JP2023112691A - Power system, control method for power system, and program - Google Patents

Abstract

To provide a power system, a control method for the power system, and a program for suppressing deterioration of a storage battery.SOLUTION: The power system includes a plurality of power supply units each connected in parallel, and a control unit for controlling the plurality of power supply units. Each of the plurality of power supply units includes a storage battery, and one or more power supply portions connected in parallel to the storage battery. The control unit controls the power output from a desired power supply portion by controlling the desired power supply portion among the power supply portions included in the plurality of power supply units and controls the current output from the storage battery included in each of the power supply units.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power supply system, a power supply system control method, and a program.

Conventionally, it is possible to charge a plurality of storage batteries from a charger connected in parallel to the plurality of storage batteries, and to supply power to a load connected in parallel to the plurality of storage batteries. A power supply system capable of performing by is disclosed (see, for example, Patent Document 1). This power supply system consists of a BMU (Battery Management Unit) that controls the total charging current flowing through multiple storage batteries, and an individual charging current that flows through multiple storage batteries while they are being charged from a charger. and a current sensor that detects each battery, and the BMU detects when the maximum deviation of the individual charging currents, which is the difference between the maximum individual charging current and the minimum individual charging current of the plurality of storage batteries, exceeds the limit threshold. Limit the charging current.

JP 2019-106816 A

However, in the above-described prior art, sufficient consideration has not been given to the deterioration of the storage battery.

SUMMARY OF THE INVENTION The present invention has been made in consideration of such circumstances, and one of the objects thereof is to provide a power supply system, a power supply control method, and a program capable of suppressing deterioration of a storage battery.

One aspect of the present invention includes a plurality of power supply units each connected in parallel, and a control unit that controls the plurality of power supply units, and each of the plurality of power supply units includes a storage battery and and one or more power supply units connected in parallel to each other, and the control unit controls the desired power supply unit among the power supply units included in the plurality of power supply units to obtain the desired power supply unit. The power supply system controls the electric power output by the power supply unit to control the current output by the storage battery included in each of the power supply units.

ADVANTAGE OF THE INVENTION According to this invention, deterioration of a storage battery can be suppressed by a control part controlling the electric current which the storage battery contained in each of a power supply unit outputs.

1 is a diagram showing an example of a configuration of a power supply system 1; FIG. 4 is a flowchart showing an example of the flow of process 1 executed by the control device 100; FIG. 4 is a diagram for explaining processing that is executed when a detected current value exceeds a specified current value; FIG. 4 is a diagram for explaining processing that is executed when there is a deviation in detected current values; 7 is a flowchart showing an example of the flow of process 2 executed by the control device 100. FIG. FIG. 10 is a diagram for explaining processing that is executed when the capacity ratio deviates from a predetermined range; 4 is a flowchart showing an example of the flow of processing executed by the control device 100; 8 is a diagram conceptually showing the processing of the flowchart of FIG. 7; FIG. It is a figure which shows an example of a one part functional structure of the power supply system 1 of 2nd Embodiment. 4 is a flowchart showing an example of the flow of processing executed by the control device 100A; 4 is a diagram showing an example of contents of temperature correction information 142. FIG. 4 is a diagram showing an example of contents of state information 144. FIG. It is a figure for demonstrating the process of step S412.

Embodiments of a power supply system, a power supply system control method, and a program according to the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram showing an example of the configuration of a power supply system 1. As shown in FIG. The power supply system 1 includes, for example, a circuit C and a control device 100 . The power supply system 1 may be stationary or portable.

[circuit]
Circuit C includes, for example, terminal 10, terminal 20, and units A through E. FIG. A load L is connected between the terminals 10 and 20 via an electric wire. An electric line EL1 is connected to the terminal 10, and an electric line EL2 is connected to the terminal 20. As shown in FIG. Units A to E are connected in parallel between the electric line EL1 and the electric line EL2. Unit A, unit B, unit C, unit D, and unit E are connected in this order from the side closer to terminal 10 and terminal 20 . A switch 30 is provided between the terminal 10 and a contact P1A, which will be described later. Note that the number of units is not limited to five, and may be any number. Unit A to unit E may or may not be separated from each other (for example, the configuration included in unit A to unit E may be included in one housing).

Unit A will be described below. Since Unit B-Unit E also has the same functional configuration and contacts as Unit A, description of Unit B-Unit E will be omitted. The code of the functional configuration and the code of the contact of the unit B - unit E are indicated by replacing the "A" of the code of the functional configuration and the code of the contact of the unit A with the code of the unit ("B" - "E"). It is

[unit]
The contact P1A is a contact to which the electric line EL1 and the unit A are connected. A contact P2A is a contact to which the electric line EL2 and the unit A are connected. Unit A includes a storage battery 50A, a DC-DC converter 60A, an AC-DC converter 70A, a diode 80A, a voltage detector 82A, and a current detector 84A.

The storage battery 50A, the DC-DC converter 60A, and the AC-DC converter 70A are electrically connected in parallel. The electric wire on the contact P1A side of the storage battery 50A, the electric wire on the contact P1A side of the DC-DC converter 60A, and the electric wire on the contact P1A side of the AC-DC converter 70A are connected to the contact P3A. The contact point P1A is connected by an electric wire. The electric wire on the contact P2A side of the storage battery 50A, the electric wire on the contact P2A side of the DC-DC converter 60A, and the electric wire on the contact P2A side of the AC-DC converter 70A are connected to the contact P4A. The contact point P2A is connected by an electric wire.

Diode 80A is connected between contacts P1A and P3A. In the power supply system 1, a diode is provided to suppress current flowing from the storage battery 50 of another unit or the like from flowing into the unit (the storage battery 50 of the unit A or the like). Instead of (or in addition to) the diode 80A, a diode having the same function as the diode 80A may be provided at another position. Voltage detector 82A is connected between diode 80A and contact P3A. The current detector 84A is connected between the storage battery 50A and the contact P4A.

