JP5303024B2 - Battery system - Google Patents

Abstract

This battery system includes: a power source device that supplies electrical power; a battery device resulting from a plurality of battery units that are essentially the same being connected in parallel, the battery units each being provided with a power conversion unit, which converts the power supplied from the power source device, and a battery module, which is charged by the power converted by the power conversion unit; and a control device. The control device has: a recording unit that records first information pertaining to the baseline power value of the power conversion units; an acquisition unit that acquires second information pertaining to the supplied power that the power source device supplies; and a selection unit that sets the greatest value among the plurality of baseline power values recorded by the recording unit as a first baseline power value, determines the number of battery units that can allocate the supplied power acquired by the acquisition unit as power that is at least the first baseline power value, and selects and charges the determined number of battery units.

Description

  The present invention relates to a battery system, and more particularly to a battery system that efficiently charges a plurality of battery modules.

  Conventionally, a battery system is known in which a plurality of battery modules each composed of a plurality of chargeable / dischargeable battery cells are connected in parallel. In this battery system, for example, power from a power source using natural energy such as wind power generation or solar power generation or power from a commercial power source is charged to a battery module via a power converter such as an inverter or a converter.

  Here, as a method of charging a plurality of battery modules connected in parallel, for example, a method of supplying power from a power source to a plurality of battery modules in parallel (for example, see Patent Document 1) is known. . In addition, a method of selecting and supplying power from a power source to one battery module and switching the power supply destination to another battery module when the selected battery module is fully charged (for example, patents) Document 2) and a method of selecting and supplying one battery module over time with power from a power source (for example, see Patent Document 3) are also known.

JP 2008-220104 A JP 2010-028881 A JP 2011-103746 A

  However, since the invention described in Patent Document 1 charges all the plurality of battery modules in parallel, if the power supplied from the power source to each battery module is not sufficiently large, for example, between each battery module and the power source When each of the power converters is arranged, the power input to each of the power converters becomes very small. Therefore, there is a problem that the power conversion efficiency of the power converter is lowered, and as a result, the charging efficiency of the entire battery system is also lowered. As will be described in detail later, power converters such as inverters and converters are generally known to have an extremely low power conversion efficiency if there is no input power above a certain level.

  Moreover, the case where the power conversion efficiency of each power converter arranged between each battery module and the power source is not substantially the same due to factors such as the degree of deterioration thereof is assumed. In this case, if an attempt is made to evenly distribute the power to all of the plurality of battery modules, the power input to the power converter arranged in front of each battery module has a condition of good power conversion efficiency in a certain power converter. Although it becomes more than an electric power value, in other electric power converters, it may become smaller than the electric power value on the conditions with good electric power conversion efficiency. As a result, there is a problem that the charging efficiency of the entire battery system is lowered.

  Further, the inventions described in Patent Document 2 and Patent Document 3 are methods for charging a plurality of battery modules individually, but when the charging time is short, the battery modules connected in parallel cannot be charged equally. There was a problem. When the charging time is short, for example, when power supply from a power source (for example, a power source such as wind power generation or solar power generation) stops immediately after starting charging, or power supply from the power source is sufficient However, even when the power of the battery module needs to be discharged with respect to the load, and when it is necessary to switch from the charging mode to the discharging mode, the battery modules cannot be charged evenly. If a plurality of battery modules cannot be charged evenly, for example, the charge / discharge load concentrates on a specific battery module, and many problems occur, such as deterioration worsening compared to other battery modules. It is desirable to charge the battery modules as evenly as possible.

  Therefore, in view of the above problems, an object of the present invention is to provide a new battery system capable of increasing the charging efficiency of a plurality of battery modules connected in parallel.

  A battery system according to the present invention includes a power supply device that supplies power, a battery unit that includes a power conversion unit that converts power supplied from the power supply device, and a battery module that charges the power converted by the power conversion unit. A storage unit that stores information related to the reference power value of each of the plurality of power conversion units, an acquisition unit that acquires information related to the power supplied by the power supply device, and a storage unit The largest value among the plurality of reference power values is set as the first reference power value, and the number of battery units that can distribute the supply power acquired by the acquisition unit to power equal to or higher than the first reference power value is determined. And a control unit including a selection unit that selects and charges the determined number of battery units.

  According to such a battery system, a battery unit to be supplied among a plurality of battery units connected in parallel according to the power supplied from the power supply device and also taking into account the power conversion efficiency of the power converter. Since it can be selected, an optimal number of battery modules can be charged while maintaining high charging efficiency.

  According to the battery system of the present invention configured as described above, in consideration of the power conversion efficiency of the power converter, a plurality of battery modules connected in parallel are charged while maintaining high charging efficiency. be able to.

The schematic block diagram of the battery system of embodiment of this invention is shown. The figure for demonstrating specific structures, such as a battery apparatus in embodiment of this invention, is shown. The relationship figure of the input power and conversion efficiency of a general converter is shown. It is a flowchart which shows the operation processing content of the battery system of embodiment of this invention. It is a flowchart which shows the operation processing content of the battery system of embodiment of this invention. It is a flowchart which shows the operation processing content of the battery system of embodiment of this invention. It is a flowchart which shows the operation processing content of the battery system of embodiment of this invention. It is a figure which shows an example of the transition of a charge state at the time of operating the battery system of embodiment of this invention. It is a figure for demonstrating an example of switching of the switch for charging each battery unit equally in the battery system of embodiment of this invention. It is a figure which shows another example of the transition of a charge state at the time of operating the battery system of embodiment of this invention. It is a figure which shows another example of the transition of a charge state at the time of operating the battery system of embodiment of this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. In the following embodiments, a description will be given using a wind power generator as an example of a power supply device, and a converter that converts AC power into DC power as an example of a power conversion unit.

  FIG. 1 is a schematic configuration diagram of a battery system 1 according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining a specific configuration of the battery device 20 and the like. 1 and 2 indicate signal lines (wired or wireless) that can transmit and receive various types of information to and from the control device.

  As shown in FIG. 1, the battery system 1 includes a wind power generator 10, a battery device 20, a load 30, a control device 40, and a display device 50, and supplies power generated by the wind power generator 10 to the battery device 20. In this system, the electric power charged (stored) in the battery device 20 is supplied to the load 30. In addition, the battery system 1 of this embodiment is not limited to the said structure, It is also possible to add and change a structure suitably. For example, a configuration may be added in which power generated by the wind power generator 10 is converted and then directly supplied to the load 30. In this case, the power generated by the wind power generator 10 and the battery device 20 are stored. It is also possible to supply electric power to the load 30 in combination with the electric power.

  The wind power generator 10 is a power supply device that generates three-phase AC power (AC power) by rotating a rotating machine with wind power, which is natural energy, and the configuration itself is the same as that of a general wind power generator. be able to. The wind power generator 10 supplies the generated AC power to the battery device 20 via the power wiring.

  The battery device 20 converts the AC power supplied from the wind power generator 10 into DC power for charging (storage), and converts the supplied DC power into power suitable for the load 30 and supplies it. As shown in FIG. 2, the battery device 20 includes a plurality of battery units 20 </ b> A to 20 </ b> D connected in parallel.

  The battery unit 20 </ b> A includes a battery module 21 </ b> A in which a plurality of chargeable / dischargeable battery cells are connected in series, a converter 22 </ b> A that receives AC power input from the wind power generator 10 and converts it into DC power, and the wind power generator 10. And a switch 23A that can cut off the input of AC power to the converter 22A. The battery unit 20B includes a battery module 21B, a converter 22B, and a switch 23B so that the battery unit 20C has substantially the same configuration as the battery unit 20A. The battery unit 20C includes the battery module 21C, the converter 22C, and a switch. The battery unit 20D includes a battery module 21D, a converter 22D, and a switch 23D. Any of the battery units 20A to 20D can be supplied with the AC power from the same common power wiring. In the battery system 1 of the present embodiment, four battery units 20A to 20D are described as battery units connected in parallel. However, the number of battery units is not limited to four, and at least The number may be two or more. For example, the number can be appropriately changed according to various conditions such as the maximum generated power of the wind power generator 10 or the power required by the load 30.

