JP2017212825A - Power storage device, power conditioner, and dispersed power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To charge a storage battery by a self-supported output of a photovoltaic generation power conditioner by making full utilization of electric power generated by a photovoltaic power generator.SOLUTION: A power storage device 100 includes: a storage battery 101; an input terminal 114 capable of receiving electric power supplied from a self-supported output terminal 22 of a photovoltaic generation power conditioner 20; and a control part 103 for controlling an upper-limit setting value of a received current from the input terminal 114 according to a value of a received voltage from the input terminal 114.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device, a power conditioner, and a distributed power supply system.

  2. Description of the Related Art A distributed power supply system that controls a distributed power supply such as a solar power generation device or a power storage device linked to a system is known (see, for example, Patent Document 1).

  Conventionally, in a distributed power supply system in which both a photovoltaic power generation device and a power storage device are connected to the grid, a storage battery in the power storage device is supplied with power supplied by the independent output of the photovoltaic power conditioner when the power failure occurs. It was difficult to charge.

  However, in recent years, power storage device products having a dedicated terminal for receiving the self-sustained output of a photovoltaic power conditioner are on the market. According to the power storage device provided with such a dedicated terminal, it is possible to charge the storage battery in the power storage device with power received from the self-sustained output of the photovoltaic power conditioner during a power failure.

JP 2011-101523 A

  The self-sustained output of the photovoltaic power conditioner has an overload protection function for stopping the self-sustained output when normal power supply cannot be performed. For example, when the voltage of the self-sustained output decreases to 80 V and the state continues for 2 seconds, the solar power generation power conditioner stops the self-sustained output by the overload protection function.

  For power storage devices with dedicated terminals that can receive the stand-alone output of the photovoltaic power conditioner, set the maximum value of the received current to a larger value in order to use the stand-alone output of the photovoltaic power conditioner without waste. It is preferable. Since the general maximum output current of the photovoltaic power conditioner is 15A, many power storage devices set the maximum value of the received current to a value close to 15A (for example, 14A).

  However, if the maximum value of the power receiving current of the power storage device is set to a larger value, the risk that the self-sustained output of the photovoltaic power conditioner stops due to the overload protection function when the amount of solar radiation decreases is increased. Then, the time when the photovoltaic power conditioner is stopped by the overload protection function becomes longer, and as a result, the generated power of the photovoltaic power generation device may not be fully utilized for charging the storage battery. .

  An object of the present invention made in view of such a point is to provide a power storage device and a power conditioner that can fully utilize the power generated by the solar power generation device and charge a storage battery by the independent output of the solar power generation power conditioner. And providing a distributed power supply system.

  The power storage device according to the embodiment of the present invention includes a storage battery, an input terminal capable of receiving power supplied from a self-supporting output terminal of the photovoltaic power conditioner, and a value of a received voltage from the input terminal, And a control unit that controls an upper limit set value of the received current from the input terminal.

  Moreover, the power conditioner which concerns on embodiment of this invention is a power conditioner for storage batteries which converts into direct-current power or alternating current power. The power conditioner has an input terminal capable of receiving power supplied from a self-sustained output terminal of a photovoltaic power conditioner, and a received current from the input terminal according to a value of a received voltage from the input terminal. A control unit for controlling the upper limit set value.

  Moreover, the distributed power supply system which concerns on embodiment of this invention is provided with a photovoltaic power conditioner and an electrical storage apparatus. The power storage device includes: a storage battery; an input terminal capable of receiving power supplied from a self-sustained output terminal of the photovoltaic power conditioner; and a value of a received voltage from the input terminal, from the input terminal. And a control unit that controls an upper limit set value of the received current.

  According to the power storage device, the power conditioner, and the distributed power supply system according to the embodiment of the present invention, the storage battery is charged by the self-sustained output of the photovoltaic power conditioner by fully utilizing the generated power of the photovoltaic power generator. Can do.

1 is a diagram illustrating a schematic configuration of a distributed power supply system according to a first embodiment of the present invention. It is a figure which shows a mode that the total amount of received electric power changes depending on the upper limit setting value of an incoming current. It is a figure which shows a mode that the total received electric energy increases when the upper limit set value of a received electric current is made variable. When the amount of solar radiation decreases in the daytime, it is a figure which shows a mode that the total received electric energy increases when the upper limit setting value of an incoming current is made variable. It is a figure which shows a mode that a receiving current is reduced. 2 is a flowchart illustrating an example of an operation in which the power storage device of FIG. 1 reduces an upper limit set value of a received current. It is a figure which shows schematic structure of the distributed power supply system which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, the distributed power supply system 1 includes a solar cell 10, a photovoltaic power conditioner 20, a load 30, and a power storage device 100. In FIG. 1, a solid line connecting each functional block mainly indicates a power line, and a broken line mainly indicates a communication line or a signal line.