The storage battery 50A is, for example, a secondary battery that can be repeatedly charged and discharged, such as a lithium ion battery or a lead battery. Electric power output from the storage battery 50A is supplied to the contact P3A side.

The DC-DC converter 60A converts the DC power supplied by the photovoltaic power generation device 62A into desired DC power, and outputs the converted DC power to the contact P3A side. The DC-DC converter 60A controls power output by PWM control or the like. The DC-DC converter 60 changes the duty of the pulse width of the input signal to control the output, for example, based on an instruction from the control device 100 .

The AC-DC converter 70A converts AC power supplied from the power system 72A (commercial power supply) into desired DC power and outputs the converted DC power to the contact P3A side. Like the DC-DC converter 60A, the AC-DC converter 70A also controls the output power by PWM control or the like.

Either the DC-DC converter 60A or the AC-DC converter 70A may be omitted, or another DC-DC converter or another AC-DC converter may be connected in parallel with the storage battery 50. good. Further, instead of the photovoltaic power generation device 62A, another power generation device (for example, a power generation device using natural energy or renewable energy, or a power generation device using a fuel cell) may be used. , other power sources may be used.

Diode 80A allows current to flow from contact P3A to contact P1A and suppresses current from contact P1A to contact P3A. Voltage detector 82A detects the voltage at contact P3A (or near contact P3A). Current detection unit 84A detects a current flowing between contact P4A and storage battery 50A. The current detector 84A detects the current flowing through the storage battery 50A. In the following description, the alphabetic symbols “A” to “E” may be omitted when the functional configurations and the like included in each unit are not distinguished.

[Control device]
The control device 100 acquires the detection result of the voltage detection section 82A or the current detection section 84A, and controls each unit (DC-DC converter 60A and AC-DC converter 70A) based on the acquired information.

The control device 100 includes, for example, an information management unit 110, a control unit 120, and a storage unit . The information management unit 110 and the control unit 120 are realized, for example, by executing a program by a processor such as a CPU (Central Processing Unit). Further, each component of the information management unit 110 or the control unit 120 may be implemented by hardware such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), and FPGA (Field-Programmable Gate Array).

The storage unit 130 is, for example, a storage device such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory such as SSD (Solid State Drive), or HDD (Hard Disk Drive). Control information 140 is stored in the storage unit 130 . The control information 140 is, for example, information such as a program related to processing executed by the information management unit 110 and the control unit 120 and specifications of the storage battery 50 . The specification of the storage battery 50 is information such as capacity, suitable output current value, maximum output current value, and the like. The specification of the storage battery 50 may be, for example, information such as capacity or a suitable capacity ratio. The preferred capacity ratio is the ratio of the current value (maximum output current value or preferred output current value) output by the storage battery 50 to the capacity of the storage battery 50 .

The information management unit 110 acquires and manages the operating states of the DC-DC converter 60 and the AC-DC converter 70, the detection result of the voltage detection unit 82, and the detection result of the current detection unit 84. FIG. The control unit 120 controls one or both of the DC-DC converter 60 and the AC-DC converter 70 based on the information acquired by the information management unit 110 . When not distinguishing between the DC-DC converter 60 and the AC-DC converter 70, they may be referred to as "converters."

[Overview of processing]
In the present embodiment, when each storage battery 50 is outputting current, the power supply system 1 has the DC-DC converter 60 or It controls the power (current) output by the AC-DC converter 70 . As a result, the impedance of a specific storage battery 50 among the storage batteries 50 is suppressed from being maintained in a state where it deviates from the impedance of the other storage batteries 50, and the impedance change is suppressed from becoming large. . Then, the utilization state of each storage battery 50 is made uniform, which leads to suppression of deterioration of each storage battery 50 and further extension of the life of each storage battery 50 .

In the present embodiment, when the capacities of the storage batteries 50 are the same or close, processing 1 is executed to bring the current values output by the storage batteries 50 closer together. A process 2 is executed to bring the capacity ratios of . [Processing 1] and [Processing 2] will be described below.

[Processing 1]
FIG. 2 is a flowchart showing an example of the flow of process 1 executed by the control device 100. As shown in FIG. In this process, it is assumed that the capacities of the storage batteries 50 included in each unit are the same or similar. The control information 140 corresponding to this process includes, for example, a specified current value specified for the storage battery 50 . The specified specified current value is an output current value at which the storage battery 50 is less likely to deteriorate, an output current value at which the life is less likely to be shortened, and a maximum output current value. This process is executed when the control unit 120 controls the switch 30 from the cut-off state to the on state and the storage battery 50 is outputting electric power.

First, the information management section 110 acquires the detection result of the current detection section 84 of each unit (step S100). Next, the control unit 120 compares each current value (detected current value) that is the detection result of the current detection unit 84 of each unit with the prescribed current value, and out of the detected current values, the prescribed It is determined whether or not there is a detected current value exceeding the current value (step S110). When there is a detected current value exceeding the specified current value among the detected current values, the process proceeds to step S130. The control unit 120 controls the output of the DC-DC converter 60 or the AC-DC converter 70 so that each detected current value is equal to or less than the specified current value and each detected current value approaches. A specific example will be described with reference to FIG.

When none of the detected current values exceeds the specified current value, the control unit 120 determines whether or not there is a deviation of a predetermined degree or more between the detected current values (step S120). If there is no divergence of a predetermined degree or more, the processing of one routine of this flowchart ends.

If there is a deviation of a predetermined degree or more, control section 120 controls the output of DC-DC converter 60 or AC-DC converter 70 so that the deviation of each detected current value falls within a predetermined range. A specific example will be described with reference to FIG. As a result, the processing of one routine in this flowchart ends.

FIG. 3 is a diagram for explaining the processing that is executed when the detected current value exceeds the specified current value. At time T, among the current values output by the storage batteries 50 of each unit, the current output by the storage batteries 50 of unit A, unit B, unit C, and unit E (current detected by the voltage detection unit 82) exceeds the specified current value. is exceeded and the converter is not outputting power. Further, it is assumed that the total current value output by the storage battery 50 of each unit is 250 [A], which is the required current value required according to the load.

