Charging system, control device, method for controlling a charging system, and power control system

Abstract

To provide a charging system that suppresses unbalance in a three-phase power supply.SOLUTION: A charging system includes a plurality of charging units to which single-phase AC is supplied from three-phase AC having a first phase, a second phase, and a third phase, and a control unit that controls each of the plurality of charging units. The plurality of charging units includes a power adjustment unit that adjusts the charging power supplied to a charging target, and a detection unit that detects the charging power. When it is determined that the three-phase AC is in an unbalanced state, the control unit controls the power adjustment unit in any of the plurality of charging units to avoid or improve the unbalanced state, based on the charging power detected by the detection unit of each of the plurality of charging units.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a charging system, a control device, a control method for a charging system, and a power control system.

Background Art

[0002] Patent Document 1 discloses a power control device including an aggregating means for aggregating alternating-current power or alternating-current current by each phase, and a calculating means for calculating the surplus or deficiency of alternating-current power or alternating-current current input / output by each phase based on the aggregation result of the aggregating means. Patent Document 1 discloses that in order to adjust the surplus or deficiency calculated by the calculating means, the power control device controls at least one of the presence or absence of execution of power conversion, the magnitude of converted power, the conversion direction of power, and the on / off of switches for some or all of the plurality of power conversion units. Patent Document 1 discloses that even when the power control device connects a plurality of power conversion units for inputting and outputting single-phase alternating-current power between each phase of a three-phase power system, it can suppress the imbalance of each phase current with respect to the power system.

[0003] Patent Document 2 discloses a phase balancing system for a power distribution system. Patent Document 2 discloses that the phase balancing system includes a load prediction module configured to obtain a predicted load amount for the power distribution system over a period of interest, and a phase imbalance identification module configured to obtain a voltage imbalance amount in the power distribution system over the period of interest.

[0004] Patent Document 3 discloses a power conversion system including a plurality of power conversion means for converting single-phase alternating-current power respectively supplied from between each phase of a three-phase alternating-current power system into direct-current power. Patent Document 3 discloses that when the power conversion system outputs direct-current power from a first power conversion means among the plurality of power conversion means, it performs control to bring the three-phase unbalanced state caused by active power supplied from the power system to the first power conversion means into three-phase balance.

[0005] Patent Document 4 discloses an energy storage device comprising a power conversion unit that, in charging mode, converts AC power from the first phase of a three-phase power grid within an internal power grid into DC power. Patent Document 4 also discloses that, in discharge mode, the power conversion unit converts DC power stored in at least one battery pack into AC power. Patent Document 4 also discloses an energy storage device comprising a communication module for exchanging data, the communication module transmitting voltage information to an external energy storage device via wireless communication. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2016-025775 [Patent Document 2] Patent No. 5814718 [Patent Document 3] Patent No. 6559106 [Patent Document 4] Patent No. 6700007 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Electric vehicles equipped with batteries are becoming widespread. There are two types of chargers for charging the batteries in electric vehicles: fast chargers and standard chargers. Fast chargers can charge vehicles in a short time, while standard chargers require a longer time. However, fast chargers are more expensive than standard chargers. Therefore, in large parking lots where many electric vehicles are to be charged simultaneously, it is expected that many standard chargers will be installed. Furthermore, in large parking lots with many standard chargers, it is expected that many standard chargers will be used simultaneously.

[0008] Standard electric chargers generally operate using single-phase alternating current (AC) as their power source. Single-phase AC is obtained, for example, by connecting to any two wires of a three-phase, three-wire AC power line. In a large parking lot, for example, if electric vehicles are concentrated on a charger supplied with a specific single-phase AC power source, i.e., if the phases to which the load is connected become unbalanced, an imbalance may occur in the three-phase, three-wire AC power line. When a three-phase imbalance occurs, it can lead to, for example, noise, vibration, heat generation in three-phase motors connected to the same system, and excessive rotation of the wattage meter.

[0009] Therefore, in a three-phase power supply, it is desirable that the load be connected in a balanced manner between each phase.

[0010] This disclosure provides a charging system, a control device, a control method for the charging system, and a power control system for suppressing imbalance in a three-phase power supply. [Means for solving the problem]

[0011] According to one aspect of the present disclosure, a charging system is provided comprising: a plurality of charging units to which single-phase AC is supplied from a three-phase AC having a first phase, a second phase, and a third phase; and a control unit that controls each of the plurality of charging units, wherein each of the plurality of charging units comprises a power adjustment unit that adjusts the charging power supplied to a charging target and a detection unit that detects the charging power, and the control unit controls the power adjustment unit in any of the plurality of charging units to avoid or improve the unbalanced state when it is determined that the three-phase AC is in an unbalanced state based on the charging power detected by the detection unit of each of the plurality of charging units. [Effects of the Invention]

[0012] According to the charging system, control device, control method for the charging system, and power control system of this disclosure, imbalance in a three-phase power supply can be suppressed. [Brief explanation of the drawing]

[0013] [Figure 1]FIG. 1 is a diagram illustrating an outline of the configuration of a charging system according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an outline of the configuration of a charging unit in the charging system according to the first embodiment. [Figure 3] FIG. 3 is a flow diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 4] FIG. 4 is a flow diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 5] FIG. 5 is a flow diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 6] FIG. 6 is a flow diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 7] FIG. 7 is a flow diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 9] FIG. 9 is a diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 10] FIG. 10 is a diagram illustrating processing by a control unit in the charging system according to the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating an outline of the configuration of a charging system according to a second embodiment. MODE FOR CARRYING OUT THE INVENTION

[0014] Specific examples of the charging system, control device, charging system control method, and power control system of the present disclosure will be described below with reference to the drawings. It should be noted that the present disclosure is not limited to these examples, and is defined by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

[0015] It should be noted that, regarding the descriptions in the specification and drawings according to each embodiment, components having substantially the same or corresponding functional configurations are denoted by the same reference numerals, and duplicate explanations may be omitted. In addition, for ease of understanding, the scale of each part in the drawings may differ from the actual scale.

[0016] Deviations that do not impair the effect of the embodiment are allowed for directions including parallel, right angle, orthogonal, horizontal, vertical, up-down, left-right, front-back and the like. The shape of a corner is not limited to a right angle, and may be rounded. Expressions of parallel, right angle, orthogonal, horizontal, and vertical may each include substantially parallel, substantially right angle, substantially orthogonal, substantially horizontal, and substantially vertical, respectively.

[0017] For example, substantially parallel means that even if two lines or two surfaces are not completely parallel to each other, they can be treated as parallel to each other within a manufacturing allowable range. For other expressions of substantially right angle, substantially orthogonal, substantially horizontal, and substantially vertical, similar to substantially parallel, it is intended that they fall under the respective definitions as long as the mutual positional relationship between two lines or two surfaces is within a manufacturing allowable range.

[0018] <<First Embodiment>> <Charging System> A charging system according to the first embodiment will be described. FIG. 1 is a diagram illustrating an outline of a configuration of a charging system 1 which is an example of the charging system according to the first embodiment. The charging system 1 is a system capable of simultaneously charging a plurality of electric vehicles in a parking lot or the like. The charging system 1 is installed in a parking lot of a shopping center or the like. The charging system 1 performs normal charging for a plurality of electric vehicles at the same time.

