Control device, charging system, control method, and control program

Abstract

To provide a control device, a charging system, a control method, and a control program by which the power conversion efficiency of a power conversion device can be improved.SOLUTION: A control device 7 includes an acquisition unit 74 that acquires the power conversion efficiencies of a plurality of power converters 50 for each output value, a setting unit 76 that conducts a calculation for optimizing the power conversion efficiency of a power conversion device 5 on the basis of the power conversion efficiencies of the power converters 50 for each output value and sets an operation of each of the power converters 50 in accordance with the calculation result, and a control unit 78 that controls operation of each of the power converters 50 on the basis of the operation set by the setting unit 76.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a control device, a charging system, a control method, and a control program.

Background Art

[0002] In a system including a plurality of power converters, a control device for controlling the operation of the power converters is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power conversion device including a plurality of power converters, since power conversion can be performed and output in each of the plurality of power converters, it is possible to operate each of the plurality of power converters with the highest efficiency. Here, generally, the highest efficiency of a power converter is often set for operation at the rated output capacity. However, in a power conversion device, any one of the plurality of power converters may perform conversion with power smaller than the rated output capacity. In this case, the control device performs control such as switching the on / off of the power converter or uniformly selecting the power converter to operate based on a preset order. In this control, since one or more power converters operate outside the rated output capacity, there is a risk that the power conversion efficiency will decrease.

[0005] An object of the present invention is to provide a control device, a charging system, a control method, and a control program capable of improving the power conversion efficiency in a power conversion device.

Means for Solving the Problems

[0006] The control device according to the present invention is a control device that controls the operation of a power conversion device including a plurality of power converters, and for each of the plurality of power converters, an acquisition unit that acquires the power conversion efficiency for each output value, and based on the power conversion efficiency for each output value of each of the plurality of power converters, performs an optimization calculation of the power conversion efficiency in the power conversion device, and a setting unit that sets the operation of each of the plurality of power converters according to the calculation result, and a control unit that controls the operation of each of the plurality of power converters based on the operation set by the setting unit.

[0007] In the control device according to the present invention, for each of the plurality of power converters, the power conversion efficiency for each output value is acquired. Thereby, the control device can acquire the unique power conversion efficiency for each output of the power converter. The control device performs an optimization calculation of the power conversion efficiency in the power conversion device based on the power conversion efficiency for each output value, and sets the operation of each of the plurality of power converters according to the calculation result. Therefore, even when the power converter operates outside the rated output capacity, the control device can cause the power converter with good variable power conversion efficiency to perform power conversion. Therefore, the control device can improve the power conversion efficiency in the power conversion device.

[0008] The setting unit may set the allocation of the power to be converted for each of the plurality of power converters, and the control unit may control the operation of each of the plurality of power converters based on the allocation set by the setting unit. In this configuration, the operation of the power converter can be controlled so that the power conversion efficiency in the power conversion device becomes optimal.

[0009] The setting unit may perform an optimization calculation on the output power output from the power conversion device and set the operation of each of the plurality of power converters. When fluctuations occur in the required power from the load and the output voltage from the power conversion device becomes smaller than the rated output capacity, power conversion at maximum efficiency may not be possible in the power converter. The control device performs an optimization calculation so that the power conversion efficiency in the power conversion device is optimized according to the output power, and sets the operation of each of the plurality of power converters. Therefore, the control device can improve the power conversion efficiency in the power conversion device even when fluctuations occur in the output power.

[0010] The setting unit may perform an optimization calculation when the output power output from the power conversion device is smaller than the rated output capacity of the power conversion device and set the operation of each of the plurality of power converters. In this configuration, even when fluctuations occur in the output power and it becomes smaller than the rated output capacity, power conversion can be performed with optimal efficiency.

[0011] The setting unit may perform an optimization calculation on the input power input to the power conversion device and set the operation of each of the plurality of power converters. When fluctuations occur in the input voltage from the power source and the output voltage from the power conversion device becomes smaller than the rated output capacity, power conversion at maximum efficiency may not be possible in the power converter. The control device performs an optimization calculation so that the power conversion efficiency in the power conversion device is optimized according to the input power, and sets the operation of each of the plurality of power converters. Therefore, the control device can improve the power conversion efficiency in the power conversion device even when fluctuations occur in the input power.

[0012] The setting unit may perform an optimization calculation when the input power drops below a predetermined power and set the operation of each of the plurality of power converters. For example, when power is input from a distributed power source (such as a solar cell), fluctuations may occur in the input voltage. In the control device, when fluctuations occur in the input voltage and it drops below a predetermined power (such as the rated output capacity), an optimization calculation is performed to set the operation. Therefore, even when fluctuations occur in the input power, the power conversion efficiency in the power conversion device can be improved.

[0013] The acquisition unit acquires the rated output capacity of each of the plurality of power converters, and the setting unit may perform an optimization calculation so as not to exceed the rated output capacity in each of the plurality of power converters, and set the operation of each of the plurality of power converters. In this configuration, since it is possible to avoid the execution of an operation exceeding the rated output capacity in the power converter, it is possible to suppress the occurrence of problems such as failures in the power converter.

[0014] The setting unit generates efficiency data based on the power conversion efficiency for each output value of each of the plurality of power converters, and when each of the plurality of power converters has the highest efficiency at the rated output capacity in the efficiency data, the operation at the highest efficiency in the power converter may be preferentially set. In this configuration, since one or more power converters can be operated at the highest efficiency, it is possible to improve the power conversion efficiency in the power conversion device.

[0015] The setting unit generates efficiency data based on the power conversion efficiency for each output value of each of the plurality of power converters, and when each of the plurality of power converters does not have the highest efficiency at the rated output capacity in the efficiency data, a distributed operation that distributes the operation to each of the plurality of power converters may be preferentially set. In this configuration, since each of the plurality of power converters can be operated at the highest efficiency, it is possible to improve the power conversion efficiency in the power conversion device.

