JP6257425B2 - Power supply system - Google Patents

Description

  The present invention provides a plurality of self-systems having an AC line to which a plurality of power consumers are connected, a power storage device, and a self-supporting inverter device that connects the power storage device and the AC line using a self-connection line. And connecting the power storage device of one self-system and the AC line of the other self-system using interconnection lines so that a plurality of self-systems are electrically connected in series The present invention relates to a power supply system including an inverter device between self systems.

  Conventionally, a power supply system has been proposed that includes a plurality of self-systems having an AC line to which a plurality of power consumers are connected, a power storage device, and a self-supporting inverter device that connects the power storage device and the AC line. Has been. For example, a power supply system described in Patent Document 1 (International Publication No. 2010/103650) includes a power storage device included in one self-system and another one so that a plurality of self-systems are electrically connected in series. The inverter system which connects the alternating current line which one self system has is provided between self systems. Furthermore, each of the self-supporting inverter devices of the plurality of self-systems has a target frequency at which the voltage of the power on the AC line becomes the target voltage and the frequency of the power on the AC line is determined according to the amount of power stored in the power storage device. For two self-systems that are electrically connected via a single inverter device, power is transferred from the self-system with the higher target frequency to the self-system with the lower target frequency. The operation of the connected inverter device is controlled so as to be supplied. That is, since the frequency of the power on the AC line of each self system is a value reflecting the amount of power stored in the power storage device, the connected inverter device is connected to each AC line with respect to the two electrically connected self systems. It is possible to know which power storage amount of the power storage device of the self system is large only by detecting the frequency of. And according to the magnitude of the detected frequency value, it is possible to equalize the amount of power stored in the power storage device of each self system by performing power interchange between the self systems.

International Publication No. 2010/103650

In the conventional power supply system described above, the self-supporting inverter device uses a power storage device to set the voltage and frequency of power on the AC line to predetermined values. That is, while the self-supporting inverter device controls the voltage and frequency of power on the AC line to predetermined values, current flows from the power storage device to the AC line via the self-supporting inverter device, or from the AC line to the power storage device. For example, current flows through the self-supporting inverter device.
In a conventional power supply system, it has been unclear what kind of charging should be performed on a power storage device that is constantly used for such power quality control.

  The present invention has been made in view of the above problems, and an object of the present invention is to be able to charge the power storage device while performing power quality control for maintaining the power quality of the AC line using the power storage device. The point is to provide a supply system.

In order to achieve the above object, the characteristic configuration of the power supply system according to the present invention includes an AC line to which a plurality of power consumers are connected, a power storage device, and a self-connection between the power storage device and the AC line. A plurality of self-systems having a self-supporting inverter device connected using wires,
The power storage device of one of the self systems and the AC line of the other self system are connected using an interconnection line so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device between the self systems,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
A control device is provided that performs power quality control on the independent inverter device, and performs power interchange control and first charge control on the linked inverter device,
To the self-supporting inverter device, the other power storage device of the other self-system is connected with a jumper,
The controller is
As the first charging control, when it is determined that a charging start condition for one power storage device included in one self-system is satisfied, the first power connection device is connected to the one power storage device using the first interconnection line. The connected inverter device is supplied with target charging power for the one power storage device from the second interconnect line to the first interconnect line to charge the one power storage device. Let
As the power quality control, when the first charge control for charging the one power storage device in the one self-system is not performed, the one self-inverter device included in the one self-system Then, using the one power storage device of the one self-system, the power voltage on the one AC line of the one self-system is set as a target voltage, and the frequency of the power on the one AC line is set. Is controlled to be a target frequency determined according to the amount of power stored in the one power storage device, and the first charge control is performed to charge the one power storage device in the one self-system. The one self-standing inverter device is connected to the one self-standing inverter device included in the one self-system using the crossover. The other power storage device included in the other self-system is used to set the voltage of power on the one AC line of the one self-system as a target voltage and the power of the power on the one AC line. Control the frequency to be a target frequency determined according to the amount of power stored in the one power storage device, and
As the power interchange control, when power is interchanged between the specific self-system connected to each other using the interconnect line and another self-system using the interconnect line, the interconnect line is used. For the connected inverter device provided between the first interconnection line and the second interconnection line that constitute the first interconnection line, the specific self system and the other self system in the alternating current line On the basis of the target frequency, the power is configured to be accommodated from the self system in which the power storage amount of the power storage device is relatively large to the self system in which the power storage amount of the power storage device is relatively small.