In this case, the control unit 120 controls the output current of the converter so that the current value output by the storage battery 50 of each unit is equal to or less than the specified current value and the respective current values approach each other. At time T+n, by controlling the output current of the converter as described above, the current value output by the storage battery 50 of each unit becomes equal to or less than the specified current value and each current value approaches the current value, and the current output by the storage battery 50 The sum of the value and the current value output by each converter is the required current value. For example, the total current value output by the storage batteries 50 of unit A to unit E is 150 [A], the total current value output by each converter is 100 [A], and the total of these is 250 [A]. ] becomes.

For example, in the above process, the control unit 120 performs constant current control to match the current value to be output to the converter with the target value. For example, the control unit 120 increases the current to be output from the converter by a predetermined unit, and controls the converter so that the detected current values after the increase become closer to each other. Further, at this time, the control unit 120 refers to the detection result of each voltage detection unit 82 and controls each unit so that the voltages of the contacts P3A to P3E become closer. As a result, the current output from the storage battery 50A is made uniform, and the current flowing from each unit is made uniform. In FIG. 4 below, the control unit 120 controls each unit based on the same concept. Also, when decreasing the current to be output to the converter, the control unit 120 similarly decreases the current by a predetermined unit, and controls the converter so that each detected current value after the decrease approaches each other.

In addition, in the above process (or each process to be described later), when the current output from the storage battery 50 satisfies the required current value, the control unit 120 preferentially selects the conversion unit that supplies electric power using natural energy. You may make it operate and output the electric current which runs short. For example, the controller 120 may preferentially operate the DC-DC converter 60 over the AC-DC converter 70 to output the insufficient current. Preferential means, for example, not operating the AC-DC converter 70 or increasing the output of the DC-DC converter 60 over the output of the AC-DC converter 70 . For example, the control unit 120 supplies the current to the AC-DC converter 70 when the current value output by the storage battery 50 and the current value output by the DC-DC converter 60 do not meet the required current value. can be output to Control may be performed such that the output from the source connected to the AC-DC converter 70 as described above is minimized.

In addition, in FIG. 3 described above (FIG. 4 to be described later and FIG. 5 to be described later), in order to simplify the description, it is assumed (described) that the converter does not output current. A similar process may be performed while the device is outputting current. Moreover, although the current output from the storage battery 50 has been described as being preferentially used, the current output from the converter may be preferentially used and the current output from the storage battery 50 may be used auxiliary. good. For example, the current value output by the converter may be controlled to be greater than the current value output by the storage battery 50 .

FIG. 4 is a diagram for explaining the processing that is executed when there is a divergence in detected current values. At time T, the current values output by the storage batteries 50 of each unit deviate (or all the detected current values do not fall within a predetermined range), and the converter does not output power. Deviating from or not within a predetermined range means, for example, deviating from the average value of the detected current values by a predetermined value or more, or from a predetermined current value based on the average value of the detected current values. is not within the range of It is also assumed that the total current value output by the storage battery 50 of each unit is 250 [A], which is the requested current value.

In this case, the control unit 120 controls the output current of the converter so that the current values output by the storage batteries 50 of each unit do not deviate (or fall within a predetermined range). At time T+n, by controlling the output current of the converter as described above, the current value output by the storage battery 50 of each unit approaches, and the current value output by the storage battery 50 and the current value output by each converter is the required current value.

For example, at time T, a current of 50 [A] is flowing through the storage battery 50A, 40 [A] through the storage battery 50B, 55 [A] through the storage battery 50C, 45 [A] through the storage battery 50D, and 60 [A] through the storage battery 50E. In this case, at time T+n, control unit 120 controls the converter so that 20 [A] of power flows through each of storage batteries 50A to 50E. For example, the total current value output by the storage battery 50 of unit A to unit E is 100 [A], the total current value output by each converter is 150 [A], and the total of these is 250 [A]. ] becomes.

For example, without considering the converter, the storage battery 50 outputs current when the switch 30 becomes conductive. A certain storage battery 50 may output a large current due to a difference in internal impedance of the storage battery 50 . In this case, deterioration of the storage battery 50 is likely to progress, and the life of the storage battery 50 may be shortened. Therefore, in the present embodiment, the current values of the storage battery 50 are arranged so that the impedance of the storage battery 50 becomes uniform as described above. As described above, the control unit 120 controls the converter so that the detected current value becomes equal to or less than the specified value, and further approaches the detected current value. can contribute to

[Processing 2]
FIG. 5 is a flowchart showing an example of the flow of process 2 executed by the control device 100. As shown in FIG. In this process, it is assumed that the capacity of the storage battery 50 included in each unit is different. The control information 140 corresponding to this process includes, for example, a specified current value and capacity specified for the storage battery 50 . The control information 140 may be information for specifying a suitable capacity ratio for the storage battery 50 (for example, a capacity ratio corresponding to the maximum output current value). This process is executed when the control unit 120 controls the switch 30 from the cut-off state to the on state and the storage battery 50 is outputting electric power.

First, the information management section 110 acquires the detection result of the current detection section 84 of each unit (step S200). Next, the control unit 120 derives the capacity ratio of each storage battery 50 based on the detection result of the current detection unit 84 of each unit (step S210).

Next, the control unit 120 determines whether the capacity ratio of each storage battery 50 is within a predetermined range (step S220). The predetermined range is, for example, a range based on a reference capacity ratio. The reference capacity ratio is the result of statistically processing the capacity ratio of each storage battery 50, and is, for example, the average value of the capacity ratios of each storage battery 50. FIG.

When the capacity ratio of each storage battery 50 is within a predetermined range, one routine of the flow chart of this process ends. If any one of the capacity ratios of the storage batteries 50 does not fall within the predetermined range, the control unit 120 controls the converter based on the determination result (step S230). The controller 120 controls the converter so that the capacity ratio does not deviate from a predetermined range. This completes the processing of one routine in this flow chart.

