JP2018174679A - Power conversion device, power conversion system, and DC power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device, a power conversion system, and a DC power supply device capable of enhancing a degree of freedom of an installation location of the DC power supply device.SOLUTION: A power conversion device 2 comprises an inverter circuit 220, and an inverter control circuit 221 that controls the inverter circuit 220. The inverter circuit 220 converts a DC power inputted from a DC line DC1 connected with a DC power supply device 3, which outputs the DC power, into an AC power, and outputs the AC power to an AC power system 100. The inverter control circuit 221 transmits to the DC power supply device 3 power information that includes at least one of a flow power outputted to the AC power system 100 by the inverter circuit 220 and a target value of an output of the DC power supply device 3 depending on the flow power, by communication.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power conversion device, a power conversion system, and a DC power supply device, and more particularly to a power conversion device, a power conversion system, and a DC power supply device that convert direct current to alternating current.

  Conventionally, there has been a power control system including a power conditioner that interconnects distributed power supplies and an additional unit for adding additional power supplies (see, for example, Patent Document 1).

  The power conditioner includes a DC / DC converter that boosts or lowers the voltage of power output from the distributed power supply, an inverter that converts the output of the DC / DC converter into alternating current, a power conditioner that controls the output of the DC / DC converter and the inverter. A control unit. A system and a load are connected to the output end of the inverter, and the inverter is connected to the system and supplies power to the load.

  The additional unit includes a DC / DC converter that boosts or lowers the voltage of power output from the additional distributed power source, and an additional control unit that controls the DC / DC converter. The output terminal of the DC / DC converter of the additional unit is electrically connected to a DC intermediate link portion that is a connection point between the DC / DC converter and the inverter in the power conditioner.

  The power control unit monitors the voltage of the DC intermediate link portion, and performs PWM (Pulse Width Modulation) control of the power conditioner and the DC / DC converter of the additional unit based on the monitoring result.

JP-A-2015-122906

  In the above-described power control system, the additional power source connected to the additional unit (DC power supply device) may be a power source (for example, a storage battery) that does not allow reverse power flow to the system. When the additional power source is outputting (discharged in the case of a storage battery), the additional control unit performs control to limit the output of the DC / DC converter so that a reverse power flow to the system does not occur in the entire power control system. In addition, when power is supplied from the grid (forward power flow), the additional control unit performs control to alleviate the discharge of the storage battery within the range where no reverse power flow to the grid occurs in the entire power control system. The output of the DC / DC converter is controlled so that the state does not always continue.

  The inverter of the inverter is connected to the system, but the additional unit is connected to the DC intermediate link portion of the inverter. Therefore, there is a high possibility that the distance between the current sensor and the additional unit is longer than the distance between the current sensor and the power conditioner for detecting the reverse flow power to the system. Therefore, it takes time to wire the wire connecting the current sensor for detecting the reverse power flow to the system and the additional control unit, and the installation position of the additional unit is restricted by the wiring route of the wire. There was a problem.

  The objective of this invention is providing the power converter device, power conversion system, and DC power supply device which can raise the freedom degree of the installation place of a DC power supply device.

  The power converter of one aspect of the present invention is an inverter circuit that converts the DC power input from a DC line connected to a DC power supply device that outputs DC power into AC power and outputs the AC power to the AC power system, An inverter control circuit for controlling the inverter circuit. The inverter control circuit includes at least one of a power flow flowing bidirectionally with respect to the DC power supply device and a target value of an output of the DC power supply device according to the power flow. Power information is transmitted by communication.

  The power conversion system of 1 aspect of this invention is equipped with the said power converter device and the said DC power supply device which outputs the said DC power to the said DC track | line of the said power converter device.

  The DC power supply device according to one aspect of the present invention includes a first connection unit, a second connection unit, a converter circuit, a reception unit, and a converter control unit. The first connection unit is connected to a DC power source. The second connection unit is connected to the DC line of the power converter that converts DC power input from the DC line into AC power and outputs the AC power to the AC power system. The converter circuit converts a voltage value of a DC voltage between the first connection portion and the second connection portion. The receiving unit communicates power information including at least one of a tidal power flowing bidirectionally with the AC power system and a target value of an output of the converter circuit corresponding to the tidal power from the power converter. Receive. The converter control unit controls the converter circuit based on the power information received by the receiving unit.

  ADVANTAGE OF THE INVENTION According to this invention, the power converter device, power conversion system, and DC power supply device which can raise the freedom degree of the installation place of a DC power supply device can be provided.

FIG. 1 is a system configuration diagram of a power conversion system according to an embodiment of the present invention. FIG. 2 is a system configuration diagram of a power conversion system according to Modification 1 of the embodiment of the present invention.

  The embodiment described below is only one of various embodiments of the present invention. Embodiments of the present invention are not limited to the following embodiments, and may include other embodiments. In addition, the following embodiments can be variously changed according to the design or the like as long as they do not depart from the technical idea according to the present invention.

(1) Configuration FIG. 1 is a system configuration diagram of a power conversion system 1 according to the present embodiment.