According to the above characteristic configuration, the voltage and frequency of the power of the AC line can be controlled to predetermined values by the independent inverter device performing power quality control. In particular, in the power quality control, control is performed so that the frequency of the power of the AC line becomes a target frequency determined according to the amount of power stored in the power storage device. That is, information on the amount of power stored in the power storage device is given to the frequency (target frequency) of power on the AC line of each self system. As a result, when performing power interchange control for accommodating power from a self-system with a relatively large amount of power stored in the power storage device to a self-system with a relatively small amount of power stored in the power storage device, the AC line of each self-system By simply looking at the frequency of the power, it can be easily determined which power storage amount of the power storage device of the own system is large.
Further, when the first charging control for charging the power storage device included in the own system is not performed, the control device uses the power storage device to set the voltage of the power on the AC line as the target voltage and the AC line. Power quality control is performed with the frequency of power at the target frequency determined according to the amount of power stored in the power storage device. On the other hand, when the first charging control for charging the power storage device included in the self system is performed, another self system in which the self-contained inverter device is connected by a crossover without using the power storage device The power quality control is performed using the power storage device included in the power supply, with the voltage of power on the AC line as the target voltage and the frequency of power on the AC line as the target frequency determined according to the amount of power stored in the power storage device. . In other words, the control device determines whether the self-supporting inverter of the self-system is for power quality control when the first charge control for charging the power storage device of the self-system is performed or not. Different power storage devices are used. By doing in this way, in one self system, charge of the target charging power to the power storage device (first charge control) and power quality control of the power line of the self system can be performed together.

Another characteristic configuration of the power supply system according to the present invention includes an AC line to which a plurality of power consumers are connected, a power storage device, and a connection between the power storage device and the AC line using a self-connection line. A plurality of self-systems having a self-standing inverter device
The power storage device of one of the self systems and the AC line of the other self system are connected using an interconnection line so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device between the self systems,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
An inverter device for charging that uses an external connection line to connect one power storage device of one of the plurality of self systems and an external power system; and
A control device for performing power quality control on the self-supporting inverter device, performing power interchange control on the linked inverter device, and performing second charge control on the charging inverter device; With
The external connection line includes a first external connection line for connecting the charging inverter device and the power system, and a second external connection line for connecting the charging inverter device and the one power storage device. And consists of
To the self-supporting inverter device, the other power storage device of the other self-system is connected with a jumper,
The controller is
When it is determined that the charging start condition for the one power storage device connected to the charging inverter device using the second external connection line is satisfied as the second charging control, the charging inverter device In contrast, the target charging power to the one power storage device is supplied from the first external connection line to the second external connection line to charge the one power storage device,
As the power quality control, when the second charging control for charging the one power storage device in the one self system is not performed, the one self-inverted inverter device included in the one self system Then, using the one power storage device of the one self-system, the power voltage on the one AC line of the one self-system is set as a target voltage, and the frequency of the power on the one AC line is set. Is controlled to be a target frequency determined according to the amount of power stored in the one power storage device, and the second charge control is performed to charge the one power storage device in the one self-system. The one self-standing inverter device is connected to the one self-standing inverter device included in the one self-system using the crossover. The other power storage device included in the other self-system is used to set the voltage of power on the one AC line of the one self-system as a target voltage and the power of the power on the one AC line. Control the frequency to be a target frequency determined according to the amount of power stored in the one power storage device, and
As the power interchange control, when power is interchanged between the specific self-system connected to each other using the interconnect line and another self-system using the interconnect line, the interconnect line is used. For the connected inverter device provided between the first interconnection line and the second interconnection line that constitute the first interconnection line, the specific self system and the other self system in the alternating current line On the basis of the target frequency, the power is configured to be accommodated from the self system in which the power storage amount of the power storage device is relatively large to the self system in which the power storage amount of the power storage device is relatively small.

