Power system

Abstract

To provide a power system capable of dispersively controlling a plurality of inverters.SOLUTION: A power system S1 comprises a plurality of inverter devices A each of which is connected with a storage battery 9 and supplies power to a load L. Each of the plurality of inverter devices A comprises: a first measurement section 11 for measuring an active power output; a second measurement section 12 for measuring an individual charging rate which is a charging rate of the storage battery 9; a processing section 3 including an output average calculation section 31 for calculating an output average value which is the average value of active power outputs, and a charging rate average calculation section 32 for calculating a charging rate average value which is the average value of individual charging rates; a setting section 4 for setting an active power target value; and a control section 5 for controlling output power. The setting section 4 includes: a charging rate difference calculation section 41 for calculating a charging rate difference which is a difference between the charging rate average value and the individual charging rate; a correction width calculation section 42 for calculating a correction width which is a difference between the output average value and rated output of the own device; and a target calculation section 43 for calculating the active power target value by using the charging rate difference and the correction width.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a power system.

Background Art

[0002] Conventionally, some power systems are disconnected from the power grid and perform independent operation when an abnormality occurs in the power grid (for example, during a power outage). A power system that performs independent operation includes a distributed power source, and supplies power obtained from the distributed power source to a load without receiving power supply from the power grid during independent operation. For example, a plurality of storage batteries may be used in parallel as a distributed power source. In such a power system that operates a plurality of storage batteries in parallel, a technology that prevents the state of charge of each storage battery from reaching the upper or lower limit is required. For example, when one of a plurality of storage batteries is discharged to the lower limit of the state of charge, it can be charged but cannot be discharged. In such a case, since power output from the storage battery becomes impossible, there is a risk that the output will be insufficient for the power consumption of the load. For example, Patent Document 1 discloses a power system that manages the remaining charge of a plurality of storage batteries. The power system (storage battery system) described in Patent Document 1 includes two inverters, two storage batteries, and a storage battery monitoring and control device. Charging and discharging of the two inverters and the two storage batteries are individually controlled by the storage battery monitoring and control device. The storage battery monitoring and control device acquires the charge amount of each storage battery, sends a charge / discharge command to each inverter, and individually controls charging or discharging.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0004] In the power system described in Patent Document 1, the battery monitoring and control device calculates charge and discharge commands for each inverter, resulting in a concentration of load on the battery monitoring and control device.

[0005] This disclosure was conceived in view of the above circumstances, and its purpose is to provide a power system that enables distributed control of multiple inverters. [Means for solving the problem]

[0006] The power system provided by this disclosure comprises a plurality of inverter devices, each connected to a battery and supplying power to a load, wherein each of the plurality of inverter devices includes a processing unit including a first measurement unit for measuring active power output, a second measurement unit for measuring an individual charge rate which is the charge rate of the battery, an output average calculation unit for calculating an output average value which is the average value of the active power output measured by each of the plurality of inverter devices, and a charge rate average calculation unit for calculating an average charge rate which is the average value of the individual charge rates measured by each of the plurality of inverter devices, a setting unit for setting an active power target value which is a target value of the active power output, and a control unit for controlling the output power based on the measured value of the active power output and the active power target value, wherein the setting unit includes a charge rate difference calculation unit for calculating a charge rate difference which is the difference between the average charge rate and the individual charge rate of the device, a correction width calculation unit for calculating a correction width which is the difference between the output average value and the rated output of the device, and a target calculation unit for calculating the active power target value using the charge rate difference and the correction width.

[0007] In a preferred embodiment of the power system, the setting unit calculates the target active power value by performing the following equation (1), where Pref is the target active power value, Pavg is the average output value, Pmax is the rated output, SoCme is the individual charge rate, SoCavg is the average charge rate, and α is the gain.

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[0008] In a preferred embodiment of the power system, each of the plurality of inverter devices further comprises a communication unit that communicates with at least one other inverter device among the plurality of inverter devices, the communication connection state of the plurality of inverter devices is a connected state, and the output average calculation unit and the charge rate average calculation unit communicate with the other inverter devices to calculate the output average value and the charge rate average value, respectively.