  The solar cell 10 generates DC power from sunlight energy and supplies it to the photovoltaic power conditioner 20.

  The photovoltaic power conditioner 20 converts the DC power supplied from the solar cell 10 into AC power. The photovoltaic power conditioner 20 is used in conjunction with the system 40. The photovoltaic power conditioner 20 can sell electric power from the interconnection output terminal 21 to the grid 40 (electric power company) at normal times.

  The photovoltaic power conditioner 20 performs a self-sustained operation when power from the grid 40 is stopped, and supplies power from the self-sustained output terminal 22. When the power from the system 40 stops, for example, when a power failure occurs or when the power is disconnected from the system 40. In the following description, the case of a power failure will be described as an example. The self-supporting output terminal 22 is connected to the self-supporting input terminal 114 of the power storage device 100, and the photovoltaic power conditioner 20 can supply power from the self-supporting output terminal 22 to the power storage device 100 during a power failure of the system 40. it can.

  The photovoltaic power conditioner 20 has an “overcurrent protection function” and an “overload protection function” as protection functions for stopping the self-sustained output when there is a possibility of causing a failure in an internal power conversion circuit or the like. .

  The overcurrent protection function is activated when a state in which the voltage of the self-sustained output is within a predetermined voltage range and a current larger than the predetermined current flows continues for a predetermined time, and stops the self-sustained output. As a specific value, for example, when the voltage of the self-sustained output is in the range of 80 to 90 V and a state in which a current exceeding 15 A flows continues for 30 seconds, the photovoltaic power conditioner 20 is activated by the operation of the overcurrent protection function. Independent output is stopped. In general, photovoltaic power conditioners sold for residential use do not automatically return because there is a possibility that the equipment will cause a serious failure such as heat generation in the situation where the overcurrent protection function operates. Is set to For this reason, once the operation is stopped, the generated power is thrown away until an artificial return operation is performed.

  The overload protection function is a protection function for quickly responding to, for example, insufficient output of solar power due to insufficient solar radiation, resulting in excessive load power consumption, or an emergency condition such as an output short circuit. The overload protection function operates when a state where the voltage of the self-supporting output is equal to or lower than a predetermined voltage value continues for a predetermined time, and stops the self-supporting output. As a specific value, for example, when the state where the output voltage is less than 80 V continues for 2 seconds, the photovoltaic power conditioner 20 stops the self-sustained output by the operation of the overload protection function. In general, photovoltaic power conditioners sold for home use are often set to automatically return after a lapse of about 300 seconds even if the overload protection function is activated. The reason for this automatic recovery setting is that the overload protection function is activated due to excessive load power consumption due to insufficient solar radiation. This is due to the consideration of sex.

  The load 30 is an electric device connected to the specific output terminal 113 of the power storage device 100. The load 30 is a highly important electrical device that is operated even during a power failure of the system 40, and is, for example, a charger for a mobile terminal or a television. In this embodiment, the case where the load 30 can be controlled from the outside by a predetermined protocol via the home network will be described. However, when the load 30 is not controlled from the outside, the operation is performed by opening the switching relay 110 of the power storage device 100. It may be stopped. For example, ECHONET Lite (registered trademark) can be used as the predetermined protocol.

  In the event of a power failure, the power storage device 100 receives the power supplied from the independent output terminal 22 of the photovoltaic power conditioner 20 by drawing it into the independent input terminal 114. Hereinafter, the power received from the independent output terminal 22 to the independent input terminal 114 is referred to as “received power”. The voltage of the received power is referred to as “received voltage”, and the current of the received power is referred to as “received current”.

  The power storage device 100 sets the upper limit value of the received current received from the photovoltaic power conditioner 20 as the upper limit set value, and controls the received current so that the received current does not exceed the upper limit set value. The upper limit set value may be a value given by the manufacturer of power storage device 100 as an initial set value, or may be a set value set by a user by remote operation or manual operation by communication means. However, it may be a value set by an installer or an electrician. The power storage device 100 reduces the amount of charge of the storage battery 101, for example, when reducing the received current. Alternatively, when reducing the received current, the power storage device 100 reduces the power supplied to the load 30 connected to the specific output terminal 113, for example.