  Each of the battery modules 21A to 21D is an assembled battery as a DC power source configured by connecting a plurality of battery cells in series, and charges the electric power converted by the converters 22A to 22D, respectively. Each battery cell which comprises each battery module 21A-21D is a battery cell which can be charged / discharged, Comprising: For example, the battery cell of a lithium ion secondary battery can be used. The number of battery cells constituting each of the battery modules 21A to 21D can be determined according to the maximum generated power of the wind power generator 10, the number of battery units connected in parallel, or the power required by the load 30. .

In addition, the battery module 21A to 21D, a voltage sensor _V 1 ~V ₄ measuring the voltage of both ends of the battery modules 21A to 21D, a current sensor I for measuring the current flowing through each battery module 21A to 21D, respectively and ₁ ~I ₄ is provided. Each voltage value measured by the voltage sensor V ₁ ~V _4, and the current value measured by the current sensor I ₁ ~I ₄ is sent to the control unit 40 via the signal line. In addition, a voltage sensor is not restricted to the case where it is provided for every battery module, For example, you may make it provide for every battery cell which comprises a battery module.

  Converters 22 </ b> A to 22 </ b> D are power converters that convert AC power supplied from wind power generator 10 into DC power. In addition, converters 22 </ b> A to 22 </ b> D are controlled to be started (ON) and stopped (OFF) in response to a command from control device 40. It is known that converters 22 </ b> A to 22 </ b> D generally generate power loss when converting input AC power to DC power.

  Here, FIG. 3 shows a diagram representing the relationship between input power and conversion efficiency in a general converter. Although the maximum input (maximum input power value) Pmax and the maximum efficiency input (input power value when the maximum conversion efficiency is reached) Pe are different for each converter manufacturer, a general converter is as shown in FIG. In addition, when the input power is smaller than the input Pe at the maximum efficiency, the conversion efficiency is rapidly deteriorated, and the conversion efficiency tends to be gradually lowered until the input Pe at the maximum efficiency reaches the maximum input Pmax. Therefore, any converter can be applied to the battery system 1 of the present embodiment by using the maximum input Pmax and the maximum efficiency input Pe that are generalized values. However, even in the same converter, values such as the maximum efficiency input Pe may change due to factors such as the usage frequency and usage environment.

  The switches 23 </ b> A to 23 </ b> D are switching means that can switch whether or not to interrupt the input of AC power from the wind turbine generator 10 to each of the converters 22 </ b> A to 22 </ b> D via the power wiring. In response to this, ON (closed) / OFF (open) is switched. If each switch 23A-23D is ON, the alternating current power from the wind power generator 10 will be supplied to each converter 22A-22D, and if it is OFF, the alternating current power from the wind power generator 10 to each converter 22A-22D Supply is cut off. Note that when the switches 23A to 23D are turned OFF, the control device 40 desirably controls the converters 22A to 22D corresponding to the switches 23A to 23D, respectively. In this case, the waste in the converters 22A to 22D Power consumption can be suppressed.

  The load 30 is driven by receiving power supplied from the battery device 20, and is an AC power load driven by AC power or a DC power load driven by DC power. If the load 30 is an AC power load, each of the battery units 20A to 20D is provided with an inverter (not shown) that converts DC power into AC power. If the load 30 is a DC power load, the battery units 20A to 20D are provided. 20D is provided with a DC-DC converter (not shown) capable of converting DC power into DC power (DC voltage) desired by the load 30.

  The control device 40 is based on the supply power (generated power) that can be supplied by the wind power generator 10, the charging rates of the battery modules 21A to 21D, and the power conversion efficiencies of the converters 22A to 22D. The battery device 20 is controlled to select at least one of the battery units 20A to 20D to which AC power is to be supplied. Moreover, the control apparatus 40 can also control the display apparatus 50, and causes the display apparatus 50 to appropriately display various information such as the supply power of the wind power generation apparatus 10 and the charging rate of the battery unit.

  As shown in FIG. 2, for example, the control device 40 includes a storage unit 41, an acquisition unit 42, a selection unit 43, and a switching unit 44 as processing functions for charging the battery units 20 </ b> A to 20 </ b> D. The control device 40 includes, for example, a processor for performing various calculations and control, a temporary storage of information (data), a RAM that functions as a working area at the time of control, a ROM that stores programs, and peripheral circuits. It is comprised and the processing function of said each part is realizable. The charging operation of the battery system 1, that is, a specific control flow performed by the control device 40 will be described later.

  Storage unit 41 stores and stores information related to reference power values PbA to PbD corresponding to predetermined power conversion efficiencies of converters 22A to 22D. Here, the reference power value in the present embodiment is a value that can guarantee power conversion at a power conversion efficiency above a certain level in the converter if a power value equal to or higher than that value is input to the converter. As described above with reference to FIG. 3, the power conversion efficiency decreases relatively gently from the maximum efficiency input Pe to the maximum input power Pmax, but the power conversion efficiency can be maintained at a substantially high level. In the battery system 1 of the present embodiment, the maximum efficiency input Pe corresponding to the optimum power conversion efficiency in each of the converters 22A to 22D is set as the reference power values PbA to PbD. In addition, in the battery system 1 of the present embodiment, the case where the respective maximum efficiency inputs Pe of the converters 22A to 22D are used as the reference power values PbA to PbD will be described as an example, but the present invention is not limited to this. Instead of the maximum-efficiency input Pe, for example, as shown in FIG. 3, the configuration of the battery system, such as using the input power value P ′ having the smallest value among the power with power conversion efficiency of 90 (%) or more, and Each reference power value can be set as appropriate according to the characteristics of the power conversion efficiency of the converter.

  The acquisition unit 42 obtains information on the power (supplied power) supplied by the wind turbine generator 10 and each module information (voltage value and current value information) of the battery modules 21A to 21D included in each of the battery units 20A to 20D. Acquired at a predetermined timing. The acquisition unit 42 calculates the state of charge (SOC) of each of the battery units 20A to 20D using a known calculation method based on the acquired voltage value and each current value, and the calculated result is input to the selection unit 43. Notice. The charge rate SOC is a ratio (percentage) indicating how much charge is remaining with respect to the capacity of the battery at the time of full charge. A known calculation method is used depending on the voltage and current flowing for each battery module. It can be calculated. In addition, in the battery system 1 of this embodiment, although the case where the information of each voltage value and each current value is used as module information and the charge rate SOC is calculated will be described as an example, the present invention is not limited to this. For example, the charging rate SOC may be obtained by using information on each voltage value or information on each current value as module information. When using information on each voltage value, for example, a table of voltage values and charging rate SOC at the time of settling is prepared in advance, each voltage value is acquired at the time of settling, and from the acquired voltage value using the above table The charging rate SOC can be obtained. Further, the predetermined timing can be, for example, a timing immediately before the start of charging and a timing at regular intervals after the start of charging.

  The selection unit 43 sets the largest reference power value among the reference power values PbA to PbD of the converters 22A to 22D stored in the storage unit 41 as the first reference power value. Moreover, the selection part 43 can distribute supply power to electric power more than the said 1st reference | standard power value based on each information of supply power which the acquisition part 42 acquired, and each charging rate SOC of each battery module 21A-21D. Determine the number of battery units. And the selection part 43 selects and charges the battery unit which supplies electric power from the wind power generator 10 among several battery unit 20A-20D by the determined number.

  However, the selection unit 43 is, for example, one of the reference power values smaller than the first reference power value among the plurality of reference power values PbA to PbD, and the reference power value having the next largest value after the first reference power value. Of the battery unit having a converter in which the reference power value is less than or equal to the second reference power value, rather than the number of battery units that can distribute the supplied power to power that is greater than or equal to the first reference power value. If the number of battery units that can distribute the supplied power with power equal to or greater than the second reference power value is large, the second reference power value is selected from the battery units having converters whose reference power value is equal to or less than the second reference power value. The number of battery units that can be distributed to the above power is determined, and the determined number of battery units that supply power from the wind turbine generator 10 are selected.

  Moreover, the selection part 43 determines the priority which supplies electric power with respect to battery unit 20A-20D based on the information of the charge rate of each battery module 21A-21D in order with low charge rate SOC, and each battery unit 20A. Based on the reference power values PbA to PbD of ˜20D, the supplied power, and the charging rate, the number that can distribute the supplied power is determined, and the determined number of battery units are selected based on the priority. In addition, the detailed selection method of the control apparatus 40 (selection part 43) in the battery system 1 of this embodiment is demonstrated in the flowchart mentioned later.

