Power control device, battery system, method for controlling charging power of battery, and program

Abstract

To provide, in a power control device which controls charging to a storage battery, a technique which can automatically set charge power to the storage battery according to supplied power without complicated calculation processing.SOLUTION: The power control device includes: a storage battery connection unit which includes an output power change means capable of selecting a power value to be output to the storage battery, from among a plurality of preset different output power values; a power input unit which accepts power supply from outside; and charge power control means which determines a power value to be output to the storage battery. At a charge power setting mode execution time which determines an output power value to the storage battery, the charge power control means changes to select a higher output power value by the output power change means, whereas the power control device determines the charge power value to the storage battery to be a lower output power value than the output power value selected when power output to the storage battery and the load satisfies a predetermined first condition.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a power control device, a battery system, a method for controlling the charging power of a battery, and a program.

Background Art

[0002] Conventionally, a distributed power generation system in which a power generation device such as solar power and a battery are installed together is known. In a system equipped only with a power generation device, if the commercial power grid (hereinafter, also simply referred to as the grid) experiences a power outage, the power generated by the power generation device cannot be fed back to the grid, so the generated power may be wasted. On the other hand, in a system equipped with a battery as described above, the generated power can be utilized by charging the co-installed battery so as not to be wasted.

[0003] However, in a mechanism where the power to charge the battery is set manually, since the power generation capacity of the power generation device that changes moment by moment is unknown, the power setting is complicated, and there is a problem that the chargeable power is wasted.

[0004] On the other hand, in a system including a solar power generation device, a battery, and other loads, the required load power to be supplied to the other loads is obtained, and when the required load power is equal to or less than a reference power corresponding to the power generation power that the solar power generation device can supply, power is supplied to the battery, and when the load power is greater than the reference power, a power control system has been proposed that adjusts the charging power so as not to supply power to the battery (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, according to the technique described in Patent Document 1, it is necessary to determine the reference power, and the generated power of the photovoltaic power generation device and the required load power are obtained. From the value of the reference power corresponding to the generated power and the value of the load power, it is determined whether to charge the storage battery and the value of the power to be charged. In order to perform such processing, there is a problem that the processing performed by the control device becomes complicated.

[0007] The present invention has been made in view of the above circumstances, and in a power control device that controls charging of a storage battery, it is an object to provide a technique capable of automatically setting the charging power to the storage battery according to the supplied power without performing complicated arithmetic processing.

Means for Solving the Problems

[0008] A power control device that controls at least charging of power to a storage battery, a storage battery connection part including output power switching means capable of selecting a value of power output to the storage battery from a plurality of different preset output power values; a load connection part that outputs power to a load different from the storage battery; a power input part that receives supply of external power; a power supply circuit that supplies the power input from the power input part to the load connection part and the storage battery connection part; charging power control means for determining the value of the power output to the storage battery by selecting one output power value output to the storage battery from the plurality of different output power values, The charging power control means executes a charging power setting mode for determining an output power value to the storage battery. During the execution, until the power output to the storage battery and the load satisfies a predetermined first condition, the output power switching means switches the output power value to a higher value every predetermined time to output power. When the first condition is satisfied, an output power value lower than the output power value selected when the first condition was satisfied is determined as the charging power value to the storage battery. It is characterized by the following.

[0009] Here, the "output power switching means" can be, for example, the secondary output terminal of a load tap changing transformer (LTC). Also, the output terminal can include a terminal where no power is output, i.e., a 0 W terminal. Further, the "load different from the storage battery" is not limited to a specific load and may be a general load. Regarding the "power input section", it may be an input terminal for self - contained power from a power source different from the commercial power system, or an input / output terminal that can also be connected to the commercial power system.

[0010] Note that "switching the output power value to a higher value and outputting power every predetermined time" is not limited to maintaining the output value to the storage battery until the predetermined time elapses and then switching the output power value to a higher one after the predetermined time has elapsed. For example, after outputting power at a certain power value for a certain period of time, after sandwiching a predetermined interval (the time for stopping or reducing the power output to the storage battery), outputting power at a power value higher than the power value output before the start of the interval for a certain period of time, and after sandwiching the interval, repeating the process of outputting power at a power value higher than the power value output before the start of the interval for a certain period of time. That is, the "predetermined time" in this case is the time obtained by adding the time of the interval to the above - mentioned certain period of time.

[0011] According to the power control device with such a configuration, by setting the content of the first condition to a state where the supplied power is insufficient (or there is a sign of insufficiency) for charging the storage battery and supplying power to the load, the output power for charging the storage battery can be lowered by one step, and power can be stably supplied to the charging battery and the load while minimizing waste.

[0012] Also, the first condition is that the power output to the storage battery and the load exceeds the stable supply level of the power supplied to the power input section, and it further includes an input section sensor that measures the voltage value and / or current value of the power supplied to the power input section. When the voltage value output by the input section sensor is equal to or lower than a predetermined first threshold value, when the current value output by the input section sensor is equal to or higher than a predetermined second threshold value, or when the power value output by the input section sensor is equal to or higher than a predetermined third threshold value, the charging power control means may determine that the first condition is satisfied. Similarly, it may further include a load output sensor that measures the current value of the power output from the load connection section, and when the current value output by the load output sensor is equal to or higher than a predetermined fourth threshold value, the charging power control means may determine that the first condition is satisfied.

