Vehicle charging system

Abstract

To provide a vehicle charging system that allows even low-priority vehicles to start charging without waiting, while ensuring that the total charging current never exceeds a predetermined value.SOLUTION: The system includes multiple chargers 1 for charging vehicles 6 and a charging control device 2 that controls the chargers 1. The charging control device 2 sets an upper limit value for the current available for vehicle charging on the basis of power reception information from the grid. If multiple vehicles 6 connected to the chargers 1 have not yet reached a predetermined amount of charge, the charging control device 2 divides the upper limit value among those multiple vehicles and performs charging at the same current value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle charging system, and more particularly to a vehicle charging system capable of charging multiple vehicles. [Background technology]

[0002] BACKGROUND ART There is a vehicle charging system that includes a plurality of chargers for charging a vehicle equipped with a storage battery, such as an electric vehicle (see, for example, Patent Document 1). By providing multiple chargers in this way, we were able to reduce waiting times for charging in response to the increasing number of electric vehicles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-66278 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional system equipped with multiple chargers, when multiple vehicles are being charged, the total charging current can sometimes exceed a set value such as a demand value. In such cases, priority is determined in the order in which the chargers are connected, and vehicles with lower priority may have to wait to be charged, making efficient charging impossible.

[0005] In view of these problems, the present invention aims to provide a vehicle charging system that allows charging to begin without having to wait, even for vehicles with low priority, and that prevents the overall charging current from exceeding a predetermined value. [Means for solving the problem]

[0006] In order to solve the above problem, the invention of claim 1 is a vehicle charging system comprising a plurality of chargers for charging vehicles and a charging control device that controls the chargers, wherein the charging control device sets an upper limit value of the current that can be used for vehicle charging based on information on the power received from the grid, and if there are multiple vehicles connected to the charger and the charged amount has not reached a predetermined amount of power, the upper limit value is divided among the multiple vehicles and charging is performed at the same current value. The predetermined amount of power is, for example, the amount of power that allows the vehicle to travel a certain distance. [Effects of the Invention]

[0007] According to the present invention, even if a vehicle starts charging later, if the predetermined amount of power has not been reached, the vehicle is charged with the same current as other vehicles, so that the user who starts charging later does not feel uncomfortable as if charging has been put off. Furthermore, even if the number of vehicles being charged increases, the overall charging current is controlled so as not to exceed the upper limit, so it can be controlled so as not to exceed the contract current of the commercial power, the demand value, or the capacity of the circuit breaker. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram illustrating an example of a vehicle charging system. [Figure 2] FIG. 2 is a block diagram of a charging control device. [Figure 3] 10 is a flowchart showing a flow of charging control. [Figure 4] 10 is a flowchart showing a flow of charging control. [Figure 5] FIG. 10 is a table showing the relationship between priority and charging current when rotating charge control is performed. [Figure 6] 10 is a flowchart showing the flow of charge equalization control. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiments of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a configuration diagram showing an example of a vehicle charging system. As shown in Fig. 1, the vehicle charging system has a plurality of chargers (chargers) 1 and a charging control device 2 that controls each of the chargers 1. Also, 3 denotes a commercial power source that receives power from a grid, 4 denotes a watt-hour meter consisting of a smart meter, 5 denotes a switch including a circuit breaker that opens and closes an electric circuit L, 6 denotes a vehicle such as an EV to be charged, and 7 denotes a load other than the charger 1 to which the commercial power source 3 is supplied. The charge control device 2 is connected to the watt-hour meter 4 via a communication line L1, and each charger 1 receives power from a commercial power source 3 and is connected to the charge control device 2 via a communication line L2.

[0010] 2 shows a block diagram of the charge control device 2. The charge control device 2 includes a first communication unit 21 that obtains power information (current information) from the watt-hour meter 4 via communication line L1, a plurality of second communication units 22 that communicate with each charger 1 via communication line L2, a memory unit 23 that stores an upper limit value and the like, which will be described later, an operation unit 24 that sets the charge control method, a charge control device CPU 25 that controls the charger 1 and the charge control device 2, and the like.

[0011] The upper limit value is the maximum current that can be used for charging the vehicle, and is a current value that is set so that the received power does not exceed the maximum power set by the demand value, etc., and this current value changes each time depending on the power supplied to other loads 7.