  The power storage device 100 includes a storage battery 101, a bidirectional inverter 102, a control unit 103, a storage unit 104, a current sensor 105, an interconnection relay 107, a system link relay 108, a self-supporting relay 109, and a switching relay 110. A solar power link relay 111, a grid output terminal 112, a specific output terminal 113, and a self-supporting input terminal (input terminal) 114.

  The storage battery 101 is charged with DC power supplied from the bidirectional inverter 102 during charging. Further, the storage battery 101 supplies DC power to the bidirectional inverter 102 during discharging.

  The bidirectional inverter 102 can charge the storage battery 101 by converting the AC power supplied from the grid 40 into DC power and supplying the converted DC power during grid connection. The bidirectional inverter 102 can charge the storage battery 101 by converting the AC power supplied from the photovoltaic power conditioner 20 into DC power and supplying the converted DC power during a power failure. Further, the bidirectional inverter 102 can convert the DC power supplied from the storage battery 101 into AC power and supply it to the load 30.

  The control unit 103 controls and manages the entire power storage device 100, and can be configured by a processor, for example.

  The control unit 103 controls the upper limit set value of the received current based on the value of the received voltage acquired from the voltage detection line 106.

  The control unit 103 controls the power receiving current received from the photovoltaic power conditioner 20 so that the value of the power receiving current does not exceed the upper limit set value. The control unit 103 can control the value of the received current by controlling the bidirectional inverter 102 to increase or decrease the amount of charge to the storage battery 101. The control unit 103 can also control the power reception current by controlling the amount of power supplied to the load 30 connected to the specific output terminal 113.

  Details of the function of the control unit 103 will be described later.

  The storage unit 104 can be configured by a semiconductor memory, a magnetic memory, or the like. The storage unit 104 stores various types of information such as programs used for processing executed by the control unit 103.

  The memory | storage part 104 has memorize | stored the operating condition of the overload protection function of the photovoltaic power conditioner 20 of each manufacturer and each model. As the operating condition of the overload protection function, a published value such as a value described in the specification document may be stored. If there is no published value, a general value is stored. You may keep it. Moreover, the memory | storage part 104 may memorize | store the value of the operating condition of an overload protection function as a common value instead of a value which changes for every model. Note that the storage in the storage unit 104 may be written by the manufacturer at the time of manufacture, or may be additionally inputable at the installation site. In addition, a new setting value may be automatically added / updated by periodically accessing an external server using the Internet.

  The current sensor 105 detects the received current from the photovoltaic power conditioner 20. In FIG. 1, the current sensor 105 is installed at a position where the current received from the independent input terminal 114 can be detected by one current sensor, but the installation position of the current sensor 105 is not limited to this. For example, one current sensor is installed at a position where the charging current to the storage battery 101 can be detected and a position where the current supplied to the specific output terminal 113 can be detected. From the sum of the current values detected by these two current sensors The received current may be detected. Further, in the example of FIG. 1, one current sensor 105 is used as a single-phase two-wire system, but if the single-phase three-wire system is used, two current sensors 105 may be used.

  The voltage detection line 106 is a wire drawn into the control unit 103 in order to acquire the value of the received voltage. In the example of FIG. 1, one voltage detection line 106 is used as a single-phase two-wire system. What is necessary is just to calculate.

  The interconnection relay 107 is controlled by the control unit 103 so as to be in a closed state at the time of grid interconnection and to be in an open state at the time of a power failure.

  The system link relay 108 is controlled by the control unit 103 so as to be in a closed state when power from the system 40 is supplied to the specific output terminal 113 during system interconnection.

  The self-supporting relay 109 is controlled by the control unit 103 to be in an open state at the time of grid connection and to be in a closed state at the time of a power failure. In the event of a power failure, the DC power output from the storage battery 101 is converted into AC power by the bidirectional inverter 102. It can be supplied to the load 30. Further, the self-supporting relay 109 is controlled to be in an open state when priority is given to power supply to the load 30 during the self-sustaining operation of the photovoltaic power conditioner 20 even during a power failure.

  The switching relay 110 is controlled by the control unit 103 to be in a closed state when power is supplied to the specific output terminal 113 and to be in an open state when power is not supplied to the specific output terminal 113. When giving priority to charging of the storage battery 101 during the self-sustaining operation of the photovoltaic power conditioner 20, or when the load 30 does not have a function of receiving control from the power storage device 100, the control unit 103 is a switching relay. 110 is controlled to be in an open state.