  The power conversion system 1 of this embodiment is provided in the customer facility 10 in which the solar power generation device 11 is installed as a power generation device. The power conversion system 1 is connected to the AC power system 100 and supplies power to the load 5 connected to the AC power system 100 in the customer facility 10. The power conversion system 1 outputs the surplus generated power to the AC power system 100 (reverse power flow) when the generated power generated by the solar power generation device 11 exceeds the power consumption of the load 5. Here, the customer facility 10 is a facility of a customer who receives supply of energy resources from an energy resource supplier. In the present embodiment, a detached house will be described as an example of the customer facility 10.

  The power conversion system 1 includes a DC power supply device 3 that is electrically connected to the DC line DC1 of the power conversion device 2, and a power conversion device 2 that converts DC power input from the DC line DC1 into AC power. .

  A storage battery unit 12 is connected to the DC power supply device 3. The DC power supply device 3 converts the voltage value of the DC voltage input (discharged) from the storage battery unit 12 and outputs the converted voltage value to the DC line DC1. Further, the DC power supply device 3 converts the voltage value of the DC voltage input from the DC line DC1 and outputs it to the storage battery unit 12, that is, charges the storage battery unit 12.

  Next, the configuration of each part of the power conversion system 1 will be described.

(1.1) Power Converter The power converter 2 converts the DC voltage value input from the solar power generator 11 and outputs the DC voltage to the DC line DC1, and the DC line DC1. And a DC / AC converter 22 that converts the DC power to be converted into AC power.

  The DC / DC converter 21 includes a first converter circuit 211 (a converter circuit of a power conversion device), a first control processing unit 212 (a converter control unit of a power conversion device), and a first measurement unit 213.

  The first converter circuit 211 includes, for example, a step-up type chopper circuit, converts the DC voltage input from the solar power generation device 11 into a DC voltage having a predetermined voltage value (for example, DC 300 V), and outputs the DC voltage to the DC line DC1. The switching element of the first converter circuit 211 is PWM-controlled by a control signal (PWM signal) input from the first control processing unit 212. The first converter circuit 211 may be a conversion circuit that converts a voltage value of a DC voltage, and may be a step-down type or a step-up / down type chopper circuit.

  The first measurement unit 213 includes, for example, a current sensor (for example, a Hall element, a resistor for current detection) for detecting an output current output from the first converter circuit 211 to the DC line DC1. The first measuring unit 213 measures the output current of the first converter circuit 211 at a predetermined sampling interval (for example, a time interval of several mS).

  The first control processing unit 212 includes, for example, a microcomputer having a CPU (Central Processing Unit) and a memory. The function of the first control processing unit 212 is realized by the CPU executing the program stored in the memory. The program executed by the CPU is stored in advance in a memory of a microcomputer, for example, but may be provided through an electric communication line such as the Internet or may be provided by being recorded on a recording medium such as a memory card. .

  The first control processing unit 212 controls the output of the first converter circuit 211 based on the power information input from the system management unit 223. The power information input from the system management unit 223 is a target value of the output current of the first converter circuit 211 determined by the system management unit 223, for example. The first control processing unit 212 performs PWM control of the switching element included in the first converter circuit 211 so that the output current of the first converter circuit 211 matches the target value of the output current that is power information. (PWM signal) is output to the first converter circuit 211. The first control processing unit 212 obtains an output current based on the measurement result of the first measurement unit 213, and outputs a control signal for performing PWM control so that the output current matches the target value to the first converter. The operation is repeated at predetermined time intervals.

  Here, the power information is input from the system management unit 223 to the first control processing unit 212 at a predetermined time interval (for example, 100 mS interval), and the first control processing unit 212 uses the first converter circuit 211 for this time interval. Longer than the time interval for outputting the control signal. In other words, the time interval at which the first control processing unit 212 outputs a control signal to the first converter circuit 211 is shorter than the time interval at which power information is input from the system management unit 223 to the first control processing unit 212. Therefore, the first control processing unit 212 can control the output of the first converter circuit 211 at a time interval shorter than the time interval at which the power information is input, and the control responsiveness is improved. In addition, the time interval at which the power information is input from the system management unit 223 to the first control processing unit 212 is longer than the time interval at which the first control processing unit 212 outputs the control signal to the first converter circuit 211. The communication traffic can be reduced by reducing the number of transmissions of power information.

  The DC / AC converter 22 includes an inverter circuit 220 and an inverter control circuit 221.

  The inverter circuit 220 is, for example, a full-bridge inverter circuit, and converts DC power input from the DC line DC1 into AC power. The inverter circuit 220 performs at least one of an operation of connecting AC power to the AC power system 100 and supplying AC power to the load 5 and an operation of outputting AC power to the AC power system 100. The inverter circuit 220 is not limited to a full bridge type inverter circuit, and may be a half bridge type inverter circuit.

  The inverter control circuit 221 includes an inverter control processing unit 222 and a system management unit 223. The inverter control circuit 221 controls the inverter circuit 220 as a whole.

  The inverter control processing unit 222 controls the output of the inverter circuit 220 based on the control signal input from the system management unit 223. For example, the inverter control processing unit 222 includes a microcomputer having a CPU and a memory. The function of the inverter control processing unit 222 is realized by the CPU executing a program stored in the memory. The program executed by the CPU is stored in advance in a memory of a microcomputer, for example, but may be provided through an electric communication line such as the Internet or may be provided by being recorded on a recording medium such as a memory card. .