[0012] The vehicle charging system configured as described above operates as follows: First, a charging method is set by operating the operation unit 24. This charging method may be, for example, a rotational charging method in which the vehicle 6 that starts charging first is given priority, or an equalized charging method that does not depend on the order in which charging starts. For example, when the rotation charging method is set, the operation is as follows: In this explanation, the maximum current value that can be used for vehicle charging in the power facility is the upper limit value, the current value that can be supplied to one vehicle 6 is the maximum current setting value (first current value), the minimum current value set when charging one vehicle 6 is the minimum current setting value, and the charging amount that enables driving a predetermined distance, such as 20 km, is the predetermined amount of power (predetermined value).

[0013] The upper limit is a value that depends on the power supplied to the load 7, and is set by the charging control device CPU 25 by calculating the maximum value of the current that can be used for charging the vehicle from the received power information of the watt-hour meter 4. The first current value is set to, for example, 30 amperes, but is changed depending on fluctuations in the upper limit. On the other hand, the predetermined value is calculated based on the travel distance per unit amount of power of the vehicle 6, and is calculated by the charging control device CPU 25 by obtaining information from the vehicle 6 when the charger 1 is connected, for example.

[0014] 3 and 4 are flowcharts showing the flow of control for rotational charging, and the following description will be made with reference to these flowcharts. Note that rotational charging is a control for when multiple vehicles are being charged, so the charging control for only one vehicle will be omitted here. When multiple vehicles 6 are connected to the charger 1, charging is performed under the control of the charge control device CPU 25. First, it is calculated whether the current obtained by subtracting the first current value from the set upper limit value is greater than the minimum current setting value (S11). If this calculation determines that a current greater than the minimum current setting value can be supplied (YES in S11), the first priority vehicle (YES in S12) is first charged at the first current value (S13). Then, for vehicles 6 with second or lower priority (NO in S12) that have not yet reached the predetermined amount (YES in S14), the remainder obtained by subtracting the first current value from the upper limit is distributed among the vehicles (S15).

[0015] On the other hand, among the vehicles that have reached the predetermined amount (NO in S14), vehicles 6 that are fully charged (YES in S16) are removed from the priority order and charging is terminated (S17). Also, vehicles 6 that have reached the predetermined amount but are not fully charged are given the lowest priority, and if the remaining current obtained by subtracting the current supplied to vehicles 6 that have not reached the predetermined amount from the upper limit (referred to as the "upper limit difference") is equal to or greater than the minimum current setting (YES in S18), charging is performed using the upper limit difference (S19). Then, if the upper limit difference is smaller than the minimum current setting, charging is terminated without supplying charging current to the vehicle 6 that has reached the predetermined amount (S20).

[0016] Next, we will explain the case where, after subtracting the first current value, the remaining current is equal to or less than the minimum current setting value (NO in S11). In this case, the vehicle 6 with the highest priority (YES in S21) is supplied with the remaining current obtained by subtracting the current for all vehicles that needs to be supplied at the minimum current setting value from the upper limit value (S22). Then, vehicles 6 with a priority of second or lower (NO in S21) and which have not yet reached the predetermined amount (YES in S23) are charged at the minimum current setting value (S24).

[0017] On the other hand, among the vehicles 6 that have been charged to a predetermined amount or more (NO in S23), charging is terminated for the vehicles that are fully charged (YES in S25) (S26). For vehicles 6 that are not fully charged, the difference between the upper limit values ​​is compared with the minimum current setting value (S27), and if they are equal to or greater than the minimum current setting value (YES in S27), the vehicle is charged using the current corresponding to the difference between the upper limit values ​​(S28). On the other hand, if the difference between the upper limit values ​​is smaller than the minimum current setting value (NO in S27), charging is terminated without supplying any charging current (S29). In this way, rotational charging is performed.

[0018] 5 is a table showing the relationship between the priority of rotation charge control and charging current, and the following explanation will be given with reference to this table. However, here, the upper limit is 50A, the maximum current setting value (first current value) is 30A, and the minimum current setting value is 6A, and the explanation will be given for a case where four vehicles 6 are connected to the charger 1. If all four vehicles do not reach the specified power capacity, the first vehicle 6 with the highest priority will begin charging at 30A, and the other three vehicles 6 will be charged at a current equal to 50A minus 30A, i.e., 20A, divided into thirds (approximately 6A).