  The solar link relay 111 is controlled by the control unit 103 so as to be in an open state at the time of grid connection and in a closed state at the time of a power failure.

  The interconnection output terminal 112 is a terminal for linking the power storage device 100 to the grid 40 during grid interconnection.

  The specific output terminal 113 is a terminal that supplies power from the power storage device 100 to the load 30.

  The independent input terminal 114 is connected to the independent output terminal 22 of the photovoltaic power conditioner 20. The independent input terminal 114 can receive the independent output of the photovoltaic power conditioner 20 from the independent output terminal 22 during a power failure.

<Dependence of total received power amount on upper limit set value of received current>
In general, when the power storage device 100 receives power from the self-sustained output terminal 22 of the photovoltaic power conditioner 20, it is assumed that a larger upper limit set value of the received current in the power storage device 100 can receive a larger amount of power. It is often done. However, in consideration of the stop of the self-sustained output of the photovoltaic power conditioner 20 by the overload protection function, it cannot be said that the larger the upper limit set value of the received current, the more power is received. With reference to FIG. 2, the dependency of the total amount of received power that can be received by the power storage device 100 from the self-sustained output terminal 22 of the photovoltaic power conditioner 20 for one day on the upper limit set value of the received current will be described. . The example shown in FIG. 2 shows an example when the upper limit set value of the received current is fixed for reference. Actually, the power storage device 100 according to the present embodiment has an upper limit of the received current. The setting value is variable.

  First, with reference to FIG. 2A, the total received power amount when the upper limit set value of the received current is set to 15A will be described.

  Since the amount of solar radiation is small in the morning and evening, the amount of power that can be generated by the photovoltaic power conditioner 20 is small. For example, the amount of power that can be generated by the photovoltaic power conditioner 20 during the time period from 8:00 to 9:00 is 1.0 kWh. However, since this power generation amount does not have the ability to supply a current of 15 A to the power storage device 100, the received voltage decreases to 80V or less. Therefore, the photovoltaic power conditioner 20 stops the self-sustained output by the overload protection function. The term “stop” as used herein refers to an operation of repeatedly returning automatically after a lapse of about 300 seconds and stopping the independent output again by the overload protection function. As a result, the power storage device 100 cannot receive power from the photovoltaic power conditioner 20 during the time period from 8:00 to 9:00. Similarly, during the time period from 6:00 to 8:00 and from 15:00 to 18:00, the power storage device 100 receives power from the photovoltaic power conditioner 20 due to the suspension of the independent output by the overload protection function. I can't.

  On the other hand, since the amount of power generation is sufficient in the time period from 9:00 to 15:00, the photovoltaic power conditioner 20 does not stop the self-sustained output by the overload protection function from the self-sustained output terminal 22. Electric power can be supplied to the power storage device 100.

  In the example shown in FIG. 2A, the total amount of received power that the power storage device 100 receives from the photovoltaic power conditioner 20 in one day is 8.5 kWh.

  Next, with reference to FIG. 2B, the total received power amount when the upper limit set value of the received current is set to 10A will be described.

  When the upper limit set value of the received current is 10A, unlike the case of FIG. 2 (a), the sunlight is also emitted in the time periods from 7:00 to 9:00 and 15:00 to 17:00 where the amount of solar radiation is small. The power generation power conditioner 20 has a capability of supplying a current of 10 A to the power storage device 100. Therefore, in the time zone from 7:00 to 9:00 and from 15:00 to 17:00, the photovoltaic power conditioner 20 does not stop the independent output by the overload protection function. As a result, the power storage device 100 can receive power from the photovoltaic power conditioner 20 in the time zone from 7:00 to 9:00 and from 15:00 to 17:00.

  In addition, since the amount of power generation is sufficient during the time period from 9:00 to 15:00, the photovoltaic power conditioner 20 can supply a current of 10 A or more, but the power storage device 100 sets the upper limit of the received current. Since the value is set to 10A, 10A is supplied to the power storage device 100. Therefore, in the example illustrated in FIG. 2B, the amount of power that the power storage device 100 receives in each hour from 9:00 to 15:00 is 1.0 kWh.

  In the example shown in FIG. 2B, the total amount of received power that the power storage device 100 receives from the photovoltaic power conditioner 20 in one day is 9.8 kWh. This is a value 1.3 kWh larger than the total received power amount 8.5 kWh in the case of FIG.