[0009] In a preferred embodiment of the power system, the output averaging unit generates an internal active power value based on the active power output, the communication unit transmits the generated internal active power value to the other inverter device and receives the internal active power value of the other inverter device, the output averaging unit performs a first calculation process to generate a new internal active power value using the calculation result based on the generated internal active power value and the received internal active power value, and the internal active power value converges to the output average value as the first calculation process is repeated.

[0010] In a preferred embodiment of the power system, the charge rate averaging calculation unit generates an internal charge rate value based on the charge rate, the communication unit transmits the generated internal charge rate value to the other inverter device and receives the internal charge rate value of the other inverter device, the charge rate averaging calculation unit performs a second calculation process to generate a new internal charge rate value using the calculation result based on the generated internal charge rate value and the received internal charge rate value, and the internal charge rate value converges to the average charge rate value as the second calculation process is repeated. [Effects of the Invention]

[0011] In the power system of this disclosure, each of the multiple inverter devices calculates an active power target value and controls the output power based on that active power target value. Therefore, the power system of this disclosure enables distributed control of multiple inverters.

[0012] Other features and advantages of this disclosure will become more apparent from the detailed description below, with reference to the accompanying drawings. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of the overall configuration of a power system according to one embodiment. [Figure 2] This diagram graphically represents the communication connections of a power system according to one embodiment. [Figure 3] This figure shows a detailed configuration example of an inverter device in a power system according to one embodiment. [Figure 4] This is an illustrative diagram showing the limitations imposed by the correction range of a power system according to one embodiment. [Modes for carrying out the invention]

[0014] Preferred embodiments of the power system of this disclosure are described below with reference to the drawings. Hereafter, identical or similar components are denoted by the same reference numerals, and redundant descriptions are omitted.

[0015] Figure 1 shows an example of the overall configuration of a power system S1 according to one embodiment. As shown in the figure, the power system S1 is equipped with n (n is a natural number) inverter devices A. In the example shown in Figure 1, the power system S1 is equipped with five inverter devices A. When distinguishing the five inverter devices A from each other, they are referred to as inverter devices A1 to A5. In Figure 1, thick lines indicate power connection lines, and dotted arrows indicate that the inverter devices A are communicating with each other. As shown in Figure 1, the power system S1 is equipped with multiple inverter devices A (A1 to A5) that are electrically connected in parallel to each other. The power system S1 operates independently (non-connected operation) when disconnected from the power grid K. The power system S1 controls the independent operation by having each of the multiple inverter devices A operate cooperatively and in a distributed manner. During independent operation, power is supplied to the load L from the multiple inverter devices A.

[0016] As shown in Figure 1, each of the multiple inverter devices A is connected to a storage battery 9. Each inverter device A converts the power stored in the storage battery 9 as appropriate and outputs it. In this disclosure, the rated capacities of each of the multiple storage batteries 9 are the same.

[0017] Each of the plurality of inverter devices A can communicate with at least one of the other inverter devices A. FIG. 2 is a graph representing the communication connection state of the plurality of inverter devices A. In each graph of FIG. 2, five vertices respectively represent five inverter devices A1 to A5, and sides with arrows represent the communication state between the respective inverter devices A. Each side indicates that mutual communication is performed. In the power system S1, the plurality of inverter devices A communicate with each other, for example, in the connection relationship shown in FIG. 2(a). As shown in FIG. 2(a), since a communication path exists for any two vertices (inverter devices A) in the graph, the graph is connected. The communication of each inverter device A in the power system S1 is not limited to the connection relationship shown in FIG. 2(a), and may be the connection relationship shown in FIGS. 2(b) and 2(c). The graphs shown in FIGS. 2(b) and 2(c) are also connected. As described above, it is only required that each inverter device A mutually communicates with at least one inverter device A among the plurality of inverter devices A, and a communication path exists (in a connected state) for any two inverter devices A in the power system S1, and it is not necessary that all inverter devices A mutually communicate with each other. Further, as shown in FIG. 2(d), when the two inverter devices A1 and A4 are out of service, communication may be performed by the three inverter devices A2, A3 and A5. In this case, the three inverter devices A2, A3 and A5 perform control for self-sustaining operation.