The switching unit 44 has a charging rate of a battery module included in at least one battery unit among the battery units 20 </ b> A to 20 </ b> D selected by the selection unit 43, and includes at least one battery unit among the battery units not selected by the selection unit 43. It is determined whether or not the charging rate of the battery module provided is the same or substantially the same. When the switching unit 44 determines that the charging rate is the same or substantially the same, the switching unit 44 selects the battery unit including the battery module having the charging rate selected by the selection unit 43 and the same or substantially the same. supply is switched alternately power has been supplied for charging rate identical or substantially identical batteries unit from the wind turbine generator 10. In addition, the detailed switching method of the control apparatus 40 (switching part 44) in the battery system 1 of this embodiment is demonstrated in the below-mentioned flowchart.

  The display device 50 displays various types of information such as the power supplied from the wind power generator 10 and the charging rate of the battery unit to the user, and is a monitor such as a general liquid crystal panel. In addition, what is necessary is just to provide the display apparatus 50 as needed, and you may abbreviate | omit in the battery system 1 of this embodiment.

  In the battery system 1 of the present embodiment configured as described above, the reference power values PbA to PbD that are the largest first reference power value (for example, the reference power value PbA of the converter 22A, PbA = 40 kW) or more. Is supplied to at least one battery unit selected from the battery units 20A to 20D, the converter of each selected battery unit has a first reference power value that is equal to or higher than the individual reference power value. Since power is supplied, the power conversion efficiency is high. As a result, the charging efficiency of the entire battery device 20 is also good. However, if power smaller than the first reference power value is supplied to, for example, the converter 22A having the first reference power value, the power conversion efficiency in the converter 22A decreases, which may be undesirable. Therefore, when supplying power below the first reference power value to the battery unit, the battery units 20B to 20D are excluded from the battery unit 20A having the converter 22A having the first reference power value, and these selection candidates are selected. The power supply destination is determined from the battery units 20B to 20D.

  Then, the second reference power value (for example, the reference power value PbB, PbB = 35 kW) having the second smallest value after the first reference power value is supplied to the battery units 20B to 20D as the selection candidates. For example, the converters 22B to 22D of the battery units 20B to 20D are supplied with the power of the second reference power value that is equal to or higher than the individual reference power value, so that the power conversion with a certain power conversion efficiency is guaranteed. The battery system 1 as a whole can maintain a high charging efficiency.

  Further, in the battery system 1 of the present embodiment, the supplied power P is distributed to as many battery units as possible so that they can be charged evenly. For example, when the supplied power P is distributed and power of a first reference power value (for example, PbA = 40 kW) or more is supplied to the battery unit, the supplied power P is equalized when the supplied power P is 75 kW. Cannot be distributed to two or more battery units (for example, if the supply power P is distributed to two, it becomes 37.5 kW and becomes the first reference power value (40 kW) or less). There is no choice but to select one battery unit and supply supply power P (75 kW). However, if the supply power P is distributed to supply the battery unit with power equal to or higher than the second reference power value (for example, Pb = 35 kW), which is the next smaller value than the first reference power value, the supply power P Can be evenly distributed to two battery units among the other battery units 20B to 20D except for the battery unit 20A having the converter 22A having the first reference power value. (If the supply power P is evenly distributed, it becomes 37.5 kW, which is equal to or greater than the second reference power value (35 kW)). As a result, the battery modules can be charged as evenly as possible in parallel.

  That is, in the battery system 1 of the present embodiment, the battery unit to be distributed and supplied is selected and determined based on the reference power values PbA to PbD. Further, when selecting a battery unit to be supplied, an SOC is selected in consideration of the SOC.

  Hereinafter, with reference to the flowcharts shown in FIGS. 4 to 7, the charging operation process of the battery system 1 of the present embodiment that is performed using the control device 40 will be described. Note that the processes shown in the flowcharts of FIGS. 4 to 7 can be executed in any order or in parallel as long as the process contents do not contradict each other.

First, in describing the charging operation processing of the battery system 1, the battery system 1 has the configuration described above with reference to FIGS. 1 and 2, and further assumes the following matters. The number of battery units is represented by a fixed value N. As shown in FIG. 2, four battery units 20A to 20D are used, so N = 4. Each maximum input power value to converters 22A to 22D is represented by a fixed value Pmax, and Pmax = 100 kW. Accordingly, the maximum allowable input power of the battery device 20 shown in FIG. 2 is N × Pmax = 400 kW (supplied power of the wind power generator 10 does not exceed this value). Further, as the reference power value PbA~PbD having a predetermined power conversion efficiency of the respective converter 22A~22D, PbA = 40kW, PbB = 3 0 kW, PbC = 3 5 kW, the PbD = 25 kW. In addition, it is assumed that these reference power values PbA to PbD are stored in the storage unit 41 in advance. The reason why the reference power values are different in the converters 22A to 22D is because, for example, it is assumed that the battery system 1 is configured by mixing converters from a plurality of manufacturers.

  Further, as a further premise, it is assumed that the SOCs of the battery modules 21A to 21D before charging (the initial values of the SOC before the charging operation processing of the battery system 1) are 80%, 60%, 70%, and 50%, respectively. To do.

  Based on the above, the charging operation processing of the battery system 1 performed using the control device 40 will be described below.

  First, the acquisition unit 42 acquires the reference power value of each converter from the storage unit 41, sorts the plurality of reference power values in descending order, and arranges the values in the array Pb [i] (1 ≦ i ≦ N) and stored in the storage unit 41 (step S100). As described in the above preconditions, in this example, the reference power values PbA to PbD of the converters 22A to 22D are large when PbA = 40 kW, PbB = 30 kW, PbC = 35 kW, and PbD = 25 kW, respectively. As a result of sorting in order, PbA> PbC> PbB> PbD. When the values are stored in the reference power value array Pb [i], N = 4 in this example, so Pb [1] = 40 kW (PbA), Pb [2] = 35 kW (PbC), Pb [ 3] = 30 kW (PbB) and Pb [4] = 25 kW (PbD) are created. In this example, Pb [1] is the first reference power value.

  Next, the acquisition unit 42 acquires information on the power supply P of the wind power generator 10 from the wind power generator 10 (step S101). In this example, the acquisition part 42 shall acquire the information that the supply electric power P of the wind power generator 10 is 75 kW from the wind power generator 10, for example.

  Next, the selection unit 43 divides the supplied power P by the number N of battery units from the acquired information on the supplied power P, and the divided value P / N is the reference power values Pb [1] to Pb [N]. It is judged whether it is more than the largest reference electric power value Pb [1] among these (step S102). That is, in this example, the selection unit 43 determines whether or not a value P / N obtained by dividing 75 kW that is the supplied power P by 4 that is the number N of battery units is 40 kW or more that is the reference power value Pb [1]. Determine whether.

  When the divided value P / N is equal to or greater than the reference power value Pb [1] (step S102: Yes), the selection unit 43 selects the switches 23A to 23D of the battery units 20A to 20D via the signal lines. A control signal is sent to turn on the switches 23A to 23D (step S103). In this case, even if each of the switches 23A to 23D is turned on, the power input to each of the converters 22A to 22D is equal to or higher than the reference power value Pb [1], and thus all the power conversion efficiency in the converters 22A to 22D is high. In the state, each battery module 21A-21D can be charged. The selection unit 43 also sends control signals to the converters 22A to 22D of the battery units 20A to 20D via the signal lines when turning on the switches 23A to 23D, and activates the converters 22A to 22D. To do.