[0016] The setting unit generates efficiency data based on the power conversion efficiency for each output value of each of the plurality of power converters, and when the characteristics of the efficiency data are different among the plurality of power converters, a plurality of regions having a relationship between the output value and the power conversion efficiency are set based on the efficiency data, and the operation of each of the plurality of power converters may be set based on the regions. In this configuration, since the operation of each of the plurality of power converters is set based on the regions, it is possible to control the operation of the power converter so that the power conversion efficiency in the power conversion device becomes optimal.

[0017] The setting unit may include a notification unit that generates efficiency data based on the power conversion efficiency for each output value of a plurality of power converters, obtains the measured values of the power conversion efficiency of each of the plurality of power converters, calculates the difference between the efficiency data and the measured values of the power conversion efficiency, and notifies when the difference is equal to or greater than a threshold value. In this configuration, it is possible to notify that there is a deviation from the measured value. As a result, it becomes possible to correct the efficiency data and the like.

[0018] The charging system according to the present invention includes a power conversion device including a plurality of power converters, the above-described control device, and a charging device that performs charging with the power output from the power conversion device.

[0019] In the charging system according to the present invention, the above-described control device is provided. Therefore, in the charging system, it is possible to improve the power conversion efficiency in the power conversion device.

[0020] The control method according to the present invention is a control method for controlling the operation of a power conversion device including a plurality of power converters, and includes: an acquisition step of acquiring the power conversion efficiency for each output value for each of the plurality of power converters; an optimization calculation step of performing an optimization calculation of the power conversion efficiency in the power conversion device based on the power conversion efficiency for each output value of each of the plurality of power converters, and setting the operation of each of the plurality of power converters according to the calculation result; and a control step of controlling the operation of each of the plurality of power converters based on the operation set in the setting step.

[0021] In the control method according to the present invention, for each of a plurality of power converters, the power conversion efficiency for each output value is obtained. Thereby, in the control method, the unique power conversion efficiency for each output of the power converter can be obtained. In the control method, based on the power conversion efficiency for each output value, an optimization calculation of the power conversion efficiency in the power conversion device is performed, and the operation of each of the plurality of power converters is set according to the calculation result. Therefore, in the control method, even when the power converter operates outside the rated output capacity, power conversion can be performed in a power converter with good variable power conversion efficiency. Accordingly, in the control method, the power conversion efficiency in the power conversion device can be improved.

[0022] The control program according to the present invention is a control program for controlling the operation of a power conversion device including a plurality of power converters, and includes an acquisition step of obtaining the power conversion efficiency for each output value for each of the plurality of power converters, an optimization calculation of the power conversion efficiency in the power conversion device based on the power conversion efficiency for each output value of each of the plurality of power converters, and setting the operation of each of the plurality of power converters according to the calculation result, and a control step of controlling the operation of each of the plurality of power converters based on the operation set in the setting step, and causing a computer to execute them.

[0023] In the control program according to the present invention, for each of a plurality of power converters, the power conversion efficiency for each output value is obtained. Thereby, in the control program, the unique power conversion efficiency for each output of the power converter can be obtained. In the control program, based on the power conversion efficiency for each output value, an optimization calculation of the power conversion efficiency in the power conversion device is performed, and the operation of each of the plurality of power converters is set according to the calculation result. Therefore, in the control program, even when the power converter operates outside the rated output capacity, power conversion can be performed in a power converter with good variable power conversion efficiency. Accordingly, in the control program, the power conversion efficiency in the power conversion device can be improved.

Effect of the Invention

[0024] According to the present invention, it is possible to improve the power conversion efficiency in a power conversion device.

Brief Description of the Drawings

[0025]

Figure 1

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Embodiments for Carrying Out the Invention

[0026] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0027] [First Embodiment] FIG. 1 is a diagram showing a vehicle charging system according to the first embodiment. As shown in FIG. 1, the vehicle charging system 1 is a system for charging a storage battery (not shown) of a vehicle V such as an EV (Electric Vehicle) or a PHV (Plug-in Hybrid Vehicle). In the vehicle charging system 1, it is possible to charge one or a plurality of vehicles V. In the vehicle charging system 1, the vehicle V is charged using the electric power supplied from the power source 100. The power source 100 is, for example, commercial power and supplies alternating current power (three-phase 200V).

[0028] The vehicle charging system 1 includes a measuring instrument 3, a power conversion device 5, a control device 7, and a charging device 9.

[0029] The measuring instrument 3 measures the electric power supplied from the power source 100 to the power conversion device 5. FIG. 2 is a diagram showing the configuration of the measuring instrument 3. As shown in FIG. 2, the measuring instrument 3 includes a voltage measuring unit 30, a current measuring unit 32, a calculation unit 34, and a communication unit 36.

[0030] The voltage measuring unit 30 measures the output voltage supplied from the power source 100 to the power conversion device 5. The voltage measuring unit 30 outputs the measured voltage value to the calculation unit 34. The current measuring unit 32 measures the output current supplied from the power source 100 to the power conversion device 5. The current measuring unit 32 outputs the measured current value to the calculation unit 34.

[0031] The calculation unit 34 calculates a power value based on the voltage value output from the voltage measurement unit 30 and the current value output from the current measurement unit 32. The calculation unit 34 outputs measurement information including the power value, the voltage value, and the current value to the communication unit 36. The communication unit 36 communicates with the control device 7. The communication unit 36 performs wired communication or wireless communication with the control device 7. The communication unit 36 transmits the measurement information output from the calculation unit 34 to the control device 7.

[0032] As shown in FIG. 1, the power conversion device 5 converts the power supplied from the power source 100 and supplies it to the charging device 9. The power conversion device 5 has a plurality of power converters 50. In the present embodiment, the power conversion device 5 has four power converters 50. In the present embodiment, the power converter 50 is a single-phase transformer. The power conversion device 5 converts AC power into single-phase power and supplies it to the charging device 9. The rated output capacity of each of the power converters 50 is, for example, 10 kW. In this case, the power conversion device 5 can output 40 kW. In the following description, the four power converters 50 may be described separately as the power converter 50A, the power converter 50B, the power converter 50C, and the power converter 50D.