[0019] As a result of continuing this charging, when the charging of the first vehicle reaches a predetermined amount of power, the priority is changed and the second vehicle 6 becomes the first priority and begins charging at 30A. Then, the remaining 20A is divided in half for the third and fourth vehicles 6, resulting in 10A charging, and charging of the vehicle 6 that has reached the predetermined amount of power is stopped. Here, charging of the first vehicle 6 has been stopped because it has reached the specified power level, but if the charging current for the third and fourth vehicles is set to 6A instead of 10A, the first vehicle will continue to be charged at 6A.

[0020] After that, when the charge level of the second device reaches a predetermined amount of power, the third device takes priority and starts charging at 30A, and the fourth device is charged at 20A. Charging of the first and second devices then stops. In this case, if the charging current for the fourth vehicle is set to 6A, the first and second vehicles can be continuously charged at 6A.

[0021] Furthermore, when the third device's charge reaches a predetermined amount of power, the fourth device becomes the first device to be charged at 30A. In this case, the second device no longer has priority, so the first three devices are charged equally at 6A. Then, when the charge amount of all vehicles 6 reaches a predetermined amount of power, the upper limit of 50A is distributed evenly, and charging continues at 12A for each vehicle. When the vehicles 6 reach full charge, charging ends.

[0022] In this way, the priority of vehicle charging is set in the order of connection, and the vehicle 6 that starts charging earliest is given top priority for charging. Even vehicles 6 that start charging later will start charging, so users who start charging later will not feel uncomfortable as if their charging has been put off. Furthermore, since the total charging current is controlled so as not to exceed the upper limit regardless of the number of vehicles 6 being charged, it is possible to control so as not to exceed the contract current of the commercial power, the demand value, or the capacity of the circuit breaker. Furthermore, priority is given to charging vehicles 6 whose charge amount has not yet reached the predetermined amount of power, so they can be charged up to the predetermined amount of power in a short time, and since charging continues even after the charge amount reaches the predetermined amount of power, charging can be continued until the vehicle is fully charged. In addition, once the charge amount of all vehicles 6 being charged reaches a predetermined amount of power, priority is lost and charging continues with the upper limit current being distributed evenly, so the power available for charging can be used effectively and there is no risk of vehicles not being fully charged due to low priority.

[0023] Fig. 6 is a flowchart showing another flow of charging control. Fig. 6 shows a flow of charging control without prioritizing the vehicles 6. Charging control for only one vehicle will be omitted, and control when charging multiple vehicles will be explained. For the vehicles 6 for which the predetermined amount has not been reached (YES in S31), the upper limit is equally distributed among the vehicles 6 for which the predetermined amount has not been reached (S32). Of the vehicles 6 that have reached the predetermined amount (NO in S31), if the vehicle 6 is fully charged (YES in S33), charging is terminated (S34), and if the vehicle 6 that has not reached full charge (NO in S33) is charged with the difference in the upper limit value if the difference is greater than the minimum current setting value (YES in S35), charging is performed (S36). If the difference between the upper limit values ​​does not reach the minimum current setting value (NO in S35), charging is not performed (S37) and the process ends.

[0024] In this way, even if a vehicle 6 starts charging later, if the predetermined charge amount has not been reached, it is charged with the same current as other vehicles 6, so users who start charging later will not feel uncomfortable as if their charging has been put off. Furthermore, since the total charging current is controlled so as not to exceed the upper limit regardless of the number of vehicles 6 being charged, it is possible to control so as not to exceed the contract current of the commercial power, the demand value, or the capacity of the circuit breaker.

[0025] In the above embodiment, the predetermined amount of power is set based on information obtained from the vehicle 6 to be charged, but it may also be set uniformly without being based on information from the vehicle 6. [Explanation of symbols]

[0026] 1·· Charger, 2·· Charging control device, 6·· Vehicle, 23·· Memory unit, 25·· Charging control device CPU

Claims

[Claim 1] A vehicle charging system including a plurality of chargers for charging vehicles and a charge control device for controlling the chargers, The charging control device sets an upper limit of the current that can be used for vehicle charging based on information about the power received from the grid, and if there are multiple vehicles connected to the charger whose charged amount has not reached a predetermined amount of power, the charging control device divides the upper limit and charges the multiple vehicles at the same current value.

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