  The system management unit 223 performs overall control of the power conversion system 1, and includes the first converter circuit 211, the inverter circuit 220, and the second converter circuit 31 (the converter circuit of the DC power supply device) included in the DC power supply device 3. Control the behavior. The system management unit 223 includes, for example, a microcomputer having a CPU and a memory. The function of the system management unit 223 is realized by the CPU executing a program stored in the memory. The program executed by the CPU is stored in advance in a memory of a microcomputer, for example, but may be provided through an electric communication line such as the Internet or may be provided by being recorded on a recording medium such as a memory card. . Note that the system management unit 223 and the inverter control processing unit 222 may be realized by a single microcomputer.

  Further, the system management unit 223 includes a communication unit 224, a measurement unit 225, and a control command unit 226.

  The communication unit 224 communicates with the DC power supply device 3 by wireless communication. The communication unit 224 includes a low-power wireless communication module that does not require a wireless station license. For this type of low-power radio, specifications such as the frequency band to be used and the antenna power are defined in each country depending on the application. In Japan, low power radio (specific low power radio) using radio waves such as 920 MHz band, 420 MHz band, 2.4 GHz band, and 5 GHz band is defined. Note that the communication unit 224 is not limited to a low-power wireless communication interface and can be changed as appropriate. For example, a communication interface compliant with the ZigBee (registered trademark) standard, a communication interface compliant with the Bluetooth (registered trademark) standard, or the like. But you can.

  The communication unit 224 also has a function of communicating with the first control processing unit 212 of the DC / DC converter 21. Communication between the communication unit 224 and the first control processing unit 212 may be wired or wireless.

  Using the current sensor 227, the measuring unit 225 measures the current I1 that flows through the electric circuit that connects the AC power system 100 and the customer facility F1. The current sensor 227 is a current transformer, a Hall element, or the like. For example, the customer facility F1 is provided with power receiving equipment such as a distribution board for storing a main breaker and a branch breaker, and a load 5 is connected to a branch circuit branched by the branch breaker. The current sensor 227 measures the current I1 flowing through the electric path connecting the AC power system 100 and the power receiving facility, and measures the current I1 on the AC power system 100 side with respect to the power receiving facility. The tidal power (forward power, reverse power) can be obtained based on the value.

  Based on the polarity of the current I1 measured by the measuring unit 225, the control command unit 226 outputs power to the AC power system 100 in a state where power is being input from the AC power system 100 (power purchase state). It is judged whether it is in a state (power sale state). Then, the control command unit 226 obtains input power from the AC power system 100 based on the current value of the current I1 in the power purchase state, and AC based on the current value of the current I1 in the power sale state. The output power to the power system 100 is obtained. Here, power flowing from the AC power system 100 to the customer facility F1 is referred to as “forward power flow”, and power flowing from the customer facility F1 to the AC power system 100 is referred to as “reverse power flow power”. Further, forward power and reverse power are collectively referred to as “tidal power”. The tidal current power is power that flows in both directions without the direction of power movement being fixed in one direction between the AC power system 100 and the customer facility F1. The tidal power when flowing from the AC power system 100 to the customer facility F1 is forward power, and the tidal power when flowing from the customer facility F1 to the AC power system 100 is reverse power. The power purchase state is a state in which power is input from the AC power system 100. For example, the total of the generated power of the solar power generation device 11 and the power supplied from the storage battery unit 12 is consumed by the load 5. The power is in excess. The power sale state is a state in which power is output to the AC power system 100, for example, a state in which the generated power of the solar power generation device 11 exceeds the power consumption of the load 5.

  The control command unit 226 sends power information for instructing the first control processing unit 212 of the DC / DC converter 21 to output power corresponding to the generated power of the solar power generation device 11 from the communication unit 224. It transmits to the 1st control processing part 212 by communication.

  On the other hand, the control command unit 226 determines power information to be output to the DC power supply device 3 connected to the storage battery unit 12 depending on whether the power purchase state or the power sale state, and this power information is transmitted from the communication unit 224. It transmits to the 2nd control processing part 32 by communication.

  Further, the operation unit 4 such as a dip switch is connected to the system management unit 223, and data corresponding to ON / OFF of the switch is input to the system management unit 223.

(1.2) DC Power Supply Device The DC power supply device 3 includes a first connection unit 301, a second connection unit 302, a second converter circuit 31 (a converter circuit of the DC power supply device 3), and a second control processing unit 32. (Converter control unit of DC power supply device 3), second measurement unit 33, and communication unit 34 (reception unit). The DC power supply device 3 is a charge / discharge device that charges or discharges the storage battery unit 12.

  The 1st connection part 301 is connected to the storage battery unit 12 which is DC power supply.

  The second connection unit 302 is electrically connected to the DC line DC <b> 1 of the power conversion device 2 via the electric wire 6.