[0013] Here, the stable supply level refers to a state where the supplied power has a margin over the sum of the power output to the storage battery and the load. For example, when receiving power supply from a power generation device, it is a state where the power generation amount of the power generation device is not exceeded. Note that it does not prevent some or all of the above first to fourth threshold values from being the same value. With such a configuration, it is possible to control the charging power to the storage battery based on the voltage value and / or current value detected by the sensor without performing particularly complex arithmetic processing, thereby enhancing the stability of power control.

[0014] Also, the charging power setting mode may include a first charging power setting mode executed at the start of the operation of the device, a second charging power setting mode executed at predetermined time intervals during the operation of the device, and a third charging power setting mode executed when the power output to the storage battery and the load during the operation of the device satisfies a predetermined second condition.

[0015] Note that the above second condition may be the same as the first condition, or may be a condition with a greater safety margin than the first condition. With such a configuration, it is possible to execute processing optimized according to the operating status of the device.

[0016] Further, the charging power control means executes control to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value in the first charging power setting mode, and in the second charging power setting mode, executes control to switch the output power value from the power value selected at the time of executing the second charging power setting mode to a higher power value, and in the third charging power setting mode, may execute control to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value after once stopping the power output to the storage battery.

[0017] With such a configuration, the charging power to the storage battery is automatically set at the time of starting up the device, and even when the device is in operation, the charging power is periodically checked to see if it is appropriate and re-set as necessary. Also, when it becomes impossible to guarantee a stable power supply for charging and output to the load, the charging power to the storage battery can be reduced. As a result, the charging power to the storage battery can be automatically and efficiently set from the time of starting up the device, so that even a user without specialized knowledge can operate the device.

[0018] Further, the charging power control means may execute processing to temporarily reduce the output power value to the storage battery between the start of one of the predetermined times and the start of the next predetermined time.

[0019] Further, the storage battery system according to the present invention a storage battery, a power storage control device that is electrically connected to the storage battery and a load different from the storage battery and controls at least the charging of power to the storage battery, A battery system having an independent power supply facility that supplies power from a power source different from the commercial power system to the power storage control device. The power storage control device is provided with output power switching means capable of selecting, from a plurality of preset different output power values, the value of the power output to the battery at the connection portion with the battery. Executes a charging power setting mode for determining the output power value to the battery, and during the execution, until the power output to the battery and the load satisfies a predetermined first condition, the output power value is switched to a higher value by the output power switching means every predetermined time to output power. When the first condition is satisfied, an output power value lower than the output power value selected when the predetermined first condition was satisfied is determined as the charging power value to the battery. Characterized by this.

[0020] Note that the independent power supply facility can include power generation devices of renewable energy such as solar power generation devices, fuel cells, storage batteries, and their control devices.

[0021] Also, the first condition is that the power output to the battery and the load exceeds the stable supply level of the power supplied from the independent power supply facility. When the current value of the power output to the load becomes equal to or higher than a predetermined first threshold value, It may be determined that the first condition is satisfied when any of the cases where the power value of the power output to the load becomes equal to or higher than a predetermined second threshold value is included.

[0022] Moreover, a first condition is that the power output to the storage battery and the load exceeds the stable supply level of the power supplied from the self-powered power supply facility. The self-powered power supply facility includes a power conditioner having a DC / DC converter and a DC / AC inverter. When the voltage value of the power output from the power conditioner is equal to or lower than a predetermined third threshold value, when the current value of the power output from the power conditioner is equal to or higher than a predetermined fourth threshold value, when the power value of the power output from the power conditioner is equal to or higher than a predetermined fifth threshold value, when the voltage value of the power output from the DC / DC converter is equal to or lower than a predetermined sixth threshold value, or when the deviation of the voltage value of the power output from the DC / DC converter is equal to or higher than a predetermined seventh threshold value, the power storage control device may include any of these cases.

[0023] Note that the first to seventh threshold values mentioned here are not precluded from being the same value in part or in whole. With such a configuration, it is possible to control the charging power to the storage battery based on the behavior (output) of the power conditioner (hereinafter, also simply referred to as the self-powered power conditioner) in the self-powered power supply facility, so that it is possible to prevent the self-powered power conditioner from becoming overloaded and stopping.

[0024] In addition, the charging power setting mode may include a first charging power setting mode executed at the start of the device operation, a second charging power setting mode intermittently executed during the operation of the device, and a third charging power setting mode executed when the value output from the input unit sensor during the operation of the device satisfies a predetermined second condition.

[0025] Further, in the first charging power setting mode, the power storage control device executes control to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value, and in the second charging power setting mode, executes control to switch the output power value from the power value selected when the second charging power setting mode is executed to a higher power value. In the third charging power setting mode, after once stopping the power output to the battery, control may be executed to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value.