In the above process, it is determined whether or not any of the detected current values exceeds the maximum current value determined for each storage battery 50 (the capacity ratio of each storage battery 50 is determined by the storage battery 50 It is determined whether or not the maximum capacity ratio determined for each unit is exceeded), and if the detected current value exceeds the maximum output current value, the detected current value is prevented from exceeding the maximum output current value in step S230. controlled by

FIG. 6 is a diagram for explaining processing that is executed when the capacity ratio deviates from a predetermined range. In FIG. 6, it is assumed that the detected current value is equal to or less than the specified current value and the converter does not output power. At time T, the capacity ratio of the storage battery 50 of each unit deviates from the reference capacity ratio (there is a capacity ratio outside the predetermined range).

In this case, the control unit 120 controls the output current of the converter so that the capacity ratios of the storage batteries 50 of each unit become closer. At time T+n, by controlling the output current of the converter, the capacity ratio of the storage battery 50 of each unit approaches, and the sum of the current value output by the storage battery 50 and the current value output by each converter is equal to the required current value. Note that the capacity ratio in this case must be equal to or less than the upper limit capacity ratio determined for each storage battery 50 . In other words, the current output by the storage battery 50 is determined for each storage battery 50 and must be equal to or less than a specified current value (maximum current value or less).

For example, the capacity of the storage battery 50A is 50 [Ah], the capacity of the storage battery 50B is 100 [Ah], the capacity of the storage battery 50C is 150 [Ah], the capacity of the storage battery 50C is 200 [Ah], and the capacity of the storage battery 50E is 250 [Ah]. ]. At time T, the storage battery 50A outputs 10 [A], the storage battery 50B outputs 40 [A], the storage battery 50C outputs 80 [A], the storage battery 50D outputs 100 [A], and the storage battery 50E outputs 170 [A]. Current is output.

The capacity ratio of each storage battery 50 at time T is as follows.
Storage battery 50A; 0.20 (=10 [A]/50 [Ah])
Storage battery 50B; 0.40 (=40 [A]/100 [Ah])
Storage battery 50C; 0.53 (=80 [A]/150 [Ah])
Storage battery 50D; 0.50 (=100 [A]/200 [Ah])
Storage battery 50E; 0.68 (=170 [A]/250 [Ah])

For example, control unit 120 controls the converter so that the capacity ratios of storage batteries 50A-50E are close to each other. As a result, the capacity ratio of each storage battery 50 at time T+n is as follows.
Storage battery 50A; 0.10 (=5 [A]/50 [Ah])
Storage battery 50B; 0.10 (=10 [A]/100 [Ah])
Storage battery 50C; 0.10 (=15 [A]/150 [Ah])
Storage battery 50D; 0.10 (=20 [A]/200 [Ah])
Storage battery 50E; 0.10 (=25 [A]/250 [Ah])

Although the capacity ratio is set to 0.1 as an example, the capacity ratio is not limited to this, and may be set according to the specifications of the storage battery 50 . For example, when it is desired to increase (maximize) the current output from the storage battery 50 , each capacity ratio is controlled so as to match the smallest capacity ratio among the maximum capacity ratios of each storage battery 50 .

The control unit 120 outputs a current of 5 [A] for the storage battery 50A, 10 [A] for the storage battery 50B, 15 [A] for the storage battery 50C, 20 [A] for the storage battery 50D, and 25 [A] for the storage battery 50E. to control the transducer. The total current output by the storage battery 50 is 75 [A], and the controller 120 causes the converter to output the shortfall of 325 [A].

For example, in the above process, the control unit 120 performs constant current control to match the current value to be output to the converter with the target value. The control unit 120 increases the current to be output from the converter by a predetermined unit, and controls the converter so that the capacity ratios based on the respective detected current values after the increase approach each other. Further, at this time, the control unit 120 refers to the detection result of each voltage detection unit 82 and controls each unit so that the voltages of the contacts P3A to P3E become closer. As a result, the capacity ratio of the storage battery 50A is made uniform, and the current flowing from each unit is made uniform.

For example, without considering the converter, the storage battery 50 outputs current when the switch 30 becomes conductive. The current flowing through the storage battery 50 varies due to the difference in the internal impedance of the storage battery 50, and a given storage battery 50 may output a large current. In this case, deterioration of the storage battery 50 is likely to progress, and the life of the storage battery 50 may be shortened. Therefore, in the present embodiment, the current values of the storage battery 50 are arranged so that the impedance of the storage battery 50 becomes uniform as described above. That is, the control unit 120 controls the converter so that the detected current value becomes equal to or less than the specified current value and the capacity ratio of the storage battery 50 approaches, thereby suppressing the deterioration of the storage battery 50 and further increasing the length of the storage battery 50. It can contribute to longer life.

[Control during charging]
In the processing 1 and processing 2 above, the processing when the storage battery 50 is discharged has been described. Next, an example of the processing when the storage battery 50 is charged will be described with reference to FIGS. 7 and 8. FIG.

FIG. 7 is a flowchart showing an example of the flow of processing executed by the control device 100. As shown in FIG. First, the control unit 120 determines whether or not the voltage of the storage battery 50 is equal to or lower than the first threshold (step S300). The voltage of the storage battery 50 is determined based on the detection result of a voltage detector (not shown). For example, when the voltage of the reference storage battery 50 becomes equal to or less than the first threshold value, the next process may be performed, or when the voltage of all the storage batteries 50 becomes equal to or less than the first threshold value, the next process may be performed. You may proceed.

When the voltage of the storage battery 50 is equal to or less than the first threshold, the control unit 120 executes control for charging the storage battery 50 (step S310). For example, the control unit 120 controls each converter to increase the voltage of the power output by the converter so that the current output from the converter is input to the storage battery 50 . Also in charging, the current input to the storage batteries 50 is controlled so that the capacity ratio of each storage battery 50 is the same as in discharging.

Next, control unit 120 determines whether or not the voltage of storage battery 50 exceeds the second threshold (step S320). For example, when the voltage of the reference storage battery 50 exceeds the second threshold, the next process may be performed, or when the voltage of all the storage batteries 50 exceeds the second threshold, the next process may be performed. good.