[0019] The charging system 1 is connected to a three-phase power supply PS. The three-phase power supply PS is a three-phase, three-wire power supply. The three-phase power supply PS outputs a three-phase AC TAC having a phase a, a phase b, and a phase c that are 120 degrees apart from each other. The three-phase power supply PS outputs the a phase, a phase b, and a phase c of the three-phase AC TAC to wiring La, wiring Lb, and wiring Lc, respectively. Wiring La, wiring Lb, and wiring Lc are sometimes collectively referred to as the three-phase AC line Labc. Three-phase AC equipment 20 is connected to the three-phase power supply PS. Three-phase AC equipment 20 is, for example, a motor for an air conditioner, a rapid charger, etc.

[0020] Although the charging system 1 has a direct connection between the three-phase power supply PS and the three-phase AC line Labc, the charging system 1 may also include a transformer between the three-phase power supply PS and the three-phase AC line Labc.

[0021] The charging system 1 is connected to wiring La, wiring Lb, and wiring Lc, thereby receiving power from the three-phase power supply PS.

[0022] The charging system 1 is supplied with single-phase AC ACab from the a-phase (ab-phase) space between phases a and b in the three-phase AC TAC. By connecting the charging system 1 to wiring La and wiring Lb, single-phase AC ACab is supplied to the charging system 1 from the a-phase (ab-phase) space in the three-phase AC TAC.

[0023] Furthermore, single-phase AC ACbc is supplied to the charging system 1 from the phase-to-phase (bc-to-b) space between the b-phase and c-phase of the three-phase AC TAC. By connecting the charging system 1 to wiring Lb and wiring Lc, single-phase AC ACbc is supplied to the charging system 1 from the bc-to-b space in the three-phase AC TAC.

[0024] Furthermore, single-phase AC ACca is supplied to the charging system 1 from the phase between the c phase and the a phase (between the ca phases) of the three-phase AC TAC. By connecting the charging system 1 to wiring Lc and wiring La, single-phase AC ACca is supplied to the charging system 1 from the phase between the ca phases of the three-phase AC TAC.

[0025] The charging system 1 comprises a control unit 10 and a plurality of charging units. The plurality of charging units include a plurality of charging units 30A supplied with single-phase AC ACab from a three-phase power supply PS, a plurality of charging units 30B supplied with single-phase AC ACbc from a three-phase power supply PS, and a plurality of charging units 30C supplied with single-phase AC ACca from a three-phase power supply PS. When there is no need to distinguish between charging units 30A, 30B, and 30C, they are collectively referred to as charging unit 30. Each of the plurality of charging units 30 is provided in the parking space 40.

[0026] [Control Unit 10] The control unit 10 controls the entire charging system 1. The control unit 10 is composed of, for example, a microprocessing unit that includes a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory). The control unit 10 performs processing by having the CPU load a program stored in ROM into RAM and execute it.

[0027] The control unit 10 controls each of the multiple charging units 30. The control unit 10 controls each of the multiple charging units 30 so that the three-phase AC TAC does not become unbalanced when charging the electric vehicle.

[0028] [Charging part 30] The charging unit 30 supplies power to the electric vehicle for charging. The charging unit 30 receives single-phase alternating current as input. The charging unit 30 performs normal charging of the battery in the electric vehicle using single-phase alternating current.

[0029] Figure 2 is a diagram illustrating the general configuration of the charging unit 30 in a charging system 1, which is an example of a charging system according to the first embodiment. The charging unit 30 comprises a charging control unit 31, a power adjustment unit 32, a detection unit 33, and a cutoff unit 34. The charging unit 30 supplies one of single-phase AC ACab, single-phase AC ACbc, or single-phase AC ACca to the electric vehicle EV via a charging connector 41 provided in the parking space 40. The charging unit 30 adjusts the power of one of the single-phase AC ACab, single-phase AC ACbc, or single-phase AC ACca using the power adjustment unit 32, and supplies the adjusted power to the electric vehicle EV.

[0030] (Charging control unit 31) The charging control unit 31 controls the entire charging unit 30. The charging control unit 31 operates based on control commands transmitted from the control unit 10. The charging control unit 31 controls the power adjustment unit 32. The charging control unit 31 also obtains the results of measuring the charging power, which is the power supplied to the electric vehicle EV, from the detection unit 33. Furthermore, the charging control unit 31 controls the circuit breaker unit 34 to connect or disconnect the circuit. In addition, the charging control unit 31 communicates with the electric vehicle EV to obtain, for example, the charge rate from the electric vehicle EV.

[0031] The charging control unit 31 communicates with the control unit 10. The charging control unit 31 receives control commands from the control unit 10. The charging control unit 31 also transmits the detection result of the charging power detected by the detection unit 33 to the control unit 10. Furthermore, the charging control unit 31 transmits data such as the charge rate acquired from the electric vehicle EV to the control unit 10.

[0032] (Power adjustment section 32) The power adjustment unit 32 adjusts the power supplied to the electric vehicle (EV) based on control commands transmitted from the control unit 10. The charging control unit 31 calculates the charging power that can be supplied to the electric vehicle (EV) based on charging power change commands transmitted from the control unit 10. The charging control unit 31 then instructs the power adjustment unit 32 to supply the calculated available charging power. The power adjustment unit 32 supplies power to the electric vehicle (EV) based on the charging power instructed by the charging control unit 31. As described above, the power adjustment unit 32 adjusts the charging power based on charging power change commands transmitted by the control unit 10 and received by the charging unit 30.

[0033] (Detection unit 33) The detection unit 33 detects the power of the charging power supplied to the electric vehicle (EV) by the power adjustment unit 32. The detection unit 33 also detects the current value and voltage value of the charging power supplied to the electric vehicle (EV) by the power adjustment unit 32. The detection unit 33 outputs the results of detecting the power, current value and voltage value of the charging power to the charging control unit 31.

[0034] (Blocking section 34) The circuit breaker 34 connects or disconnects the circuit between the three-phase power supply PS and the charging connector 41. The circuit breaker 34 is, for example, an electromagnetic contactor.

[0035] The charging system 1 includes a charging unit 30 comprising a plurality of charging units 30A connected to wiring La and wiring Lb, a plurality of charging units 30B connected to wiring Lb and wiring Lc, and a plurality of charging units 30C connected to wiring Lc and wiring La.

[0036] Each of the multiple charging units 30A is connected to wiring La1, which is connected to wiring La, and wiring Lb1, which is connected to wiring Lb. Wiring La1 branches off from wiring La. Wiring Lb1 branches off from wiring Lb. Each of the multiple charging units 30A supplies single-phase ACb to the electric vehicle EV via the charging connector 41.

[0037] Each of the multiple charging units 30B is connected to wiring Lb2, which is connected to wiring Lb, and wiring Lc1, which is connected to wiring Lc. Wiring Lb2 branches off from wiring Lb. Wiring Lc1 branches off from wiring Lc. Each of the multiple charging units 30B outputs single-phase AC ACbc to the electric vehicle EV via the charging connector 41.

