JP7693446B2 - Control device, charging system, control method, and control program - Google Patents

Description

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

In a system having multiple power converters, a control device that controls the operation of the power converters is known (see, for example, Patent Document 1).

JP 2014-112984 A

In a power conversion device equipped with multiple power converters, each of the multiple power converters can perform power conversion and output, making it possible to operate each of the multiple power converters at maximum efficiency. Generally, the maximum efficiency of a power converter is often set to operation at the rated output capacity. However, in a power conversion device, one of the multiple power converters may perform conversion at a power smaller than the rated output capacity. In this case, the control device performs control such as switching the power converters on and off or uniformly selecting the power converters to operate based on a preset order. With this control, one or more power converters operate at a capacity other than the rated output capacity, which may reduce the power conversion efficiency.

The present invention aims to provide a control device, a charging system, a control method, and a control program that can improve the power conversion efficiency in a power conversion device.

The control device according to the present invention is a control device that controls the operation of a power conversion device that has multiple power converters, and includes an acquisition unit that acquires the power conversion efficiency for each output value for each of the multiple 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 output value of each of the multiple power converters and sets the operation of each of the multiple power converters in accordance with the calculation result, and a control unit that controls the operation of each of the multiple power converters based on the operation set in the setting unit.

The control device according to the present invention obtains the power conversion efficiency for each output value for each of the multiple power converters. This allows the control device to obtain a specific power conversion efficiency for each output of the power converter. The control device performs optimization calculations for the power conversion efficiency in the power converter based on the power conversion efficiency for each output value, and sets the operation of each of the multiple power converters according to the calculation results. Therefore, even if the power converter is operating at a capacity other than the rated output capacity, the control device can convert power using a power converter with good power conversion efficiency. Therefore, the control device can improve the power conversion efficiency in the power converter.

The setting unit may set an allocation of power to be converted for each of the multiple power converters, and the control unit may control the operation of each of the multiple power converters based on the allocation set by the setting unit. In this configuration, the operation of the power converters can be controlled so as to optimize the power conversion efficiency in the power conversion device.

The setting unit may perform optimization calculations on the output power output from the power conversion device and set the operation of each of the multiple power converters. If fluctuations occur in the power required by the load and the output voltage from the power conversion device becomes smaller than the rated output capacity, the power converter may not be able to perform power conversion at maximum efficiency. The control device performs optimization calculations to optimize the power conversion efficiency of the power conversion device according to the output power and sets the operation of each of the multiple power converters. Therefore, the control device can improve the power conversion efficiency of the power conversion device even when fluctuations occur in the output power.

The setting unit may perform optimization calculations and set the operation of each of the multiple power converters when the output power output from the power conversion device is smaller than the rated output capacity of the power conversion device. In this configuration, even if the output power fluctuates and becomes smaller than the rated output capacity, power conversion can be performed with optimal efficiency.

The setting unit may perform optimization calculations on the input power input to the power conversion device, and set the operation of each of the multiple power converters. If 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, the power converter may not be able to perform power conversion at maximum efficiency. The control device performs optimization calculations to optimize the power conversion efficiency of the power conversion device according to the input power, and sets the operation of each of the multiple power converters. Therefore, the control device can improve the power conversion efficiency of the power conversion device even when fluctuations occur in the input power.

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

The acquisition unit may acquire the rated output capacity of each of the multiple power converters, and the setting unit may perform optimization calculations so that the rated output capacity is not exceeded in each of the multiple power converters, and set the operation of each of the multiple power converters. In this configuration, it is possible to prevent the power converter from performing an operation that exceeds the rated output capacity, thereby suppressing malfunctions such as failures in the power converters.

The setting unit may generate efficiency data based on the power conversion efficiency for each output value of the multiple power converters, and if the efficiency data indicates that each of the multiple power converters is at its maximum efficiency at its rated output capacity, the setting unit may preferentially set the power converter to operate at its maximum efficiency. In this configuration, one or more power converters can be operated at their maximum efficiency, thereby improving the power conversion efficiency of the power conversion device.

The setting unit may generate efficiency data based on the power conversion efficiency for each output value of the multiple power converters, and if the efficiency data indicates that each of the multiple power converters is not at its highest efficiency at its rated output capacity, the setting unit may preferentially set a distributed operation that distributes operation among the multiple power converters. With this configuration, each of the multiple power converters can be operated at its highest efficiency, thereby improving the power conversion efficiency of the power conversion device.