  Thus, when the upper limit set value of the power reception current is set to a large value, the time during which the power storage device 100 can receive power from the photovoltaic power conditioner 20 is shortened due to the stop of the self-sustained output by the overload protection function. As a result, the total amount of received power received per day may be smaller than when the upper limit set value of the received current is set to a small value.

  The power storage device 100 according to the present embodiment appropriately sets the upper limit setting value of the received current based on the received voltage in consideration of the dependency of the total received power amount on the upper limit set value of the received current as illustrated in FIG. It is something to control.

<Control to suppress operation of overload protection function>
An example of the operation in which the power storage device 100 controls the upper limit set value of the received current so that the overload protection function of the photovoltaic power conditioner 20 does not operate will be described.

  The control unit 103 sets an upper limit set value for the received current. The control unit 103 sets a larger value as an initial value of the upper limit set value of the received current so that the generated power that can be supplied by the photovoltaic power conditioner 20 can be received without waste. Here, the “large value” is a current value that is assumed to be close to the upper limit of the suppliable current of the photovoltaic power conditioner 20, for example, during the autonomous operation of the photovoltaic power conditioner 20. This is a design value that can be stably output to the self-supporting output terminal 22. The control unit 103 sets the initial value of the upper limit setting value to 15A, for example.

  The control unit 103 acquires the value of the received voltage from the self-sustained output terminal 22 of the photovoltaic power conditioner 20 from the voltage detection line 106. When the value of the received voltage becomes equal to or lower than the predetermined voltage value (first predetermined voltage value), the control unit 103 reduces the upper limit set value of the received current to a predetermined value (for example, 10 A) smaller than the initial value. The first predetermined voltage value is, for example, 91V. The first predetermined voltage value is set to a value with a margin larger than that value based on a voltage value (for example, 80 V) that the photovoltaic power conditioner 20 is assumed to activate the overload protection function. Value.

  When the upper limit set value of the received current is reduced to a value smaller than the initial value, the control unit 103 receives power from the photovoltaic power conditioner 20 so that the value of the received current does not exceed the upper limit set value after the reduction. To control the incoming current.

  Thus, the control part 103 will perform control which reduces the upper limit setting value of receiving power, when the receiving voltage from the self-sustained output terminal 22 of the photovoltaic power conditioner 20 becomes below a predetermined voltage value. Thereby, it is possible to prevent the photovoltaic power conditioner 20 from stopping the self-sustained output due to the operation of the overload protection function, and even if the generated power is reduced due to a decrease in the amount of solar radiation or the like, it is stable for a long time, The photovoltaic power conditioner 20 can be allowed to continue the independent operation output. Therefore, the power storage device 100 can fully utilize the generated power of the solar battery 10 that can be supplied by the solar power generator 20 for charging the storage battery 101.

  In addition, when the load 30 is started up, inrush electric power is generated and a large current is drawn, and the received voltage may be greatly reduced temporarily. In order to allow such a temporary decrease in the received voltage due to the inrush power, the control unit 103 determines that the time during which the received voltage is equal to or lower than the predetermined voltage value is predetermined. May be controlled so as not to reduce the upper limit set value of the received current. Specifically, since the time until the operation of the overload protection function of the general photovoltaic power conditioner 20 is 2 to 3 seconds, less than 2 seconds may be a grace period.

  With reference to FIG.3 and FIG.4, the total power reception which the electrical storage apparatus 100 can receive from the self-sustained output terminal 22 of the photovoltaic power conditioner 20 on the 1st by control of the electrical storage apparatus 100 which concerns on this embodiment It shows how the ability increases.

  First, a case where the amount of solar radiation in the morning and evening is small will be described with reference to FIG. In the example shown in FIG. 3, it is assumed that the amount of solar radiation is small during the time before 9:00 and the time after 15:00, and the photovoltaic power conditioner 20 does not have the ability to supply 15A.

  FIG. 3A is a diagram showing a case where the upper limit set value of the received current is fixed at 15A for comparison with the present embodiment. In the example shown in FIG. 3A, the time before 9:00 and the time after 15:00 are low in the amount of solar radiation, and the power generation amount of the solar cell 10 is insufficient. If the current of 15 A is received from the power conditioner 20, the received voltage is lowered and the overload protection function is activated.

  As a result, the power storage device 100 can receive power from the photovoltaic power conditioner 20 only in the time zone from 9:00 to 15:00, and the total received power amount of the power storage device 100 is 9.0 kWh.