[0038] Each of the multiple charging units 30C is connected to wiring Lc2, which is connected to wiring Lc, and wiring La2, which is connected to wiring La. Wiring Lc2 branches off from wiring Lc. Wiring La2 branches off from wiring La. Each of the multiple charging units 30C outputs single-phase AC ACca to the electric vehicle EV via the charging connector 41.

[0039] <Processing in the charging system according to the first embodiment> Next, the processing in the charging system 1 will be described. By describing the processing in the charging system 1, the steps included in the control method of the charging system 1 will be explained. Figure 3 is a flowchart illustrating the processing of the control unit 10 in the charging system 1, which is an example of a charging system according to the first embodiment.

[0040] (Step S10) First, the control unit 10 determines the current state of the charging system 1 (step of determining the current state).

[0041] In order to understand the current state, the control unit 10 acquires information regarding the operating status (operating status information) from each of the multiple charging units 30, in other words, from each of the multiple charging units 30A, each of the multiple charging units 30B, and each of the multiple charging units 30C. In order to acquire operating status information from each of the multiple charging units 30, the control unit 10 acquires, for example, a flag indicating whether or not the electric vehicle EV is being charged, the charging power supplied by the charging unit 30 (charging current and charging voltage), and the charge rate of the electric vehicle EV being charged.

[0042] The control unit 10 then determines the current status of the charging system 1 based on the acquired operating status information. Here, we will explain the number of electric vehicles (EVs) connected to the charging system 1 and the charging power, which the control unit 10 determines as the current status.

[0043] Based on the acquired operating status information, the control unit 10 calculates the number of electric vehicles (EVs) currently being charged in the charging system 1. The control unit 10 also calculates the number of electric vehicles (EVs) being charged by multiple charging units 30A, multiple charging units 30B, and multiple charging units 30C. In other words, the control unit 10 calculates the breakdown of the number of electric vehicles (EVs) connected to each of the single-phase AC ACab, single-phase AC ACbc, and single-phase AC ACca in the charging system 1.

[0044] (Step S20) Next, the control unit 10 assumes the worst-case scenario predicted to occur after a predetermined time (the process of assuming the worst-case scenario in the future). The specific process will be explained based on the flowchart shown in Figure 4. Figure 4 is a flowchart illustrating the process of assuming the worst-case scenario in the future in the control unit 10 of a charging system 1, which is an example of a charging system according to the first embodiment.

[0045] Let's discuss the worst-case scenario for the future. We'll explain the current situation, specifically the phase-to-phase AC with the highest charging power and the phase-to-phase AC with the lowest charging power. For example, suppose a total of 60 electric vehicles (EVs) are being charged to the phase-to-phase AC with the highest charging power, in other words, the phase-to-phase AC with the maximum load. Also, suppose a total of 20 electric vehicles (EVs) are being charged to the phase-to-phase AC with the lowest charging power, in other words, the phase-to-phase AC with the minimum load.

[0046] Because there is a difference in charging power between phases, the voltages between phases ab, b, and ca are all different, with one of the phases having the lowest voltage. Now, suppose that 10 more electric vehicles (EVs) are charged to the AC current with the maximum load. In that case, a total of 70 EVs will be charged to the AC current with the maximum load, and the voltage in the phase with the lowest voltage will drop even further. As the voltage drops, the unbalance ratio increases.

[0047] Therefore, for the AC phase with the highest charging power, the unbalance rate worsens as the number of additional electric vehicles (EVs) increases. Thus, when considering the worst-case scenario in the AC phase with the highest charging power, the worst-case scenario occurs when the number of additional electric vehicles (EVs) is the largest.

[0048] On the other hand, because there is a difference in charging power between phases, the voltages between phases ab, b, and ca are all different, with one of the phases having the maximum voltage. Now, suppose that in the phase-to-phase AC with the minimum load, 10 more electric vehicles (EVs) have finished charging. In that case, a total of 10 electric vehicles (EVs) will be charged in the phase-to-phase AC with the minimum load, and the voltage will rise further in the phase where the phase-to-phase voltage is at its maximum. As the voltage rises, the unbalance ratio increases.

[0049] Therefore, for the AC phase with the lowest charging power, the unbalance rate worsens as the number of electric vehicles (EVs) that have finished charging increases. Thus, when considering the worst-case scenario in the future for the AC phase with the lowest charging power, the worst-case scenario is when the number of electric vehicles (EVs) that have finished charging is the highest.

[0050] Therefore, the control unit 10 assumes that, in the charging system 1, all electric vehicles (EVs) added by the assumed time will be connected to the charging unit 30 supplied with the phase-to-phase alternating current that provides the highest charging power. The control unit 10 also assumes that, in the charging system 1, all electric vehicles (EVs) whose charging will be completed by the assumed time will be connected to the charging unit 30 supplied with the phase-to-phase alternating current that provides the lowest charging power. By making these assumptions, the control unit 10 assumes the worst-case scenario at the assumed time.

[0051] (Step S21) First, the control unit 10 determines the current charging power between each phase (step of determining the current charging power between each phase).

[0052] Based on the operating status information acquired in step S10, the control unit 10 calculates the charging power currently being used in the charging system 1. The control unit 10 calculates the inter-phase charging power Pab0, which is the sum of the charging power being used to charge the electric vehicle EV in the multiple charging units 30A. Similarly, the control unit 10 calculates the inter-phase charging power Pbc0, which is the sum of the charging power being used to charge the electric vehicle EV in the multiple charging units 30B. The control unit 10 also calculates the inter-phase charging power Pca0, which is the sum of the charging power being used to charge the electric vehicle EV in the multiple charging units 30C.

[0053] (Step S22) Next, the control unit 10 identifies the phase with the minimum current charging power from the inter-phase charging powers Pab0, Pbc0, and Pca0 calculated in step S21 (step to identify the phase with the minimum current charging power). In other words, the control unit 10 identifies whether the single-phase AC with the lowest charging power in the charging system 1 is one of the single-phase ACs ACab, ACbc, or ACca.

[0054] (Step S23) Next, the control unit 10 determines the power reduction amount between phases where the charging power is minimized (step of determining the power reduction amount between phases where the charging power is minimized).

[0055] The specific process will be explained based on the flowchart shown in Figure 5. Figure 5 is a flowchart illustrating the process of determining the power reduction amount between phases that minimizes the charging power in the control unit 10 of the charging system 1, which is an example of a charging system according to the first embodiment.

[0056] (Step S231) The control unit 10 acquires actual values ​​of the start and end times of charging for each of the charging units 30 over a predetermined period in the past (a process of acquiring data on the start and end times of charging for each of the charging units over a predetermined period in the past). The control unit 10 acquires actual values ​​of the start and end times of charging for each of the charging units 30 over a predetermined period, for example, the past 7 days, as data on the actual operation of the charging system 1. The control unit 10 may acquire the actual data from a database stored in an external storage device, for example, or from an external server.

[0057] For example, the control unit 10 acquires the actual start and end times of charging for each of the charging units 30 over a period T1. By summarizing the actual start and end times of charging for each of the charging units 30 over a period T1, the control unit 10 summarizes, for example, the number of electric vehicles (EVs) being charged at each time of day in the charging system 1. Then, the control unit 10 summarizes the number of electric vehicles (EVs) whose charging is completed at each time of day.