  After the process of step S103, the acquisition unit 42 acquires again the information on the supplied power P from the wind power generator 10 (step S104), and the supplied power P is obtained from the acquired information on the supplied power P by the number N of battery units. Then, it is determined whether or not the divided value P / N is greater than or equal to the reference power value Pb [1] (step S105). In the processes in steps S104 to S105, when the supplied power P changes after a predetermined time has elapsed, the number N (= 4) of battery units that receive power supply is changed in order to maintain high charging efficiency in the battery device 20. This process is performed to determine whether or not it is better. That is, before the process of step S104, the number of battery units that receive power supply is determined as N (= 4) based on the supply power P acquired in the process of the previous step S101. This is determined because it is possible to supply the battery units 20A to 20D with power equal to or higher than the reference power value Pb [1] even if the supply power P is distributed to the battery units 20A to 20D. However, in a power supply device using natural energy such as the wind power generator 10, the supply power P changes, so the optimum number of battery units that can be supplied with power of the reference power value Pb [1] or more also changes. Will get. Therefore, it is preferable to change the optimal number of battery units that receive power supply according to the supplied power P. In addition, the timing which acquires the information of the supplied electric power P can be suitably set according to factors, such as the characteristic of the wind power generator 10, for example.

  In the process of step S105, when the divided value P / N is equal to or greater than the reference power value Pb [1], that is, when it is not necessary to change the number N of battery units that supply power (step S105: Yes), the selection unit 43 determines whether or not the battery modules 21A to 21D have finished charging (step S106). Here, the end of charging in each of the battery modules 21A to 21D means that, for example, when each of the battery modules 21A to 21D is fully charged, or the power charged in each of the battery modules 21A to 21D needs to be discharged. Is the case. When at least one of the battery modules 21A to 21D is fully charged (for example, when the charging rate reaches 90% as a predetermined value), the selection unit 43 sets the battery module to On the other hand, it is possible to control to turn off the corresponding switch so as to cut off the power supply, and to continue the power supply of P / (N-1) to the other battery modules.

  If the charging is finished (step S106: Yes), the process flow is finished. If the charging is not finished (step S106: No), the process proceeds to step S104. In this example, if the supplied power P is 75 kW and the number N of battery units is 4, the divided value P / N is about 18.75 kW, which is smaller than 40 kW, which is the reference power value Pb [1]. Therefore, after the process of step S102, the process does not proceed to the processes of steps S103 to S106, but proceeds to the process of the following step S107.

In the process of step S102 (or in the process of step S105), when the divided value P / N is smaller than the reference power value Pb [1] (step S102: No (or step S105: No)), the acquisition unit 42 Acquires information indicating the state of charge of each of the battery modules 21A to 21D, and calculates the SOC (step S107). In this example, the divided value P / N is about 18.75 kW, which is smaller than 40 kW, which is the reference power value Pb [1]. Therefore, the acquisition unit 42 determines the charging state of each of the battery modules 21A to 21D. as information indicating the respective voltage values measured by the voltage sensor _V 1 ~V _4, and the current value measured by the current sensor _I 1 ~I _4, the voltage sensor _V 1 ~V ₄ and the current Obtained from the sensors I _{1 to} I ₄ via signal lines. The acquisition part 42 calculates SOC of each battery module 21A-21D using a well-known calculation method with each acquired said voltage value and each current value. As described in the above preconditions, in this example, as a result of the calculation performed by the acquisition unit 42, the SOC before the charging operation processing of each of the battery modules 21A to 21D (the initial value SOC) is 80% and 60%, respectively. %, 70%, and 50%.

  Next, the selection unit 43 determines a priority order for supplying power to each of the battery units 20A to 20D based on the obtained SOC of each of the battery modules 21A to 21D (step S108). That is, the selection unit 43 determines the priority for supplying power to the battery units 20A to 20D in order of increasing SOC, and in this example, the obtained SOC of the battery modules 21A to 21D is 80%, Since the priority is 60%, 70%, and 50%, the priority of battery unit 20D is 1, the priority of battery unit 20B is 2, the priority of battery unit 20C is 3, and the priority of battery unit 20A is 4. It is decided with the number.

  Next, moving to the flowchart shown in FIG. 5, the selection unit 43 represents the number of battery units that can supply power simultaneously (number of switches that can be turned on simultaneously) among the candidate battery units as a variable M. = N-1 is set (step S109). In addition, each process of steps S109 to S118 determines the number of battery units to which power is supplied from the wind turbine generator 10 so that the power supplied to each battery unit is equal to or higher than the individual reference power value. This is processing to select the previous battery unit to the determined number.

  The selection unit 43 sets the variable i to 1 (step S110). Then, the selection unit 43 calls the value of the largest reference power value Pb [1] in the array Pb [i] (1 ≦ i ≦ N) in which the reference power values are sorted in descending order.

  The selection unit 43 determines whether or not a value P / M obtained by dividing the supplied power P by M is equal to or greater than the reference power value Pb [i] (step S111). In this example, since i = 1 at this stage, the selection unit 43 obtains a value P / M obtained by dividing 75 kW which is the supplied power P by 3 which is M (= N (4) −1). It is determined whether or not the reference power value Pb [1] is 40 kW or more.

  When the divided value P / M is smaller than the reference power value Pb [i] (step S111: No), the selection unit 43 determines whether or not to remove the battery unit corresponding to the converter having Pb [i] from the selection candidates. Is determined (step S112). Whether or not to remove the determination target battery unit from the selection candidates is determined based on, for example, whether or not the priority of the determination target battery unit is No. 1, and if the priority is No. 1, Since this battery unit is a battery unit that should supply power most preferentially, it is not excluded as a selection candidate.

  Note that whether or not to remove the battery unit from the selection candidates is not limited to the determination based on the priority order. As another example, the average value of the SOC of each of the battery modules 21A to 21D is calculated, and the average value is calculated from the average value. You may judge by whether it is below the predetermined range. For example, the average value of the SOC of each of the battery modules 21A to 21D is about 60%, and the SOC of the battery module included in the battery unit to be determined exceeds a predetermined range from the average value (for example, 10% If the battery unit is lower than the above, this battery unit is one of the battery units to which power should be supplied most preferentially. Therefore, it may be determined that this battery unit is not excluded as a selection candidate.

When it is determined that the selection candidate is excluded (step S112: Yes), the selection unit 43 determines whether or not a relational expression of i ≧ N−M + 1 is satisfied (step S113). When the relational expression is not satisfied in the process of step S113 (step S113; No), the selection unit 43 sets i to i + 1 (step S114), and proceeds to the process of step S111. On the other hand, when the relational expression is satisfied in the process of step S113 (step S113: Yes) or when it is determined not to be excluded from the selection candidates in the process of step S112 (step S112: No), the selection unit 43 It resets as M = M-1 (step S115), and if M is 2 or more (step S116: Yes), it will move to the process of step S110. On the other hand, when M is smaller than 2 (that is, when M is 1) (step S116: No), the selection unit 43 represents the number of battery units that can be supplied with power by a variable Q, and Q = 1. Set (step S117).

  On the other hand, when the divided value P / M is equal to or greater than the reference power value Pb [i] (step S111: Yes), the selection unit 43 represents the number of battery units that can be supplied with power by a variable Q, Q = M is set (step S118).

  In the processes in steps S110 to S118, first, it is determined whether or not the supply power P can be distributed and supplied to the M (= N−1) battery units with power equal to or higher than the reference power value Pb [1]. If it is determined that supply is not possible, the supply power P is supplied to the M battery units with powers of the reference power values Pb [2] to Pb [4] which are smaller than the reference power value Pb [1]. Determine if it is possible. In other words, the above processing is based on the premise that the supplied power P is distributed to the battery units at the maximum reference power value Pb [1] or more. However, the SOC of each battery module is taken into account and the reference power value Pb is taken into consideration. When the number of battery units that can be selected is larger when the power is distributed with reference power values Pb [2] to Pb [4] smaller than [1], that is selected.

  Specifically, in this example, if P = 75, M = 3 (N−1), and i = 1, first, in the process of step S111, the divided value P / M is 25 kW. Since it is smaller than Pb [1] (= 40 kW), the process proceeds to step S112. In the process of step S112, it is determined whether or not to remove the battery unit 21A corresponding to the converter 22A having Pb [1] from the selection candidates. Since the priority order of the battery unit 21A is set to No. 4, the battery unit 21A is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, i (here, i = 1) is not equal to or greater than NM + 1 (here, NM + 1 = 2), so the process proceeds to step S114, and i = i + 1 (here, i = 2) is set, and the process proceeds to step S111.