  FIG. 3B is a diagram illustrating a case where control of the power storage device 100 according to the present embodiment is executed. In this case, the control unit 103 reduces the upper limit set value of the received current from 15 A to 10 A when the received voltage decreases, so that the overload protection function is activated if the photovoltaic power conditioner 20 has the ability to supply 10 A. do not do. Further, if the upper limit set value of the received current is returned to 15 A at regular intervals, the received current can be received at 15 A when the amount of solar radiation is recovered (for example, 9:00 in the figure). Details of this will be described later.

  As a result, the power storage device 100 can receive a current of 10 A in the time zone from 7:00 to 9:00 and the time zone from 15:00 to 17:00, and the total power received by the power storage device 100 is 13.0 kWh.

  As described above, in the example illustrated in FIG. 3, by executing the control of the power storage device 100 according to the present embodiment, the total received power amount that the power storage device 100 can receive per day is from 9.0 kWh to 13 Increase to 0.0 kWh.

  Next, with reference to FIG. 4, a description will be given of a case where there is a time zone in which the amount of solar radiation decreases during the daytime due to worsening weather such as showers in addition to a small amount of morning and evening solar radiation. In the example shown in FIG. 4, it is assumed that the amount of solar radiation is small during the time before 9:00 and the time after 15:00, and the photovoltaic power conditioner 20 does not have the ability to supply 15A. In addition, it is assumed that the solar radiation power conditioner 20 does not have the ability to supply 15A because the solar radiation amount is small due to the deterioration of the weather during the time period from 12:00 to 14:00.

  FIG. 4A is a diagram showing a case where the upper limit set value of the received current is fixed at 15A for comparison with the present embodiment. In the example shown in FIG. 4A, the amount of solar radiation 10 is small and the amount of power generated by the solar cell 10 is insufficient during the time before 9:00, the time after 15:00, and the time zone from 12:00 to 14:00. Therefore, when the power storage device 100 tries to receive a current of 15 A from the photovoltaic power conditioner 20, the received voltage is lowered and the overload protection function is activated.

  As a result, the power storage device 100 can receive power from the photovoltaic power conditioner 20 only in the time zone from 9:00 to 12:00 and the time zone from 14:00 to 15:00. The total amount of received power is 6.0 kWh.

  FIG. 4B is a diagram illustrating a case where control of the power storage device 100 according to the present embodiment is executed. In this case, the control unit 103 reduces the upper limit set value of the received current from 15 A to 10 A when the received voltage decreases, so that the overload protection function is activated if the photovoltaic power conditioner 20 has the ability to supply 10 A. do not do.

  As a result, the power storage device 100 can receive a current of 10 A in the time zone from 7:00 to 9:00, the time zone from 12:00 to 14:00, and the time zone from 15:00 to 17:00. The total received power amount of the power storage device 100 is 12.0 kWh.

  As described above, in the example illustrated in FIG. 4, by executing the control of the power storage device 100 according to the present embodiment, the total received power amount that the power storage device 100 can receive per day is from 6.0 kWh to 12 Increase to 0.0 kWh.

<Setting of upper limit set value of received current based on received voltage>
With reference to FIG. 5, an example of an operation in which power storage device 100 sets the upper limit set value of the received current based on the received voltage so that the overload protection function of photovoltaic power conditioner 20 does not operate will be described. . In addition, the numerical value used in FIG. 5 is an example to the last, and is not limited to this numerical value.

  The control unit 103 is assumed to set the initial value of the upper limit set value of the received current to, for example, 15A. In the example shown in FIG. 5, it is assumed that the value of the received voltage gradually decreases from time t1 due to a decrease in the amount of solar radiation.

  When the value of the received voltage becomes equal to or lower than the predetermined voltage value (first predetermined voltage value), the control unit 103 executes control to gradually decrease the received current. In the example shown in FIG. 5, it is assumed that the first predetermined voltage value is 91V.

  In the example shown in FIG. 5, the received voltage reaches 91V at time t2. Therefore, the control unit 103 executes control to gradually decrease the received current from time t2.

  The control unit 103 decreases the received current until the received voltage reaches a predetermined voltage value (second predetermined voltage value). In the example shown in FIG. 5, it is assumed that the second predetermined voltage value is 95V. Note that the second predetermined voltage value is set to 95 V as an example, and other values may be used. The second predetermined voltage value is a value set as a value sufficiently larger than the voltage at which the photovoltaic power conditioner 20 activates the overload protection function.

  The control unit 103 starts control for reducing the received current from time t2, and ends the control for reducing the received current when the value of the received voltage reaches 95 V at time t3. Then, control unit 103 updates the upper limit set value of the received current to 10A, which is the value of the received current at time t3.