[0058] (Step S232) Next, the control unit 10 calculates the maximum power that will be lost due to the completion of charging by a time that is expected from the present moment, for example, a few seconds from the present moment, based on the acquired actual data (a process to calculate the maximum power that will be lost due to the completion of charging by a time that is expected from the present moment). Based on the charging status of electric vehicles (EVs) whose charging is about to be completed, which was compiled from the actual data acquired in step S231, the control unit 10 calculates the maximum power that will be lost by electric vehicles (EVs) whose charging is about to be completed by a time that is expected from the present moment.

[0059] For example, the control unit 10 calculates the maximum power P1, which is the total power used to charge electric vehicles (EVs) from the present time to a time T2 after the current time, based on past performance values.

[0060] (Step S233) Next, the control unit 10 uses the maximum power calculated in step S232 to calculate an assumed power greater than the calculated maximum power, taking a safety factor into consideration (step of calculating assumed power greater than the calculated maximum power). Since the maximum power obtained in step S231 is an actual value, in reality, for example, a larger number of electric vehicles (EVs) may finish charging, and the charging power greater than the calculated maximum power may decrease. Therefore, the control unit 10 calculates an assumed power greater than the maximum power, taking a safety factor into consideration. If it is not necessary to consider a safety factor, the control unit 10 calculates the maximum power as the assumed power.

[0061] For example, the control unit 10 multiplies the power P1, which is the maximum power calculated in step S232, by a coefficient k1 (k1≧1). Then, the power P2 obtained by multiplying power P1 by the coefficient k1 is taken as the assumed power.

[0062] (Step S234) Next, the control unit 10 calculates the number of electric vehicles (EVs) that will be finished charging by a predetermined time based on the charge rate of the EVs being charged in each of the charging units 30 (a process to calculate the power of the charging units that will be finished charging by a predetermined time based on the charge rate of the EVs being charged). The control unit 10 obtains the charge rate for each of the EVs being charged from each of the charging units 30. Then, the control unit 10 identifies the charging units 30 that will be finished charging by a predetermined time based on the charge rate. The control unit 10 also calculates the power consumed by the charging units 30 that will be finished charging.

[0063] For example, the control unit 10 calculates the power P3 in the charging unit 30 that will complete charging by a time T2 from the present.

[0064] (Step S235) Next, the control unit 10 calculates the maximum power that will decrease by the assumed time (step of calculating the maximum power that will decrease by the assumed time). Based on the results calculated in step S233 and step S234, the control unit 10 calculates the maximum power that will decrease by the assumed time.

[0065] For example, the control unit 10 calculates the larger of the power P2 calculated in step S233 and the power P3 calculated in step S234 as the power reduction amount P4 (estimated power value).

[0066] Let's explain with a more specific example. For instance, let's assume that the period T1 is 7 days, the time T2 is 5 seconds, and the coefficient k1 is 1.5. If the maximum power P1 calculated in step S232 is 18 kilowatts, then the assumed power P2 calculated in step S233 will be 27 kilowatts. Also, for example, let's assume that the power P3 at the charging section 30 where charging ends in step S234 is 6 kilowatts. Then, the power reduction P4 calculated in step S235 will be 27 kilowatts.

[0067] (Step S24) Next, the control unit 10 identifies the phase with the highest current charging power from the inter-phase charging powers Pab0, Pbc0, and Pab0 calculated in step S21 (step to identify the phase with the highest current charging power). In other words, the control unit 10 identifies whether the single-phase AC with the highest charging power in the charging system 1 is single-phase ACab, single-phase ACbc, or single-phase ACca. The phase with the highest current charging power is sometimes called the maximum phase.

[0068] (Step S25) Next, the control unit 10 determines the power increase in the phase where the charging power is maximized (step of determining the power increase in the phase where the charging power is maximized). Figure 6 is a flowchart illustrating the process by which the control unit 10 determines the power increase in the phase where the charging power is maximized in a charging system 1, which is an example of a charging system according to the first embodiment.

[0069] (Step S251) The control unit 10 acquires actual values ​​of the start and end times of charging for each of the charging units 30 over a predetermined period in the past (a process of acquiring data on the start and end times of charging for each of the charging units over a predetermined period in the past). The control unit 10 acquires actual values ​​of the start and end times of charging for each of the charging units 30 over a predetermined period, for example, the past 7 days, as data on the actual operation of the charging system 1. The control unit 10 may acquire the actual data from a database stored in an external storage device, for example, or from an external server.

[0070] For example, the control unit 10 acquires the actual start and end times of charging for each of the charging units 30 over a period T1. By summarizing the actual start and end times of charging for each of the charging units 30 over a period T1, the control unit 10 summarizes, for example, the number of electric vehicles (EVs) being charged at each time of day in the charging system 1. Then, the control unit 10 summarizes the number of electric vehicles (EVs) that start charging at each time of day.

[0071] (Step S252) Next, the control unit 10 calculates the maximum power increase that can be achieved by starting charging from the present time to a predetermined time, for example, a few seconds from the present time, based on the acquired actual data (a process to calculate the maximum power increase that can be achieved by starting charging from the present time to a predetermined time). Based on the number of electric vehicles (EVs) that will start charging, which has been compiled from the actual data acquired in step S251, the control unit 10 calculates the maximum power increase that can be achieved by electric vehicles (EVs) that will start charging from the present time to a few seconds from the present time.

[0072] For example, the control unit 10 calculates the maximum power P11, which is the total power used to charge electric vehicles (EVs) that started charging from the present time to time T2 later, based on past performance values.

[0073] (Step S253) Next, the control unit 10 uses the maximum power calculated in step S252 to calculate an assumed power greater than the calculated maximum power, taking a safety factor into consideration (a step to calculate an assumed power greater than the calculated maximum power). Since the maximum number of vehicles obtained in step S251 is an actual value, in reality, for example, more electric vehicles (EVs) may start charging, and the charging power may increase to a level greater than the maximum power. Therefore, the control unit 10 calculates an assumed power greater than the maximum power, taking a safety factor into consideration. If there is no need to consider a safety factor, the control unit 10 calculates the maximum power as the assumed power.

[0074] For example, the control unit 10 multiplies the power P11, which is the maximum power calculated in step S252, by a coefficient k11 (k11≧1). Then, the power P12 obtained by multiplying power P11 by the coefficient k11 is taken as the assumed power.

[0075] Let's explain with a more specific example. For instance, let's assume that the period T1 is 7 days, the time T2 is 5 seconds, and the coefficient k11 is 1.5. If the maximum power P11 calculated in step S252 is 24 kilowatts, then the assumed power calculated in step S253, i.e., the increase in power P12, will be 36 kilowatts.

[0076] (Step S30) Next, the control unit 10 calculates the unbalance rate in the event that the assumed worst-case scenario is realized (step to calculate the unbalance rate in the assumed worst-case scenario). The control unit 10 calculates the unbalance rate in the worst-case scenario calculated in step S20.