[0018] FIG. 3 shows a detailed configuration example of each of the plurality of inverter devices A. As shown in the figure, each of the plurality of inverter devices A includes a first measurement unit 11, a second measurement unit 12, a communication unit 2, a processing unit 3, a setting unit 4, a control unit 5, an acquisition unit 6, and an inverter circuit INV. The following description is given for any one of the plurality of inverter devices A. The inverter device A to be described may be referred to as the target inverter device A. Note that the first measurement unit 11, the second measurement unit 12, the communication unit 2, the processing unit 3, the setting unit 4, the control unit 5, the acquisition unit 6, and the inverter circuit INV described below are common to each inverter device A unless otherwise specified.

[0019] The first measuring unit 11 measures the output value of active power of the target inverter device A. The first measuring unit 11 outputs the measured active power output value as the active power measured value Pout to each of the processing unit 3 and the control unit 5.

[0020] The second measuring unit 12 measures the state of charge (SoC: State of Charge) of the storage battery 9 connected to the target inverter device A (inverter circuit INV). The second measuring unit 12 outputs the measured state of charge as the individual state of charge SoCme to each of the processing unit 3 and the setting unit 4.

[0021] The communication unit 2 performs communication with other inverter devices A. The communication method may be wireless communication or wired communication. The communication unit 2 includes a transmitting unit 21 and a receiving unit 22. The transmitting unit 21 receives an internal value input from the processing unit 3, and transmits the input internal value to other communicable inverter devices A. The receiving unit 22 receives the internal value from other communicable inverter devices A, and outputs the received internal value to the processing unit 3. Details of the internal value will be described later.

[0022] The obtaining unit 6 obtains the rated output of the inverter circuit INV of the target inverter device A. Information on the rated output is stored, for example, in a storage unit not shown in the figure. The obtaining unit 6 outputs the obtained rated output information to the setting unit 4.

[0023] The processing unit 3 calculates state values ​​that represent the electrical and physical states of the power system S1. These state values ​​are used for each inverter device A to perform distributed and cooperative autonomous operation control. In this embodiment, the state values ​​calculated by the processing unit 3 include the average value of the active power output of each inverter device A (average output value) and the average value of the charge rate of the battery 9 connected to each inverter device A (average charge rate value). In other words, the processing unit 3 calculates the average output value and the average charge rate value, respectively. The average output value and the average charge rate value are used by the setting unit 4 when setting the active power target value, which is the target value of the active power output. The processing unit 3 generates internal values ​​in each inverter device A in order to calculate the state values. The processing unit 3 transmits the generated internal values ​​to other inverter devices via the transmitting unit 21 and receives internal values ​​from other inverter devices A via the receiving unit 22. The processing unit 3 performs the calculation of equation (2) below using the generated internal value Xi and each internal value Xj received by the receiving unit 22 to generate a new internal value Xi. The internal value Xi is the internal value generated by the target inverter device A (the i-th inverter device A), where i is a natural number from 1 to n. The internal value Xj is the internal value received from the j-th inverter device A among the other inverter devices A, where j is a natural number from 1 to n-1. The coefficient ε is a value that satisfies 0 < ε < 1 / dmax. dmax is the number of internal values ​​Xj received by the receiving unit 22, even though the inverter device A communicates with the most other inverter devices A among the multiple inverter devices A. The coefficient ε is used to suppress the fluctuation of the internal value Xi from becoming too large, and if the processing in the processing unit 3 is continuous time processing, it is not necessary to multiply by the coefficient ε. The coefficient αij is set to "1" or "0". The coefficient αij is set to "1" for internal values ​​Xj received by the receiving unit 22, and to "0" for internal values ​​Xj that are not received. The processing unit 3 repeatedly performs the calculation in equation (2) below. Through the repetition of this calculation process, the internal values ​​Xi and Xj converge to the arithmetic mean of the initial values ​​of the internal value Xi generated by each inverter device A. This can be understood from the technical concept described in Patent Document 2. In this embodiment, the internal values ​​include an active power internal value based on the active power output and a charge rate internal value based on the charge rate.The processing unit 3 includes an output average calculation unit 31 and a charge rate average calculation unit 32.