The setting unit generates efficiency data based on the power conversion efficiency for each output value of the multiple power converters, and when the efficiency data characteristics differ among the multiple power converters, may set multiple regions having a relationship between the output value and the power conversion efficiency based on the efficiency data, and set the operation of each of the multiple power converters based on the regions. In this configuration, since the operation of each of the multiple power converters is set based on the regions, the operation of the power converters can be controlled so that the power conversion efficiency in the power conversion device is optimized.

The setting unit may be equipped with a notification unit that generates efficiency data based on the power conversion efficiency for each output value of the multiple power converters, acquires actual values of the power conversion efficiency of each of the multiple power converters, calculates the difference between the efficiency data and the actual value 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 a deviation has occurred with respect to the actual value. This makes it possible to correct the efficiency data, etc.

The charging system according to the present invention includes a power conversion device having multiple power converters, the above-mentioned control device, and a charging device that charges with the power output from the power conversion device.

The charging system according to the present invention is equipped with the above-mentioned control device. Therefore, the charging system can improve the power conversion efficiency of the power conversion device.

The control method according to the present invention is a control method for controlling the operation of a power conversion device having 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, 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, 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.

In the control method of the present invention, the power conversion efficiency for each output value is obtained for each of the multiple power converters. In this way, the control method can obtain a specific power conversion efficiency for each output of the power converter. In the control method, an optimization calculation is performed for the power conversion efficiency in the power conversion device based on the power conversion efficiency for each output value, and the operation of each of the multiple power converters is set according to the calculation result. Therefore, in the control method, even if the power converter operates at a capacity other than the rated output capacity, it is possible to convert power in a power converter with good power conversion efficiency. Therefore, the control method can improve the power conversion efficiency in the power conversion device.

The control program according to the present invention is a control program for controlling the operation of a power conversion device having multiple power converters, and causes a computer to execute an acquisition step of acquiring the power conversion efficiency for each output value for each of the multiple 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 output value of the multiple power converters and setting the operation of each of the multiple power converters in accordance with the calculation result, and a control step of controlling the operation of each of the multiple power converters based on the operation set in the setting step.

The control program according to the present invention obtains the power conversion efficiency for each output value for each of the multiple power converters. This allows the control program to obtain the specific power conversion efficiency for each output of the power converter. The control program performs optimization calculations for 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 multiple power converters according to the calculation results. Therefore, even if the power converter operates at a capacity other than the rated output capacity, the control program can convert power using a power converter with good power conversion efficiency. Therefore, the control program can improve the power conversion efficiency in the power conversion device.

The present invention makes it possible to improve the power conversion efficiency of a power conversion device.

FIG. 1 is a diagram showing the configuration of a charging system according to a first embodiment. FIG. 2 is a diagram showing the configuration of the measuring device. FIG. 3 is a diagram showing a configuration of the power converter. FIG. 4 is a diagram illustrating an example of efficiency information stored in the storage unit. FIG. 5 is a diagram showing the configuration of the control device. FIG. 6 is a graph showing the efficiency information of the power converter. FIG. 7 is a graph showing the efficiency information of the power converter. FIG. 8 is a diagram for explaining a method of generating efficiency data. FIG. 9 is a flowchart showing a method for setting an area. FIG. 10 conceptually shows a method for setting the area. FIG. 11 is a diagram for explaining the difference between the efficiency data and the actual measured values. FIG. 12 is a flowchart showing the operation of the control device. FIG. 13 is a diagram showing the configuration of a control system according to the second embodiment. FIG. 14 is a flowchart showing the operation of the control device.

A preferred embodiment of the present invention will be described in detail below with reference to the attached drawings. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicate descriptions will be omitted.

[First embodiment]
Fig. 1 is a diagram showing a vehicle charging system according to a first embodiment. As shown in Fig. 1, the vehicle charging system 1 is a system that charges a storage battery (not shown) of a vehicle V, such as an EV (Electric Vehicle) or a PHV (Plug-in Hybrid Vehicle). The vehicle charging system 1 is capable of charging one or a plurality of vehicles V. The vehicle charging system 1 charges the vehicle V using power supplied from a power source 100. The power source 100 is, for example, a commercial power source, and supplies AC power (three-phase 200V).