According to the above characteristic configuration, the voltage and frequency of the power of the AC line can be controlled to predetermined values by the independent inverter device performing power quality control. In particular, in the power quality control, control is performed so that the frequency of the power of the AC line becomes a target frequency determined according to the amount of power stored in the power storage device. That is, information on the amount of power stored in the power storage device is given to the frequency (target frequency) of power on the AC line of each self system. As a result, when performing power interchange control for accommodating power from a self-system with a relatively large amount of power stored in the power storage device to a self-system with a relatively small amount of power stored in the power storage device, the AC line of each self-system By simply looking at the frequency of the power, it can be easily determined which power storage amount of the power storage device of the own system is large.
Furthermore, when the second charging control for charging the power storage device included in the self system is not performed, the control device uses the power storage device to set the voltage of the power on the AC line as the target voltage and the AC line. Power quality control is performed with the frequency of power at the target frequency determined according to the amount of power stored in the power storage device. On the other hand, when the second charging control for charging the power storage device included in the self-system is performed, another self-system in which the self-contained inverter device is connected by a crossover without using the power storage device The power quality control is performed using the power storage device included in the power supply, with the voltage of power on the AC line as the target voltage and the frequency of power on the AC line as the target frequency determined according to the amount of power stored in the power storage device. . In other words, the control device determines whether the self-supporting inverter of the self-system is for power quality control when the second charge control for charging the power storage device of the self-system is performed or not. Different power storage devices are used. By doing in this way, in one self system, charge of the target charging power to the power storage device (second charge control) and power quality control of the power line of the self system can be performed together.

  Still another characteristic configuration of the power supply system according to the present invention is that, when the total voltage by a plurality of cells constituting the power storage device is less than a reference voltage, the control device supplies the target charging power to the power storage device, Constant current charging derived by the product of the total voltage and a constant reference current is performed, and when the total voltage is equal to or higher than the reference voltage, the target charging power to the power storage device is expressed as the reference voltage and the target charging current. The target charging current is determined by a current curve that decreases the current with the lapse of time using the constant reference current as an initial value, and the current curve is configured as the power storage device. The determination is based on at least one of the degree of deterioration of the cell and the temperature.

According to the above characteristic configuration, in a state where the total voltage by the plurality of cells is less than the reference voltage, that is, in a state where the total amount of electricity stored by the plurality of cells is relatively small, a relatively large constant reference current is supplied Charging can be performed rapidly by performing constant current charging. On the other hand, in a state where the total voltage by the plurality of cells is equal to or higher than the reference voltage, that is, in a state where the total amount of electricity stored by the plurality of cells is relatively large, the current is decreased with the passage of time using the reference current as an initial value. Overcharge can be suppressed by performing constant voltage charging.
Furthermore, since the current curve is determined according to at least one of the actual cell deterioration degree and the cell temperature related to the ease of cell deterioration, the cell deterioration during charging is suppressed. It is possible to set to

  Still another characteristic configuration of the power supply system according to the present invention is that the control device is based on a relational expression between the highest cell voltage and the target charging current among the cell voltages of the plurality of cells constituting the power storage device. A target charging current corresponding to the current highest cell voltage is determined, and a product of the target charging current and a total voltage of a plurality of cells constituting the power storage device is derived as the target charging power to the power storage device. In the relational expression, there is a relation that the target charging current decreases as the maximum cell voltage increases.