[0033] Each of the plurality of power converters 50 has the same configuration. Therefore, the configuration of the power converter 50 will be described taking one power converter 50 as an example. FIG. 3 is a diagram showing the configuration of the power converter 50. As shown in FIG. 3, the power converter 50 includes a current sensor 500, a first capacitor unit 502, a switching unit 504, a reactor unit 506, a second capacitor unit 508, a voltage sensor 510, an output control unit 512, a storage unit 514, and a communication unit 516.

[0034] The current sensor 500 detects the output current supplied from the power source 100 to the power conversion device 5. The current sensor 500 outputs the current value of the detected output current to the output control unit 512. The first capacitor unit 502 smoothes the input power supplied from the power source 100.

[0035] The switching unit 504 has a plurality of switching elements (not shown). The switching element is an element that can switch electrical opening and closing. As the switching element, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), a bipolar transistor, etc. are used.

[0036] The reactor unit 506 and the second capacitor unit 508 smooth the output power output from the switching unit 504. The voltage sensor 510 detects the output voltage of the power converter 50. The voltage sensor 510 outputs the detected voltage value of the output voltage to the output control unit 512.

[0037] The output control unit 512 controls the operation of the power converter 50. The output control unit 512 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and an input / output interface, etc. Various programs or data can be stored in the ROM.

[0038] The output control unit 512 controls the magnitude (capacity) of the output power supplied to the charging device 9 by controlling the switching unit 504. The output control unit 512 controls the switching unit 504 based on the control instruction from the control device 7. The power control is performed using, for example, phase shift control. The output control unit 512 performs phase shift control to change the magnitude (frequency) of the AC power by changing the on-period of the switching unit 504. The output control unit 512 adjusts the switching frequency of each switching element and changes the on-period of each switching element using the drive signals to the plurality of switching elements of the switching unit 504.

[0039] The output control unit 512 controls to transmit, from the communication unit 516 to the control device 7, the efficiency information and the rated information described later stored in the storage unit 514 in response to an information request signal from the control device 7. The output control unit 512 calculates the output power in the power converter 50 based on the current value output from the current sensor 500 and the voltage value output from the voltage sensor 510. The output control unit 512 outputs power information related to the output power to the storage unit 514 and the communication unit 516.

[0040] The storage unit 514 can store various information. The storage unit 514 stores efficiency information related to the power conversion efficiency of the power converter 50. FIG. 4 is a diagram showing an example of the efficiency information stored in the storage unit 514. As shown in FIG. 4, in the efficiency information, the output capacity [kW] and the efficiency [%] are associated with each other. In the example shown in FIG. 4, the efficiency is associated with each 1 kW of output. In the example shown in FIG. 4, the efficiency is associated with each 1 kW of output, but the output capacity may be set as appropriate, for example, every 0.5 kW or the like. The efficiency information stored in the storage unit 514 can be changed (rewritten).

[0041] The storage unit 514 stores rated information related to the rated output capacity of the power converter 50. In the present embodiment, the storage unit 514 stores rated information indicating 10 KW as the rated output capacity of the power converter 50. The storage unit 514 stores the power information output from the output control unit 512.

[0042] The communication unit 516 communicates with the control device 7. The communication unit 516 performs wired communication or wireless communication with the control device 7. The communication unit 516 receives a control instruction from the control device 7. The communication unit 516 outputs the control instruction to the output control unit 512. The communication unit 516 transmits, to the control device 7, the efficiency information and the rated information stored in the storage unit 514 based on an instruction from the output control unit 512. The communication unit 516 transmits the power information output from the output control unit 512 to the control device 7.

[0043] As shown in FIG. 1, the control device 7 controls the operation of the power conversion device 5. The control device 7 is a computer system or a processor implemented on an integrated circuit. The monitoring control device 14 is composed of a CPU, a ROM, a RAM, etc., and an input / output interface, etc. Various programs or data are stored in the ROM. FIG. 5 is a diagram showing the configuration of the control device 7. As shown in FIG. 5, the control device 7 has a communication unit 70, a storage unit 72, an acquisition unit 74, a setting unit 76, a control unit 78, and a notification unit 80.

[0044] The communication unit 70 communicates with the measuring instrument 3, the power conversion device 5 (power converter 50), and the charging device 9. The communication unit 70 receives the measurement information transmitted from the measuring instrument 3. The communication unit 70 outputs the measurement information to the storage unit 72. The communication unit 70 receives efficiency information, rating information, and power information from each of the power converters 50 of the power conversion device 5. The communication unit 70 outputs the efficiency information, the rating information, and the power information to the storage unit 72. The communication unit 70 receives a request instruction from the charging device 9. The communication unit 516 outputs the request instruction to the setting unit 76.

[0045] The storage unit 72 can store various information. The storage unit 72 stores the measurement information, the efficiency information, the rating information, and the power information output from the communication unit 70. A control program P is stored in the storage unit 72. The control program P is a program for operating the control device 7, and operates a computer or the like so that control by the control unit 78 and the like is executed.

[0046] The control program P causes a computer to execute an acquisition step of acquiring the power conversion efficiency for each output value for each of the plurality of power converters 50, an optimization calculation of the power conversion efficiency in the power conversion device 5 based on the power conversion efficiency for each output value of each of the plurality of power converters 50, and a setting step of setting the operation of each of the plurality of power converters 50 according to the calculation result, and a control step of controlling the operation of each of the plurality of power converters 50 based on the operation set in the setting step. The control program P may be provided after being fixedly recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory. Alternatively, the control program P may be provided via a communication network as a data signal superimposed on a carrier wave.