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

The measuring instrument 3 measures the 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 has a voltage measuring unit 30, a current measuring unit 32, a calculation unit 34, and a communication unit 36.

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

The calculation unit 34 calculates the 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, voltage value, and current value to the communication unit 36. The communication unit 36 communicates with the control device 7. The communication unit 36 communicates with the control device 7 via wired or wireless communication. The communication unit 36 transmits the measurement information output from the calculation unit 34 to the control device 7.

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 this embodiment, the power conversion device 5 has four power converters 50. In this embodiment, the power converters 50 are single-phase transformers. 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 is capable of outputting 40 kW. In the following description, the four power converters 50 may be distinguished and described as power converter 50A, power converter 50B, power converter 50C, and power converter 50D.

Each of the multiple power converters 50 has a similar configuration. Therefore, the configuration of the power converter 50 will be described using 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 has a current sensor 500, a first capacitor section 502, a switching section 504, a reactor section 506, a second capacitor section 508, a voltage sensor 510, an output control section 512, a memory section 514, and a communication section 516.

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.

The switching unit 504 has multiple switching elements (not shown). A switching element is an element that can be electrically switched between open and closed. Examples of switching elements that can be used include MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), IGBTs (Insulated Gate Bipolar Transistors), and bipolar transistors.

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

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.

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 a 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 using a drive signal to the multiple switching elements of the switching unit 504, and changes the on-period of each switching element.

In response to an information request signal from the control device 7, the output control unit 512 controls the communication unit 516 to transmit efficiency information and rated information (described below) stored in the memory unit 514 to the control device 7. The output control unit 512 calculates the output power of 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 memory unit 514 and the communication unit 516.

The memory unit 514 may store various information. The memory 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 efficiency information stored in the memory unit 514. As shown in FIG. 4, the efficiency information associates output capacity [kW] with efficiency [%]. In the example shown in FIG. 4, the efficiency is associated for every 1 kW of output. In the example shown in FIG. 4, the efficiency is associated for every 1 kW of output, but the output capacity may be set appropriately, for example, every 0.5 kW. The efficiency information stored in the memory unit 514 can be changed (rewritten).

The memory unit 514 stores rated information related to the rated output capacity of the power converter 50. In this embodiment, the memory unit 514 stores rated information indicating 10 kW as the rated output capacity of the power converter 50. The memory unit 514 stores the power information output from the output control unit 512.

The communication unit 516 communicates with the control device 7. The communication unit 516 performs wired or wireless communication with the control device 7. The communication unit 516 receives control instructions from the control device 7. The communication unit 516 outputs the control instructions to the output control unit 512. The communication unit 516 transmits the efficiency information and rated information stored in the memory unit 514 to the control device 7 based on instructions 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.

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 processor implemented in an integrated circuit. The monitoring control device 14 is composed of a CPU, ROM, RAM, etc., and an input/output interface, etc. Various programs and 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 memory unit 72, an acquisition unit 74, a setting unit 76, a control unit 78, and an alarm unit 80.

The communication unit 70 communicates with the measuring device 3, the power conversion device 5 (power converter 50), and the charging device 9. The communication unit 70 receives measurement information transmitted from the measuring device 3. The communication unit 70 outputs the measurement information to the storage unit 72. The communication unit 70 receives efficiency information, rated 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, rated information, and 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.

The memory unit 72 can store various information. The memory unit 72 stores the measurement information, efficiency information, rated information, and power information output from the communication unit 70. The memory unit 72 stores a control program P. 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 is performed.

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

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

The setting unit 76 performs optimization calculations for the power conversion efficiency in the power conversion device 5 based on the power conversion efficiency for each output value (output capacity) of the multiple power converters 50, and sets the operation of each of the multiple power converters 50 according to the calculation results. The setting unit 76 generates efficiency data for each power converter 50 based on the efficiency information stored in the memory 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 first order or higher, and the order is not specified. The setting unit 76 sets the polynomial as the efficiency data.

The method of generating efficiency data in the setting unit 76 will be specifically described with reference to Figs. 6 and 7. Figs. 6 and 7 are diagrams illustrating efficiency information of the power converter 50 in the form of a graph. Fig. 8 is a diagram for explaining the method of generating efficiency data. In Figs. 6 to 8, the vertical axis indicates efficiency [%] and the horizontal axis indicates output capacity [kW]. The graphs shown in Figs. 6 to 8 are shown to facilitate understanding of the explanation. In this embodiment, the setting unit 76 does not create a graph when generating efficiency data, but generates the efficiency data by calculation processing.