  The second converter circuit 31 is, for example, a step-up / step-down bidirectional converter circuit, and converts the voltage value of the DC voltage between the first connection unit 301 and the second connection unit 302. The operation of the second converter circuit 31 is controlled by a control signal (PWM signal) input from the second control processing unit 32. When discharging from the storage battery unit 12, the second converter circuit 31 converts (boosts) the DC voltage value input from the storage battery unit 12 to a predetermined voltage value, and outputs the voltage value to the DC line DC <b> 1 via the electric wire 6. When charging the storage battery unit 12, the second converter circuit 31 converts (steps down) a DC voltage value input from the DC line DC <b> 1 via the electric wire 6 and outputs the voltage to the storage battery unit 12, that is, the storage battery unit 12. Charge.

  The second measurement unit 33 includes, for example, a current sensor (for example, a hall element, a current detection resistor, etc.) provided in an electric circuit that connects the second converter circuit 31 and the second connection unit 302. . The second measuring unit 33 measures the output current or the input current of the second converter circuit 31 at a predetermined sampling interval (for example, a time interval of several mS).

  The communication unit 34 communicates with the communication unit 224 of the power conversion device 2 by wireless communication. The communication unit 34 receives power information transmitted from the power conversion device 2. The power information is, for example, the target of the output current or input current of the second converter circuit 31 (output current to the DC line DC1 when the storage battery unit 12 is discharged, and input current from the DC line DC1 when the storage battery unit 12 is charged). Value. The communication unit 34 includes a communication module having the same communication method as that of the communication unit 224 of the power conversion device 2, and performs communication with the communication unit 224 by wireless communication.

  The second control processing unit 32 controls the output of the second converter circuit 31. The second control processing unit 32 includes, for example, a microcomputer having a CPU and a memory. The function of the second control processing unit 32 is realized by the CPU executing the program stored in the memory. The program executed by the CPU is stored in advance in a memory of a microcomputer, for example, but may be provided through an electric communication line such as the Internet or may be provided by being recorded on a recording medium such as a memory card. .

  The second control processing unit 32 periodically sets the target value of the output current of the second converter circuit 31 based on the power information (target value of the output current) that the communication unit 34 periodically receives from the power conversion device 2. Update to

  The second control processing unit 32 generates a control signal (PWM signal) for PWM control of the switching element included in the second converter circuit 31 so that the output current measured by the second measurement unit 33 matches the target value. The operation of outputting to the second converter circuit 31 is repeatedly performed continuously.

  Here, power information is input from the system management unit 223 to the communication unit 34 at a predetermined time interval (for example, an interval of 100 mS), and the second control processing unit 32 sends a control signal to the second converter circuit 31 during this time interval. Longer than the output time interval. In other words, the time interval at which the second control processing unit 32 outputs the control signal to the second converter circuit 31 is shorter than the time interval at which power information is input from the system management unit 223 to the communication unit 34. Therefore, the second control processing unit 32 can control the output of the second converter circuit 31 at a time interval shorter than the time interval at which the power information is input, and the control responsiveness is improved. Further, since the time interval at which the power information is input from the system management unit 223 to the communication unit 34 is longer than the time interval at which the second control processing unit 32 outputs the control signal to the second converter circuit 31, the power information Communication traffic can be reduced by reducing the number of times of transmission.

(2) Operation The operation of the power conversion system 1 of the present embodiment will be described below.

  The measurement unit 225 of the system management unit 223 uses the current sensor 227 to measure the current I1 at a predetermined time interval. Based on the measurement result of the measurement unit 225, the control command unit 226 of the system management unit 223 is in a power purchase state in which power is input from the AC power system 100 or power sale that outputs power to the AC power system 100. Judge whether it is in the state, and obtain the tidal current power. The control command unit 226 determines the target value of the input / output current of the DC power supply device 3 and the target value of the output current of the DC / DC converter 21 based on the result of obtaining the power flow.

  In the power purchase state, the control command unit 226 controls the output of the DC power supply device 3 to discharge from the storage battery unit 12 in order to reduce the input power from the AC power system 100. That is, the control command unit 226 determines the target value of the output power from the DC power supply device 3 based on the power value of the input power from the AC power system 100, the output capability of the inverter circuit 220, and the like. Then, the control command unit 226 transmits a control signal instructing the target value of the output current corresponding to the target value of the output power from the communication unit 224 to the communication unit 34 of the DC power supply device 3 by communication.

  Further, in the current operation, since it is not permitted to reversely flow the electric power discharged from the storage battery unit 12 to the AC power system 100, the control command unit 226 allows the direct current power supply so that the reverse power flow becomes zero. A target value of output power (that is, output current) from the device 3 is determined. Then, the control command unit 226 transmits a control signal indicating the determined output current from the communication unit 224 to the communication unit 34 of the DC power supply device 3 by communication. Further, in the power sale state, when the generated power of the solar power generation device 11 exceeds the output capability of the inverter circuit 220, the control command unit 226 transmits a control signal that instructs the storage battery unit 12 to be charged. To the communication unit 34 of the DC power supply device 3 by communication.

  As described above, the control command unit 226 determines the target value of the input / output current of the DC power supply device 3 and the target value of the output current of the DC / DC converter 21 depending on whether the power purchase state or the power sale state. . Then, the control command unit 226 transmits the target value of the input / output current of the DC power supply device 3 and the target value of the output current of the DC / DC converter 21 from the communication unit 224 at a predetermined time interval. / Controls the output of the DC converter 21. Further, the system management unit 223 controls the output of the inverter circuit 220 by outputting a control signal to the inverter control processing unit 222 at predetermined time intervals.