[0026] Further, the power storage control device may execute a process of once reducing the output power value to the battery between the start of one of the predetermined times and the start of the next predetermined time.

[0027] Moreover, the power control method according to the present invention is a method for controlling the charging power of a storage battery using a power storage control device including output power switching means capable of selecting the value of the power to be output from a plurality of different preset output power values, the method including: a step of selecting any one of the plurality of different output power values; a step of supplying power to the storage battery for a predetermined time at the selected power value; a step of determining whether the power supplied to the power storage control device satisfies a predetermined condition; and a step of, when it is determined that the predetermined condition is satisfied, determining an output power value lower than the output power value selected at the time of the determination as the charging power to the storage battery.

[0028] The present invention can also be regarded as a program for causing a control device of a storage battery to execute the above method, and a computer-readable recording medium on which such a program is non-temporarily recorded.

[0029] Further, each of the above configurations and processes can be combined with each other to constitute the present invention as long as no technical contradiction occurs. invention.

Advantages of the Invention

[0030] According to the present invention, in a power control device that controls charging of a storage battery, it is possible to provide a technology capable of automatically setting the charging power to the storage battery according to the supplied power without performing complex arithmetic processing.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0032] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0033] <Application Example> (Configuration of the Application Example) The present invention can be applied, for example, to a power control device 910 as shown in FIG. 1. FIG. 1 is a block diagram showing the schematic configuration of the power control device 910 according to this application example, and the relationships of a storage battery 920, a load 930, and an independent power supply source 940 connected to the power control device 910. The power control device 910 according to this application example corresponds to a so-called power conditioner that converts DC power into AC power and outputs it. Hereinafter, DC (Direct Current) is used to represent direct current, AC (Alternating Current) is used to represent alternating current, and a power conditioner is also referred to as a power converter.

[0034] The power control device 910 includes a power storage control unit 911, a storage battery connection unit 912, a load connection unit 913, a power input unit 914, a bidirectional DC / DC converter 915, a bidirectional DC / AC inverter 916, and a power circuit 919.

[0035] The storage battery 920 is a secondary battery such as a lithium-ion battery, and is connected to the power control device 910 via the storage battery connection unit 912. In addition, although not shown in the figure, the storage battery 920 is provided with sensors for monitoring voltage, temperature, etc., and the output values of the sensors are transmitted to the power storage control unit 911 of the power control device 910.

[0036] The load 930 is a general device that consumes power, etc., and is connected to the power control device 910 via the load connection unit 913 and receives power supply from the power control device 910. Specifically, for example, various electrical products such as air conditioners, microwave ovens, and televisions used in households, and machines such as air conditioners and lighting fixtures used in commercial and industrial facilities, lighting equipment, etc.

[0037] The independent power supply source 940 is a power generation device of renewable energy such as a solar power generation device or a wind power generation device, a fuel cell, a storage battery, and a power converter that converts the power of these into DC / AC, etc., and supplies power to the power control device 910 via the power input unit 914. The power input to the power control device 910 is supplied to the storage battery 920 and the load 930.

[0038] (Configuration of the Power Control Device) The power storage control unit 911 is, for example, a microcomputer and has a storage medium for storing a control program and a processor for executing control procedures according to the control program. In this application example, the power storage control unit 911 corresponds to the charging power control means, acquires information from various sensors provided in the device as described later, and controls each component of the power control device 910 including the battery connection unit 912 based on the information acquired by these sensors.

[0039] The battery connection unit 912 includes terminals for inputting and outputting power to and from the battery 920. Further, the output terminal is configured to include a plurality of output connection points (hereinafter also referred to as taps) with different power values to be output, and by switching the tap to be connected under the control of the power storage control unit 911, the power value output to the battery 920 can be switched. Specifically, for example, it can be the secondary output terminal of a load tap-changing transformer, etc., and by outputting a constant current thereto, the output power value can be switched. Although it is arbitrary how to set the output power value, for example, it can be set in steps of 250W such as 0W, 250W, 500W ··· 1250W, 1500W, etc. Note that the plurality of output connection points correspond to the output power switching means in the present invention.

[0040] The load connection unit 913 includes a terminal for outputting power to the load 930 and an ammeter (not shown). The current value measured by the ammeter is transmitted to the power storage control unit 911.

[0041] The power input unit 914 includes a terminal for inputting power supplied from the self-powered power supply 940 and a voltmeter and an ammeter (not shown). The respective values measured by the voltmeter and the ammeter are transmitted to the power storage control unit 911.

[0042] Further, the bidirectional DC / DC converter 915 steps down the DC voltage output from the bidirectional DC / AC inverter 916 and outputs it to the battery connection part 912, and steps up the DC voltage input (discharged) from the battery 920 and outputs it to the bidirectional DC / AC inverter 916.

[0043] The bidirectional DC / AC inverter 916 converts the alternating current supplied from the self - contained power supply source 940 into direct current and outputs it to the bidirectional DC / DC converter 915, and also converts the direct current input (discharged) from the battery 920 via the bidirectional DC / DC converter 915 into alternating current and outputs it to the load connection part 913.