[0077] (Step S40) Next, the control unit 10 determines whether the calculated unbalance rate is equal to or greater than the reference value (step of determining whether the calculated unbalance rate is equal to or greater than the reference value). In other words, the control unit 10 determines whether the three-phase AC TAC will be unbalanced. The control unit 10 determines whether the unbalance rate calculated in step S30 is equal to or greater than the reference unbalance rate (reference value). If the unbalance rate is equal to or greater than the reference value, the control unit 10 determines that the three-phase AC TAC will be in an unbalanced state after the assumed time has elapsed. In other words, if the unbalance rate is equal to or greater than the reference value, the control unit 10 determines that the three-phase AC TAC will be in an unbalanced state.

[0078] If the calculated unbalance rate is greater than or equal to the reference value (Yes in step S40), the control unit 10 proceeds to step S50. If the calculated unbalance rate is less than the reference value (No in step S40), the control unit 10 proceeds to step S60.

[0079] In step S40, if the unbalance rate is equal to the reference value, the control unit 10 proceeds to step S50, but it may also proceed to step S60. In other words, in step S40, the control unit 10 may determine whether the unbalance rate calculated in step S30 is greater than the reference unbalance rate (reference value).

[0080] In step S30, the unbalance rate is calculated in the worst-case scenario assumed to occur after a predetermined time. However, if the voltages of single-phase ACab, single-phase ACbc, and single-phase ACca can be measured, and it can be determined from these measurements that the three-phase AC TAC is already in an unbalanced state, the control unit 10 may omit the execution of steps S20, S30, and S40 and proceed to step S50 after identifying the phase with the maximum current charging power.

[0081] (Step S50) Next, the control unit 10 performs unbalance suppression measures (step of performing unbalance suppression measures). When the control unit 10 anticipates that the three-phase AC TAC will become unbalanced after a predetermined time has elapsed, it controls the charging unit 30 to prevent the three-phase AC TAC from becoming unbalanced. In other words, when the control unit 10 anticipates that the three-phase AC TAC will become unbalanced after a predetermined time has elapsed, it controls one of the charging units 30 to avoid or improve the unbalanced state.

[0082] Figure 7 is a flowchart illustrating the process of unbalance suppression measures in the control unit 10 of a charging system 1, which is an example of a charging system according to the first embodiment.

[0083] (Step S51) The control unit 10 calculates the charging power required to resolve the unbalanced state in order to avoid an unbalanced state (step of calculating the charging power required to resolve the unbalanced state).

[0084] This section describes the circuit model assumed when calculating the charging power required to resolve the unbalanced state. Figures 8 and 9 are diagrams illustrating the processing of the control unit 10 in the charging system 1, which is an example of a charging system according to the first embodiment. Specifically, Figures 8 and 9 are diagrams illustrating the circuit model assumed when calculating the charging power required to resolve the unbalanced state.

[0085] In the charging system 1, the sum of the charging power of each of the multiple charging units 30A is defined as the inter-phase charging power Pab (unit: kilowatts). The inter-phase charging power Pab is the sum of the charging power used to charge the electric vehicle EV to which each of the multiple charging units 30A, to which single-phase AC ACab is supplied between phases a and b, is connected. In other words, the inter-phase charging power Pab is the power consumed by the single-phase AC ACab between phases a and b.

[0086] In the charging system 1, the sum of the charging power of each of the multiple charging units 30B is defined as the inter-phase charging power Pbc (unit: kilowatts). The inter-phase charging power Pbc is the sum of the charging power used to charge the electric vehicle EV to which each of the multiple charging units 30B, to which single-phase AC ACbc is supplied between phases bc, is connected. In other words, the inter-phase charging power Pbc is the power consumed by the single-phase AC ACbc between phases bc.

[0087] In the charging system 1, the sum of the charging power of each of the multiple charging units 30C is defined as the inter-phase charging power Pca (unit: kilowatts). The inter-phase charging power Pca is the sum of the charging power used to charge the electric vehicle EV to which each of the multiple charging units 30C, to which single-phase AC ACca is supplied between phases ca, is connected. In other words, the inter-phase charging power Pca is the power consumed by the single-phase AC ACca between phases ca.

[0088] In Figure 8, the power supply voltage for single-phase AC ACab is denoted as power supply voltage Eab, the power supply voltage for single-phase AC ACbc is denoted as power supply voltage Ebc, and the power supply voltage for single-phase AC ACca is denoted as power supply voltage Eca. Also in Figure 8, the impedance between the three-phase power supply PS and the load LD is denoted as impedance Zbw. The impedance between the three-phase power supply PS and the load LD is, for example, the sum of the impedances of the transmission lines and transformers between the three-phase power supply PS and the load LD.

[0089] In Figure 8, the load line voltage between phases ab is denoted as voltage Vab, the load line voltage between phases bc is denoted as voltage Vbc, and the load line voltage between phases ca is denoted as voltage Vca.

[0090] This section explains how to calculate the maximum possible charging power. It is assumed that power supply voltages Eab, Ebc, and Eca, and impedance Zbw are known. However, voltages Vab, Vbc, and Vca are unknown.

[0091] Here, we consider as an example a situation where the inter-phase charging power Pca is the largest among the inter-phase charging powers Pab, Pbc, and Pca. The values ​​of the inter-phase charging powers Pab and Pbc are assumed to remain unchanged from the values ​​obtained when the worst-case future scenario assumed in step S20 is realized. That is, assuming the inter-phase charging powers Pab and Pbc are known, we find the maximum inter-phase charging power Pca such that the unbalance rate is below a threshold. The inter-phase charging power Pca at this point is the maximum possible charging power.

[0092] Unlike this example, if the inter-phase charging power Pab is the largest among the inter-phase charging powers Pab, Pbc, and Pca, then we can determine the inter-phase charging power Pab by assuming that the inter-phase charging powers Pbc and Pca are known.

[0093] Furthermore, unlike this example, if the inter-phase charging power Pbc is the largest among the inter-phase charging powers Pab, Pbc, and Pca, then we can assume that the inter-phase charging powers Pab and Pca are known and only need to find the inter-phase charging power Pbc.

[0094] The inter-phase charging powers Pab, Pbc, and Pca are each assumed to be constant power loads. However, since the circuit equations cannot be solved algebraically under constant power load conditions, they are treated as constant resistance loads.

[0095] Figure 9 shows the phase-to-phase charging powers Pab, Pbc, and Pca converted to resistance values ​​Rab, Rbc, and Rca, respectively.

[0096] The resistance value Rab is calculated from the interphase charging power Pab, assuming that the load terminal voltage is equal to the rated voltage. The resistance value R is calculated from the power P and voltage V as R=V 2 It is determined from the relationship / P. Similarly, the resistance Rbc is calculated from the phase-to-phase charging power Pbc, assuming that the load terminal voltage is equal to the rated voltage. The resistance Rca is left unknown.

[0097] As shown in Figure 9, currents Iab, Ibc, and Ica are defined. Current Iab is the current flowing from a power supply with voltage Eab through impedance Zbw through a resistor with resistance Rab. Current Ibc is the current flowing from a power supply with voltage Ebc through impedance Zbw through a resistor with resistance Rbc. Current Ica is the current flowing from a power supply with voltage Eca through impedance Zbw through a resistor with resistance Rca. The circuit equations for the circuit model shown in Figure 9 are shown in Equation 1.