[0047] The acquisition unit 74 acquires the power conversion efficiency for each output value for each of the plurality of power converters 50. The acquisition unit 74 acquires the efficiency information stored in the storage unit 72 and outputs it to the setting unit 76. The acquisition unit 74 acquires the rated output capacity for each of the plurality of power converters 50. The acquisition unit 74 acquires the rated information stored in the storage unit 72 and outputs it to the setting unit 76.

[0048] The setting unit 76 performs an optimization calculation of the power conversion efficiency in the power conversion device 5 based on the power conversion efficiency for each output value (output capacity) of each of the plurality of power converters 50, and sets the operation of each of the plurality of power converters 50 according to the calculation result. The setting unit 76 generates efficiency data for each power converter 50 based on the efficiency information stored in the storage unit 72. The setting unit 76 creates an approximation curve for a graph obtained from the efficiency information (output capacity [kW], efficiency [%]) and obtains a polynomial. The approximation curve is a curve of the first degree or higher, and the degree is not specified. The setting unit 76 sets the polynomial as the efficiency data.

[0049] Referring to FIGS. 6 and 7, a method for generating efficiency data in the setting unit 76 will be specifically described. FIGS. 6 and 7 are diagrams that image the efficiency information of the power converter 50 as a graph. FIG. 8 is a diagram for explaining the method for generating efficiency data. In FIGS. 6 to 8, the vertical axis represents efficiency [%], and the horizontal axis represents output capacity [kW]. The graphs shown in FIGS. 6 to 8 are shown to assist in understanding the explanation. In the present embodiment, when generating efficiency data, the setting unit 76 does not create a graph but generates efficiency data through calculation processing.

[0050] In FIGS. 6 and 7, for example, the conversion information of one of the plurality of power converters 50 is imaged as a graph. Taking the generation of efficiency data of the power converter 50 having the characteristics shown in FIG. 6 as an example, as shown in FIG. 8, the setting unit 76 creates an approximation curve for the graph and obtains a polynomial from the approximation curve. The setting unit 76 obtains polynomials for the power converters 50A, 50B, 50C, and 50D and sets them as efficiency data.

[0051] The setting unit 76 sets the operation of each of the plurality of power converters 50 so as not to exceed the rated output capacity in each of the plurality of power converters 50. The setting unit 76 executes a constrained calculation based on the rating information so as not to exceed the rated output capacity. The setting unit 76 executes a constrained calculation using a known technique such as the Karush-Kuhn-Tucker condition (KKT condition), for example. In the present embodiment, since the rated output capacity of the power converter 50 is 10 kW, the setting unit 76 executes a constrained calculation so as not to exceed 10 kW.

[0052] The setting unit 76 performs an optimization calculation with constraints based on the efficiency data so that the power conversion efficiency in the power conversion device 5 is optimized. In the present embodiment, the setting unit 76 performs an optimization calculation to maximize the power conversion efficiency in the power conversion device 5. The setting unit 76 sets the operation of each of the plurality of power converters 50 based on the calculation result. The setting unit 76 sets the allocation of the power to be converted for each of the plurality of power converters 50. In the present embodiment, the setting unit 76 performs an optimization calculation when the output power output from the power conversion device 5 is smaller than the rated output capacity of the power conversion device 5, and sets the operation of each of the plurality of power converters 50 based on the calculation result.

[0053] Specifically, when the required capacity from the charging device 9 is smaller than the rated output capacity (40 kW) of the power conversion device 5, the setting unit 76 performs an optimization calculation and sets the operation of each of the plurality of power converters 50 according to the calculation result. The setting unit 76 acquires the required capacity from the charging device 9 based on the request instruction output from the communication unit 70. The setting unit 76 executes an optimization calculation based on the efficiency data of each of the plurality of power converters 50 and the required capacity (output power), and sets the operation of the plurality of power converters 50. Specifically, the setting unit 76 sets the operation of the power converter 50 as follows based on the characteristics of the efficiency data.

[0054] (1) First control In the efficiency data of the plurality of power converters 50 (50A, 50B, 50C, 50D), when each of the plurality of power converters 50 has the highest efficiency at the rated output capacity, the setting unit 76 preferentially sets the operation at the highest efficiency in the power converter 50. When all of the plurality of power converters 50 have characteristics as shown in FIG. 6 in the efficiency data, that is, when the highest efficiency is achieved at the rated output capacity (10 kW), the setting unit 76 sets the power converter 50 to operate at the highest efficiency.

[0055] Specifically, when the required capacity is 20 kW, for example, the setting unit 76 sets, by means of optimization calculation, the two power converters 50 to operate with the highest efficiency. The setting unit 76 sets, for example, to convert 10 kW of power in the power converter 50A and convert 10 kW of power in the power converter 50B. That is, the setting unit 76 assigns to convert 10 kW of power in the power converter 50A and assigns to convert 10 kW of power in the power converter 50B. The setting unit 76 outputs a control signal related to the set assignment to the control unit 78.

[0056] (2) Second control When, in the efficiency data of the plurality of power converters 50 (50A, 50B, 50C, 50D), each of the plurality of power converters 50 does not achieve the highest efficiency at the rated output capacity, the setting unit 76 preferentially sets a distributed operation in which the operations are distributed to each of the plurality of power converters 50. When all of the plurality of power converters 50 have characteristics such that the efficiency data is as shown in FIG. 7, that is, when the highest efficiency is not achieved at the rated output capacity (10 kW), the setting unit 76 distributes and sets the operations to each of the plurality of power converters 50.

[0057] In the example shown in FIG. 7, the power converter 50 achieves the highest efficiency at 5 kW. In this case, when the required capacity is 20 kW, for example, the setting unit 76 sets, by means of optimization calculation, the four power converters 50 to operate with the highest efficiency. That is, the setting unit 76 sets to convert 5 kW of power in the power converter 50A, the power converter 50B, the power converter 50C, and the power converter 50D. The setting unit 76 assigns to convert 5 kW of power in the power converter 50A, assigns to convert 5 kW of power in the power converter 50B, assigns to convert 5 kW of power in the power converter 50C, and assigns to convert 5 kW of power in the power converter 50D. The setting unit 76 outputs a control signal related to the set assignment to the control unit 78.