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[0024] The output average calculation unit 31 calculates the average value of the active power output (output average value) by repeatedly performing an calculation process (first calculation process) that generates an internal active power value. The output average calculation unit 31 sets the active power measurement value Pout input from the first measurement unit 11 as the initial value of the internal active power value. This initial value is updated when the active power measurement value in the first measurement unit 11 is updated. In inverter device A where the active power measurement value has been updated, the difference between the updated active power measurement value Pout(t) and the previous active power measurement value Pout(t-1) is added to the internal active power value Pi, so that the internal active power value becomes the updated initial value. In the first calculation process, the output average calculation unit 31 generates a new internal active power value Pi using the calculation result based on the generated internal active power value Pi and each internal active power value Pj input from the receiving unit 22. Specifically, in the first calculation process, the active power internal value Pi is used as the internal value Xi in equation (2) above, and the active power internal value Pj is used as the internal value Xj. The newly generated active power internal value Pi is output to the transmission unit 21 and used in the next first calculation process. As this first calculation process is repeated, the active power internal value converges to the arithmetic mean of the active power outputs of the multiple inverter devices A. The output average calculation unit 31 outputs the converged active power internal value as the output average to the setting unit 4.

[0025] The charge rate average calculation unit 32 calculates the average charge rate (charge rate average) by repeatedly performing a calculation process (second calculation process) that generates an internal charge rate value. The charge rate average calculation unit 32 sets the individual charge rate SoCme input from the second measurement unit 12 as the initial value of the internal charge rate. This initial value is updated when the individual charge rate SoCme in the second measurement unit 12 is updated. In inverter device A where the individual charge rate has been updated, the difference between the updated individual charge rate SoCme(t) and the previous individual charge rate SoCme(t-1) is added to the internal charge rate value, so that the internal charge rate value becomes the updated initial value. In the second calculation process, the charge rate average calculation unit 32 generates a new internal charge rate value using the calculation result based on the generated internal charge rate value Ui and each internal charge rate value Uj input from the receiving unit 22. For example, in the second calculation process, the internal charge rate value Ui is used as the internal value Xi in equation (2) above, and the internal charge rate value Uj is used as the internal value Xj. The newly generated internal charge rate value Ui is output to the transmission unit 21 and used in the next second calculation process. As this second calculation process is repeated, the internal charge rate value converges to the arithmetic mean of the charge rates of the multiple storage batteries 9. The charge rate average calculation unit 32 outputs the converged internal charge rate value as the charge rate average to the setting unit 4.

[0026] The setting unit 4 sets a target value for the active power output of the device (active power target value). The setting unit 4 calculates the active power target value by performing the calculation in equation (3) below. In equation (3) below, Pref is the active power target value, Pavg is the average output value (abs(Pavg) is the absolute value of the average output value), Pmax is the rated output, SoCme is the individual charge rate (the current charge rate of the connected battery 9), SoCavg is the average charge rate, and α is the gain coefficient. The gain coefficient α is set to a value that satisfies, for example, 0 ≤ α ≤ 1, but it may also be a value greater than 1. In this disclosure, the gain coefficient α is 1. Also, in equation (3) below, SoCme - SoCavg corresponds to the charge rate difference described later, and Pmax - abs(Pavg) corresponds to the correction range described later. The setting unit 4 includes a charge rate difference calculation unit 41, a correction range calculation unit 42, and a target calculation unit 43 in order to perform the calculation in equation (3) below.

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[0027] The charge rate difference calculation unit 41 calculates the charge rate difference, which is the difference between the average charge rate SoCavg and the charge rate of the battery 9 connected to the device (individual charge rate SoCme). Therefore, the charge rate difference calculation unit 41 performs the SoCme-SoCavg calculation in equation (3) above. The charge rate difference calculation unit 41 outputs the calculated charge rate difference to the target calculation unit 43.