When the voltage of the storage battery 50 exceeds the second threshold, the controller 120 stops charging the storage battery 50 (step S330). For example, the control unit 120 controls each converter to reduce the voltage of the power output by the converter so that the current output from the converter and the current output by the storage battery 50 flow to the load (the voltage is reduced). Control). As a result, the processing of one routine in this flowchart ends.

FIG. 8 is a diagram conceptually showing the processing of the flowchart of FIG. In the example of FIG. 8, the capacity of the storage battery 50A, the storage battery 50B, and the storage battery 50C is the same as the first capacity, the capacity of the storage battery 50D and the storage battery 50E is the same as the second capacity, and the second capacity is the first capacity. shall be greater than Also, it is assumed that the charging rate and voltage of the storage battery 50 are correlated.

At time T, the state of charge (SOC) of each storage battery 50 is greater than or equal to the first threshold Th (the voltage of the storage battery 50 is greater than or equal to the first threshold), and the storage battery 50 is discharged. At time T+1, the charging rate of each storage battery 50 became less than the first threshold Th (the voltage of the storage battery 50 was less than the first threshold). Since the storage batteries 50 have different output currents but the same capacity ratio, the ratio of the discharge amount to the charge amount of each storage battery 50 is the same, and the degree of decrease in the charging rate of each storage battery 50 has the same tendency. Then, charging of the storage battery 50 is started.

At time T+2, the charging rate of each storage battery 50 increases due to charging. Although the capacity of each storage battery 50 is different, the capacity ratio, which is the ratio of the current charged to the capacity of each storage battery 50, is the same, and the degree of increase in the charging rate of each storage battery 50 has the same tendency. In this way, when charging is performed with the same capacity ratio, the charging rate of each storage battery 50 exceeds the second threshold (at time T+3) (the voltage of each storage battery 50 exceeds the second threshold) at the same timing. When the voltage of each storage battery 50 exceeds the second threshold (or when the voltage of the reference storage battery 50 exceeds the second threshold), discharging is started instead of charging.

As described above, control unit 120 charges and discharges so that the capacity ratios are close to each other, so that storage battery 50 is discharged and charged with the same tendency, and the usage state of storage battery 50 is uniformed. As a result, the deterioration of the storage battery 50 is suppressed, and further, the service life of the storage battery 50 is expected to be extended.

According to the embodiments described above, the power supply system 1 can suppress deterioration of the storage battery. By applying the processing of the above embodiment, for example, a used storage battery 50 or a storage battery 50 with a different capacity can be included in a unit, and the power output from the storage battery 50 and the unit including the storage battery 50 can be controlled. Specifically, even when a second-hand battery with a different capacity is installed in the power supply system 1, the power supply system 1 can output an appropriate current while suppressing deterioration by the processing of the present embodiment. can. As a result, the deterioration of the storage battery 50 is suppressed as described above, the cost required to introduce the power supply system 1 is suppressed, the running cost is suppressed, the effective use of resources, and the environmental load such as CO ₂ is realized. can contribute to the reduction of

[others]
In the above description, the power supply system 1 includes the storage battery 50, but the storage battery 50 may be omitted. For example, the power supply system 1 may be shipped without the storage battery 50 and the storage battery 50 may be installed at the delivery destination to which the power supply system 1 is delivered. In this case, for example, the power supply system 1 may include a mounting unit on which the storage battery 50 is mounted, a connection section to which terminals of the storage battery 50 are connected, and the like.

Also, in the above description, the configuration shown in FIG. 1 is shown as the configuration of the power supply system 1, but a part of the configuration or another configuration may be added. For example, a voltage detector or a current detector is provided on the output side of each converter or on the input side or output side of a predetermined device, and the control device 100 refers to these detection results to perform various processes. may

Moreover, the power supply system 1 may have additional units added later. For example, in addition to Unit A-Unit E as shown in FIG. 1, Unit F may be added. For example, the unit F may be added as the load applied by the power supply system 1 is changed. Furthermore, a configuration in which a predetermined unit is removable may be used. Alternatively, a switch may be provided between each unit (for example, unit D and unit E), and a predetermined unit (unit E) may be temporarily disconnected by controlling the switch to be in a cut-off state.

Also, the control information described above may be rewritten. Rewriting may be performed by the user operating an input unit (not shown) or an operation unit (not shown) provided in the control device 100, or a communication unit (not shown) of the control device 100 may control the rewriting. Information may be acquired, and the control device 100 may automatically rewrite the current control information to the acquired control information for rewriting. For example, when the installed storage battery 50 is replaced with another storage battery and the capacity of the other storage battery is different from the capacity of the installed storage battery 50, the control information for rewriting is the capacity of the other storage battery and the maximum output. It includes information such as current values and a control program that takes into account the specifications of other storage batteries. As a result, the power supply system 1 can execute each of the processes described above even when the storage battery is replaced.

The specifications and length of the power line (wiring) in the circuit may be taken into account as the circuit configuration when performing the above processing. For example, it is preferable that the power lines connected to the storage batteries 50 have the same specifications and length, and the power lines are configured so that the impedance of each storage battery 50 is not affected by the specifications and length of the power lines.

<Second embodiment>
A second embodiment will be described below. The second embodiment is a highly accurate method for diagnosing deterioration of a storage battery or a method for performing appropriate discharge control. The following description will focus on differences from the first embodiment. The functions of the first embodiment and the functions of the second embodiment may be included in separate systems or devices, or the functions of the first embodiment and the functions of the second embodiment may be included in the same system or device. may be included and implemented. A configuration including the information management unit 110 and the control unit 120 is an example of a “control unit”.

FIG. 9 is a diagram showing an example of a partial functional configuration of the power supply system 1 of the second embodiment. FIG. 9 shows only the functional configuration used for explaining the second embodiment among the functional configurations in FIG. 1 described above, and other functional configurations are omitted.