[0044] The power circuit 919 is a circuit for the power transmitted among the battery connection part 912, the load connection part 913, the power input part 914, the bidirectional DC / DC converter 915, and the bidirectional DC / AC inverter 916 within the power control device 910. Note that the power circuit corresponds to the power supply circuit in the present invention.

[0045] (Charging power control method) In the power control device 910 having the above - described configuration, the process of performing charge control on the battery 920 will be described. First, at the start of the operation of the device, the power supply amount from the self - contained power supply source 940 is determined, and the charging power to the battery 920 is determined so that a certain margin can be ensured for the supply amount. That is, the charging power to the battery 920 is determined.

[0046] Specifically, the connection tap of the battery connection part 912 is connected to the tap with the lowest power value for a certain period of time (for example, 10 seconds), and then the connection is switched to the tap with a higher power value (for example, the tap with a power value one step higher), and the tap with the power value at which the voltage value of the power supplied to the power input part 914 decreases is searched for.

[0047] When the voltage value of the power supplied to the power input unit 914 decreases, it is considered that the self-powered power supply source 940 is in an overloaded state. Therefore, once the connection tap of the battery connection unit 912 is switched to the 0W tap, the supply of power to the battery 920 is stopped. Then, when it can be determined from the value of the voltage (or current or power) detected by the sensor of the power input unit 914 that the self-powered power supply source 940 has recovered from the overloaded state, a tap with a lower power value than the tap of the power value that was connected when the voltage value of the power supplied to the power input unit 914 decreased (for example, a tap with a power value one step lower) is selected, and thereby the charging power to the battery 920 is determined.

[0048] Also, even after the charging power is once determined as described above, during the operation of the power control device 910, the charging power is reviewed at any time. Specifically, at regular intervals (for example, every 30 minutes), control is performed to switch to a tap with a power value one step higher than the power value of the currently connected tap, and after a predetermined time (for example, 10 seconds) has elapsed, it is determined whether the voltage value of the power supplied to the power input unit 914 decreases. Here, if the voltage value decreases, control is performed to switch back to the previously connected tap after waiting for the self-powered power supply source 940 to recover from the overloaded state, and the operation is continued with the previous power value as the charging power. On the other hand, if the voltage value does not decrease, the taps are sequentially switched to taps with higher power values, and when the voltage value of the power supplied to the power input unit 914 decreases, a tap with a lower power value than the tap that was connected at that time is selected, and the operation is continued with the power value as the charging power. Note that the process of reviewing the charging power value does not necessarily have to be based on the power value of the currently connected tap, and the same process as when determining the charging power may be performed by returning the tap to be connected to 0W at regular intervals.

[0049] Also, when the self-powered power supply source 940 becomes overloaded during operation due to an increase in the supply to the load 930 or a decrease in the supply power of the self-powered power supply source 940, the battery control unit 911 once switches the connection to the 0W tap, and when the overloaded state has recovered, the same process as at the start of the operation of the device is executed to reset the charging power.

[0050] According to the configuration of the power control device 910 as described above, in a system configured with a power supply source and a storage battery, when power is supplied to a load and the storage battery is charged in parallel, the charging power of the storage battery can be automatically set. Further, based on the voltage value of the power input to the power control device, the charging power to the storage battery is determined by stepwise switching of taps, so that the charging power can be determined without complicated arithmetic processing.

[0051] <Embodiment 1> Next, a storage battery system 10 which is an example of an embodiment of the present invention will be described. However, dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only to those, unless otherwise specified.

[0052] (System Configuration) With reference to FIG. 2, the overall configuration of a storage battery system 10 according to an embodiment of the present invention will be described. FIG. 2 is a block diagram showing a schematic configuration of the storage battery system 10 according to the present embodiment. As shown in FIG. 2, the storage battery system 10 includes a storage battery 120, a storage power conditioner 110, a load 130, a solar cell 140, and a PV (Photovoltaic) power conditioner 141, and the storage power conditioner 110, the load 130, and the PV power conditioner 141 are connected to a commercial power system 150.

[0053] In the system, the power generated by the solar cell 140 is supplied to the load 130 and the storage power conditioner 110 via the PV power conditioner 141, and the power supplied to the storage power conditioner 110 is further output to the storage battery 120 and used to charge the storage battery 120. Also, when the power consumed by charging the load 130 and the storage battery 120 is small and there is surplus power generated by the solar cell 140, the surplus power is fed back to the commercial power system 150.

[0054] Also, when the power generated by the solar cell 140 is insufficient for the power consumption at the load 130, the insufficient power is supplied from the commercial power system 150 to the load 130. Further, when the SOC (States Of Charge) of the storage battery 120 is not sufficient during a time period with a low electricity rate such as at night, the storage battery 120 is charged by receiving power supply from the commercial power system 150.

[0055] Note that since the storage battery 120 and the load 130 are the same as those described in the application example, detailed description thereof is omitted.