  Subsequently, an example of an operation in which the power storage device 100 sets the upper limit set value of the received current based on the received voltage so that the overload protection function of the photovoltaic power conditioner 20 does not operate is illustrated in the flowchart illustrated in FIG. Will be described with reference to FIG.

  The control unit 103 reads the initial value of the upper limit set value of the received current from the photovoltaic power conditioner 20 connected to the power storage device 100 from the storage unit 104 (step S101). The memory | storage part 104 has memorize | stored the initial value of the upper limit setting value of receiving power for every model of the photovoltaic power conditioner 20, for example.

  The control part 103 reads the predetermined voltage value which suppresses the electric power reception from the photovoltaic power conditioner 20 from the memory | storage part 104 (step S102). Here, the predetermined voltage value is, for example, 91V.

  The control unit 103 starts receiving power from the independent output terminal 22 of the photovoltaic power conditioner 20 to the independent input terminal 114 (step S103).

  The control unit 103 acquires the value of the received voltage from the voltage detection line 106 and acquires the value of the received current from the current sensor 105 (step S104).

  The control unit 103 determines whether or not the acquired power reception voltage value is equal to or lower than a predetermined voltage value (step S105).

  When the acquired power reception voltage value is greater than the predetermined voltage value (step S105: No), the control unit 103 proceeds to step S107.

  When the acquired value of the received voltage is equal to or less than the predetermined voltage value (step S105: Yes), the control unit 103 executes control to reduce the received current (step S106), and returns to step S104. In step S106, when the control for reducing the received current is executed, the control unit 103 causes the storage unit 104 to store the execution of the control.

  When it determines with No in step S105, the control part 103 has progressed after performing the control which reduces the receiving current by step S106 after the operation start which sets the upper limit setting value of this receiving current (after step S101). Is determined (step S107).

  When the control for reducing the received current is being executed (step S107: Yes), the control unit 103 updates the upper limit set value of the received current to the current value of the received current (step S108).

  When the control for reducing the received current has not been executed (step S107: No), the control unit 103 ends this flow.

<Increase in the upper limit set value of the receiving current>
After executing the control to reduce the upper limit set value of the received current, the control unit 103 executes control to return the upper limit set value of the received current to the initial value when a predetermined condition is satisfied.

  For example, when the value of the received voltage becomes equal to or higher than a predetermined value (third predetermined voltage value), the control unit 103 performs control to return the upper limit set value of the received current to the initial value. For example, in the example illustrated in FIG. 5, the upper limit set value of the received current is set so that the received voltage is 95 V, but the received voltage may increase due to the recovery of the amount of solar radiation thereafter. For example, the control unit 103 may perform control so as to return the upper limit set value of the received current to the initial value when the received voltage rises to 100V.

  Further, the control unit 103 may return the upper limit set value of the received current to the initial value at a predetermined timing. For example, the control unit 103 may perform control so that the upper limit set value of the received current is returned to the initial value at a certain time interval (for example, one hour interval) or at a predetermined designated time (for example, night).

  Further, the control unit 103 acquires the value of the generated power amount from the photovoltaic power conditioner 20, and when the generated power amount is equal to or greater than a predetermined value, the upper limit set value of the received current is returned to the initial value. You may control.

  In addition, the control unit 103 obtains weather information from the Internet or the like, and controls to return the upper limit set value of the received current to the initial value when the weather recovers and the amount of solar radiation is estimated to increase. May be.

[Second Embodiment]
As shown in FIG. 7, the distributed power supply system 2 includes a solar cell 10, a photovoltaic power conditioner 20, a load 30, a storage battery 101, and a power conditioner 150. In FIG. 7, a solid line connecting the functional blocks mainly indicates a power line, and a broken line mainly indicates a communication line or a signal line.

  In the second embodiment, portions that are different from the first embodiment will be mainly described, and description of contents that are the same as or similar to those of the first embodiment will be omitted.

  The second embodiment is different from the first embodiment in that the power storage device 100 in the first embodiment is replaced with a power conditioner 150. The power conditioner 150 does not have the storage battery 101 inside, and the storage battery 101 installed outside is connected to the bidirectional inverter 102 in the power conditioner 150. Since the other structure of the power conditioner 150 is the same as that of the electrical storage apparatus 100 in 1st Embodiment, description is abbreviate | omitted.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each component, each step, etc. can be rearranged so that there is no logical contradiction, and multiple components, steps, etc. can be combined or divided into one It is. Further, although the present invention has been described mainly with respect to the apparatus, the present invention is a method including steps executed by each component of the apparatus, a method executed by a processor included in the apparatus, a program, or a storage medium storing the program. It should be understood that these can also be realized and are included in the scope of the present invention.