  When the first control processing unit 212 of the DC / DC converter 21 receives the target value of the output current from the system management unit 223, the first converter circuit so that the output current from the first converter circuit 211 matches the target value. The switching element 211 is PWM controlled.

  In addition, when the communication unit 34 receives the target value of the output current from the system management unit 223, the second control processing unit 32 of the DC power supply device 3 ensures that the output current from the second converter circuit 31 matches the target value. Then, the switching element of the second converter circuit 31 is PWM-controlled.

  As described above, the system management unit 223 of the power conversion device 2 transmits the target value of the input / output current based on the power flow (forward power or reverse power) to the DC / DC converter 21 and the DC power supply device 3. Therefore, there is no need for the DC power supply device 3 and the DC / DC converter 21 to include a circuit for measuring the power flow. Therefore, between a DC power supply device (DC power supply device 3 and DC / DC converter 21) connected to a DC power supply that does not allow reverse power flow and a circuit (for example, a current sensor) for measuring power flow. No need to connect wires. Therefore, there is an advantage that the labor of wiring work is reduced and the degree of freedom of the installation position of the DC power supply device 3 is improved. Further, when the DC power supply 3 is added, it is not necessary for the DC power supply 3 to be added to include a circuit for measuring the power flow, and the DC power supply 3 to be added and a circuit for measuring the power flow (for example, There is an advantage that an electric wire connecting between the current sensor and the like becomes unnecessary. Here, the system management unit 223 converts the direct-current voltage input from the direct-current power source and outputs the target value of the output current or output power to the direct-current power supply device and the DC / DC converter that perform only one-way voltage conversion. Can be sent. In addition, the system management unit 223 transmits a target value of input / output current or input / output power to the DC power supply device and the DC / DC converter that perform bidirectional voltage conversion.

(3) Modified Examples Below, power converters according to modified examples of the above embodiment are listed. In addition, each structure of the modified example demonstrated below is applicable in combination with each structure demonstrated in the said embodiment suitably.

(3.1) Modification 1
FIG. 2 is a system configuration diagram of a power conversion system 1A according to the first modification. Hereinafter, components similar to those in the above embodiment are denoted by common reference numerals and description thereof is omitted as appropriate.

  In the power conversion system 1 of the above embodiment, the power conversion device 2 includes the DC / DC converter 21, but in the power conversion system 1 </ b> A of the first modification, the power conversion device 2 </ b> A includes only the DC / AC converter 22. Two DC power supply devices 3 and 3A are connected to the DC line DC1 of the power conversion device 2A via electric wires 6 and 6A. A storage battery unit 12 is connected to the DC power supply device 3, and a photovoltaic power generation device 11 is connected to the DC power supply device 3A.

  The DC power supply device 3 </ b> A has the same configuration as the DC power supply device 3. The first connection unit 301A, the second connection unit 302A, the second control processing unit 32A, the second measurement unit 33A, and the communication unit 34A of the DC power supply device 3A are respectively connected to the first connection unit 301 and the second connection unit of the DC power supply device 3. This corresponds to the connection unit 302, the second control processing unit 32, the second measurement unit 33, and the communication unit 34. Therefore, description of the first connection unit 301A, the second connection unit 302A, the second control processing unit 32A, the second measurement unit 33A, and the communication unit 34A is omitted. Further, the second converter circuit 31A of the DC power supply device 3A is the same as the second converter circuit 31 of the DC power supply device 3 except that only one-way voltage conversion is performed, and thus the description thereof is omitted.

  In the first modification, DC power supply devices 3 and 3A that convert a DC voltage input from a DC power source into a DC voltage having a predetermined voltage value and a power conversion device 2A that includes only the DC / AC converter 22 are modularized. Yes. Desired DC power supply devices 3 and 3A can be connected to the DC line DC1 of the power conversion device 2A, and the power conversion device 2A converts DC power input from the DC power supply devices 3 and 3A into AC power.

  Also in the first modification, the DC power supply devices 3 and 3A receive the target value (power information) of the input / output current based on the power flow from the power conversion device 2, so the DC power supply devices 3 and 3A measure the power flow. It is not necessary to provide a circuit for performing the above. Therefore, a circuit for measuring power flow (for example, a current sensor) and the DC power supply devices 3 and 3A are not required, and the wiring work is reduced, so that the DC power supply devices 3 and 3A are reduced. The degree of freedom of the installation position is improved.

  In Modification 1, two DC power supply devices 3 and 3A are connected to the power conversion device 2A. However, one DC power supply device may be connected to the power conversion device 2A, or three or more DC power supplies may be connected. A power supply device may be connected.