[0056] The power storage power conditioner 110 includes a power storage control unit 111, a storage battery connection unit 112, a system side connection unit 113, a bidirectional DC / DC converter 115, a bidirectional DC / AC inverter 116, and a power circuit. That is, the power storage power conditioner 110 in the present embodiment is different from the power control device 910 in the application example in that it does not have a load connection unit 913 and a power input unit 914, and is provided with a system side connection unit 113. The system side connection unit 113 includes power input / output terminals, a voltmeter, and an ammeter (both not shown), and outputs power to the load 130 and the commercial power system 150 via a distribution board (not shown), and receives power supply from the PV power conditioner 141 and the commercial power system 150.

[0057] Other points are generally the same as those of the power control device according to the application example. That is, the power storage control unit 111 corresponds to the charging power control means in the present application example, and acquires information from various sensors in the system via a power line and a communication line. Then, based on the acquired information, each component of the power storage power conditioner 110 including the storage battery connection unit 112 is controlled.

[0058] Note that detailed description of the storage battery connection unit 112, the DC / DC converter 115, and the bidirectional DC / AC inverter 116 is omitted.

[0059] The solar cell 140 is configured such that, for example, power generation units each having a photoelectric conversion cell are connected in a matrix and output a predetermined short-circuit current. The type of the solar cell 140 is not particularly limited as long as it can perform photoelectric conversion, such as a silicon-based polycrystalline solar cell, a silicon-based single-crystalline solar cell, a chalcopyrite-based solar cell, or a perovskite solar cell.

[0060] Further, the PV power conditioner 141 includes a PV power input unit 142, a PV power output unit 143, a PV control unit 144, a DC / DC converter 145, and a DC / AC inverter 146, and controls the power extracted from the generated power generated by the solar cell 140.

[0061] The PV power input unit 142 includes a power input terminal, a voltmeter, and an ammeter (none of which are shown), and is configured to take in the DC power output by the solar cell 140 into the PV power conditioner. Further, the PV power output unit 143 includes a power output terminal, a voltmeter, and an ammeter (none of which are shown), and outputs the power converted into AC, as will be described later, to the power storage power conditioner 110, the load 130, and the commercial power system 150.

[0062] The DC / DC converter 145 boosts the DC voltage of the solar cell 140, and the DC / AC inverter 146 converts the DC voltage output from the DC / DC converter 145 into AC and outputs it to the PV power output unit 143. For example, the DC voltage is converted into 100V / 200V of single-phase three-wire sinusoidal wave output for general household use.

[0063] The PV control unit 144 is, for example, a microcomputer, and has a storage medium for storing a control program and a processor for executing control procedures according to the control program. The PV control unit 144 is configured to control the PV power conditioner 140, and outputs, for example, control signals for controlling the operations of the DC / DC converter 145 and the DC / AC inverter 146. Note that the PV control unit 140 may perform MPPT (Maximum Power Point Tracking) control so that the output power from the solar cell 140 is maximized.

[0064] (Battery Charging Power Control Process) Next, the process flow of the power storage converter 110 controlling the charging power to the battery 120 during independent operation when the connection with the commercial power system 150 is interrupted, such as when the power supply from the commercial power system 150 stops, will be described. FIG. 3 is a flowchart showing the process flow of the charging power control of the power storage converter 110 during independent operation.

[0065] As shown in FIG. 3, at the start of independent operation, the power storage control unit 111 of the power storage converter 110 first performs a charging power setting process at the start of operation, that is, a process of setting how much of the power output from the PV converter 141 is used for charging the battery 120 (step S101).

[0066] FIG. 4 is a flowchart showing the process flow of the charging power setting process at the start of operation. As shown in FIG. 4, the power storage control unit 111 first sets the connection tap of the battery connection unit 112 to the tap with the lowest power value (step S201). Then, it is determined whether or not a predetermined condition is satisfied, such as the voltage value detected from the PV power output unit 143 being decreased or the detected current value being an overcurrent (step S202). Thereby, it is judged whether or not the PV converter 141 will become overloaded when charging the battery 120 with the power of the connected tap.

[0067] In step S202, if the predetermined condition is not satisfied, that is, if it is determined that the PV converter 141 is not overloaded, after waiting for a predetermined time (e.g., 10 seconds) to elapse (step S203), it is determined whether or not the currently connected tap is the tap with the maximum power value (step S204). Here, if it is determined that it is the tap with the maximum power, the process proceeds to step S209, and the charging power to the battery is determined to be the power value of the currently connected tap. On the other hand, in step S204, if it is determined that the currently connected tap is not the tap with the maximum power value, the power storage control unit 111 switches to the tap with a power value one step higher (step S205), returns to step S202, and repeats the subsequent processing.