[0098]

number

[0099] Transforming Equation 1 yields the relationship shown in Equation 2. Here, the resistance values ​​Rab and Rbc are known as described above. The resistance value Rca is unknown.

[0100]

number

[0101] From Equation 2, currents Iab, Ibc, and Ica can each be expressed as a function of the resistance Rca.

[0102] As shown in Equation 3, the voltages Vab, Vbc, and Vca can each be expressed as a function of the resistance value Rca.

[0103]

number

[0104] Using the voltages Vab, Vbc, and Vca obtained by Equation 3, the unbalance ratio UR can be expressed as a function of the resistance value Rca. The unbalance ratio UR can be calculated by Equation 5, where the average voltage Es is given by Equation 4. Alternatively, the positive-sequence voltage and negative-sequence voltage can be calculated from the voltages Vab, Vbc, and Vca using the symmetrical coordinate method, and the unbalance ratio UR can be calculated as: negative-sequence voltage / positive-sequence voltage × 100.

[0105]

number

[0106]

number

[0107] Figure 10 shows the results of calculating the unbalance rate UR shown in Equation 5 at multiple points and graphing them. The horizontal axis of Figure 10 represents the resistance value Rca. The vertical axis represents the unbalance rate calculated using Equation 5. The line Lur in Figure 10 shows the unbalance rate UR when the resistance value Rca is changed. URth in Figure 10 represents the threshold for the unbalance rate.

[0108] From the threshold value URth of the unbalance ratio UR, we determine the resistance value R1, which is the lower limit of the resistance value between the phases we want to find (in this case, between phases ca). From the results in Figure 10, if the resistance value Rca is greater than the resistance value R1, the unbalance ratio UR is less than or equal to the threshold value URth. The threshold value URth is an example of a reference value.

[0109] According to Equation 6, the inter-phase charging power Pca can be determined from the resistance value Rca.

[0110]

number

[0111] Therefore, by using the resistance value R1 and calculating the interphase charging power Pca using Equation 7, if the load between phases ca is less than or equal to Pca(R1), the unbalance ratio will be less than or equal to the reference threshold URth.

[0112]

number

[0113] (Step S52) The control unit 10 calculates the amount of charging power that can be supplied to the charging unit 30 to which the single-phase AC with the largest inter-phase charging power is supplied (a process of calculating the charging power to control each charging unit). The control unit 10 controls the charging unit 30 by setting the charging power so that it is limited to less than or equal to the maximum possible charging power calculated in step S51.

[0114] <Equal distribution> The control unit 10 calculates the charging power in each charging unit 30 by dividing the maximum possible charging power by the number of electric vehicles (EVs) connected.

[0115] For example, let Pmax (in kilowatts (kW)) be the maximum possible charging power in multiple charging units 30 supplied with the single-phase AC power having the greatest inter-phase charging power, and let N be the number of electric vehicles (EVs) connected. The charging power Pex1 (in kilowatts (kW)) in each charging unit 30 is calculated by Equation 8, where i is an integer between 1 and N.

[0116]

number

[0117] When power is distributed using the charging power Pex1, the distribution is even, giving users a sense of fairness.

[0118] <Distribution considering charge level> The control unit 10 calculates the charging power in each charging unit 30 based on the charge level of the connected electric vehicle EV.

[0119] Specifically, the control unit 10 controls the charging power in each charging unit 30 based on the charge level of the electric vehicle (EV). The control unit 10 controls the power adjustment unit 32 in each charging unit 30 so that the charging unit 30 with a low charge level of the connected electric vehicle (EV) is charged with a higher charging power than the charging unit 30 with a high charge level of the connected electric vehicle (EV). By prioritizing the charging of electric vehicle (EV) vehicles with low charge levels, the closer the electric vehicle (EV) battery is to empty, the more quickly it can be charged.

[0120] For example, let Pmax (in kilowatts (kW)) be the maximum possible charging power in each of the multiple charging units 30 supplied with the single-phase AC power with the greatest inter-phase charging power, and let N be the number of electric vehicles (EVs) connected. Let SOC(i) (in percent (%)) be the charge rate of the electric vehicles connected to each of the multiple charging units 30, and the charging power Pex2(i) (in kilowatts (kW)) in each of the charging units 30 be calculated by Equation 9. Here, i represents an integer between 1 and N, inclusive.

[0121]

number

[0122] Furthermore, if the charging power Pex2(i) calculated using Equation 9 exceeds the rated power of each of the charging units 30, then, for example, the charging power Pex2(i) will be allocated the rated power.

[0123] By distributing power using the Pex2 charging power distribution system, electric vehicle (EV) batteries with lower charge levels are given priority for charging, leading to increased user satisfaction.

[0124] Furthermore, the control unit 10 may control the power adjustment unit 32 in each charging unit 30 so that the charging unit 30 with a higher charge rate of the connected electric vehicle EV charges with a higher charging power than the charging unit 30 with a lower charge rate of the connected electric vehicle EV. By prioritizing the charging of electric vehicle EVs with a higher charge rate, electric vehicle EVs that are close to being fully charged can be charged preferentially.

[0125] <Distribution considering wiring length> The control unit 10 calculates the charging power in each charging unit 30 based on the wiring length (distance) from each charging unit 30 to the three-phase AC line Labc. The charging power set by the equal distribution and distribution considering the charging rate described above may be corrected based on the wiring length (distance) to the three-phase AC line Labc. Here, the distance from each charging unit 30 to the three-phase AC line Labc refers to the length of the wiring from each charging unit 30 to the three-phase AC line Labc.

[0126] Specifically, the control unit 10 calculates the charging power of each charging unit 30 based on its distance from the three-phase AC line Labc. The control unit 10 controls the power adjustment unit 32 in each charging unit 30 so that the charging unit 30 closer to the three-phase AC line Labc is charged with a higher charging power than the charging unit 30 further away from the three-phase AC line Labc.

[0127] For example, let Pmax (in kilowatts (kW)) be the maximum possible charging power at multiple charging units 30 supplied with the single-phase AC power with the highest inter-phase charging power, and let N be the number of electric vehicles (EVs) connected. Let L(i) (in meters (m)) be the distance of each of the multiple charging units 30 to the three-phase AC line Labc, and the charging power Pex3(i) (in kilowatts (kW)) at each charging unit 30 is calculated by Equation 10. Here, i represents an integer between 1 and N. Note that Lmax (in meters (m)) is the distance from the three-phase AC line Labc to the charging unit 30 furthest away.

[0128]

number

[0129] Since the charging power is suppressed in the charging section 30 closer to the end of the single-phase line, that is, in the charging section 30 where the losses due to the line are greater, the losses due to the distribution line can be further reduced, and the unbalance rate can be further improved with the same amount of charging suppression.

[0130] Next, we will explain an example of correcting the charging power set by equal distribution based on the wiring length (distance) to the three-phase AC line Labc. First, the control unit 10 calculates the charging power Pex1(i) = Pavg. Then, the control unit 10 corrects the charging power Pex1(i) based on the wiring length (distance) to the three-phase AC line Labc to calculate the charging power Pex4(i).