[0028] The correction width calculation unit 42 calculates a correction width, which is the difference between the rated output Pmax of the target inverter device A (inverter circuit INV) and the absolute value of the average output Pavg. Therefore, the correction width calculation unit 42 performs the calculation Pmax-abs(Pavg) in equation (3) above. The correction width calculation unit 42 outputs the calculated correction width to the target calculation unit 43. Note that the rated output Pmax of inverter device A (inverter circuit INV) has a rated output during discharge (discharge rating) and a rated output during charging (charge rating). In this disclosure, the discharge rating and charge rating are the same magnitude for each inverter device A. Also, in this disclosure, the rated output Pmax of multiple inverter devices A are the same magnitude for each other.

[0029] The target calculation unit 43 calculates the active power target value Pref using the output average value Pavg, the charge rate difference, and the correction range. Specifically, the target calculation unit 43 performs the calculation Pavg - α × (correction range × charge rate difference) / 100. In this way, the power system S1 calculates the active power target value Pref considering the charge rate difference and the correction range. By considering the charge rate difference, the deviation in the charge rate of each battery 9 is controlled to be small, and by considering the correction range, the active power target value Pref is limited to within the range of the correction range.

[0030] Figure 3 illustrates the limitations imposed by the correction range. Figures 3(a) and 3(b) show the state where the average output value of each inverter device A is a value indicating discharge (a value greater than 0 in Figure 3), and the range indicated by the arrow is the correction range. Figure 3(a) shows the state where the power consumption of load L is relatively low, and Figure 3(b) shows the state where the power consumption of load L is relatively high.

[0031] As mentioned above, the correction range is calculated as the difference between the rated output Pmax of the inverter device A and the absolute value of the average output Pavg. By using this correction range to calculate the active power target value Pref, the calculated active power target value Pref is limited to a range from the average output to the closer of the charging rating or the discharging rating, and a range from the average output to the farther of the charging rating or the discharging rating, by the same magnitude as the aforementioned range. In the examples shown in Figures 3(a) and 3(b), since the average output is a value indicating discharge, the active power target value Pref is limited to a range from the average output to the discharging rating, taken from the average output in the direction of the discharging rating (right in Figure 3) and the direction of the charging rating (left in Figure 3). Also, in Figure 3(a), since the power consumption of the load L is relatively low, the average output of each inverter device A is small (close to 0), and the difference from the discharging rating (correction range) is large. On the other hand, in Figure 3(b), since the power consumption of load L is relatively high, the average output value of each inverter device A is large, and the difference from the discharge rating (correction range) is small. In other words, the correction range shown in Figure 3(b) imposes stricter restrictions on the value of the active power target value Pref than the correction range shown in Figure 3(a).

[0032] The setting unit 4 performs the calculation of equation (3) above using the charge rate difference calculation unit 41, the correction range calculation unit 42, and the target calculation unit 43, and sets the calculation result as the active power target value Pref. Then, it outputs the set active power target value Pref to the control unit 5. Note that the configuration of the setting unit 4 is not limited to the example described above.

[0033] The control unit 5 controls the output power of the inverter circuit INV so that the active power measurement value Pout becomes the active power target value Pref. The inverter circuit INV is located between the battery 9 and the first measurement unit 11. The inverter circuit INV converts the DC power input from the battery 9 into AC power and outputs it to another inverter device A or load L. The inverter circuit INV also converts the AC power input from the other inverter device A into DC power and outputs it to the battery 9. The inverter circuit INV is, for example, a single-phase full-bridge type PWM controlled inverter and is equipped with multiple switching elements. The inverter circuit INV converts between DC power and AC power by switching each switching element according to the drive signal input from the control unit 5. The inverter circuit INV can be any inverter that performs DC-AC conversion, for example, a half-bridge type or an inverter circuit with other configurations.