The power supply system 1A includes a control device 100A instead of the control device 100. FIG. 100 A of control apparatuses are replaced with the memory|storage part 130, and are provided with 130 A of memory|storage parts. In addition to control information 140, for example, temperature correction information 142 and state information 144 are stored in the storage unit 130A. Details of the temperature correction information 142 and the state information 144 will be described later.

Unit A, for example, in addition to the functional configuration of FIG. -N. Although only the unit A is shown in the example of FIG. 9, for example, other units also have the same functional configuration. Hereinafter, when the first cell voltage detection section 90A-1 to the Nth cell voltage detection section 90A-N are not distinguished, they are referred to as "cell voltage detection section", and the first temperature detection section 92A-1 to the Nth temperature detection section are referred to as "cell voltage detection sections". When 92A-N are not distinguished from each other, they are referred to as "temperature detectors 92". The above "N" is any natural number.

The cell voltage detection unit 90 is provided in each of the plurality of cells and detects the voltage of each cell (for example, voltage on the output side).

The temperature detection unit 92A is provided, for example, at a position where the temperature of a predetermined cell among the plurality of cells included in the storage battery 50A can be detected. The temperature detector 92A may be provided for a predetermined cell among the plurality of cells. Depending on the number of cells, for example, it may be provided only in the middle cell among the plurality of cells, or in addition to this, it may be provided in the cells located between the middle and the end. The number of cells provided with the temperature detector 92A may be determined arbitrarily. For example, it is preferable to provide the temperature detector 92A in the cell (middle) where the temperature is the highest.

[flowchart]
FIG. 10 is a flowchart showing an example of the flow of processing executed by the control device 100A. First, the information management unit 110 acquires the voltage of each cell from each of the cell voltage detection units 90 (step S400). Next, the information management unit 110 acquires the current output by the storage battery 50 from the current detection unit 84 (step S402).

Next, the information manager 110 acquires the temperature from the temperature detector 92 (step S404). Next, the information management unit 110 estimates the temperature of the cell (other cell) in which the temperature detection unit 92 is not provided based on the temperature acquired in step S404 (step S406). For example, the information management unit 110 refers to the temperature correction information 142 to estimate temperatures of other cells.

FIG. 11 is a diagram showing an example of the content of the temperature correction information 142. As shown in FIG. The temperature correction information 142 is, for example, information in which a cell number, which is cell identification information, and a coefficient (correction value) are associated with each other. For example, the center cell of the plurality of cells tends to have a higher temperature than the other cells, and the temperature tends to decrease as the distance from the center increases. For example, if the temperature of the middle cell can be detected and the temperatures of the other cells cannot be detected, the temperatures of the other cells are estimated by applying the correction value of the temperature correction information 142 to the temperature of the middle cell. . The coefficient of the temperature correction information 142 may be obtained experimentally or obtained by simulation. Also, the coefficient of the temperature correction information 142 may be prepared for each combination of cell voltage and current.

Return to the description of the flowchart. Next, the information management unit 110 acquires information indicating the state of the cell and generates state information (step S408). FIG. 12 is a diagram showing an example of the contents of the state information 144. As shown in FIG. The state information 144 is the current detected by the current detection unit 84 (the current output by the storage battery 50), the voltage detected by the cell voltage detection unit 90, the internal resistance, the temperature detection unit 92, and the time when the information was acquired. is information associated with detected temperature (or estimated temperature), SOC (State Of Charge), and the like. Internal resistance and SOC are information obtained using known techniques. For example, it is information obtained based on a model with parameters such as current, voltage, and temperature. For example, the SOC may be obtained based on the charge/discharge history, temperature, etc., or the relationship between the charge/discharge characteristics and the SOC using previously obtained parameters such as voltage, current, and temperature. The SOC may be obtained by performing a fitting process on the relationship between the charge/discharge characteristics and the SOC using parameters such as voltage, current, and temperature that are actually obtained or estimated.

Next, the information management unit 110 determines whether or not the cell state determination timing has arrived (step S410). For example, when sufficient information for determination is collected in the state information 144, it is determined that the determination timing has arrived. Sufficiently collected means, for example, that information such as current and voltage for a predetermined number of times (timings) or more has been collected. For example, when information on a plurality of timings such as two timings is gathered, it may be determined that the determination timing has arrived.

When the cell state determination timing has not arrived, control unit 120 controls one or both of DC-DC converter 60 and AC-DC converter 70 to change the current output from storage battery 50. (Step S412), the process proceeds to step S400. When the cell state determination timing arrives, the information management unit 110 determines the cell state based on the state information 144 (step S414). As a result, the processing of one routine in this flowchart ends. Details of the processing in steps S412 and S414 will be described later.

FIG. 13 is a diagram for explaining the process of step S412. The vertical axis of FIG. 13 is current, and the horizontal axis is time. For example, in the processing of the routine at time T, the information management unit 110 changes the current output by the storage battery 50 in step S412. At this time, the current that the unit should output to supply the required current to the load is the current I1. Control unit 120 controls one or both of DC-DC converter 60 and AC-DC converter 70 so that current I1 can be output even if the current output from storage battery 50 changes. For example, at time T+1, control unit 120 maintains the output of DC-DC converter 60 and increases the output of AC-DC converter 70, thereby reducing the current output from storage battery 50. FIG.

Similarly, when the current required by the load increases and the current to be output by the unit is current I2, which is larger than current I1, as at time T+5, control unit 120 controls DC-DC converter 60 and By increasing the output of one or both of the AC-DC converters 70, the current output by the storage battery 50 is decreased. Which one of the DC-DC converter 60 and the AC-DC converter 70 is controlled or how much the output is changed depends on the preset priority or the number of converters connected to the converter. It may be determined by the power supply capability. Further, in the above example, the case where the current output by the storage battery 50 is reduced has been described. should be reduced.