  Next, since the divided value P / M is 25 kW and not equal to or larger than Pb [2] (= 35 kW), the process proceeds to step S112. In the process of step S112, it is determined whether or not the battery unit 21C corresponding to the converter 22C having Pb [2] is excluded from the selection candidates. Since the priority order of the battery unit 21C is set to No. 3, it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, i (here, i = 2) is equal to or greater than NM + 1 (here, NM + 1 = 2). Therefore, the process proceeds to step S115, where M = M-1 (here, , M = 2), and the process proceeds to step S116.

  Since M ≧ 2 (here, M = 2) is satisfied in the process of step S116, the process proceeds to step S110. Since i = 1 is reset in the process of step S110 and M = 2, the divided value P / M is 37.5 kW and is not equal to or greater than Pb [1] (= 40 kW). Proceed to the process. In the process of step S112, it is determined whether or not to remove the battery unit 21A corresponding to the converter 22A having Pb [1] from the selection candidates. Since the priority order of the battery unit 21A is set to No. 4, the battery unit 21A is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, i (here, i = 1) is not equal to or greater than NM + 1 (here, NM + 1 = 2), and thus the process proceeds to step S114. In the process of step S114, i = i + 1 (here, i = 2) is set, and the process proceeds to step S111.

  Next, since the divided value P / M is 37.5 kW and is equal to or greater than Pb [2] (= 35 kW), the process proceeds to step S118. In the process of step S118, since the number of battery units that can simultaneously supply power among the battery units that are candidates for selection is M = 2, Q = M (= 2) is set.

  By performing these processes, if it is attempted to supply the supplied power P (= 75 kW) to the battery unit at the reference power value Pb [1] (= 40 kW) or more, only one battery unit can be selected. If the power is supplied to the battery unit at the reference power value Pb [2] (= 35 kW) or more, two battery units can be selected.

  Next, returning to the flowchart of FIG. 5, if i = 1 (step S119: Yes), the selection unit 43 responds to supply power (P / M) to the Q battery units based on the priority order. The switch to be turned on is turned on (step S120), and the process proceeds to step S130 of the flowchart shown in FIG. The process of step S120 is a process when i = 1, that is, when the supplied power P is distributed to power equal to or higher than the reference power value Pb [1] and supplied to the Q battery units. In this case, no matter which battery unit is selected, each battery unit is distributed with power that is equal to or higher than the reference power value of each converter. Therefore, all of the battery units 20A to 20D are selected as candidates, and the above priority order is selected. Follow the steps to select the battery unit.

  On the other hand, if i is not 1 (step S119: No), it is selected to supply power (P / M) to the Q battery units selected based on the priority order and excluding the predetermined battery unit. The unit 43 turns on the corresponding switch (step S121), and proceeds to the process of step S122 of the flowchart shown in FIG. The process of step S121 is when i ≠ 1, that is, the supplied power P is distributed to power smaller than the reference power value Pb [1] and greater than the reference power value Pb [i] and supplied to the Q battery units. Process. Therefore, for example, if power smaller than the reference power value Pb [1] is supplied to a battery unit having a converter having the reference power value Pb [1], the power conversion efficiency decreases. A battery unit excluding the battery unit is selected as a power supply selection candidate, and a battery unit is selected from the selection candidate battery units according to the above priority.

  Specifically, in this example, since i = 2 is set as a result of the above processing, power equal to or higher than the reference power value Pb [2] is supplied to Q battery units, and the processing in step S119 is performed. To go to step S121. In the process of step S121, since Q = 2 is set in the above process, the battery units 20B to 20D excluding the battery unit 20A having the converter having the reference power value Pb [1] are selected as power supply selection candidates. Two battery units are selected from these battery units 20B to 20D in accordance with the priority order. That is, among the selection candidate battery units 20B to 20D, the battery unit 20D with the highest priority and the battery unit 20B with the next highest priority are selected, and 37.5 kW is supplied (charged) to each of them. Therefore, the selection unit 43 turns on the corresponding switches 23B and 23D, and also activates the converters 22B and 22D. When the switches 23B and 23D are turned ON, the converters 22B and 22D are input with electric powers equal to or higher than the reference power values PbB (= 30 kW) and PbD (= 20 kW), respectively. As a result, the battery modules 21B and 21D are charged while maintaining high power conversion efficiency in the converters 22B and 22D. In addition, the result of having performed the process so far is shown in the table of FIG.

  Next, each process after the process of step S121 will be described with reference to FIG. 6, and then each process after the process of step S120 will be described with reference to FIG.

First, as shown in the flowchart of FIG. 6, after a predetermined time (for example, 1 minute) has elapsed from the process of step S <b> 121, the acquisition unit 42 acquires information indicating the state of charge of the battery module being charged, and calculates the SOC. (Step S122). In other words, in this example, the acquisition unit 42 uses the voltage sensors V ₂ , VD as the information indicating the charging state of the battery modules 21 B, 21 D being charged. ₄ and the current sensors I ₂ and I ₄ through signal lines, and calculates the SOC of each of the battery modules 21B and 21D. In the process of step S122, not only the battery module being charged, but also the voltage values and current values of all the battery modules 21A to 21D are used as the voltage sensors V _{1 to} V ₄ and the current sensors I _{1 to} I, respectively. ₄ through a signal line, and the SOC of each of the battery modules 21A to 21D may be calculated. In this case, it is possible to make a more accurate determination or the like by the process of step S123 below.

  Next, the selection unit 43 determines whether or not the SOCs of the battery modules of the respective battery units that are selection candidates are all the same or substantially the same based on the obtained SOCs of the battery modules that are being charged (Step S43). S123).

  In the process of step S123, when it is determined that the SOCs of the battery modules of the selection candidate battery units are not all the same or substantially the same (step S123: No), the selection unit 43 obtains each SOC of the battery module being charged. Based on the above, it is determined whether or not the SOC of the battery module being charged has reached the SOC of the battery module that is the selection candidate and not being charged (whether or not they are the same or substantially the same) (step S124). ). In this example, the selection unit 43 determines whether at least one of the SOC of the battery module 21B being charged and the SOC of the battery module 21D has reached the SOC of the battery module 21C that is a selection candidate and is not being charged. Judging.

  When the SOC of the battery module being charged has reached the SOC of the battery module that is a candidate for selection and not being charged (step S124: Yes), the switching unit 44 has the same or substantially the same battery module. A signal is sent to the corresponding switch via the signal line so that the electric power P / M is evenly supplied to the battery unit, and each switch is turned on and off at a predetermined timing (step S125). . At this time, the power P / M is still supplied to the battery unit that has not reached the SOC.

  On the other hand, when the SOC of the battery module being charged does not reach the SOC of the battery module that is not being charged among the selection candidates (step S124: No), the process proceeds to step S127. Similarly, if there is no battery module that is not being charged among the selection candidates, the process proceeds to step S127.

In this example, for example, as shown in the table of FIG. 8B, when the SOCs of the battery modules of the selection candidate battery units are not all the same or substantially the same, the SOC of the battery module 21B being charged is Assuming that the SOC (= 70%) of the battery module 21C of the battery unit 20C that is a candidate for selection and that is not being charged is reached, the switching unit 44 mutually supplies power of 37.5 kW to the battery unit 20B and the battery unit 20C. In order to supply, control is performed so that the respective switches 23B and 23C are switched on and off at a predetermined timing. As a result, the battery module 21B and the battery module 21C can be charged uniformly. At this time, still it is powered 37.5 kW The battery unit 20D charging of the battery module 21 D is made. The predetermined timing for switching between the switch 23B and the switch 23C can be, for example, every 50 msec to 100 msec.

  In the process of step S123, when it is determined that the SOCs of the battery modules of the selection candidate battery units are all the same or substantially the same (step S123: Yes), the switching unit 44 determines that the selection candidate battery unit is not Control is performed so that the corresponding switches are switched to each other so that the battery units of the selection candidates are equally charged (step S126).

  In this example, for example, if the processing proceeds to step S122 as a result of the processing in steps S127 to S129 described later, that is, the supplied power P is 75 kW and does not change, and the supplied power P continues to be battery units 20A to 20A. Assuming that supply to 20D is possible, as shown in the table of FIG. 8C, when the SOCs of the battery modules of the selection candidate battery units are all the same or substantially the same SOC (= 79%), switching is performed. The unit 44 controls the switches 23A to 23D corresponding to each other so as to charge the selected candidate battery units 20B to 20D and the non-selected candidate battery units 20A equally.