(3.2) Other Modifications In the above-described embodiment and Modification 1, the inverter control circuit 221 supplies power to the second control processing units 32 and 32A of the DC power supply devices 3 and 3A including the bidirectional converter. The current value (target current value) of the corresponding input / output current is transmitted as power information. Further, the inverter control circuit 221 transmits the current value (target current value) of the output current corresponding to the power flow as power information to the first control processing unit 212 of the DC / DC converter 21 including the unidirectional converter. Yes. Since the voltage value of the DC line DC1 is constant at about 300V, the inverter control circuit 221 transmits the current value (target current value) of the input / output current or the output current as the target value, so that the output power is a desired value. Can be controlled. The inverter control circuit 221 transmits a target value (target current value) of a current (output current or input / output current) corresponding to the tidal power as power information, but power (output power or A target value (target power value) of (input / output power) may be transmitted to the second control processing units 32 and 32A and the first control processing unit 212 as power information. When the variation in output voltage between the DC / DC converter 21 and the DC power supply devices 3 and 3A is large, the inverter control circuit 221 transmits the target value of power to the DC / DC converter 21 and the DC power supply devices 3 and 3A. Thus, the power (output power or input / output power) can be controlled to a desired value (target power value).

  Here, the target values of current and power may be absolute values of current and power, or may be relative values that are changes in current and power from the previous transmission.

  Further, the inverter control circuit 221 may transmit the power flow itself to the second control processing units 32 and 32A and the first control processing unit 212 as power information. When the second control processing units 32 and 32A and the first control processing unit 212 receive the tidal power as power information, the currents of the second converter circuits 31 and 31A and the first converter circuit 211 based on the received tidal power ( A target value of output current or input current) or power (output power or input power) is determined. The second converter circuits 31, 31A and the first converter circuit 31, 31A and the first converter circuit 211 have a current (output current or input current) or power (output power or input power) that matches the target value. The switching element of the first converter circuit 211 is PWM controlled. For example, when reverse power flow is generated, the second control processing units 32 and 32A of the DC power supply devices 3 and 3A connected to the storage battery unit 12 that does not allow reverse power flow are connected to the second converter circuits 31 and 31A. Is determined so that the reverse power flow is zero. Then, the output current or output power of the second converter circuit 31, 31A is controlled so that the output current or output power of the second converter circuit 31, 31A matches the target value, that is, the reverse power flow power becomes zero. To do. Further, the inverter control circuit 221 may transmit both the power flow and the output target value corresponding to the power flow as power information to the second control processing units 32 and 32A and the first control processing unit 212 by communication. Good. In this case, the second control processing units 32 and 32A and the first control processing unit 212 may control input / output based on at least one of the tidal power and the input / output target value corresponding to the tidal power.

  In the embodiment and the first modification, the communication units 34 and 34A of the DC power supply devices 3 and 3A and the first control processing unit 212 of the DC / DC converter 21 receive power information from the communication unit 224 of the inverter control circuit 221. Then, a reply signal may be transmitted to the communication unit 224. In this case, the inverter control circuit 221 may confirm the reception of the power information depending on whether or not a reply signal is received after transmitting the power information. Inverter control circuit 221 determines that communication partner 34, 34A or first control processing unit 212 of the transmission partner has failed to receive power information if it cannot receive a reply signal within a certain time from the time of transmission of power information. . At this time, the inverter control circuit 221 may retransmit the power information to the communication partner 34, 34A or the first control processing unit 212 of the transmission partner, or at the next transmission timing, the communication partner 34, 34A or the first of the transmission partner. The power information may be transmitted to one control processing unit 212. In addition, when the inverter control circuit 221 transmits the target value of the output current or output power as a relative value, the inverter control circuit 221 determines that the current relative value for which transmission failed and the relative value at the next transmission timing are What is necessary is just to transmit at the next transmission timing by making the value which added together into the target value.

  Further, in the above-described embodiment and Modification 1, when a plurality of DC power supply devices are connected to the DC line DC1, the inverter control circuit 221 supplies power information including a target value of output to each of the plurality of DC power supply devices. Send by communication. Here, when the inverter control circuit 221 transmits the output target value to the plurality of DC power supply devices, the plurality of DC power supply devices are set so that the sum of the outputs of the plurality of DC power supply devices becomes a value corresponding to the reverse power flow. What is necessary is just to determine the target value transmitted to each of the apparatuses. The inverter control circuit 221 transmits a target to be transmitted to each DC power supply device so as to reduce the output power of each DC power supply device by a value obtained by equally dividing the reverse power flow by the number of DC power supply devices that do not allow reverse power flow, for example. The value may be determined. In addition, when priority is set for each of a plurality of DC power supply devices that do not allow reverse power flow, the target power transmitted to each DC power supply device is set according to the priority so that the reverse power flow becomes zero. It may be set by assigning with different weights. This priority (priority order) may be set, for example, according to the response characteristic of the output suppression control of each DC power supply device, or may be set according to the rated value of the input / output power of each DC power supply device. Good. Moreover, when each DC power supply device is a storage battery, the priority (priority order) may be set according to the chargeable capacity (remaining power storage amount) at that time.

  In the embodiment and the first modification, DC power from two DC power sources is input to the DC line DC1, but DC power from three or more DC power sources may be input to the DC line DC1. In the said embodiment and the modification 1, although the solar power generation device 11 which is a power generation device and the stationary storage battery unit 12 were illustrated as DC power supply, DC power supply is power generation devices, such as a fuel cell and a wind power generator. However, it may be a storage battery of an electric vehicle. The electric vehicle is, for example, a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle, or the like.