[0034] In power system S1, each inverter device A calculates the average output value, which is the average of the active power output, and the average charge rate value, which is the average of the individual charge rates. Then, using the average output value, the charge rate difference (the difference between the average charge rate value and the individual charge rate), and the correction range (the difference between the average output value and the rated output), the active power target value is calculated. With this configuration, each inverter device A adjusts the active power target value based on the difference between the average charge rate value and the individual charge rate (charge rate difference), thereby reducing the bias in the charge rate of each battery 9. At this time, each inverter device A adjusts the active power target value based on the difference between the average output value and the rated output (correction range), so it is possible to limit the output power based on the current output status of the load L and prevent the output power from exceeding the rated output. Therefore, power system S1 can perform distributed power control of multiple inverter devices A without using a management system to manage multiple inverter devices A.

[0035] In the power system S1, the setting unit 4 calculates the active power target value by performing the calculation in equation (3) above. With this configuration, in each inverter device A, the active power target value is calculated by correcting the average output value with the charge rate difference (difference between the average charge rate and the individual charge rate) and the correction range (difference between the average output value and the rated output). Therefore, each inverter device A can calculate an active power target value that takes into account the rated output and the charge state of the connected battery 9.

[0036] In power system S1, the communication connection state of the multiple inverter devices A is linked, and each inverter device A calculates the average output value and the average charge rate value through communication with at least one other inverter device A among the multiple inverter devices A. With this configuration, power system S1 can obtain values ​​for calculating the active power target value (e.g., average output value and average charge rate value) through communication between the multiple inverter devices A without using a management system to manage the multiple inverter devices A.

[0037] In the power system S1, the output average calculation unit 31 calculates the output average value by repeatedly performing the first calculation process described above using the internal value of the active power. With this configuration, each inverter device A can calculate the output average value in a distributed manner, thereby suppressing the bias in the calculation load among multiple inverter devices A. Suppressing this bias in the calculation load is preferable for each inverter device A to perform power control in a distributed manner in the power system S1.

[0038] In the power system S1, the charge rate average calculation unit 32 calculates the charge rate average value by repeatedly performing the second calculation process described above using the internal charge rate value. With this configuration, each inverter device A can calculate the charge rate average value in a distributed manner, thus suppressing the bias in the calculation load among multiple inverter devices A. Suppressing this bias in the calculation load is preferable for each inverter device A to perform power control in the power system S1 in a distributed manner.

[0039] In a configuration different from the above embodiment, the output average calculation unit 31 may calculate the output average value as follows. For example, one of the multiple inverter devices A (hereinafter referred to as "target inverter device Ax") receives the value of the active power output of each of the other inverter devices A through communication with each of them. The output average calculation unit 31 of the target inverter device Ax then calculates the output average value by dividing the sum of the values ​​of all active power outputs (including the active power output of its own device) by the number of the multiple inverter devices A. Subsequently, the target inverter device Ax transmits the calculated output average value to the other inverter devices A so that the output average value is shared among the multiple inverter devices A. However, in order to suppress the bias in the computation load among the multiple inverter devices A, it is preferable to calculate the output average value by repeatedly performing the first calculation process using the internal value of active power.

[0040] In a configuration different from the above embodiment, the charge rate average calculation unit 32 may calculate the charge rate average value as follows. For example, one of the multiple inverter devices A (target inverter device Ax) receives the charge rate value of each battery 9 through communication with each of the other inverter devices A. The charge rate average calculation unit 32 of the target inverter device Ax then calculates the charge rate average value by dividing the sum of all charge rate values ​​(including the charge rate of the battery 9 connected to itself) by the number of the multiple inverter devices A. Subsequently, the target inverter device Ax transmits the calculated charge rate average value to the other inverter devices A so that the charge rate average value is shared among the multiple inverter devices A. However, in order to suppress the bias in the computation load among the multiple inverter devices A, it is preferable to calculate the charge rate average value by repeatedly performing the above second calculation process using the internal charge rate value.

[0041] In a configuration different from the above embodiment, the distributed control of each inverter device A of this disclosure can also be applied to a power system that operates in grid-connected mode.