As described above, when sufficient time parameters of storage battery 50 included in state information 144 are collected, information management unit 110 determines deterioration of storage battery 50 or a region in which charging/discharging is possible appropriately. For example, the information management unit 110 compares the history of change in internal resistance with the history of change in internal resistance in a non-deteriorated state, and determines that cell deterioration is progressing according to the degree of divergence. judge. In this process, the information management unit 110 derives an index based on the obtained or estimated temperature and internal resistance of the cell, and this index and an index based on the temperature and internal resistance of the pre-deterioration cell prepared in advance. You may estimate progress of deterioration of a cell by comparing the divergence with . Furthermore, in addition to the internal resistance and temperature, other parameters included in the state information may be taken into account to estimate the progress of deterioration of the cell. Further, the progression of deterioration may be determined by a model or formula that derives an index indicating the degree of progression of deterioration by inputting these parameters. Further, for example, the information management unit 110 may diagnose cell deterioration as follows. That is, the information management unit 110 keeps the discharge current constant, measures the discharge time until the set voltage is reached, calculates the discharge time reduction rate, and compares this reduction rate with a predetermined threshold value. A degree of deterioration may be determined. On the other hand, the depth of deterioration (progress of deterioration) may be detected by changing the discharge current.

In addition to (or in place of) the progress of deterioration, the information management unit 110 may derive a region in which appropriate charge/discharge is possible (for example, current, voltage, or a combination thereof). For example, in the history of changes in internal resistance with respect to changes in voltage or current, there appear points where changes in internal resistance become small and points where internal resistance changes abruptly. An appropriate charge/discharge region may be identified based on these points. For example, a point different from the point where the internal resistance abruptly changes may be determined as the charge/discharge region.

Also, the appropriate charging/discharging region may be used as a parameter for determining deterioration. For example, deterioration may be determined based on the degree of divergence between an appropriate charging/discharging region and a predetermined appropriate charging/discharging region.

As described above, the power supply system 1A can easily determine (diagnose) the deterioration of the storage battery 50 and identify an appropriate charging/discharging region while supplying the required power to the load. Furthermore, since the temperature of each cell of the storage battery 50 is taken into consideration, it is possible to accurately and easily determine the deterioration or specify the appropriate charging/discharging region.

For example, when the control device 100A determines that the deterioration determination result is at a predetermined degree of deterioration, the control device 100A provides information to that effect to a display device (not shown), or notifies a preset terminal device such as a smartphone of that fact. You may provide information to that effect. At this time, information on the number and position of the deteriorated cell may also be provided. As a result, the administrator or user of the storage battery 50 can easily recognize the degree of deterioration and the deteriorated cells.

As described above, the control device 100A of the second embodiment can provide information for appropriately determining when to replace the cells of the storage battery. Furthermore, since an appropriate charging/discharging region can be specified, optimum charging/discharging control can be performed to slow down the deterioration rate of the storage battery and extend the life of the storage battery. Considering these comprehensively, the control device 100A grasps the state, voltage, current, and temperature of the storage battery 50, and controls so that the magnitude of the charging current or discharging current is optimal, thereby determining the life. life-prolonging measures are possible.

Furthermore, if the service life and deterioration of the storage battery can be clearly determined, it becomes possible to connect storage batteries with different capacities or to connect storage batteries with different degrees of deterioration. For example, it becomes easier to reuse used storage batteries, reused storage batteries, and discarded storage batteries, and the system can be provided at low cost. In addition, it is possible to safely use the used storage battery, the reused storage battery, the discarded storage battery, and the like.

The power supply system 1A of the second embodiment can be expressed as follows. For example, the above-described functions of the power supply system 1A can be implemented independently of the first embodiment. For example, in the power supply system 1A of the second embodiment, the control according to the second embodiment may be implemented in each of a plurality of units (power supply units) or may be implemented in one unit. Also, the power supply system 1A may include one unit, and the control according to the second embodiment may be implemented in this unit.

<Appendix 1>
a power supply unit;
A control unit that controls the power supply unit,
The power supply unit includes a storage battery and one or more power supply units connected in parallel to the storage battery,
The control unit controls one or more power supply units to change the current output by the storage battery, while changing the current before and after the change and the voltage of each of the plurality of cells included in the power supply unit. and the temperature detected by the plurality of cells of the power supply unit or the temperature detected by the temperature detection section provided in the plurality of cells,
Diagnosing the degree of deterioration of each of the plurality of cells using the current, the voltage, and the temperature obtained by the obtaining process;
power system.

<Appendix 2>
a power supply unit;
A control unit that controls the power supply unit,
The power supply unit includes a storage battery and one or more power supply units connected in parallel to the storage battery,
The control unit controls one or more power supply units to change the current output by the storage battery, while changing the current before and after the change and the voltage of each of the plurality of cells included in the power supply unit. and the temperature detected by the plurality of cells of the power supply unit or the temperature detected by the temperature detection section provided in the plurality of cells,
Using the current, the voltage, and the temperature obtained by the obtaining process, the magnitude of the charging current or discharging current of the storage battery that reduces deterioration is specified, and the magnitude of the specified charging current or discharging current is specified. controlling the charging or discharging of the storage battery based on
power system.

In the above functional configuration, the control unit controls the one or more power supply units so that the current output by the one or more power supply units and the current output by the storage battery meet the required current. You may change the electric current which a storage battery outputs.

In the above functional configuration, comprising a detection unit that detects the temperature of a predetermined cell among the plurality of cells,
The control unit estimates a temperature of a cell different from the predetermined cell among the plurality of cells based on the temperature of the predetermined cell,
(A) diagnosing the degree of deterioration of the predetermined cell using the current, the voltage, and the temperature obtained by the obtaining process;
The degree of deterioration of the different cells may be diagnosed using the current, the voltage, and the estimated temperature obtained by the obtaining process.

Also, (B) may be performed instead of (in addition to) (A).
(B) Using the current, the voltage, and the temperature obtained by the obtaining process, the magnitude of the charging current or discharging current of the storage battery that reduces deterioration is specified, and the specified charging current or discharging The charging or discharging of the storage battery is controlled based on the magnitude of the current.

As described above, the mode for carrying out the present invention has been described using the embodiments, but the present invention is not limited to such embodiments at all, and various modifications and replacements can be made without departing from the scope of the present invention. can be added.