[0131] The control unit 10 supplies a minimum amount of power equal to a predetermined percentage of the charging power Pavg. The control unit 10 then corrects the remaining charging power Pavg based on the distance. The control unit 10 calculates the charging power Pex4 based on equation 11.

[0132]

number

[0133] Note that η is a real number between 0 and 1 that represents the predetermined proportion mentioned above.

[0134] Let's explain with a specific example. For instance, suppose three (N=3) charging units 30 are connected to the phase with the longest possible distance between phases. Hereafter, let's assume that each of the three charging units 30 is charging unit 30(1), charging unit 30(2), and charging unit 30(3). And let's assume that the maximum possible charging power (Pmax) is 15 kilowatts.

[0135] Furthermore, if the distribution is set considering equal distribution, and the charging power is Pex1(i), then Pex1(i) = Pavg = 15 / N = 5 kilowatts. Here, i is an integer between 1 and N, in this case between 3 and 1.

[0136] Furthermore, the distance L(1) of the charging unit 30(1) from the three-phase AC line Labc is set to 30 meters, the distance L(2) of the charging unit 30(2) from the three-phase AC line Labc is set to 60 meters, and the distance L(3) of the charging unit 30(3) from the three-phase AC line Labc is set to 90 meters.

[0137] Of the evenly distributed charging power Pavg, 20 percent of the charging power is corrected for distance. In that case, η = 0.8. The control unit 10 calculates the charging power Pex4(i) based on equation 11, and Pex4(1) is 6 kilowatts, Pex4(2) is 5 kilowatts, and Pex4(3) is 4 kilowatts.

[0138] Next, we will explain an example of correcting the charging power set by distribution considering the charge rate based on the wiring length (distance) to the three-phase AC line Labc. First, the control unit 10 calculates the charging power Pex2(i). Then, the control unit 10 corrects the charging power Pex2(i) based on the wiring length (distance) to the three-phase AC line Labc to calculate the charging power Pex5(i). The control unit 10 adds or subtracts the power value calculated by the charging power Pex2(i) to the power value calculated by the charging power Pex2(i) so that the charging section 30 closer to the three-phase AC line Labc is charged with a higher charging power than the charging section 30 further from the three-phase AC line Labc.

[0139] For example, the control unit 10 calculates the charging power Pex5(i) based on equation 12.

[0140]

number

[0141] The function fcal() is a function that decreases as the distance increases, that is, as the distance L(i) increases. Note that the function fcal() is a function that satisfies Equation 13. N is the number of electric vehicles EV connected to the charging unit 30 that is supplied with single-phase AC, which results in the largest inter-phase load. Therefore, the power value obtained by charging power Pex5(i) approaches the state in which the charging unit 30 closer to the three-phase AC line Labc is charged with a higher charging power than the charging unit 30 further from the three-phase AC line Labc, compared to the power value obtained by charging power Pex2(i).

[0142]

number

[0143] (Step S53) Next, the control unit 10 sends a command to each of the charging units 30 so that the charging power in each of the charging units 30 becomes the charging power calculated in step S52 (the process of commanding each charging unit to charge power). The control unit 10 controls the power adjustment unit 32 of each of the charging units 30 connected to the maximum phase so that the sum of the charging powers of the charging units 30 connected to the maximum phase is less than or equal to the maximum possible charging power. Alternatively, the control unit 10 may control the allocation of charging power to each of the charging units 30 so that the sum of the charging powers of the charging units 30 connected to the maximum phase is equal to the maximum possible charging power. Furthermore, the control unit 10 may monitor the sum of the charging powers of the charging units 30 and control the power adjustment unit 32 in the charging units 30 in real time so that the sum of the charging powers of the charging units 30 connected to the maximum phase is always less than or equal to the maximum possible charging power.

[0144] (Step S60) Next, it is determined whether to continue or terminate the process (step to determine whether to continue or terminate the process). If the process is to continue (Yes in step S60), the control unit 10 returns to step S10 and repeats the process. If the process is to be terminated (No in step S60), the control unit 10 terminates the process.

[0145] <Summary> According to the charging system of the first embodiment, imbalance in the three-phase power supply can be suppressed. Furthermore, according to the charging system of the first embodiment, since processing is performed assuming the occurrence of an imbalance in the near future, the occurrence of an imbalance in the three-phase power supply can be prevented in advance.

[0146] Furthermore, for example, it is conceivable to prohibit the addition of new devices to be charged when an imbalance occurs in the three-phase power supply. However, if the addition of new devices to be charged is prohibited, users may be unable to charge their devices, potentially leading to a decrease in user satisfaction with the service. According to the charging system of the first embodiment, even if there is a possibility of an imbalance in the three-phase power supply, new devices to be charged can be added.

[0147] For example, if phase a is an example of the first phase, then phase b is an example of the second phase, and phase c is an example of the third phase. Also, the phase relationship between phase a and phase b (between phases a and b) is an example of the first phase relationship, the phase relationship between phase b and phase c (between phases b and c) is an example of the second phase relationship, and the phase relationship between phase c and phase a (between phases ca) is an example of the third phase relationship. Furthermore, the control unit 10 is an example of a control device. An electric vehicle (EV) is an example of a device to be charged.

[0148] ≪Second Embodiment≫ Next, we will describe a charging system 2, which is an example of a charging system according to the second embodiment. Figure 11 is a diagram illustrating the general configuration of the charging system 2, which is an example of a charging system according to the second embodiment.

[0149] Charging system 2 further includes a plurality of single-phase transformers 60 in addition to charging system 1. Charging system 2 includes a single-phase transformer 60 between wiring La and wiring Lb, and between wiring La1 and wiring Lb1. Charging system 2 also includes a single-phase transformer 60 between wiring Lb and wiring Lc, and between wiring Lb2 and wiring Lc1. Furthermore, charging system 2 includes a single-phase transformer 60 between wiring Lc and wiring La, and between wiring Lc2 and wiring La2.

[0150] <Summary> The charging system according to the second embodiment can suppress imbalance in the three-phase power supply, similar to the charging system according to the first embodiment. Furthermore, the charging system according to the second embodiment can convert the voltage to an optimal single-phase AC voltage for the charging target and charge the charging target.

[0151] <Variation> In the above disclosure, a three-phase power supply PS was described using a three-phase three-wire power supply. However, the three-phase power supply PS is not limited to a three-phase three-wire system; for example, a three-phase four-wire power supply may also be used.

[0152] Furthermore, although the above disclosure describes a charging system 1 for charging an electric vehicle (EV), the disclosed technology may also be applied to a power control system that supplies power to a load such as a motor, instead of an electric vehicle (EV) to be charged. In the case of a power control system, the charging unit in the charging system corresponds to an example of a power supply unit that supplies power to a load, and the charging power corresponds to an example of the power supplied. Multiple charging units correspond to an example of multiple power supply units.