[0058] (3) Third control When the characteristics are different in the efficiency data of the plurality of power converters 50 (50A, 50B, 50C, 50D), the setting unit 76 sets regions A1 and A2 (see FIG. 10) having a relationship between the output value and the power conversion efficiency based on the efficiency data, and sets the operations of the plurality of power converters 50 based on the regions A1 and A2. Here, a case where the power converter 50A and the power converter 50C have characteristics as shown in FIG. 6 in terms of efficiency data and the power converter 50B and the power converter 50D have characteristics as shown in FIG. 7 in terms of efficiency data will be described as an example. The method for setting the regions A1 and A2 in the setting unit 76 will be described with reference to FIG. 9. FIG. 9 is a flowchart showing the method for setting the regions.

[0059] As shown in FIG. 9, the setting unit 76 calculates the intersection points where the approximate curves intersect (step S01). Subsequently, the setting unit 76 compares the efficiencies of the output capacities of the respective power converters 50 (step S02). Subsequently, the setting unit 76 determines whether there is the same efficiency point in the efficiencies of the output capacities of the respective power converters 50 (step S03). If the setting unit 76 determines that there is the same efficiency point (step S03: YES), it proceeds to step S04. If the setting unit 76 determines that there is no same efficiency point (step S04: NO), it proceeds to step S05.

[0060] In step S04, the setting unit 76 determines the same efficiency point as the intersection point. In step S05, the setting unit 76 sets the closest efficiency point as the intersection point in the efficiencies of the respective power converters 50. The setting unit 76 sets the regions A1 and A2 based on the intersection points (step S06). The specific setting of the regions A1 and A2 in the setting unit 76 will be described with reference to FIG. 10. FIG. 10 is a diagram that visually shows the method for setting the regions A1 and A2 to assist in understanding the explanation. In FIG. 10, the graphs related to the efficiencies of the power converters 50A and 50C are shown by solid lines, and the graphs related to the efficiencies of the power converters 50B and 50D are shown by dashed-dotted lines. In FIG. 10, since the power converters 50A and 50C show the same characteristics in terms of efficiency and the power converters 50B and 50D show the same characteristics in terms of efficiency, it appears that only two graphs are displayed.

[0061] As shown in FIG. 10, in the present embodiment, the setting unit 76 sets the region A1 and the region A2 with the intersection of the two graphs as the boundary. The region A1 is set as a region with a smaller output capacity than the region A2. In other words, the region A2 is set as a region with a larger output capacity than the region A1. In the region A1, the efficiencies of the power converters 50B and 50D are high. In the region A2, the efficiencies of the power converters 50A and 50C are high. The setting unit 76 causes the storage unit 72 to store the region information related to the set regions A1 and A2. Note that the setting unit 76 may set "region A1" as the region with a larger capacity and "region A2" as the region with a smaller capacity.

[0062] For example, when the required capacity is 4 kW, the setting unit 76 sets to operate the power converters 50B and 50D with high efficiency in the region A1. Specifically, the setting unit 76 sets, for example, to convert 2 kW of power in the power converter 50B and to convert 2 kW of power in the power converter 50D. That is, the setting unit 76 allocates to convert 2 kW of power in the power converter 50B and allocates to convert 2 kW of power in the power converter 50D. The setting unit 76 outputs a control signal related to the set allocation to the control unit 78.

[0063] For example, when the required capacity is 20 kW, the setting unit 76 sets to operate the power converters 50A and 50C with high efficiency in the region A2. Specifically, the setting unit 76 sets, for example, to operate at 10 kW in the power converter 50A and to operate at 10 kW in the power converter 50C. That is, the setting unit 76 allocates to convert 10 kW of power in the power converter 50A and allocates to convert 10 kW of power in the power converter 50C. The setting unit 76 outputs a control signal related to the set allocation to the control unit 78.

[0064] When the required capacity from the charging device 9 is equal to the rated output capacity (40 kW) of the power conversion device 5, the setting unit 76 outputs a control signal to the control unit 78 instructing the operation of the power converter 50 at the rated output capacity (10 kW). That is, when the required capacity is equal to the rated output capacity, the setting unit 76 outputs a control signal to the control unit 78 instructing the operation at the rated output capacity without performing the optimization calculation.

[0065] As shown in FIG. 5, the control unit 78 controls the operation of each of the plurality of power converters 50 based on the operation set in the setting unit 76. The control unit 78 controls the operation of each of the plurality of power converters 50 based on the control signal output from the setting unit 76. The control unit 78 outputs the control signal to the communication unit 70. The control unit 78 outputs an information request signal to the communication unit 70 requesting the efficiency information and the rated information from the power converter 50. The control unit 78 outputs the information request signal to the communication unit 70, for example, at the time of the initial setting of the control device 7.

[0066] The notification unit 80 acquires the measured value of the power conversion efficiency of each of the plurality of power converters 50, calculates the difference between the efficiency data of each of the plurality of power converters 50 and the measured value of the power conversion efficiency, and notifies when the difference is equal to or greater than the threshold value. The notification unit 80 calculates the measured value of the power conversion efficiency based on the measurement information transmitted from the measuring device 3 and the power information transmitted from the power converter 50. The notification unit 80 compares the efficiency data with the measured value, and when the difference is equal to or greater than the threshold value, outputs notification information indicating that fact. The threshold value is appropriately set according to the design.

[0067] Figure 11 is a diagram for explaining the difference between the efficiency data and the measured value. In Figure 11, the measured values at the rated output capacity (10 kW) are shown as triangular plots. In the example shown in Figure 11, a difference equal to or greater than the threshold value occurs between the efficiency data and the measured value. In this case, the notification unit 80 outputs notification information to an external device. Examples of the external device include a higher-level device (for example, a server device of a control center), a display, a buzzer, etc. For example, on the display where the notification information is output, it is displayed that a difference occurs between the efficiency data and the measured value. Thereby, an operator or the like can take measures such as correcting (resetting) the efficiency data.