[0068] In step S202, when it is determined that a predetermined condition is satisfied, that is, the PV power conditioner 141 is overloaded, the power storage control unit 111 temporarily switches the connection tap of the battery connection unit 112 to the 0W tap to stop the charging of the battery 120 (step S206). Then, the power storage control unit 111 waits for the recovery of the PV power conditioner 141 from the overloaded state (step S207), and selects a tap with a power value one level lower from the tap of the power value connected when it was determined to be overloaded (step S208). Then, the power value of the selected tap is determined as the charging power to the battery 120 (step S209), and the subroutine of the charging power setting process at the start of operation ends. FIG. 5 illustrates a timing chart showing the timing of the charging power setting process at the start of operation. Note that when the tap selected in step S208 becomes the 0W tap, charging to the battery 120 is not performed. A timing chart showing the timing is exemplified. When the tap selected in step S208 becomes the 0W tap, charging to the battery 120 is not performed.

[0069] Even after the power storage control unit 111 finishes setting the charging power at the start of operation in step S101, it continuously monitors whether the PV power conditioner 141 is overloaded (for example, a state where the sum of the power consumption of the load 130 and the charging power exceeds the output of the solar cell 140). Specifically, for example, by receiving the output signal of the voltmeter in the PV power output unit 143 and detecting a decrease in the output voltage from the PV power conditioner 141, it is determined whether the PV power conditioner 114 is overloaded (step S102). Here, if it is determined that it is not overloaded, the process proceeds to step S106.

[0070] On the other hand, when it is determined in step S102 that the PV power conditioner 141 is in an overload state, the power storage control unit 111 switches the tap of the battery connection unit 112 to the 0 W tap and temporarily stops charging the battery 120 (step S103). Then, it waits until the PV power conditioner 141 recovers from the overload state, and after recovery, it executes a process of resetting the charging power to the battery 120 (steps S104 and S105). FIG. 6 illustrates a timing chart showing the timing of the process when an overload of the PV power conditioner 141 is detected during the operation of the power storage power conditioner 110. Note that since the details of the reset process are the same as the process of setting the charging power at the start of operation, detailed description is omitted.

[0071] Also, during independent operation, the power storage control unit 111 periodically (for example, every 30 minutes) checks and adjusts whether the charging power to the battery 120 is appropriate so that the generated power of the solar cell 140 can be utilized most efficiently (steps S106 and S107). FIG. 7 is a flowchart showing the flow of the process when performing the optimization adjustment of the charging power during independent operation.

[0072] As shown in FIG. 7, the power storage control unit 111 first determines whether the currently selected tap is the tap with the maximum power value (step S301). Here, if it is determined that it is the tap with the maximum power value, the power value is continuously determined as the charging power value, and the process ends (step S307).

[0073] On the other hand, if it is determined in step S301 that it is not the tap with the maximum power value, a tap with a power value one level higher than the currently selected tap is selected (step S302). Then, it is determined whether a predetermined condition is satisfied, such as the voltage value detected from the PV power output unit 143 is decreasing or the detected current value is an overcurrent (step S303). Thereby, it is determined whether the PV power conditioner 141 will become overloaded when charging the battery 120 with the power of the power value of the connected tap.

[0074] In step S303, if it is determined that a predetermined condition is not satisfied, that is, the PV power conditioner 141 is not overloaded, then after waiting for a predetermined time (for example, 10 seconds), the process returns to step S301, and the subsequent processing is repeated.

[0075] On the other hand, in step S303, if it is determined that a predetermined condition is satisfied, that is, the PV power conditioner 141 is overloaded, the power storage control unit 111 temporarily switches the connection tap of the battery connection unit 112 to the 0W tap to stop charging the battery 120 (step S304). Then, the power storage control unit 111 waits for the PV power conditioner 141 to recover from the overload state (step S305), and selects a tap with a power value one level lower from the tap of the power value that was connected when it was determined to be overloaded (step S306). Then, the power value of the selected tap is determined as the charging power to the battery 120 (step S307), and the subroutine of the charging power adjustment process during independent operation is terminated.

[0076] During independent operation, the power storage control unit 111 continuously executes the processes from step S102 to step S107. When the independent operation ends, a series of routines are terminated (step S108). Note that the process of step S101 in this embodiment corresponds to the first charging power setting mode in the present invention, the process of step S107 corresponds to the second charging power setting mode in the present invention, and the processes from step S103 to step S105 correspond to the third charging power setting mode in the present invention.

[0077] In the above embodiment, in the first to third charging power setting modes, when it is determined that the PV power conditioner 141 is overloaded, a tap with a power value one level lower is selected from the tap of the power value that was connected at that time. However, a tap with an even lower power value may be selected. That is, as long as a power lower than the power value determined to be overloaded is selected as the output power value to the battery.

[0078] According to the power storage system described above, even when the connection with the commercial power system 150 is interrupted, a distributed power generation system can be constructed that stably supplies the generated power of the solar power generation facility to the load and charges the battery when there is surplus power. In addition, since the setting of the charging power to the battery is automatically executed, there is no need for the user to perform complicated setting processes. Furthermore, since the setting of the charging power is performed by switching the taps at the connection part with the battery based on the voltage output by the PV power conditioner, etc., complicated arithmetic processing is not required, and stable operation of the power storage power conditioner can be obtained.