[0153] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of Symbols]

[0154] 1 Charging System 10 Control Unit 20 Three-phase AC equipment 30, 30A, 30B, 30C live parts 31 Charging Control Unit 32 Power adjustment section 33 Detection unit 34. Shut-off section 40 parking spaces 41 Charging connector PS three phase power supply TAC three phase AC ACab, ACbc, ACca Single-phase AC EV (Electric Vehicle)

Claims

1. Multiple charging units supplied with single-phase AC from a three-phase AC having a first phase, a second phase, and a third phase, A control unit that controls each of the aforementioned multiple charging units, Equipped with, Each of the aforementioned multiple charging units is A power adjustment unit that adjusts the charging power supplied to the device to be charged, The detection unit for detecting the charging power, Equipped with, The control unit, If it is determined that the three-phase AC is in an unbalanced state based on the charging power detected by the detection unit of each of the plurality of charging units, the power adjustment unit in one of the plurality of charging units is controlled to avoid or improve the unbalanced state. Based on the charging power detected by the detection unit of each of the plurality of charging units, the interphase charging power between the first phase and the second phase, between the second phase and the third phase, and between the third phase and the first phase is calculated. Based on the interphase charging power between the first phase, the second phase, and the third phase, the unbalance ratio in the three-phase AC is calculated. When the aforementioned unbalance rate is greater than or equal to a standard value, it is determined that the three-phase AC is in an unbalanced state. In the first phase, second phase, and third phase, calculate the phase with the largest interphase charging power, At the maximum phase interval, the maximum possible charging power at which the unbalance rate is smaller than the reference value is calculated. The power adjustment unit of each of the multiple charging units supplied with power from the maximum phase is controlled so that the sum of the charging powers of the multiple charging units supplied with power from the maximum phase is less than or equal to the maximum possible charging power. Charging system.

2. The control unit, The power adjustment unit of each of the plurality of charging units to which power is supplied from the maximum phase interval is controlled to charge by the maximum possible charging power divided by the number of devices to be charged by the plurality of charging units to which power is supplied from the maximum phase interval. The charging system according to claim 1.

3. The control unit, Based on the charge rate of the object to be charged, the power adjustment unit is controlled in the plurality of charging units to which power is supplied from the maximum phase interval, such that the charging unit with a low charge rate is charged with a higher charging power than the charging unit with a high charge rate. The charging system according to claim 1.

4. The control unit, Based on the distance from the plurality of charging units to the three-phase AC line, the power adjustment unit is controlled so that, in the plurality of charging units to which power is supplied from the maximum phase, the charging units closer to the three-phase AC line are charged with a higher charging power than the charging units further from the three-phase AC line. The charging system according to claim 1.

5. The control unit, The maximum possible charging power is divided by the number of devices to be charged by the plurality of charging units to which power is supplied from the maximum phase interval, and the power adjustment unit is controlled based on the distance from the plurality of charging units to the three-phase AC line, so that the charging units closer to the three-phase AC line are charged with a higher charging power than the charging units further away from the three-phase AC line. The charging system according to claim 1.

6. The control unit, Based on the charge rate of the object to be charged, the power adjustment unit is controlled by calculating a power value such that the charging unit with a low charge rate is charged higher than the charging unit with a high charge rate in the plurality of charging units to which power is supplied from the maximum phase interval, and further by adjusting the power value based on the distance from the plurality of charging units to the three-phase AC line, so that the charging unit closer to the three-phase AC line is charged with a higher charging power than the charging unit further from the three-phase AC line. The charging system according to claim 1.

7. A control device that controls each of a plurality of charging units supplied with single-phase AC from a three-phase AC having a first phase, a second phase, and a third phase, Each of the aforementioned multiple charging units is A power adjustment unit that adjusts the charging power supplied to the device to be charged, The detection unit for detecting the charging power, Equipped with, If it is determined that the three-phase AC is unbalanced based on the charging power in each of the plurality of charging units, the charging power in any of the plurality of charging units is controlled to avoid or improve the unbalanced state. Based on the charging power detected by the detection unit of each of the plurality of charging units, the interphase charging power between the first phase and the second phase, between the second phase and the third phase, and between the third phase and the first phase is calculated. Based on the interphase charging power between the first phase, the second phase, and the third phase, the unbalance ratio in the three-phase AC is calculated. When the aforementioned unbalance rate is greater than or equal to a standard value, it is determined that the three-phase AC is in an unbalanced state. In the first phase, second phase, and third phase, calculate the phase with the largest interphase charging power, At the maximum phase interval, the maximum possible charging power at which the unbalance rate is smaller than the reference value is calculated. The power adjustment unit of each of the multiple charging units supplied with power from the maximum phase is controlled so that the sum of the charging powers of the multiple charging units supplied with power from the maximum phase is less than or equal to the maximum possible charging power. Control device.

8. A control method for a charging system comprising a plurality of charging units supplied with single-phase AC from a three-phase AC having a first phase, a second phase, and a third phase, and a control unit, Each of the aforementioned multiple charging units is A power adjustment unit that adjusts the charging power supplied to the device to be charged, The detection unit for detecting the charging power, Equipped with, The control unit, If it is determined that the three-phase AC is unbalanced based on the charging power in each of the plurality of charging units, the charging power in any of the plurality of charging units is controlled to avoid or improve the unbalanced state. Based on the charging power detected by the detection unit of each of the plurality of charging units, the interphase charging power between the first phase and the second phase, between the second phase and the third phase, and between the third phase and the first phase is calculated. Based on the interphase charging power between the first phase, the second phase, and the third phase, the unbalance ratio in the three-phase AC is calculated. When the aforementioned unbalance rate is greater than or equal to a standard value, it is determined that the three-phase AC is in an unbalanced state. In the first phase, second phase, and third phase, calculate the phase with the largest interphase charging power, At the maximum phase interval, the maximum possible charging power at which the unbalance rate is smaller than the reference value is calculated. The power adjustment unit of each of the multiple charging units supplied with power from the maximum phase is controlled so that the sum of the charging powers of the multiple charging units supplied with power from the maximum phase is less than or equal to the maximum possible charging power. A method for controlling a charging system.

9. Multiple power supply units supplied with single-phase AC from a three-phase AC having a first phase, a second phase, and a third phase, A control unit that controls each of the aforementioned multiple power supply units, Equipped with, Each of the aforementioned multiple power supply units is A power adjustment unit that adjusts the power supplied to the target of power supply, A detection unit for detecting the power supply, Equipped with, The control unit, based on the power supply detected by the detection unit of each of the multiple power supply units, determines that the three-phase AC is in an unbalanced state, and controls the power adjustment unit in one of the multiple power supply units to avoid or improve the unbalanced state. Based on the power supply detected by the detection unit of each of the plurality of power supply units, the interphase power supply between the first phase and the second phase, between the second phase and the third phase, and between the third phase and the first phase is calculated. Based on the inter-phase power supplied between the first phase, the second phase, and the third phase, the unbalance ratio in the three-phase AC is calculated. When the aforementioned unbalance rate is greater than or equal to a standard value, it is determined that the three-phase AC is in an unbalanced state. In the first phase, second phase, and third phase, calculate the phase with the largest inter-phase power supply, At the maximum phase interval, the maximum possible power supply power at which the unbalance rate is smaller than the reference value is calculated. The power adjustment unit of each of the multiple power supply units supplied with power from the maximum phase is controlled so that the sum of the power supplied to each of the multiple power supply units supplied with power from the maximum phase is less than or equal to the maximum possible power supply. Power control system.

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