[0068] Subsequently, the operation (control method) of the control device 7 will be described with reference to FIG. 12. FIG. 12 is a flowchart showing the operation of the control device 7.

[0069] As shown in FIG. 12, the control device 7 determines whether there is a required load from the charging device 9 (step S11). When the control device 7 determines that there is a required load (step S11: YES), it proceeds to step S12. When the control device 7 determines that there is no required load (step S11: NO), the process ends.

[0070] In step S12, the control device 7 determines whether the capacity of the required load (required capacity) is equal to the rated output capacity. When the control device 7 determines that the required capacity is equal to the rated output capacity (required capacity = rated output capacity) (step S12: YES), it sets the operation at the rated output capacity for the power converter 50 (step S13). That is, the control device 7 generates a control signal for causing the power converters 50A, 50B, 50C, and 50D to perform power conversion at the maximum efficiency (10 KW).

[0071] When the control device 7 determines that the required capacity is not the rated output capacity (required capacity ≠ rated output capacity) (step S12: NO), it performs an optimization calculation using the constrained efficiency data (step S14), and sets the operation of the power converter 50 according to the calculation result (step S15). Specifically, the control device 7 executes any one of the above first control, second control, and third control to generate a control signal. The control device 7 outputs a control instruction to the power conversion device 5 (step S16).

[0072] As shown in FIG. 1, the charging device 9 charges the battery of the vehicle V. The charging device 9 charges one or a plurality of vehicles V. The charging device 9 and the vehicle V are connected by a charging cable C. Electric power is supplied to the charging device 9 from the power conversion device 5. The charging device 9 and the control device 7 are communicably connected to each other. The charging device 9 calculates the charging capacity of the vehicle V and transmits a request instruction for requesting the charging capacity (required capacity) necessary for charging to the control device 7. The charging device 9 controls the charging current and charges the battery of the vehicle V.

[0073] As described above, in the vehicle charging system 1 according to the present embodiment, the control device 7 acquires the power conversion efficiency for each output value for each of the plurality of power converters 50. Thereby, the control device 7 can acquire the unique power conversion efficiency for each output of the power converter 50. The control device 7 performs an optimization calculation of the power conversion efficiency in the power conversion device 5 based on the power conversion efficiency for each output value, and sets the operation of each of the plurality of power converters 50 according to the calculation result. Therefore, even when the power converter 50 operates outside the rated output capacity, the control device 7 can cause the power converter 50 with good variable power conversion efficiency to perform power conversion. Therefore, the control device 7 can improve the power conversion efficiency in the power conversion device 5.

[0074] Further, in the vehicle charging system 1, since the power conversion efficiency can be improved, the heat loss of the power conversion device 5 can be reduced. As a result, the thermal design of the power conversion device 5 becomes easy, and the power conversion device 5 can be downsized.

[0075] In the control device 7 according to this embodiment, the setting unit 76 sets the allocation of the power to be converted for each of the plurality of power converters 50. The control unit 78 controls the operation of each of the plurality of power converters 50 based on the allocation set by the setting unit 76. With this configuration, the operation of the power converter can be controlled so that the power conversion efficiency in the power conversion device 5 becomes optimal.

[0076] In the control device 7 according to this embodiment, the setting unit 76 performs an optimization calculation on the output power output from the power conversion device 5 and sets the operation of each of the plurality of power converters 50. Specifically, the setting unit 76 performs an optimization calculation when the output power output from the power conversion device 5 is smaller than the rated output capacity of the power conversion device 5, and sets the operation of each of the plurality of power converters 50. When the required power from the charging device 9 (load) fluctuates and the output voltage from the power conversion device 5 becomes smaller than the rated output capacity, power conversion at the maximum efficiency may not be possible in the power converter 50. The control device 7 performs an optimization calculation so that the power conversion efficiency in the power conversion device 5 becomes maximum according to the output power, and sets the operation of each of the plurality of power converters 50. Therefore, even when the output power fluctuates and becomes smaller than the rated output capacity in the control device 7, power conversion can be performed at the maximum efficiency. Therefore, the control device 7 can improve the power conversion efficiency in the power conversion device 5.

[0077] In the control device 7 according to this embodiment, the acquisition unit 74 acquires the rated output capacity of each of the plurality of power converters 50. The setting unit 76 performs an optimization calculation so as not to exceed the rated output capacity in each of the plurality of power converters 50, and sets the operation of each of the plurality of power converters 50. With this configuration, it is possible to avoid the execution of an operation that exceeds the rated output capacity in the power converter 50, and thus it is possible to suppress the occurrence of problems such as failures in the power converter 50.

[0078] In the control device 7 according to this embodiment, the setting unit 76 generates efficiency data based on the power conversion efficiency for each output value of each of the plurality of power converters 50. When each of the plurality of power converters 50 has the highest efficiency at the rated output capacity in the efficiency data, the operation at the highest efficiency in the power converter 50 may be preferentially set. With this configuration, since one or a plurality of power converters 50 can be operated at the highest efficiency, the power conversion efficiency in the power conversion device 5 can be improved.

[0079] In the control device 7 according to this embodiment, the setting unit 76 generates efficiency data based on the power conversion efficiency for each output value of each of the plurality of power converters 50. When each of the plurality of power converters 50 does not have the highest efficiency at the rated output capacity in the efficiency data, a distributed operation that distributes the operation to each of the plurality of power converters 50 may be preferentially set. With this configuration, since each of the plurality of power converters 50 can be operated at the highest efficiency, the power conversion efficiency in the power conversion device 5 can be improved.

[0080] In the control device 7 according to this embodiment, the setting unit 76 generates efficiency data based on the power conversion efficiency for each output value of each of the plurality of power converters 50. When the characteristics of the efficiency data are different among the plurality of power converters 50, regions A1 and A2 having a relationship between the output value and the power conversion efficiency are set based on the efficiency data, and the operation of each of the plurality of power converters 50 may be set based on the regions A1 and A2. With this configuration, since the operation of each of the plurality of power converters 50 is set based on the regions A1 and A2, the operation of the power converter 50 can be controlled so that the power conversion efficiency in the power conversion device 5 becomes optimal.