  Specifically, as shown in FIGS. 9A to 9D, power is supplied to which battery units 20A to 20D so that the SOCs of all the battery units 20A to 20D can be charged evenly. Even so, the switching unit 44 sequentially switches the switches 23 </ b> A to 23 </ b> D so that each becomes equal to or higher than the reference power value.

  For example, first, as shown in FIG. 9A, when the switch 23C and the switch 23D are turned ON, the supply power P (= 75 kW) is distributed and the power of 37.5 kW is supplied to the converter 22C and the converter 22D. Is done. Next, after a predetermined time has elapsed, as shown in FIG. 9B, when the switch 23C is turned OFF and the switch 23B is turned ON, the supplied power P (= 75 kW) is distributed to the converter 22B and the converter 22D. Electric power of 37.5 kW is supplied. Similarly, after a predetermined time has elapsed, as shown in FIG. 9C, if the switch 23D is turned OFF and the switch 23C is turned ON, the supplied power P (= 75 kW) is distributed to the converter 22B and the converter 22C. Electric power of 37.5 kW is supplied. Next, as shown in FIG. 9D, when the switch 23B and the switch 23C are turned off and the switch 23A is turned on, the supplied power P (= 75 kW) is supplied to the converter 22A. By switching the supply destination of the supply power P in this way, the battery units 20A to 20D of the battery device 20 can be charged uniformly. In the example of FIG. 9, when the switch 23A is turned on, power is supplied to one battery module 21A in a concentrated manner. Therefore, the time for turning on only the switch 23A is set for the other two switches. The switching timing of each switch can be freely set as appropriate, for example, by shortening the ON time.

  Returning to the flowchart of FIG. 6, after the process of step S124, S125, or S126, the acquisition unit 42 acquires information on the power supply P of the wind power generator 10 from the wind power generator 10 (step S127).

  The acquisition unit 42 determines whether or not the value of the supplied power P acquired in the process of step S127 has changed beyond a predetermined range (step S128). In this process, whether the acquired supply power P has changed beyond a predetermined range as compared with the supply power P acquired in the previous process (for example, the supply power P acquired in the process of step S101). This process is performed to determine whether or not. The predetermined range here refers to, for example, supply when the power to distribute the supply power P from the wind power generator 10 and the number M of the battery units to be supplied change the charging efficiency in the battery system 1. This is the range of change in the power P. If it is determined that the value has changed beyond the predetermined range (step S128: Yes), the process proceeds to step S102, and if it is determined that the value has not changed beyond the predetermined range (step S128: No), step The process proceeds to S129.

  In the process of step S129, when the selection unit 43 determines that the charging is not finished (step S129: No), the process returns to step S122. On the other hand, when the selection unit 43 determines that the charging is finished (step S129: Yes) ), The operation process of the battery system 1 is terminated.

  Next, the processing after step S120 will be described with reference to FIG. As shown in the flowchart of FIG. 7, after the process of step S120, the acquisition unit 42 acquires information indicating the state of charge of the battery module being charged, and calculates the SOC (step S130).

  Next, the acquisition unit 42 determines whether or not the SOC of the battery module being charged has reached the SOC of the battery module that is the selection candidate based on the obtained SOC of each battery module being charged (same or substantially the same). Whether or not) (step S131).

  When the SOC of the battery module being charged has reached the SOC of the battery module among the above selection candidates (step S131: Yes), the selection unit 43 selects each battery unit having the same or substantially the same battery module. Then, a signal is sent to the corresponding switch via the signal line so that the power P / M is evenly supplied, and the ON and OFF of each switch are switched to each other at a predetermined timing (step S132). At this time, for the battery unit that has not reached the SOC, the power P / M is still supplied for a predetermined time (for example, 1 minute), and then the process proceeds to step S133.

  On the other hand, when the SOC of the battery module being charged does not reach the SOC of the battery module that is not being charged among the selection candidates (step S131: No), the process proceeds to step S133.

  Since the processing of steps S133 to S135 is the same as the processing of steps S127 to S129, the description thereof is omitted.

  As described above, the battery system 1 of the present embodiment operates.

<Operation Contents under Other Conditions in Battery System 1 of the Present Embodiment>
In the above description, the case where the power supply P of the wind power generator 10 is 75 kW has been described in the process of the first step S100. However, as another condition, the case where the power supply P is 35 kW is also illustrated in FIGS. A brief description will be given below with reference to FIGS.

  First, in the process of step S100, the acquisition unit 42, like the above, Pb [1] = 40 kW (PbA), Pb [2] = 35 kW (PbC), Pb [3] = 30 kW (PbB), Pb [4 ] = 25 kW (PbD).

  Next, in the process of step S <b> 101, the acquisition unit 42 acquires information on the supplied power P (= 35 kW) from the wind turbine generator 10. Next, in the processing of step S102, the selection unit 43 determines that the value (= about 8.75 kW) obtained by dividing the supplied power P (= 35 kW) by the number N (= 4) of battery units is the reference power value Pb [1]. It is determined that the value is smaller than (= 40 kW), and the processing of steps S107 to S110 is performed in the same manner as described above, and M = 3 and i = 1 are set.

  Thereafter, in the process of step S111, the selection unit 43 determines that a value of about 11.67 kW obtained by dividing the supplied power P (= 35 kW) by M (= 3) is smaller than the reference power value Pb [1] (= 40 kW). Determination is made and the process proceeds to step S112. In the process of step S112, since the priority order of the battery unit 21A corresponding to the converter 22A having Pb [1] is set to No. 4, it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, since M = 3 and i = 1 at this stage, the relational expression of i ≧ N−M + 1 is not satisfied, so the process proceeds to step S114. In the process of step S114, i = 2 is reset, and the process proceeds to step S111.

  Again, in the process of step S111, the selection unit 43 determines that the value of about 11.67 kW obtained by dividing the supplied power P (= 35 kW) by M (= 3) is smaller than the reference power value Pb [2] (= 35 kW). Determination is made and the process proceeds to step S112. In the process of step S112, since the priority order of the battery unit 21C corresponding to the converter 22C having Pb [2] is set to No. 3, it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, since M = 3 and i = 2 at the current stage, the relational expression i ≧ N−M + 1 is satisfied, and thus the process proceeds to step S115. In the process of step S115, M = M-1 (= 2) is set again, and in the process of step S116, M ≧ 2 is satisfied, so the process proceeds to step S110.

  After i = 1 is set again in the process of step S110, in the process of step S111, the selection unit 43 obtains a value of about 17.5 kW obtained by dividing the supplied power P (= 35 kW) by M (= 2). It is determined that it is smaller than the reference power value Pb [1] (= 40 kW), and the process proceeds to step S112. In the process of step S112, since the priority order of the battery unit 21A corresponding to the converter 22A having Pb [1] is set to No. 4, it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, since M = 2 and i = 1 at the present stage, the relational expression i ≧ N−M + 1 is not satisfied, so the process proceeds to step S114. In the process of step S114, i = 2 is reset, and the process proceeds to step S111.

  In the processing of step S111, the selection unit 43 determines that a value of about 17.5 kW obtained by dividing the supplied power P (= 35 kW) by M (= 2) is smaller than the reference power value Pb [2] (= 35 kW). The process proceeds to step S112. In the process of step S112, since the priority order of the battery unit 21C corresponding to the converter 22C having Pb [2] is set to No. 3, it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, since M = 2 and i = 2 at this stage, the relational expression of i ≧ N−M + 1 is not satisfied, so the process proceeds to step S114. In the process of step S114, i = 3 is reset, and the process proceeds to step S111.

  In the process of step S111, the selection unit 43 determines that a value of about 17.5 kW obtained by dividing the supplied power P (= 35 kW) by M (= 2) is smaller than the reference power value Pb [3] (= 30 kW). The process proceeds to step S112. In the process of step S112, the priority order of the battery unit 21B corresponding to the converter 22B having Pb [3] is set to No. 2, so that it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S112, since M = 2 and i = 3 at the current stage, the relational expression i ≧ N−M + 1 is satisfied, and thus the process proceeds to step S115. In the process of step S115, M = M−1 (= 1) is set again, and in the process of step S116, M ≧ 2 is not satisfied, so the process proceeds to step S117.