In Figures 6 and 7, for example, the conversion information of one of the multiple power converters 50 is visualized as a graph. To explain the generation of efficiency data for a power converter 50 having the characteristics shown in Figure 6 as an example, as shown in Figure 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 power converters 50A, 50B, 50C, and 50D and sets them as efficiency data.

The setting unit 76 sets the operation of each of the multiple power converters 50 so that the rated output capacity is not exceeded in each of the multiple power converters 50. The setting unit 76 performs a constrained calculation so as not to exceed the rated output capacity based on the rated information. The setting unit 76 performs the constrained calculation using a known technique such as the Karush-Kuhn-Tucker condition (KKT condition). In this embodiment, since the rated output capacity of the power converter 50 is 10 kW, the setting unit 76 performs the constrained calculation so as not to exceed 10 kW.

The setting unit 76 performs a constrained optimization calculation based on the efficiency data so that the power conversion efficiency in the power conversion device 5 is optimized. In this 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 multiple power converters 50 based on the calculation result. The setting unit 76 sets the allocation of power to be converted for each of the multiple power converters 50. In this 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 multiple power converters 50 based on the calculation result.

Specifically, when the requested 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 multiple power converters 50 according to the calculation result. The setting unit 76 acquires the requested capacity from the charging device 9 based on the request instruction output from the communication unit 70. The setting unit 76 performs an optimization calculation based on the efficiency data and requested capacity (output power) of each of the multiple power converters 50, and sets the operation of the multiple 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.

(1) First Control When the efficiency data of the multiple power converters 50 (50A, 50B, 50C, 50D) shows that each of the multiple power converters 50 is at its maximum efficiency at its rated output capacity, the setting unit 76 preferentially sets the power converters 50 to operate at their maximum efficiency. When the efficiency data of all of the multiple power converters 50 has the characteristics shown in Fig. 6, that is, when the efficiency is at its maximum efficiency at the rated output capacity (10 kW), the setting unit 76 sets the power converters 50 to operate at their maximum efficiency.

Specifically, when the required capacity is, for example, 20 kW, the setting unit 76 sets the two power converters 50 to operate at the highest efficiency through optimization calculations. For example, the setting unit 76 sets the power converter 50A to convert 10 kW of power and the power converter 50B to convert 10 kW of power. That is, the setting unit 76 assigns the power converter 50A to convert 10 kW of power and the power converter 50B to convert 10 kW of power. The setting unit 76 outputs a control signal related to the set assignment to the control unit 78.

(2) Second Control When the efficiency data of the multiple power converters 50 (50A, 50B, 50C, 50D) shows that each of the multiple power converters 50 does not have the highest efficiency at the rated output capacity, the setting unit 76 preferentially sets a distributed operation that distributes operation among the multiple power converters 50. When the efficiency data of all of the multiple power converters 50 has the characteristics shown in Fig. 7, that is, when the efficiency is not highest at the rated output capacity (10 kW), the setting unit 76 sets the operation of each of the multiple power converters 50 in a distributed manner.

In the example shown in FIG. 7, the power converter 50 is most efficient at 5 kW. In this case, the setting unit 76 sets the four power converters 50 to operate at the most efficient level by optimization calculation, for example, when the required capacity is 20 kW. That is, the setting unit 76 sets the power converters 50A, 50B, 50C, and 50D to convert 5 kW of power. The setting unit 76 assigns the power converter 50A to convert 5 kW of power, the power converter 50B to convert 5 kW of power, the power converter 50C to convert 5 kW of power, and the power converter 50D to convert 5 kW of power. The setting unit 76 outputs a control signal related to the set allocation to the control unit 78.

(3) Third Control When the efficiency data of the multiple power converters 50 (50A, 50B, 50C, 50D) have different characteristics, the setting unit 76 sets regions A1, A2 (see FIG. 10) having a relationship between the output value and the power conversion efficiency based on the efficiency data, and sets the operation of the multiple power converters 50 based on the regions A1, A2. Here, a case will be described as an example in which the efficiency data of the power converters 50A and 50C have characteristics as shown in FIG. 6, and the efficiency data of the power converters 50B and 50D have characteristics as shown in FIG. 7. A method of setting the regions A1, A2 in the setting unit 76 will be described with reference to FIG. 9. FIG. 9 is a flowchart showing the method of setting the regions.