  According to the above characteristic configuration, when the product of the target charging current and the total voltage of a plurality of cells is used as the target charging power, the target charging current is set such that the target charging current decreases as the maximum cell voltage increases. It is determined according to the relational expression. In other words, among the plurality of cells, the cell with the highest cell voltage (the cell with the highest cell voltage) is the cell with the largest amount of power storage, and is intended to suppress overcharging of the cell. All the cells are charged.

  Still another characteristic configuration of the power supply system according to the present invention is that the power storage device includes a plurality of cell units, and the cell unit is connected in parallel to the cell main body and the cell main body, A bypass circuit unit that adjusts an amount of bypass current that flows by bypassing the cell main body portion of the current flowing through the cell unit, and the control device charges the power storage device with the target charging power. When the charged amount of the cell main body is less than the reference charged amount, a constant reference current as a temporary charging current is determined, and when the charged amount of the cell main body is equal to or greater than the reference charged amount, the cell Using a relational expression that defines a temporary charging current that decreases as the amount of electricity stored in the main body increases, a temporary charging current corresponding to the amount of electricity stored in the cell main body is determined for each of the plurality of cell units. A first temporary target charging current derived by adding an upper limit bypass current that is an upper limit value of the bypass current to the smallest temporary charging current among the temporary charging currents for each of the plurality of cell units; Comparing the second temporary target charging current, which is the largest temporary charging current among the temporary charging currents of each of the plurality of cell units, and determining the smaller temporary target charging current of the plurality of the plurality of cell units. And determining the target charging current to flow for each cell unit, supplying the target charging current for each of the plurality of cell units, and each of the plurality of cell units includes the target charging current supplied to the cell unit. Among them, the amount of current exceeding the temporary charging current determined according to the amount of electricity stored in the cell body portion is passed through the bypass circuit portion, the other portion of the current is passed through the cell body portion, A product of a total current, which is a sum of the target charging currents flowing for each of the plurality of cell units constituting the power storage device, and a total voltage of the plurality of cell units constituting the power storage device is used as the target charging power. It is in the point which is comprised.

When there is an imbalance in the amount of electricity stored in a plurality of cell body parts of the electricity storage device, for example, a relatively small charge current is passed through the cell body part having a relatively large amount of electricity stored, and the amount of electricity stored is relatively In order to eliminate the imbalance, it is preferable to flow a relatively large charging current through the small cell body.
Therefore, in this feature configuration, the cell unit is provided with a bypass circuit unit that is connected in parallel with the cell body unit and adjusts the amount of bypass current that flows by bypassing the cell body unit among the currents flowing through the cell unit. ing. That is, since at least a part of the target charging current flowing through the cell unit can be passed through the bypass circuit unit, even if the target charging current flowing through each of the plurality of cell units is the same, the cell body within each cell unit. The charging current flowing through the part can be made different.
Furthermore, after determining the temporary charging current according to the amount of electricity stored in the cell main body, the first charging current is derived by adding the upper limit bypass current to the smallest temporary charging current among the temporary charging currents for each of the plurality of cell units. Are compared with the second temporary target charging current which is the largest temporary charging current among the temporary charging currents for each of the plurality of cell units, and the smaller temporary target charging current of the two is compared. Is determined as a target charging current for each cell unit. In other words, the target charging current supplied to each cell unit is the sum of the temporary charging current and the upper limit bypass current for itself, so that no current exceeding the upper limit bypass current can flow in the bypass circuit section. In addition, it is possible to prevent a current exceeding the temporary charging current for the cell body from flowing through the cell main body.

  Yet another characteristic configuration of the power supply system according to the present invention is that the control device determines that the charging start condition is satisfied when a set time is reached.

  According to the above characteristic configuration, it is possible to charge the power storage device by determining that the charging start condition is periodically satisfied at the set time. For example, if the set time is set before the time period in which the power demand increases during the day, it is determined that the charging start condition is satisfied prior to the time period in which the power demand increases, and the power storage device Is stored. As a result, it is possible to increase the power supply capacity for the power consumer prior to the time period when the power demand increases.