  In the process of step S117, the selection unit 43 represents the number of battery units that can be supplied with power as a variable Q, sets Q = 1, and proceeds to the process of step S119. In the process of step S119, since i = 3 (i ≠ 1) as a result of the above process, the process proceeds to step S121. When the supply power P is 35 kW, if the supply power P is distributed to at least two battery units, one battery unit is always less than or equal to the reference power value, and power conversion efficiency decreases. Then, the corresponding SW is turned ON so that power (35 kW) is supplied to one battery unit selected based on the priority order and excluding a predetermined battery unit. In this example, 35 kW, which is the supplied power P, is smaller than the reference power value Pb [1] and greater than or equal to the reference power value Pb [2]. Therefore, the battery units 20B to 20D excluding the battery unit 20A are selected as candidates. As shown in FIG. 10A, the corresponding switch 23D is selected so that the battery unit 20D is selected from the battery units 20B to 20D as the selection candidates according to the priority order and the power 35 kW is supplied to the battery ground unit 20D. Set to ON.

  Next, the process proceeds to steps S122 to S124. In the process of step S124, as shown in FIG. 10B, the SOC of the battery module 21D being charged is up to 60%, which is the SOC of the battery module 21B as the selection candidate. If it has reached, the process proceeds to step S125.

  In the process of step S125, the switching unit 44 switches the corresponding switches 21B and 21D to each other so that the battery units 20B and 20D having the same or substantially the same battery modules 21B and 21D are charged equally, step The process proceeds to S127 to S128.

  If it is assumed that the supply power P acquired by the acquisition unit 42 is not changed from 35 kW of the previous supply power P in the processes of steps S127 to S128, the process proceeds to step S129. In the process of step S129, it is assumed that charging is still in progress at this stage, and the process proceeds to step S122. Then, in the process of step S122, as shown in FIG. 10C, when the SOC of the battery module 21B (or 21D) being charged has reached 70%, which is the SOC of the battery module 21C of the selection candidate, The process proceeds to step S125.

  In the process of step S125, the switching unit 44 sequentially switches the corresponding switches so that the battery units 20B to 20C having the same or substantially the same battery modules 21B to 21C are charged equally.

  Next, the process proceeds to steps S127 to S129 and subsequent steps. If the selection unit 43 determines that the charging is finished, the process flow ends.

<In the battery system 1 of the present embodiment, the operation content under still other conditions>
In the above description, the case where the supply power P of the wind power generator 10 is 75 kW and 35 kW has been described in the process of the first step S100. However, as another condition, the case where the supply power P is 80 kW is also illustrated in FIGS. Hereinafter, a brief description will be given with reference to FIGS. 7 and 11.

  First, in the process of step S100, the acquisition unit 42, like the above, Pb [1] = 40 kW (PbA), Pb [2] = 35 kW (PbC), Pb [3] = 30 kW (PbB), Pb [4 ] = 25 kW (PbD) is created.

  Next, in the process of step S <b> 101, the acquisition unit 42 acquires information on the supplied power P (= 80 kW) from the wind turbine generator 10. Next, in the process of step S102, the control device 40 determines that the value (= 20 kW) obtained by dividing the supplied power P (= 80 kW) by the number N (= 4) of battery units is the reference power value Pb [1] (= 40 kW). ), The processes in steps S107 to S110 are performed in the same manner as described above, and M = 3 and i = 1 are set.

  Thereafter, in the process of step S111, the selection unit 43 determines that a value of about 26.7 kW obtained by dividing the supplied power P (= 80 kW) by M (= 3) is smaller than the reference power value Pb [1] (= 40 kW). Determination is made and the process proceeds to step S112. In the process of step S112, since the priority order of the battery unit 21A corresponding to the converter 22A having Pb [1] is set to No. 4, it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, since M = 3 and i = 1 at this stage, the relational expression of i ≧ N−M + 1 is not satisfied, so the process proceeds to step S114. In the process of step S114, i = 2 is reset, and the process proceeds to step S111.

  Again, in the process of step S111, the selection unit 43 determines that a value of about 26.7 kW obtained by dividing the supplied power P (= 80 kW) by M (= 3) is smaller than the reference power value Pb [2] (= 35 kW). Determination is made and the process proceeds to step S113. In the process of step S112, since the priority order of the battery unit 21C corresponding to the converter 22C having Pb [2] is set to No. 3, it is excluded from the selection candidates, and the process proceeds to step S113. In the process of step S113, since M = 3 and i = 2 at the current stage, the relational expression i ≧ N−M + 1 is satisfied, and thus the process proceeds to step S115. In the process of step S114, M = M-1 (= 2) is set again, and in the process of step S115, M ≧ 2 is satisfied, so the process proceeds to step S110.

  After i = 1 is set again in the process of step S110, in the process of step S111, the selection unit 43 determines that the value 40 kW obtained by dividing the supplied power P (= 80 kW) by M (= 2) is the reference power value. It is determined that Pb [1] (= 40 kW) or more, and the process proceeds to step S118.

In the process of step S118, the number of battery units that can be supplied with power is represented by a variable Q, Q = 2 is set, and the process proceeds to step S119. Since i = 1 in the process of step S119, the process proceeds to step S120. In the process of step S120, when the supplied power P is 80 kW, even if the supplied power P is distributed to the two battery units, the power distributed to each battery unit is equal to or higher than the individual reference power value. High efficiency can be maintained. Therefore, all the battery units 20A to 20D are selected as candidates, and as shown in FIG. 11A, the two battery units 20B and 20D are selected according to the priority order, and power (40 kW) is supplied to them. The corresponding switches 23B and 23D are turned ON.

  Next, the process proceeds to steps S130 to S131. In the process of step S131, as shown in FIG. 11B, the SOC of the battery module 21B being charged is up to 70%, which is the SOC of the battery module 21C of the selection candidate. If it has reached, the process proceeds to step S132.

  In the process of step S132, the corresponding switches 23B and 23C are switched to each other so that the battery units 20B and 20C having the same or substantially the same battery modules 21B and 21C are charged equally, and steps S133 to S134 are performed. Proceed to processing. In addition, about battery unit 20D which has not reached | attained to the said SOC, electric power 40kW is still supplied.

  If the supply power P acquired by the acquisition unit 42 is not changed from 80 kW of the previous supply power P in the processes of steps S133 to S134, the process proceeds to step S135. In the process of step S135, it is assumed that charging is still in progress at this stage, and the process proceeds to step S130. In the process of step S130, as shown in FIG. 11C, it is assumed that the SOC of the battery module 21B, 21C, or 21D being charged has reached 80%, which is the SOC of the battery module 21A as the selection candidate. The process proceeds to step S132.

  In the process of step S132, the switching unit 44 switches the corresponding switches to each other so that the battery units 20A to 20D having the same or substantially the same battery modules 21A to 21D are charged equally. That is, the battery units 20A and 20B are each 40 kW, the battery units 20B and 20C are 40 kW each, the battery units 20C and 20D are 40 kW each, and the battery units 20A and 20D are each 40 kW. Each battery unit 20A-20D can be charged equally.

  Next, the process proceeds to steps S133 to S135 and after, and if the selection unit 43 determines that the charging is finished, the process flow is finished.

  As described above, according to the battery system 1 of the present embodiment, a plurality of devices are connected in parallel according to the power supplied from the wind power generator 10 and considering the power conversion efficiency of the power converters 22A to 22D. Since the battery unit to be supplied can be selected from the battery units 20A to 20D, an optimum number of battery modules can be charged while maintaining high charging efficiency.

  Moreover, according to the battery system 1 of the present embodiment, each charging information indicating the charging state of the battery modules 21A to 21D is acquired, and the priority for supplying power to the battery unit is determined in ascending order of the charging state. It is possible to make the state of charge of the battery module uniform. It is also assumed that the voltage varies between battery modules due to factors such as the usage status of each battery module and the presence of degraded battery modules among multiple battery modules. If a plurality of battery modules connected to each other are charged at the same time, there is a problem that a mutual charging action occurs between the battery modules and the charging efficiency is lowered. However, since the priority order is determined in order from the lowest charge state, even if power is supplied to a plurality of battery units, it is possible to select and supply battery units having battery modules having similar charge states. The mutual charging effect caused by the difference in voltage between modules can be suppressed.