  Further, the control unit 103 stores the upper limit set value of the received current in the storage unit 104 in addition to linearly reducing or increasing the received current upper limit value as in the first embodiment and the second embodiment described above. The upper limit set value at the time of the previous change may be used to change rapidly.

  Specifically, for example, the control unit 103 stores the upper limit set value updated in step S108 of FIG. 6 in the storage unit 104, and stores the previous update when the received voltage decreases during the next operation. It may be changed to the upper limit setting value. After that, the control unit 103 may finely correct the updated upper limit set value to the optimum value by reducing or increasing the value as in the first and second embodiments by looking at the state of the received voltage.

  As a result, even if the output decrease of the photovoltaic power conditioner 20 rapidly occurs, the control unit 103 can reduce the received current before the received voltage drops to 80 V, and control for reducing the received current. The risk that the overload protection function operates because the processing speed cannot be fully followed can be reduced.

  In addition, as the switching of the control of changing to the upper limit set value at the time of the previous update and linearly changing in this way, for example, when the value of the received voltage has already been lowered to a low state (for example, 90 V) Since there is a high possibility that the overload protection function will be activated unless the power receiving current is quickly reduced, the control unit 103 may change the upper limit set value at the previous update. On the other hand, when the decrease is still small (for example, 94V), there is a margin up to the voltage (80V) at which the overload protection function is activated, so the control unit 103 performs control as in the first and second embodiments. Also good.

DESCRIPTION OF SYMBOLS 1, 2 Distributed power supply system 10 Solar cell 20 Photovoltaic power conditioner 21 Interconnection output terminal 22 Self-sustained output terminal 30 Load 40 System 100 Power storage device 101 Storage battery 102 Bidirectional inverter 103 Control unit 104 Storage unit 105 Current sensor 106 Voltage detection Line 107 Interconnection relay 108 System link relay 109 Autonomous relay 110 Switching relay 111 Solar power link relay 112 Interconnection output terminal 113 Specific output terminal 114 Autonomous input terminal (input terminal)
150 Inverter

Claims (10)

A storage battery,
An input terminal capable of receiving the power supplied from the independent output terminal of the photovoltaic power conditioner;
A power storage device comprising: a control unit that controls an upper limit set value of a received current from the input terminal according to a value of a received voltage from the input terminal.   2. The power storage device according to claim 1, wherein the control unit executes control to reduce the upper limit set value to a predetermined value when the power receiving voltage is equal to or lower than a first predetermined voltage value. apparatus.   2. The power storage device according to claim 1, wherein when the power reception voltage is equal to or lower than a first predetermined voltage value, the control unit gradually decreases the power reception current, and the power reception voltage reaches a second predetermined voltage value. Then, the said upper limit setting value is updated to the receiving electric current value at that time, The electrical storage apparatus characterized by the above-mentioned.   4. The power storage device according to claim 1, wherein the control unit returns the upper limit set value to an initial value at a predetermined timing. 5.   5. The power storage device according to claim 4, wherein the control unit returns the upper limit set value to an initial value when the power reception voltage is equal to or higher than a third predetermined voltage value. 6.   5. The power storage device according to claim 4, wherein the control unit returns the upper limit set value to an initial value at a constant time interval.   The power storage device according to claim 4, wherein the control unit returns the upper limit set value to an initial value at night.   The power storage device according to any one of claims 4 to 7, wherein the control unit acquires a value of the generated power amount from the photovoltaic power conditioner, and the generated power amount is equal to or greater than a predetermined value. In this case, the upper limit set value is returned to the initial value. A power conditioner for a storage battery that converts to DC power or AC power,
An input terminal capable of receiving the power supplied from the independent output terminal of the photovoltaic power conditioner;
A power conditioner comprising: a control unit that controls an upper limit set value of a received current from the input terminal according to a value of a received voltage from the input terminal. A distributed power supply system including a photovoltaic power conditioner and a power storage device,
The power storage device
A storage battery,
An input terminal capable of receiving power supplied from a self-supporting output terminal of the photovoltaic power conditioner;
A distributed power supply system comprising: a control unit that controls an upper limit set value of a received current from the input terminal according to a value of a received voltage from the input terminal.

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