  Still another characteristic configuration of the power supply system according to the present invention is that the control device determines that the charging start condition is satisfied when a power storage amount of the power storage device becomes less than a lower limit power storage amount.

  According to the above characteristic configuration, it is determined that the charging start condition is satisfied at a timing when the amount of power stored in the power storage device becomes less than the lower limit power storage amount, that is, at a timing when the power supply capacity from the power storage device to the power consumer decreases. The power storage device can be charged.

It is a figure which shows the structure of the electric power supply system of 1st Embodiment. It is a figure which shows the schematic structure of an electrical storage apparatus. It is a graph which shows the example of target charge electric power. It is a graph which shows the example of the relational expression of the highest cell voltage and target charging current among the cell voltages of the some cell which comprises an electrical storage apparatus. It is a figure which shows the schematic structure of an electrical storage apparatus. It is a graph which shows the example of the relational expression of the voltage (cell voltage) of a cell main-body part, and temporary charging current. It is a figure which shows typically the target charging current sent through a cell unit, the current sent through a cell main-body part, and the current sent through a bypass circuit part. It is a figure explaining the method of determining the target charging current sent through a cell unit. It is a figure which shows the structure of the electric power supply system of 4th Embodiment.

<First Embodiment>
The configuration of the power supply system according to the first embodiment will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of a power supply system according to the first embodiment. This power supply system includes an AC line 1 to which a plurality of power consumers D are connected, a power storage device 4, and a self-standing inverter device that connects the power storage device 4 and the AC line 1 using a self-connection line 2. The power storage device 4 of one self-system 10 and the alternating current of the other self-system 10 are provided so that the plurality of self-systems 10 are electrically connected in series. A connected inverter device 9 for connecting the line 1 with the interconnect line 3 is provided between the self systems 10. Self-connecting line 2 includes first self-connecting line 2 a (2) for connecting self-standing inverter device 5 and power storage device 4, and second self-connecting line for connecting self-standing inverter device 5 and AC line 1. 2b (2). The interconnection line 3 includes a first interconnection line 3 a (3) for connecting the linked inverter device 9 and the power storage device 4, and a second interconnection line for connecting the linked inverter device 9 and the AC line 1. 3b (3). Other power storage devices 4 possessed by other self-systems 10 are connected to the independent inverter devices 5 possessed by the respective self-systems 10 by crossovers 11. In addition, the power supply system includes a control device C that causes the independent inverter device 5 to perform power quality control and causes the linked inverter device 9 to perform power interchange control and first charging control.
FIG. 1 illustrates a state in which the three self systems 10, that is, the self system 10 </ b> A (10), the self system 10 </ b> B (10), and the self system 10 </ b> C (10) are connected via the connected inverter device 9. There is no limit to the number of self-systems 10 included in the power supply system.

  The power consumer D has a power consuming device 6 that consumes the power supplied from the AC line 1. Alternatively, the power consumer D may have the power generation device 7 in addition to the power consumption device 6. As the power consuming device 6, not only a general device such as a lighting device or an air conditioner, but also various devices that consume power for its operation can be used. As the power generation device 7, various devices such as a solar power generation device and a wind power generation device that generate power using natural energy such as sunlight and wind power, and a fuel cell that generates power using fuel can be used. As shown in FIG. 1, in the self system 10, the power generator 7 may be connected to the AC line 1 as a single unit. Further, the number of power consumers D connected to the AC line 1 and the numbers and combinations of the power consuming devices 6 and the power generators 7 included in the power consumers D are not limited to the illustrated example.

  The power storage device 4 can use a storage battery (chemical battery) such as a lithium ion battery, a nickel metal hydride battery, or a lead battery.