As shown in FIG. 9, the setting unit 76 calculates the intersection point of the approximation curves (step S01). Next, the setting unit 76 compares the efficiency of the output capacity of each power converter 50 (step S02). Next, the setting unit 76 determines whether or not there is an identical efficiency point in the efficiency of the output capacity of each power converter 50 (step S03). If the setting unit 76 determines that there is an identical efficiency point (step S03: YES), the setting unit 76 proceeds to step S04. If the setting unit 76 determines that there is no identical efficiency point (step S04: NO), the setting unit 76 proceeds to step S05.

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 in the efficiency of each power converter 50 as the intersection point. The setting unit 76 sets the areas A1 and A2 based on the intersection point (step S06). The specific setting of the areas A1 and A2 in the setting unit 76 will be described with reference to FIG. 10. FIG. 10 shows an image of the setting method of the areas A1 and A2 to help understand the explanation. In FIG. 10, the graphs related to the efficiency of the power converters 50A and 50C are shown by solid lines, and the graphs related to the efficiency of the power converters 50B and 50D are shown by dashed lines. In FIG. 10, the power converters 50A and 50C show the same efficiency characteristics, and the power converters 50B and 50D show the same efficiency characteristics, so it appears that only two graphs are displayed.

As shown in FIG. 10, in this embodiment, the setting unit 76 sets areas A1 and A2 with the intersection of the two graphs as the boundary. Area A1 is set as an area with a small output capacity compared to area A2. In other words, area A2 is set as an area with a large output capacity compared to area A1. In area A1, the efficiency of power converters 50B and 50D is high. In area A2, the efficiency of power converters 50A and 50C is high. The setting unit 76 stores area information related to the set areas A1 and A2 in the storage unit 72. Note that the setting unit 76 may set "area A1" as an area with a large capacity and "area A2" as an area with a small capacity.

When the required capacity is 4 kW, for example, the setting unit 76 sets the power converter 50B and the power converter 50D, which have high efficiency, to operate in the region A1. Specifically, the setting unit 76 sets, for example, the power converter 50B to convert 2 kW of power, and the power converter 50D to convert 2 kW of power. That is, the setting unit 76 assigns the power converter 50B to convert 2 kW of power, and the power converter 50D to convert 2 kW of power. The setting unit 76 outputs a control signal related to the set assignment to the control unit 78.

When the required capacity is, for example, 20 kW, the setting unit 76 sets the power converter 50A and the power converter 50C, which have high efficiency, to operate in the region A2. Specifically, the setting unit 76 sets, for example, the power converter 50A to operate at 10 kW and the power converter 50C to operate at 10 kW. That is, the setting unit 76 assigns the power converter 50A to convert 10 kW of power and the power converter 50C to convert 10 kW of power. The setting unit 76 outputs a control signal related to the set assignment to the control unit 78.

When the requested capacity from the charging device 9 is 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 power converter 50 to operate at the rated output capacity (10 kW). In other words, when the requested capacity is the rated output capacity, the setting unit 76 outputs a control signal to the control unit 78 instructing the power converter 50 to operate at the rated output capacity without performing an optimization calculation.

As shown in FIG. 5, the control unit 78 controls the operation of each of the multiple power converters 50 based on the operation set in the setting unit 76. The control unit 78 controls the operation of each of the multiple 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 efficiency information and rated information from the power converter 50. The control unit 78 outputs the information request signal to the communication unit 70, for example, during initial configuration of the control device 7.

The notification unit 80 acquires the actual measured value of the power conversion efficiency of each of the multiple power converters 50, calculates the difference between the efficiency data of each of the multiple power converters 50 and the actual measured value of the power conversion efficiency, and issues a notification if the difference is equal to or greater than a threshold value. The notification unit 80 calculates the actual measured value of the power conversion efficiency based on the measurement information transmitted from the measuring instrument 3 and the power information transmitted from the power converter 50. The notification unit 80 compares the efficiency data with the actual measured value, and if the difference is equal to or greater than a threshold value, outputs notification information indicating that fact. The threshold value is set appropriately according to the design.