  The communication unit 224 transmits power information to the DC power supply device 3 and the DC / DC converter 21 by wireless communication, but the communication method is not limited to wireless communication, and may be wired communication. In the case of wired communication, the communication unit 224 may perform communication using, for example, a power line carrier communication method, or may perform communication via a dedicated communication line.

  Although the case where the customer facility 10 is a detached house has been described in the above embodiment and the modified example 12, the customer facility 10 may be a dwelling unit of an apartment house or a tenant of an office building or a commercial building.

(Summary)
The power conversion device (2, 2A) of the first aspect includes an inverter circuit (220) and an inverter control circuit (221) that controls the inverter circuit (220). The inverter circuit (220) converts DC power input from a DC line (DC1) to which a DC power supply (3, 3A) that outputs DC power is connected to AC power and outputs the AC power to the AC power system (100). To do. The inverter control circuit (221) transmits power information by communication to the DC power supply (3, 3A). The power information includes at least one of a tidal power flowing bidirectionally with the AC power system (100) and a target value of the output of the DC power supply (3, 3A) according to the tidal power.

  According to this configuration, since the inverter control circuit (221) transmits power information to the DC power supply (3, 3A) by communication, the DC power supply (3, 3A) and the tidal power are measured. This eliminates the need for an electric wire that connects the circuit (for example, a current sensor). Therefore, there is an advantage that the labor of wiring work is reduced and the degree of freedom of the installation position of the DC power supply (3, 3A) is improved.

  In the power conversion device (2, 2A) of the second aspect, in the first aspect, the DC power supply device includes the charge / discharge device (3). The charging / discharging device (3) includes a bidirectional converter circuit (31) connected to the storage battery (12) and performing bidirectional voltage conversion between the storage battery (12) and the DC line (DC1). The power information transmitted from the inverter control circuit (221) to the charging / discharging device (3) includes at least one of the tidal power and the input / output target value of the bidirectional converter circuit (31) corresponding to the tidal power.

  According to this configuration, since the inverter control circuit (221) transmits power information to the charging / discharging device (3) by communication, the charging / discharging device (3) and a circuit for measuring power flow (for example, No electric wires are required to connect between the current sensor and the like. Therefore, there is an advantage that the labor of wiring work is reduced and the degree of freedom of the installation position of the charge / discharge device (3) is improved.

  In the power conversion device (2, 2A) of the third aspect, in the first or second aspect, the plurality of DC power supply devices (3, 3A) are connected to the DC line (DC1). When the inverter control circuit (221) transmits the target value of the output to the plurality of DC power supply devices (3, 3A), the sum of the outputs of the plurality of DC power supply devices (3, 3A) is a value corresponding to the tidal power. In this manner, a target value to be transmitted to each of the plurality of DC power supply devices (3, 3A) is determined.

  According to this configuration, when a plurality of DC power supply devices (3, 3A) are connected to the DC line (DC1), the inverter control circuit (221) is connected to each of the plurality of DC power supply devices (3, 3A). The target value can be adjusted.

  In the power conversion device (2, 2A) of the fourth aspect, in any one of the first to third aspects, the time interval at which the inverter control circuit (221) transmits the power information to the DC power supply device (3, 3A). However, it is longer than the time interval at which the DC power supply (3, 3A) repeats the output control operation.

  According to this configuration, since the time interval at which the DC power supply device (3, 3A) repeats the output control operation is shorter than the time interval at which the DC power supply device (3, 3A) receives power information, the control responsiveness is improved. improves. Further, since the time interval at which the DC power supply device (3, 3A) receives the power information is longer than the time interval at which the DC power supply device (3, 3A) repeats the output control operation, the number of transmissions of the power information can be reduced.

  In the power conversion device (2, 2A) of the fifth aspect, in any one of the first to fourth aspects, the target value is the current output from the DC power supply device (3, 3A) to the DC line (DC1). This is the target current value.

  According to this configuration, the current value of the current output from the DC power supply (3, 3A) to the DC line (DC1) can be controlled to the target current value.

  In the power conversion device (2, 2A) of the sixth aspect, in any of the first to fourth aspects, the target value is the power output from the DC power supply device (3, 3A) to the DC line (DC1). This is the target power value.

  According to this configuration, the power value of the power output from the DC power supply (3, 3A) to the DC line (DC1) can be controlled to the target value.

  In the power conversion device (2, 2A) of the seventh aspect, in any of the first to sixth aspects, the inverter control circuit (221) transmits power information to the DC power supply device (3, 3A). After that, the reception confirmation of the power information is performed depending on whether or not a reply signal is received from the DC power supply (3, 3A).

  According to this configuration, the inverter control circuit (221) confirms the reception of the power information depending on whether or not the reply signal is received. Therefore, when the reception confirmation cannot be performed, the inverter control circuit (221) performs processing such as resending the power information. It can be carried out.

  In the power converter device (2, 2A) of the eighth aspect, in any of the first to seventh aspects, the DC power supply device (3, 3A) is based on the power information received from the inverter control circuit (221). Control the output.