[0081] The control device 7 according to this embodiment has a setting unit 76 that generates efficiency data based on the power conversion efficiency for each output value of each of the plurality of power converters 50. The control device 7 includes a notification unit 80 that acquires the measured values of the power conversion efficiency of each of the plurality of power converters 50, calculates the difference between the efficiency data and the measured values of the power conversion efficiency, and notifies when the difference is equal to or greater than a threshold value. With this configuration, it is possible to notify that there is a deviation from the measured value. As a result, it becomes possible to correct the efficiency data and the like.

[0082] [Second Embodiment] Next, the second embodiment will be described. FIG. 13 is a diagram showing a power conversion system according to the second embodiment. As shown in FIG. 13, power is supplied to the power conversion system 1A from a distributed power source 110. The distributed power source 110 is, for example, solar power generation or wind power generation that utilizes renewable energy. The rated output (power generation amount) of the distributed power source 110 is, for example, 40 kW.

[0083] The power conversion system 1A includes a measuring instrument 3, a power conversion device 5, and a control device 7. In the power conversion system 1A, the power conversion device 5 outputs power to a predetermined output destination. The output destination can be, for example, a charging device, a storage battery, or the like.

[0084] In this embodiment, when the input power input from the distributed power source 110 is smaller than the rated output capacity of the power conversion device 5, the setting unit 76 of the control device 7 performs an optimization calculation and sets the operation of each of the plurality of power converters 50 based on the calculation result.

[0085] Specifically, when the input power from the distributed power source 110 is smaller than the rated output capacity (40 kW) of the power conversion device 5, the setting unit 76 performs an optimization calculation and sets the operations of the plurality of power converters 50 according to the calculation results. The setting unit 76 calculates the input power of the distributed power source 110 based on the measurement information output from the measuring instrument 3. The setting unit 76 executes an optimization calculation based on the efficiency data of each of the plurality of power converters 50 and the input power, and sets the operations of the plurality of power converters 50. The setting unit 76 sets the operations of the power converter 50 by the above-described first control, second control, and third control based on the characteristics of the efficiency data. Specifically, in the first control, second control, and third control, the setting unit 76 sets the operations of the power converter 50 by using the above-described required capacity as the input power.

[0086] The operation (control method) of the control device 7 will be described with reference to FIG. 14. FIG. 14 is a flowchart showing the operation of the control device 7.

[0087] As shown in FIG. 13, the control device 7 determines whether there is a decrease in the output voltage supplied from the distributed power source 110 to the power conversion device 5 (step S21). The control device 7 determines whether there is a decrease in the output voltage based on the measurement information output from the measuring instrument 3. When the control device 7 determines that there is no decrease in the output voltage (step S21: YES), it calculates the power generation amount (input power) of the distributed power source 110 (step S22). The control device 7 calculates the power generation amount based on the measurement information output from the measuring instrument 3. When the control device 7 determines that there is a decrease in the output voltage (step S21: NO), it proceeds to step S25.

[0088] Subsequently, the control device 7 determines whether the generated power is equal to the rated output capacity (step S23). When the control device 7 determines that the generated power (input power) is equal to the rated output capacity (generated power = rated output capacity) (step S23: YES), it sets the operation of the power converter 50 at the rated output capacity (step S24). That is, the control device 7 generates a control signal for causing the power converters 50A, 50B, 50C, and 50D to perform power conversion at the maximum efficiency (10 KW). When the control device 7 determines that the generated power is not equal to the rated output capacity (generated power ≠ rated output capacity) (step S23: NO), it proceeds to step S27.

[0089] In step S25, the control device 7 determines whether it is at the maximum voltage point. When the control device 7 determines that it is at the maximum voltage point (step S25: YES), it sets the operation of the power converter 50 at the rated output capacity (step S26). When the control device 7 determines that it is not at the maximum voltage point (step S25: NO), it performs an optimization calculation using the constrained efficiency data (step S27) and sets the operation of the power converter 50 according to the calculation result (step S28). Specifically, the control device 7 executes any one of the above first control, second control, and third control to generate a control signal. The control device 7 outputs a control instruction to the power conversion device 5 (step S29).

[0090] As described above, in the power conversion system 1A according to the present embodiment, the control device 7 acquires the power conversion efficiency for each output value for each of the plurality of power converters 50. Thereby, the control device 7 can acquire the unique power conversion efficiency for each output of the power converter 50. The control device 7 performs an optimization calculation of the power conversion efficiency in the power conversion device 5 based on the power conversion efficiency for each output value, and sets the operation of each of the plurality of power converters 50 according to the calculation result. Therefore, even when the power converter 50 operates at a value other than the rated output capacity, the control device 7 can cause the power converter 50 with good variable power conversion efficiency to perform power conversion. Thus, the control device 7 can improve the power conversion efficiency in the power conversion device 5.

[0091] In the control device 7 according to the present embodiment, the setting unit 76 performs an optimization calculation on the input power input to the power conversion device 5 and sets the operation of each of the plurality of power converters 50. Specifically, the setting unit 76 performs an optimization calculation when the input power drops below a predetermined power and sets the operation of each of the plurality of power converters 50. When the input voltage from the distributed power source 110 fluctuates and the output voltage from the power conversion device 5 becomes smaller than the rated output capacity, the power converter 50 may not be able to perform power conversion with maximum efficiency. The control device 7 performs an optimization calculation so that the power conversion efficiency in the power conversion device 5 becomes optimal according to the input power, and sets the operation of each of the plurality of power converters 50. Therefore, the control device 7 can improve the power conversion efficiency in the power conversion device 5 even when the input power fluctuates.

[0092] As described above, the embodiments of the present invention have been described. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the gist thereof.