[0042] In a configuration different from the above embodiment, the distributed control of each inverter device A of this disclosure can also be applied to a power system in which a processing unit and a plurality of inverter devices A cooperate to control power, as described in Patent Document 3. In this example, for example, the processing unit calculates a common induction command value for each inverter device A by calculation using the power to be adjusted (e.g., connection point power) and the target power of the power to be adjusted. The processing unit can communicate with each inverter device A and transmits the calculated induction command value to each inverter device A. Each inverter device A receives the induction command value and calculates an output target value based on an optimization problem using the received induction command value. At this time, the calculated output target value is corrected by the charge rate difference and the correction range. For example, each inverter device A calculates the output target value by an arithmetic formula derived from an evaluation function, similar to the power control device in Patent Document 3. Then, the calculated output target value is corrected so that it falls within the ranges of the charge rate difference and the correction range. As a result, each inverter device A can reduce the bias in the charge rate of each battery while suppressing the output power from exceeding the rated output. Furthermore, in this modified configuration, the processing unit only needs to calculate a common induction command value for each inverter device A, and does not need to calculate separate charge and discharge commands for each inverter device A. In other words, it is possible to suppress the concentration of computational load on the processing unit.

[0043] The power system relating to this disclosure is not limited to the embodiments described above. The specific configuration of each part of the power system relating to this disclosure can be modified in various ways. [Explanation of Symbols]

[0044] S1: Power system, A: Inverter device, 2: Communication unit, 3: Processing unit, 4: Setting unit, 5: Control unit, 9: Storage battery, 11: First measurement unit, 12: Second measurement unit, 31: Output average calculation unit, 32: Charge rate average calculation unit, 41: Charge rate difference calculation unit, 42: Correction range calculation unit, 43: Target calculation unit, L: Load

Claims

1. Each unit is connected to a battery and is equipped with multiple inverter devices that supply power to the load. Each of the aforementioned plurality of inverter devices is A first measurement unit for measuring the active power output, A second measurement unit measures the individual charge rate, which is the charge rate of the aforementioned storage battery, A processing unit including an output average calculation unit that calculates an output average value which is the average value of the active power output measured in each of the plurality of inverter devices, and a charge rate average calculation unit that calculates a charge rate average value which is the average value of the individual charge rates measured in each of the plurality of inverter devices, A setting unit for setting an active power target value, which is the target value of the active power output, A control unit controls the output power based on the measured value of the active power output and the target value of the active power, Equipped with, The aforementioned setting unit is, A charge rate difference calculation unit calculates the charge rate difference, which is the difference between the average charge rate and the individual charge rate of the device. A correction width calculation unit calculates a correction width which is the difference between the average output value and the rated output of the device, A target calculation unit that calculates the active power target value using the charge rate difference and the correction range, A power system including a power system.

2. The power system according to claim 1, wherein the setting unit calculates the target value of active power by performing the following calculation (1) with respect to the target value of active power, the average output value Pavg, the rated output Pmax, the individual charge rate SoCme, the average charge rate SoCavg, and α as the gain. [Math 1]

3. Each of the plurality of inverter devices further comprises a communication unit that communicates with at least one other inverter device among the plurality of inverter devices. The communication connection state of the aforementioned plurality of inverter devices is a connected state. The power system according to claim 1 or 2, wherein the output average calculation unit and the charge rate average calculation unit communicate with the other inverter device to calculate the output average value and the charge rate average value, respectively.

4. The output average calculation unit generates an internal value of active power based on the active power output, The communication unit transmits the generated active power internal value to the other inverter device and receives the active power internal value of the inverter device from the other inverter device. The output average calculation unit performs a first calculation process to generate a new active power internal value using the calculation result based on the generated active power internal value and the received active power internal value. The power system according to claim 3, wherein the internal value of the active power converges to the average value of the output as the first calculation process is repeated.

5. The charge rate average calculation unit generates an internal charge rate value based on the charge rate, The communication unit transmits the generated internal charge rate value to the other inverter device and receives the internal charge rate value of the inverter device from the other inverter device. The charge rate average calculation unit performs a second calculation process to generate a new charge rate internal value using the calculation result based on the generated charge rate internal value and the received charge rate internal value. The power system according to claim 3, wherein the internal charge rate value converges to the average charge rate value as the second calculation process is repeated.

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