Figure 11 is a diagram for explaining the difference between efficiency data and actual measured values. In Figure 11, the actual measured values at rated output capacity (10 kW) are plotted as triangles. In the example shown in Figure 11, a difference occurs between the efficiency data and the actual measured values that is equal to or greater than the threshold. In this case, the notification unit 80 outputs notification information to an external device. Examples of external devices include a higher-level device (e.g., a server device in a control center), a display, a buzzer, etc. For example, the display to which the notification information is output displays a message indicating that a difference occurs between the efficiency data and the actual measured values. This allows workers to take action such as correcting (resetting) the efficiency data.

Next, 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.

As shown in FIG. 12, the control device 7 determines whether or not there is a requested load from the charging device 9 (step S11). If the control device 7 determines that there is a requested load (step S11: YES), it proceeds to step S12. If the control device 7 determines that there is no requested load (step S11: NO), it ends the process.

In step S12, the control device 7 determines whether the capacity of the requested load (requested capacity) is the rated output capacity. If the control device 7 determines that the requested capacity is the rated output capacity (requested capacity = rated output capacity) (step S12: YES), it sets the power converter 50 to operate at the rated output capacity (step S13). That is, the control device 7 generates a control signal that causes the power converters 50A, 50B, 50C, and 50D to convert power at maximum efficiency (10 kW).

When the control device 7 determines that the requested capacity is not the rated output capacity (requested 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-mentioned 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).

As shown in FIG. 1, the charging device 9 charges the storage battery of the vehicle V. The charging device 9 charges one or more vehicles V. The charging device 9 and the vehicle V are connected by a charging cable C. The charging device 9 is supplied with power from the power conversion device 5. The charging device 9 and the control device 7 are connected so that they can communicate with each other. The charging device 9 calculates the charging capacity of the vehicle V and transmits a request instruction to the control device 7 requesting the charging capacity (required capacity) required for charging. The charging device 9 controls the charging current and charges the storage battery of the vehicle V.

As described above, in the vehicle charging system 1 according to this embodiment, the control device 7 acquires the power conversion efficiency for each output value for each of the multiple power converters 50. This allows the control device 7 to acquire the specific power conversion efficiency for each output of the power converter 50. The control device 7 performs optimization calculations for 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 multiple power converters 50 according to the calculation results. Therefore, even if the power converter 50 operates at a capacity other than the rated output capacity, the control device 7 can convert power in the power converter 50 with good power conversion efficiency. Therefore, the control device 7 can improve the power conversion efficiency in the power conversion device 5.

In addition, the vehicle charging system 1 can improve the power conversion efficiency, thereby reducing the heat loss of the power conversion device 5. This makes it easier to design the thermal performance of the power conversion device 5, making it possible to reduce the size of the power conversion device 5.

In the control device 7 according to this embodiment, the setting unit 76 sets the allocation of power to be converted for each of the multiple power converters 50. The control unit 78 controls the operation of each of the multiple power converters 50 based on the allocation set in the setting unit 76. In this configuration, the operation of the power converters can be controlled so that the power conversion efficiency in the power conversion device 5 is optimized.

In the control device 7 according to this embodiment, the setting unit 76 performs optimization calculations on the output power output from the power conversion device 5 and sets the operation of each of the multiple power converters 50. Specifically, the setting unit 76 performs optimization calculations 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 multiple 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, the power converter 50 may not be able to perform power conversion at maximum efficiency. The control device 7 performs optimization calculations so that the power conversion efficiency of the power conversion device 5 is maximized according to the output power, and sets the operation of each of the multiple power converters 50. Therefore, in the control device 7, even if the output power fluctuates and becomes smaller than the rated output capacity, the power conversion can be performed at maximum efficiency. Therefore, in the control device 7, the power conversion efficiency in the power conversion device 5 can be improved.

In the control device 7 according to this embodiment, the acquisition unit 74 acquires the rated output capacity of each of the multiple power converters 50. The setting unit 76 performs optimization calculations so that the rated output capacity is not exceeded in each of the multiple power converters 50, and sets the operation of each of the multiple power converters 50. In this configuration, it is possible to prevent the power converter 50 from performing an operation that exceeds the rated output capacity, thereby suppressing malfunctions such as failures in the power converter 50.

