeover switch so as not to electrically connect the storage batteries to each other.

7. The charging device according to any one of claims 1 to 6, characterized in that the control unit generates the DC current command so that the total charging power of the plurality of DC power supply units is equal to or less than an input power limit value input from outside.

8. A charging system that supplies power from an external power source to charge storage batteries installed in multiple vehicles. And, A charging device according to any one of claims 1 to 7; A device connected to the charging device via an interface and transmitting external information to the charging device. an external control device; Charging system with.

9. a data input unit for inputting the maximum charging current of each of the plurality of vehicles; a DC power supply unit number determination unit that determines the number of DC power supply units in accordance with the set charging priorities of the vehicles so that a total value of charging currents output from DC power supply units connected to storage batteries mounted on the plurality of vehicles is maximized within the range of the maximum charging current; a DC current output determination unit that determines the DC current output of the DC power supply unit so that the total value becomes maximum; a DC current command generating unit that generates a DC current command in accordance with the DC current output determined by the DC current output determining unit; an operation command generation unit that determines a connection state between the DC power supply unit and the storage battery and generates an operation command to achieve the connection state; a DC current command output unit that outputs the DC current command to the DC power supply unit; an operation command output unit that outputs the operation command to a changeover switch; Equipped with The DC current command generation unit generating an operation command to switch the connection of the DC power supply unit from the storage battery of the vehicle with the high charging priority to the storage battery of the vehicle with the low charging priority when a variable determined by the maximum charging current input from the vehicle with the high charging priority is less than a threshold value; a control device that generates an operation command to continue connection of the DC power supply unit to the storage battery of the vehicle with a high charging priority when the variable is equal to or greater than the threshold value;

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