[0079] <Others> The above-described embodiments are merely illustrative of the present invention, and the present invention is not limited to the above specific forms. The present invention can be variously modified within the scope of its technical idea. For example, in the above embodiment, in the charging power switching mode, the tap with a value one step higher was switched to increase the output power value of the battery 120 step by step, but it may be switched to a tap with a value two steps or more higher. Also, in the above embodiment, when the power value at which the PV power conditioner 140 becomes overloaded is determined, a tap with a power value one step lower than the power value of the tap connected when overloaded is selected to determine the charging power value to the battery 120, but a tap with an even lower power value may be selected.

[0080] Also, in the above embodiment, in the charging power switching mode, while continuing to charge the battery 120, the tap to a higher power value was switched, but the switching of the output power to the battery may be performed by a configuration / means other than the tap. For example, the power output terminal of the battery connection part 112 can be a terminal whose output power value can be switched steplessly.

[0081] Also, in the charging power switching mode, charging of the storage battery 120 may be intermittently performed. For example, after charging the storage battery 12 with a certain power value for a predetermined time, an interval of waiting for charging for a certain time may be interposed, and charging of the storage battery 120 may be performed for a predetermined time with a power value higher than the charging power value before the interval. FIG. 8 shows the timing when such a charging power switching process is performed. Note that in the above interval, although charging of the storage battery is waiting, that is, power output is stopped, the output power value to the storage battery may be set to a value lower than that at the start of the interval.

[0082] By performing such processing, when setting the charging power to the storage battery 120, the time during which the PV power conditioner 141 is in an overload state can be shortened, and it is possible to prevent the PV power conditioner 141 from stopping due to being overloaded as a result of the processing for determining the charging power value to the storage battery 120.

[0083] Also, in the above embodiment, based on the voltage and current output from the PV power conditioner 140 it was configured to determine the overload of the PV power conditioner 140, but by appropriately arranging a voltmeter, ammeter, and communication circuit, the overload of the PV power conditioner 10 may be detected based on other information. For example, it is also conceivable to detect an overload based on the output voltage or output current of the solar cell, the output current to a specific load, the output voltage of the DC / DC converter in the PV power conditioner, the deviation of the output voltage, and the like.

[0084] Also, the system configuration of the above embodiment can also be configured in various ways. For example, in addition to the configuration of Embodiment 1, a system configuration provided with a specific load or the like connected to the storage power conditioner 110 may be used.

[0085] Also, in the above embodiment, a photovoltaic power generation system was taken as an example, but it can also be applied to other self - contained power supply facilities, for example, power generation devices of other renewable energies such as wind power generation devices, fuel cells, a plurality of storage batteries, and the like.

[0086] In addition, in the above-described embodiment, the power control of the power storage converter when the system is disconnected from the commercial power system 150 has been described as an example. However, it does not prevent performing the same control in a state where the system and the commercial power system 150 are not disconnected.

[0087] One aspect of the present invention is a power control device (910) that controls at least charging of a power storage battery, a power storage battery connection part (912) having output power switching means capable of selecting a value of power output to the power storage battery from a plurality of different preset output power values, a load connection part (913) that outputs power to a load different from the power storage battery, a power input part (914) that receives supply of external power, a power supply circuit (919) that supplies the power input from the power input part to the load connection part and the power storage battery connection part, charging power control means (911) for determining a value of power output to the power storage battery by selecting one output power value output to the power storage battery from the plurality of different output power values, wherein the charging power control means executes a charging power setting mode for determining an output power value to the power storage battery, and at the time of execution, until the power output to the power storage battery and the load satisfies a predetermined first condition, the output power switching means switches the output power value to a higher value every predetermined time to output power, and when the first condition is satisfied, determines an output power value lower than the output power value selected when the first condition is satisfied as the charging power value to the power storage battery. characterized by the above.

[0088] Another aspect of the present invention is a power storage battery (120), a power storage control device (110) that is electrically connected to the power storage battery and a load different from the power storage battery and controls at least charging of the power storage battery, A battery system (10) having an independent power supply facility (140; 141) that supplies power from a power source different from the commercial power system to the power storage control device. The power storage control device At the connection part with the battery, it is provided with output power switching means capable of selecting the value of the power output to the battery from a plurality of different preset output power values. Execute a charging power setting mode for determining the output power value to the battery. During the execution, until the power output to the battery and the load satisfies a predetermined first condition, the output power switching means switches the output power value to a higher value every predetermined time to output power. When the first condition is satisfied, an output power value lower than the output power value selected when the predetermined first condition was satisfied is determined as the charging power value to the battery. It is characterized by the above. This is the feature.

[0089] Furthermore, another aspect of the present invention is A method for controlling the charging power of a battery using a power storage control device provided with output power switching means capable of selecting the value of the output power from a plurality of different preset output power values, comprising: A step (S201) of selecting any one of the output power values from the plurality of different output power values; A step (S203) of supplying power to the battery for a predetermined time with the selected power value; A step (S202) of determining whether the power supplied to the power storage control device satisfies a predetermined condition; When it is determined that the predetermined condition is satisfied, a step (S209) of determining an output power value lower than the output power value selected when the determination was made as the charging power to the battery. It has the above.