  According to this structure, the freedom degree of the installation position of DC power supply device (3, 3A) which can control an output based on the electric power information received from the inverter control circuit (221) can be improved.

  In the power converter (2) of the ninth aspect, in any one of the first to eighth aspects, the voltage value of the DC voltage input from the DC power supply (11) is converted and output to the DC line (DC1). A converter circuit (211) is further provided.

  According to this configuration, only the power conversion device (2) can convert DC power input from the DC power supply (11) into AC power and output the AC power to the AC power system (100).

  A power conversion system (1, 1A) according to a tenth aspect includes a power conversion device (2, 2A) according to any one of the first to ninth aspects, and a direct current line (DC1) of the power conversion device (2, 2A). And a DC power supply device (3, 3A) for outputting DC power.

  According to this structure, the freedom degree of the installation position of DC power supply device (3, 3A) can be improved.

  The DC power supply device (3, 3A) of the eleventh aspect includes a first connection unit (301, 301A), a second connection unit (302, 302A), a converter circuit (31, 31A), and a reception unit (34). , 34A) and a processing unit (32, 32A). The first connection part (301, 301A) is connected to the DC power supply (11, 12). The second connection unit (302, 302A) is connected to the DC line (DC1) of the power converter (2, 2A). The power converter (2, 2A) converts DC power input from the DC line (DC1) into AC power and outputs the AC power to the AC power system (100). The converter circuit (31, 31A) converts a DC voltage value between the first connection part (301, 301A) and the second connection part (302, 302A). The receiver (34, 34A) receives at least one of the tidal power output from the power converter (2, 2A) to the AC power system (100) and the target value of the output of the converter circuit (31) according to the tidal power. The included power information is received from the power converter (2, 2A) by communication. The converter control unit (32, 32A) controls the converter circuit (31, 31A) based on the power information received by the receiving unit (34, 34A).

  According to this structure, the freedom degree of the installation position of DC power supply device (3, 3A) can be improved.

1, 1A power conversion system 2, 2A power conversion device 3 DC power supply (charge / discharge device)
3A DC power supply 4 Operation part 5 Load 11 Solar power generator (DC power supply)
12 Storage battery unit (DC power supply)
31, 31A Second converter circuit (converter circuit of DC power supply device)
32, 32A second control processing unit (converter control unit of DC power supply device)
34, 34A Communication unit (receiving unit)
100 AC power system 211 First converter circuit (converter circuit of power converter)
212 1st control process part (converter control part of a power converter device)
220 Inverter circuit 221 Inverter control circuit 224 Communication unit 225 Measurement unit 301 First connection unit 302 Second connection unit DC1 DC line

Claims (11)

An inverter circuit that converts the DC power input from a DC line connected to a DC power supply device that outputs DC power into AC power and outputs the AC power to the AC power system;
An inverter control circuit for controlling the inverter circuit,
The inverter control circuit includes at least one of a power flow flowing bidirectionally with respect to the DC power supply device and a target value of an output of the DC power supply device according to the power flow. A power converter that transmits power information by communication. The DC power supply device includes a charging / discharging device having a bidirectional converter circuit connected to a storage battery and performing bidirectional voltage conversion between the storage battery and the DC line,
The power information transmitted to the charging / discharging device by the inverter control circuit includes at least one of the power flow and a target value of input / output of the bidirectional converter circuit according to the power flow. Power converter. A plurality of the DC power supply devices are connected to the DC line;
When the inverter control circuit transmits a target value of output to the plurality of DC power supply devices, the plurality of DC power supplies so that a sum of outputs of the plurality of DC power supply devices becomes a value according to the power flow. The power conversion device according to claim 1 or 2, wherein the target value to be transmitted to each of the devices is determined. The electric power according to any one of claims 1 to 3, wherein a time interval at which the inverter control circuit transmits the power information to the DC power supply device is longer than a time interval at which the DC power supply device repeats an output control operation. Conversion device. The power converter according to any one of claims 1 to 4, wherein the target value is a target current value of a current output from the DC power supply device to the DC line. The power conversion device according to any one of claims 1 to 4, wherein the target value is a target power value of power output from the DC power supply device to the DC line. The inverter control circuit performs reception confirmation of the power information depending on whether or not a reply signal is received from the DC power supply device after transmitting the power information to the DC power supply device. The power conversion device according to item 1. The power converter according to any one of claims 1 to 7, wherein the DC power supply device controls an output based on the power information received from the inverter control circuit. The power converter according to claim 1, further comprising a converter circuit that converts a voltage value of a DC voltage input from a DC power source and outputs the voltage value to the DC line. The power conversion device according to any one of claims 1 to 9,
The DC power supply device that outputs the DC power to the DC line of the power conversion device. A power conversion system. A first connection connected to a DC power source;
A second connection portion connected to the DC line of the power converter that converts DC power input from the DC line into AC power and outputs the AC power to the AC power system;
A converter circuit for converting a voltage value of a DC voltage between the first connection part and the second connection part;
A receiving unit that receives power information including at least one of tidal power flowing bidirectionally between the AC power system and a target value of the output of the converter circuit according to the tidal power from the power converter by communication; ,
And a converter control unit that controls the converter circuit based on the power information received by the receiving unit.

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