  Furthermore, according to the battery system 1 of the present embodiment, the second reference is smaller in the reference power value than the first reference power value than the number of battery units that can distribute the supplied power P with the power equal to or higher than the first reference power value. When there are a large number of battery units that can distribute the supplied power with power that is greater than or equal to the second reference power value from among the battery units that have converters that are less than or equal to the power value, a converter whose reference power value is less than or equal to the second reference power value The number of battery units that can distribute the supplied power P to power that is equal to or higher than the second reference power value is determined from among the battery units that the battery unit has, and the determined number of battery units that supply power from the wind power generator 10 is selected. As a result, the battery modules can be charged as evenly as possible in parallel.

Furthermore, according to the battery system 1 of the present embodiment, the charging state of the battery module selected by the selection unit 43 and being charged is the battery module of at least one of the non-selected battery units. If a same or substantially the same as the charge state, the power supply destination which has been supplied from the wind turbine generator 10, alternately switched at a predetermined timing between the state of charge the same or substantially the same batteries unit. As a result, the state of charge is increased to some extent, and power is evenly supplied to at least two battery units having the same or substantially the same state of charge, while power is supplied to battery units in a low state of charge. Can continue to supply. That is, a battery unit with a low state of charge can be charged quickly so that power can be continuously supplied to achieve a charge rate equivalent to that of other battery modules, and the state of charge of the battery modules is the same or substantially the same. The same battery unit can be charged while maintaining equality.

  Furthermore, according to the battery system 1 of the present embodiment, even if the supply power P is changed by obtaining information on the supply power P of the power supplied by the wind turbine generator 10 at a predetermined timing, the supply is performed. It is possible to determine the optimal number of battery units that receive power supply according to the power P, and to maintain high charging efficiency at all times.

<Modification>
The preferred embodiments of the battery system of the present invention have been described above. However, the present invention should not be limited to the above-described embodiments, and departs from the spirit and scope expressed in the claims. Various modifications, additions, and omissions are possible by those skilled in the art.

  For example, in the said embodiment, although demonstrated using the wind power generator as an example of a power supply device, this invention is not limited to this, For example, what uses solar power generation and a commercial power source may be used. When a solar power generation device is used as the power supply device, the power converter disposed between the power supply and the battery unit may be a DC / DC converter. In this case, the above-mentioned standard is obtained from the power conversion efficiency of the DC / DC converter. Set the power value appropriately. In addition, as long as the power supply device can receive a certain amount of power like a commercial power supply, for example, the control device 40 may acquire information on the supplied power P only immediately after the start of charging.

Further, in the above embodiment, the case where the reference power values PbA to Pb D of the converters 22A to 22D have different values has been described as an example. However, the present invention is not limited to this, and the reference power values of a plurality of converters. If there are two reference power values (one reference power value and a second reference power value smaller than the first reference power value), there may be converters having the same reference power value. That is, the reference power values of converters 22A to 22C are the same (for example, the first reference power value), and only the reference power value of converter 22D (for example, the second reference power value) is different from the reference power values of converters 22A to 22C. May be.

  Furthermore, although the said embodiment demonstrated the case where the control apparatus 40 acquires each charge information which shows the charge condition of a battery module, this invention is not limited to this, For example, the charge condition between battery units to some extent or more If it can be used under the condition that is equal, the acquisition of the charging information may be omitted. Even in this case, the control device 40 has a plurality of power supplies connected in parallel according to the power supplied from the wind power generator 10 and also taking into account the power conversion efficiency of the power converters 22A to 22D. The battery units to be supplied are selected from the battery units 20A to 20D, and then the switches 23A to 23D are turned on so that power is evenly supplied to the battery units 20A to 20D including the non-selected battery units. , OFF can be controlled so as to be switched sequentially.

  Furthermore, in the above-described embodiment, the control device 40 determines the priority for supplying power to the battery units in ascending order of charge based on each charging information, and supplies power in the determined order. The present invention is not limited to this. For example, when the variation in the charging state of each battery module falls within a predetermined range from the charging information, the control device 40 responds to the power supplied from the wind power generator 10 and the power of the power converters 22A to 22D. In consideration of conversion efficiency, a battery unit to be supplied is selected from a plurality of battery units 20A to 20D connected in parallel, and the switches 23A to 23D are turned ON / OFF in a predetermined manner so as to supply power evenly. It is also possible to perform control so as to switch between each other at the timing. On the other hand, when there is a charged battery unit that does not fall within the predetermined range, the control device 40 continues to supply power only to the battery unit, and switches the switches among the other battery units to supply power evenly. You may make it do.

Furthermore, in the said embodiment, the control apparatus 40 is selected by the selection part 43, and the charge state of the battery module in charge is the same as the charge state of the battery module which at least 1 battery unit has among non-selected battery units. or when it becomes substantially the same, the power supply destination which has been supplied from the wind turbine generator 10, but the charge state is to switch alternately between the same or substantially the same batteries unit, the present invention is limited thereto I can't. For example, the control device 40 selects the non-selected battery unit until the state of charge of all the battery modules selected and being charged is the same as or substantially the same as the state of charge of the battery module of the non-selected battery unit. You may control to stop supply of electric power.

  Furthermore, in the above-described embodiment, the configuration in which each unit having each processing function is provided in the control device 40 has been described, but the present invention is not limited to this, and each unit is connected to be able to communicate with the control device 40. It can also be configured on the network or in preparation for other devices. Furthermore, the control device 40 is provided with each unit according to the application. However, each of the units provided in the control device 40 may be configured as a single unit or a single unit. The part may be further divided into a plurality of parts.

  The battery system of the present invention can be applied to a system that uses at least charging of battery modules provided in a plurality of battery units. For example, electric power is stored in a secondary battery when a motor such as an electric vehicle is regenerated. The power stored in the secondary battery can be used as a moving system that is used when the motor is driven. In addition, a power storage system that stores power generated by using natural energy such as wind power generation or solar power generation in a secondary battery, and uses the power stored in the secondary battery for household electrical equipment, The power stored in the secondary battery can be used as a stationary system such as a power selling system that sells power to an electric power system as an AC power load.

  DESCRIPTION OF SYMBOLS 1 ... Battery system, 10 ... Wind power generator (power supply device), 20 ... Battery device, 20A-20D ... Battery unit, 21A-21D ... Battery module, 22A-22D ... Converter (power converter), 23A-23D ... Switch , 30 ... load, 40 ... control device, 50 ... display device.

Claims (5)

A power supply for supplying power;
A battery device in which a plurality of battery units each including a power conversion unit that converts power supplied from the power supply device and a battery module that charges the power converted by the power conversion unit are connected in parallel;
A storage unit that stores information on each reference power value of the plurality of power conversion units, an acquisition unit that acquires information on supply power supplied by the power supply device, and the plurality of reference powers stored in the storage unit The largest value among the values is set as the first reference power value, and the number of the battery units that can distribute the supply power acquired by the acquisition unit to power equal to or higher than the first reference power value is determined. A control unit comprising: a selection unit that selects and charges the determined number of the battery units;
A battery system comprising: The acquisition unit acquires each module information of the battery module provided in each of the plurality of battery units, obtains each charging rate for each battery module based on each module information,
The selection unit sets the supply power to the first reference power value based on information on the reference power value stored in the storage unit, information on the supply power acquired by the acquisition unit, and each charging rate. The battery system according to claim 1, wherein the number of the battery units that can be distributed to the power is determined. The selection unit includes:
Deciding the priority for supplying power to the battery unit in ascending order of the charging rate,
The battery system according to claim 2, wherein the determined number of the battery units are selected according to the priority order. The controller is
The charging rate corresponding to at least one battery unit among the battery units selected by the selection unit is the same as the charging rate corresponding to at least one battery unit among the battery units not selected by the selection unit. Or if they are nearly identical,
The electric power selected from the power supply device with respect to the same or substantially the same battery unit selected by the selection unit is at least two or more with the same or substantially the same charging rate. cell system of claim 3, further comprising a switching unit to supply switched alternately to the batteries unit. The reference power value, battery system according to any one of claims 1 to 4, wherein the power conversion unit is a power value that indicates the maximum power conversion efficiency.

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