[0093] In the above embodiment, in the vehicle charging system 1, a form in which commercial power is used as the power source 100 has been described as an example. However, the power source 100 may be a distributed power source. In this case, the control device 7 performs the control in the first embodiment and the control in the second embodiment.

[0094] In the above embodiment, in the setting unit 76, a form in which a constrained calculation is executed using the Karush-Kuhn-Tucker conditions has been described as an example. However, the setting unit 76 may execute a constrained calculation using other techniques.

[0095] In the above embodiment, the control device 7 may be provided in a server on the cloud.

Description of Reference Numerals

[0096] 1... Vehicle charging system, 5... Power conversion device, 7... Control device, 50, 50A, 50B, 50C, 50D... Power converters, 74... Acquisition unit, 76... Setting unit, 78... Control unit, 80... Notification unit, A1, A2... Areas, P... Control program.

Claims

1. A control device for controlling the operation of a power conversion device including a plurality of power converters, For each of the plurality of power converters, an acquisition unit that acquires the power conversion efficiency for each output value; Based on the power conversion efficiency for each output value of each of the plurality of power converters, an optimization calculation of the power conversion efficiency in the power conversion device is performed, and an operation of each of the plurality of power converters is set according to the calculation result. A setting unit; A control unit that controls the operation of each of the plurality of power converters based on the operation set by the setting unit, comprising: When the input power input to the power conversion device drops below a predetermined power, the setting unit performs the optimization calculation on the input power and sets the operation of each of the plurality of power converters. Control device.

2. A control device for controlling the operation of a power conversion device including a plurality of power converters, For each of the plurality of power converters, an acquisition unit that acquires the power conversion efficiency for each output value; Based on the power conversion efficiency for each output value of each of the plurality of power converters, an optimization calculation of the power conversion efficiency in the power conversion device is performed, and an operation of each of the plurality of power converters is set according to the calculation result. A setting unit; A control unit that controls the operation of each of the plurality of power converters based on the operation set by the setting unit, comprising: The acquisition unit acquires the rated output capacity of each of the plurality of power converters, The setting unit performs the optimization calculation so as not to exceed the rated output capacity in each of the plurality of power converters, and sets the operation of each of the plurality of power converters. Control device.

3. The setting unit generates efficiency data based on the power conversion efficiency for each of the output values of the plurality of power converters, and when each of the plurality of power converters has the highest efficiency at the rated output capacity in the efficiency data, preferentially sets the operation at the highest efficiency in the power converter. The control device according to claim 2.

4. The setting unit generates efficiency data based on the power conversion efficiency for each of the output values of the plurality of power converters, and when each of the plurality of power converters does not have the highest efficiency at the rated output capacity in the efficiency data, preferentially sets a distributed operation that distributes the operation to each of the plurality of power converters. The control device according to claim 2.

5. A control device for controlling the operation of a power conversion device including a plurality of power converters, an acquisition unit that acquires the power conversion efficiency for each output value for each of the plurality of power converters; a setting unit that performs an optimization calculation of the power conversion efficiency in the power conversion device based on the power conversion efficiency for each of the output values of the plurality of power converters and sets the operation of each of the plurality of power converters according to the calculation result; a control unit that controls the operation of each of the plurality of power converters based on the operation set by the setting unit, and The setting unit generates efficiency data based on the power conversion efficiency for each of the output values of the plurality of power converters, and when the characteristics of the efficiency data are different in the plurality of power converters, sets a plurality of regions having a relationship between the output value and the power conversion efficiency based on the efficiency data, and sets the operation of each of the plurality of power converters based on the regions. A control device.

6. A control device for controlling the operation of a power conversion device including a plurality of power converters, an acquisition unit that acquires the power conversion efficiency for each output value for each of the plurality of power converters; Based on the power conversion efficiency for each of the output values of the plurality of the power converters, an optimization calculation of the power conversion efficiency in the power conversion device is performed, and an operation setting unit that sets the operation of each of the plurality of the power converters according to the calculation result; A control unit that controls the operation of each of the plurality of the power converters based on the operation set in the operation setting unit, and the control device includes: The operation setting unit generates efficiency data based on the power conversion efficiency for each of the output values of the plurality of the power converters, obtains the measured value of the power conversion efficiency of each of the plurality of the power converters, calculates the difference between the efficiency data and the measured value of the power conversion efficiency, and includes a notification unit that notifies when the difference is equal to or greater than a threshold value.

7. A power conversion device including a plurality of power converters, The control device according to any one of claims 1 to 6, A charging system including a charging device that charges with the power output from the power conversion device.

8. A control method for controlling the operation of a power conversion device including a plurality of power converters, An acquisition step of acquiring the power conversion efficiency for each output value for each of the plurality of the power converters, A setting step of performing an optimization calculation of the power conversion efficiency in the power conversion device based on the power conversion efficiency for each of the output values of the plurality of the power converters, and setting the operation of each of the plurality of the power converters according to the calculation result, A control step of controlling the operation of each of the plurality of the power converters based on the operation set in the setting step, and including: In the acquisition step, the rated output capacity of each of the plurality of the power converters is acquired, In the setting step, the optimization calculation is performed so as not to exceed the rated output capacity in each of the plurality of the power converters, and the operation of each of the plurality of the power converters is set.

9. A control program for controlling the operation of a power conversion device including a plurality of power converters, for each of the plurality of power converters, an acquisition step of acquiring the power conversion efficiency for each output value; a setting step of performing an optimization calculation of the power conversion efficiency in the power conversion device based on the power conversion efficiency for each output value of each of the plurality of power converters, and setting the operation of each of the plurality of power converters according to the calculation result; a control step of controlling the operation of each of the plurality of power converters based on the operation set in the setting step, causing a computer to execute, in the acquisition step, acquiring the rated output capacity of each of the plurality of power converters, in the setting step, performing the optimization calculation so as not to exceed the rated output capacity in each of the plurality of power converters, and setting the operation of each of the plurality of power converters, control program.

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