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 the multiple power converters 50, and if the efficiency data indicates that each of the multiple power converters 50 is at its highest efficiency at its rated output capacity, the power converter 50 may be preferentially set to operate at its highest efficiency. In this configuration, one or more power converters 50 can be operated at their highest efficiency, thereby improving the power conversion efficiency of the power conversion device 5.

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 the multiple power converters 50, and if the efficiency data indicates that each of the multiple power converters 50 is not at its highest efficiency at its rated output capacity, a distributed operation that distributes operation among the multiple power converters 50 may be preferentially set. In this configuration, each of the multiple power converters 50 can be operated at its highest efficiency, thereby improving the power conversion efficiency in the power conversion device 5.

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 the multiple power converters 50, and when the efficiency data characteristics differ among the multiple power converters 50, it is possible to set regions A1 and A2 having a relationship between the output value and the power conversion efficiency based on the efficiency data, and set the operation of each of the multiple power converters 50 based on the regions A1 and A2. In this configuration, since the operation of each of the multiple power converters 50 is set based on the regions A1 and A2, it is possible to control the operation of the power converters 50 so that the power conversion efficiency in the power conversion device 5 is optimized.

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 the multiple power converters 50. The control device 7 includes a notification unit 80 that acquires the actual power conversion efficiency of each of the multiple power converters 50, calculates the difference between the efficiency data and the actual 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 a deviation has occurred with the actual measured value. This makes it possible to correct the efficiency data, etc.

[Second embodiment]
Next, a 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, a solar power generation source or a wind power generation source that utilizes renewable energy. The rated output (power generation amount) of the distributed power source 110 is, for example, 40 kW.

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 may be, for example, a charging device, a storage battery, etc.

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

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 operation of each of the multiple power converters 50 according to the calculation result. 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 performs an optimization calculation based on the efficiency data of each of the multiple power converters 50 and the input power, and sets the operation of the multiple power converters 50. The setting unit 76 sets the operation of the power converter 50 by the above-mentioned first control, second control, and third control based on the characteristics of the efficiency data. Specifically, the setting unit 76 sets the operation of the power converter 50 by using the above-mentioned required capacity as the input power in the first control, second control, and third control.

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.

As shown in FIG. 13, the control device 7 determines whether or not 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 or not there is a decrease in the output voltage based on the measurement information output from the measuring device 3. If the control device 7 determines that there is no decrease in the output voltage (step S21: YES), it calculates the amount of power generated (input power) of the distributed power source 110 (step S22). The control device 7 calculates the amount of power generated based on the measurement information output from the measuring device 3. If the control device 7 determines that there is a decrease in the output voltage (step S21: NO), it proceeds to step S25.

Then, the control device 7 judges whether the amount of power generation is the rated output capacity (step S23). If the control device 7 judges that the amount of power generation (input power) is the rated output capacity (amount of power generation = rated output capacity) (step S23: YES), the control device 7 sets the power converter 50 to operate at the rated output capacity (step S24). That is, the control device 7 generates a control signal to perform power conversion at maximum efficiency (10 kW) in the power converters 50A, 50B, 50C, and 50D. If the control device 7 judges that the amount of power generation is not the rated output capacity (amount of power generation ≠ rated output capacity) (step S23: NO), the control device 7 proceeds to step S27.

In step S25, the control device 7 determines whether or not it is the maximum voltage point. If the control device 7 determines that it is the maximum voltage point (step S25: YES), it sets the power converter 50 to operate at the rated output capacity (step S26). If the control device 7 determines that it is not 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 first control, second control, and third control described above and generates a control signal. The control device 7 outputs a control instruction to the power conversion device 5 (step S29).

As described above, in the power conversion system 1A according to this embodiment, the control device 7 acquires the power conversion efficiency for each output value for each of the multiple power converters 50. This allows the control device 7 to acquire the specific 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 multiple power converters 50 according to the calculation result. Therefore, even if the power converter 50 operates at a capacity other than the rated output capacity, the control device 7 can convert power in the power converter 50 with good power conversion efficiency. Therefore, the control device 7 can improve the power conversion efficiency in the power conversion device 5.