1, 1A... power supply system, 50... storage battery, 60... DC-DC converter, 70... AC-DC converter, 80... diode, 82... voltage detection unit, 84... current detection unit, 90... cell voltage detection unit, 92... First temperature detector, 100... Control device, 110... Information management part, 120... Control part, 130... Storage part, 140... Control information

Claims (19)

a plurality of power supply units each connected in parallel;
a control unit that controls the plurality of power supply units,
each of the plurality of power supply units includes a storage battery and one or more power supply units connected in parallel to the storage battery;
The control unit controls the power output from the desired power supply unit by controlling the desired power supply unit among the power supply units included in the plurality of power supply units. controlling the current output by the storage battery contained in
power system. The control unit controls the power output from the desired power supply unit so that the impedance of the storage battery included in each of the power supply units approaches.
The power system of claim 1. the capacity of the storage battery included in the power supply unit is the same or similar,
The control unit controls the power output by the desired power supply unit such that the current output by the storage battery included in each of the power supply units approaches.
3. The power system according to claim 1 or 2. the capacities of the storage batteries included in the power supply units are not the same or similar,
The control unit controls the power output by the desired power supply unit such that the ratio of the current output by the storage battery to the capacity of the storage battery included in each of the plurality of power supply units approaches.
3. The power system according to claim 1 or 2. The control unit controls the power supply unit included in each of the power supply units to charge the storage battery included in each of the power supply units with electric power when the voltage of the storage battery falls below a predetermined value. control the
controlling the power supply unit so that the ratio of the current input to the storage battery to the capacity of the storage battery approaches in the control;
5. The power system of claim 4. The control unit adjusts the power output from the desired power supply unit so that each storage battery does not output a current value exceeding a specified current value specified for each of the storage batteries included in the plurality of power supply units. controlling to control the current output by the storage battery;
3. The power system according to claim 1 or 2. The one or more power supply units include a first power supply unit that converts DC power generated by the solar power generation device into desired DC power and outputs the converted DC power.
3. The power system according to claim 1 or 2. The one or more power supply units include a second power supply unit that converts AC power supplied by a supply source that supplies AC power into DC power and outputs the converted DC power.
The power system of claim 7. The control unit prioritizes the first power supply unit over the second power supply unit and controls the current output by the storage battery.
9. The power system of claim 8. The plurality of power supply units each connected in parallel are three or more power supply units,
The control unit controls the power output from the desired power supply unit so that the impedance of the storage battery included in each of the power supply units approaches.
3. The power system according to claim 1 or 2. The control unit
Voltage detection for detecting the current before and after the change and the voltage of each of the plurality of cells included in the power supply unit while controlling one or more power supply units to change the current output by the storage battery. Repeating the process of acquiring the voltage detected by the unit and the temperature detected by the plurality of cells of the power supply unit or the temperature detection unit provided in the plurality of cells,
Diagnosing the degree of deterioration of each of the plurality of cells using the current, the voltage, and the temperature obtained by the obtaining process;
3. The power system according to claim 1 or 2. The control unit controls the one or more power supply units and adjusts the current output by the storage battery so that the current output by the one or more power supply units and the current output by the storage battery satisfy the required current. change,
12. The power system of claim 11. A detection unit that detects the temperature of a predetermined cell among the plurality of cells,
The control unit estimates a temperature of a cell different from the predetermined cell among the plurality of cells based on the temperature of the predetermined cell,
Diagnosing the degree of deterioration of the predetermined cell using the current, the voltage, and the temperature obtained by the obtaining process,
Diagnosing the degree of deterioration of the different cells using the current, the voltage, and the estimated temperature obtained by the obtaining process;
12. The power system of claim 11. The control unit
Voltage detection for detecting the current before and after the change and the voltage of each of the plurality of cells included in the power supply unit while controlling one or more power supply units to change the current output by the storage battery. Repeating the process of acquiring the voltage detected by the unit and the temperature detected by the plurality of cells of the power supply unit or the temperature detection unit provided in the plurality of cells,
Using the current, the voltage, and the temperature obtained by the obtaining process, the magnitude of the charging current or discharging current of the storage battery that reduces deterioration is specified, and the magnitude of the specified charging current or discharging current is specified. controlling the charging or discharging of the storage battery based on
3. The power system according to claim 1 or 2. The control unit controls the one or more power supply units and adjusts the current output by the storage battery so that the current output by the one or more power supply units and the current output by the storage battery satisfy the required current. change,
15. The power system of claim 14. A detection unit that detects the temperature of a predetermined cell among the plurality of cells,
The control unit estimates a temperature of a cell different from the predetermined cell among the plurality of cells based on the temperature of the predetermined cell,
Using the current, the voltage, and the temperature obtained by the obtaining process, the magnitude of the charging current or discharging current of the storage battery that reduces deterioration is specified, and the magnitude of the specified charging current or discharging current is specified. controlling the charging or discharging of the storage battery based on
15. The power system of claim 14. a plurality of power supply units each connected in parallel;
a control unit that controls the plurality of power supply units,
Each of the plurality of power supply units includes a connection section to which a storage battery is connected, and one or more power supply sections connected in parallel to the storage battery connected to the connection section,
The control unit controls the power output from the desired power supply unit by controlling the desired power supply unit among the power supply units included in the plurality of power supply units. controlling the current output by the storage battery connected to the connection part included in
power system. A control method for a plurality of power supply units,
each of the power supply units is connected in parallel, each of the power supply units includes a storage battery and one or more power supply units connected in parallel to the storage battery;
the computer
controlling power output from the desired power supply unit by controlling the desired power supply unit among the power supply units included in the plurality of power supply units;
controlling the current output by the storage battery included in each of the power supply units;
How to control the power system. A program for controlling a plurality of power supply units,
each of the power supply units is connected in parallel, each of the power supply units includes a storage battery and one or more power supply units connected in parallel to the storage battery;
to the computer,
controlling power output from the desired power supply unit by controlling the desired power supply unit among the power supply units included in the plurality of power supply units;
controlling the current output by the storage battery included in each of the power supply units;
program.

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