Explanation of symbols

[0090] 10... Battery system 110... Power storage power conditioner 111, 911... Power storage control unit 112, 912... Battery connection part 113... System side connection part 115, 915... Bidirectional DC / DC converter 116, 916... Bidirectional DC / AC inverter 120, 920... Battery 130, 930... Load 140... Solar cell 141... PV power conditioner 142... PV power input part 143... PV power output part 144... PV control part 145... DC / DC converter 146... DC / AC inverter 150... Commercial power system 910... Power control device 913... Load connection part 914... Power input part 919... Power circuit

Claims

1. A power control device that controls at least the charging of a storage battery, comprising: a power input unit that receives power supply from the outside; a storage battery connection unit that outputs the power supplied from the power input unit to the storage battery; a load connection unit that outputs the power supplied from the power input unit to a load different from the storage battery; a control unit that controls the power supplied to the storage battery. The storage battery connection unit includes output power switching means for switching the value of the power output to the storage battery among a plurality of preset different output power values. The control unit switches the output power value to a higher value every predetermined time by the output power switching means and outputs power until the power output to the storage battery and the load satisfies a predetermined first condition. When the first condition is satisfied, a charging power setting mode is executed in which an output power value lower than the output power value selected when the first condition was satisfied is determined as the charging power value for the storage battery. A process of temporarily reducing the output power value to the storage battery is executed between the start of one of the predetermined times and the start of the next predetermined time. A power control device characterized by the above.

2. The power control device has an input unit sensor that measures the voltage value and / or current value of the power supplied to the power input unit. The control unit when the voltage value output from the input unit sensor becomes equal to or lower than a predetermined first threshold value, when the current value output from the input unit sensor becomes equal to or higher than a predetermined second threshold value, when the power value output from the input unit sensor becomes equal to or higher than a predetermined third threshold value, determines that the first condition is satisfied in at least any one of the above cases. The power control device according to claim 1, characterized by the above.

3. The charging power setting mode includes a first charging power setting mode executed at the start of operation of the power control device; a second charging power setting mode executed every predetermined time during operation of the power control device; a third charging power setting mode executed when the power output to the storage battery and the load during operation of the power control device satisfies a predetermined second condition. The power control device according to claim 1 or 2, characterized by the above.

4. The control unit In the first charging power setting mode, control is executed to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value. In the second charging power setting mode, control is executed to switch the output power value from the power value selected at the time of executing the second charging power setting mode to a higher power value. In the third charging power setting mode, after once stopping the power output to the storage battery, control is executed to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value. The power control device according to claim 3, characterized in that.

5. A storage battery, A power storage control device that is electrically connected to the storage battery and a load different from the storage battery and controls at least the charging of power to the storage battery. A power storage system having a self - power supply facility that supplies power from a power source different from the commercial power system to the power storage control device. The power storage control device is A control unit that controls the power supplied to the storage battery, and output power switching means for switching the value of the power output to the storage battery among a plurality of preset different output power values at a connection portion with the storage battery. Until the power output to the storage battery and the load satisfies a predetermined first condition, the control unit switches the output power value to a higher value every predetermined time by the output power switching means to output power. When the first condition is satisfied, a charging power setting mode is executed in which an output power value lower than the output power value selected when the first condition is satisfied is determined as the charging power value for the storage battery. A process of once reducing the output power value to the storage battery is executed between the start of one of the predetermined times and the start of the next predetermined time. A power storage system, characterized in that.

6. The self - power supply facility includes a power conditioner including a DC / DC converter and a DC / AC inverter. The control unit is When the voltage value of the power output from the power conditioner becomes equal to or lower than a predetermined third threshold value. When the current value of the power output from the power conditioner becomes equal to or higher than a predetermined fourth threshold value. When the power value of the power output from the power conditioner becomes equal to or higher than a predetermined fifth threshold value. When the voltage value of the power output from the DC / DC converter becomes equal to or lower than a predetermined sixth threshold value. When the deviation of the voltage value of the power output from the DC / DC converter becomes equal to or greater than a predetermined seventh threshold value, in at least any one of the cases, it is determined that the first condition is satisfied. The battery system according to claim 5, characterized in that.

7. In the charging power setting mode, a first charging power setting mode executed at the start of operation of the power storage control device; a second charging power setting mode intermittently executed during operation of the power storage control device; a third charging power setting mode executed when the power output to the battery and the load during operation of the power storage control device satisfies a predetermined second condition, is included. The battery system according to claim 5 or 6, characterized in that.

8. The control unit, in the first charging power setting mode, executes control to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value; in the second charging power setting mode, executes control to switch the output power value from the power value selected at the time of execution of the second charging power setting mode to a higher power value; in the third charging power setting mode, after once stopping the power output to the battery, executes control to switch the output power value from the lowest power value among the plurality of different output power values to a higher power value. The battery system according to claim 7, characterized in that.

9. A program for causing a computer to function as the control unit of the power control device according to claims 1 to 4.

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