In the control device 7 according to this embodiment, the setting unit 76 performs optimization calculations on the input power input to the power conversion device 5 and sets the operation of each of the multiple power converters 50. Specifically, the setting unit 76 performs optimization calculations when the input power falls below a predetermined power and sets the operation of each of the multiple 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 at maximum efficiency. The control device 7 performs optimization calculations to optimize the power conversion efficiency in the power conversion device 5 according to the input power and sets the operation of each of the multiple 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.

Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

In the above embodiment, an example has been described in which commercial power is used as the power source 100 in the vehicle charging system 1. 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.

In the above embodiment, the setting unit 76 performs constrained calculations using the Karush-Kuhn-Tucker condition as an example. However, the setting unit 76 may perform constrained calculations using other techniques.

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

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 (9)

A control device that controls an operation of a power conversion device including a plurality of power converters,
an acquisition unit that acquires a power conversion efficiency for each output value for each of the plurality of power converters;
a setting unit that performs an optimization calculation of 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 operations of each of the plurality of power converters in accordance with a calculation result;
a control unit that controls an operation of each of the plurality of power converters based on the operation set by the setting unit ,
The control device, wherein the setting unit performs the optimization calculation on the input power when the input power input to the power conversion device falls below a predetermined power, and sets the operation of each of the multiple power converters . A control device that controls an operation of a power conversion device including a plurality of power converters,
an acquisition unit that acquires a power conversion efficiency for each output value for each of the plurality of power converters;
a setting unit that performs an optimization calculation of 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 operations of each of the plurality of power converters in accordance with a calculation result;
a control unit that controls an operation of each of the plurality of power converters based on the operation set by the setting unit,
The acquisition unit acquires a 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 multiple power converters, and sets the operation of each of the multiple power converters. 3. The control device according to claim 2, wherein 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 efficiency data indicates that each of the plurality of power converters has maximum efficiency at the rated output capacity, sets the power converter to operate at the maximum efficiency with priority . 3. The control device according to claim 2, wherein 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, if the efficiency data shows that each of the plurality of power converters does not have maximum efficiency at the rated output capacity, preferentially sets a distributed operation that distributes operation to each of the plurality of power converters. A control device that controls an operation of a power conversion device including a plurality of power converters,
an acquisition unit that acquires a power conversion efficiency for each output value for each of the plurality of power converters;
a setting unit that performs an optimization calculation of 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 operations of each of the plurality of power converters in accordance with a calculation result;
a control unit that controls an operation of each of the plurality of power converters based on the operation set by the setting unit,
the setting unit generates efficiency data based on the power conversion efficiency for each of the output values of the multiple power converters, and when characteristics of the efficiency data differ among the multiple 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 operation of each of the multiple power converters based on the regions. A control device that controls an operation of a power conversion device including a plurality of power converters,
an acquisition unit that acquires a power conversion efficiency for each output value for each of the plurality of power converters;
a setting unit that performs an optimization calculation of 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 operations of each of the plurality of power converters in accordance with a calculation result;
a control unit that controls an operation of each of the plurality of power converters based on the operation set by the setting unit,
The setting unit generates efficiency data based on the power conversion efficiency for each of the output values of the plurality of power converters,
a control device comprising: an alarm unit that acquires actual measured values of power conversion efficiency of each of the plurality of power converters, calculates a difference between the efficiency data and the actual measured values of the power conversion efficiency, and notifies when the difference is equal to or greater than a threshold value. A power conversion device including a plurality of power converters;
A control device according to any one of claims 1 to 6 ;
a charging device that performs charging using the power output from the power conversion device. A control method for controlling an operation of a power conversion device including a plurality of power converters, comprising:
acquiring a power conversion efficiency for each output value for each of the plurality of power converters;
a setting step of performing an optimization calculation of 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 setting operations of each of the plurality of power converters in accordance with a calculation result;
a control step of controlling an operation of each of the plurality of power converters based on the operation set in the setting step,
In the obtaining step, a rated output capacity of each of the plurality of power converters is obtained,
A control method , in which the setting step 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 . A control program for controlling an operation of a power conversion device including a plurality of power converters,
acquiring a power conversion efficiency for each output value for each of the plurality of power converters;
a setting step of performing an optimization calculation of 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 setting operations of each of the plurality of power converters in accordance with a calculation result;
a control step of controlling an operation of each of the plurality of power converters based on the operation set in the setting step ;
In the obtaining step, a rated output capacity of each of the plurality of power converters is obtained,
A control program , 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 .

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