  The self-supporting inverter device 5 and the linked inverter device 9 are power conversion devices that can convert input power into power having a desired voltage, frequency, and phase and output the converted power. For example, the self-supporting inverter device 5 and the linked inverter device 9 include a circuit unit (not shown) having a semiconductor switching element and a control unit (not shown) that controls the switching operation of the semiconductor switching element. The And the power conversion operation | movement from input electric power to output electric power is performed by switching on / off of those semiconductor switching elements.

  The control device C is a device capable of controlling operations of the self-supporting inverter device 5 and the linked inverter device 9. For example, the control device C is a device having an information input / output function, a storage function, an arithmetic processing function, and the like. The function of the control device C is that any one of the control units (not shown) included in each of the self-supporting inverter device 5 and the linked inverter device 9 functions as a master control unit, and the other control unit is a master control unit. This can be realized by functioning as a slave control unit while performing information communication. Or the function of the control apparatus C is provided separately from the control part (not shown) which each of the independent inverter apparatus 5 and the connection inverter apparatus 9 has, and the master control part comprised so that information communication with those control parts is possible Can be realized.

  Then, the control device C performs power quality control in each self system 10 and power interchange control among the plurality of self systems 10. The power quality control is control for the purpose of keeping constant the quality of power on the AC line 1 of the own system 10. The power interchange control is control for the purpose of equalizing the amount of power stored in the power storage device 4 of each self system 10.

  Supplementing the power quality control, the power of the AC line 1 is consumed by the power consuming device 6 of the power consumer D. The power consuming device 6 is usually an external commercial power system separate from this power supply system. It is assumed that it operates with the electric power supplied from. That is, the power consuming apparatus 6 is designed to operate according to the frequency of power supplied from the commercial power system. Therefore, if the frequency of the power supplied to the power consuming device 6 is different, strictly speaking, the operation of these devices will also be different. Therefore, it is necessary to perform power quality control that keeps the frequency of power on the AC line 1 of each self system 10 within a predetermined range.

  Therefore, as power quality control, the control device C uses the power voltage of the AC line 1 of one self system 10 as a target voltage for the independent inverter device 5 of one self system 10 and the AC line. 1 is controlled so that the frequency of the power at 1 is a target frequency determined according to the amount of power stored in the power storage device 4 of the self system 10. Information on the amount of power stored in the power storage device 4 may be transmitted from the power storage device 4 to the self-supporting inverter device 5, or may be transmitted from the power storage device 4 to the control device C and further from the control device C to the self-supporting inverter device. 5 may be configured to be transmitted.

For example, in one self-system 10, the power supplied from the power generation device 7 to the AC line 1 is less than the received power (load power) from the power consumption device 6 from the AC line 1 (that is, the AC line 1 is loaded). In the excessive state), the voltage of the power of the AC line 1 is smaller than the target voltage. In that case, the control device C supplies power to the AC line 1 from the self-supporting inverter device 5 (that is, by causing the power storage device 4 to discharge the AC line 1 via the self-supporting inverter device 5). The power quality control is performed so as to increase the voltage on the AC line 1.
On the other hand, in one self-system 10, the power supplied from the power generation device 7 to the AC line 1 is greater than the power received by the power consumption device 6 from the AC line 1 (that is, the AC line 1 has excessive power generation). In this state, the voltage of the power of the AC line 1 is larger than the target voltage. In that case, the control device C draws electric power from the AC line 1 to the self-supporting inverter device 5 (that is, by charging the power storage device 4 from the AC line 1 via the self-supporting inverter device 5). Power quality control is performed to reduce the voltage on the AC line 1.

  Supplementing the power interchange control, in each self system 10, the function of maintaining the power quality of the AC line 1 is performed by the power quality control of the independent inverter device 5 using the power storage device 4. As a result, how much the amount of power stored in the power storage device 4 increases or decreases varies among the plurality of self-systems 10. Therefore, with the passage of time, a difference may occur in the amount of power stored in the power storage device 4 of each self system 10. In such a case, if power can be exchanged from the self system 10 having a large amount of power stored in the power storage device 4 to the self system 10 having a small amount of power stored in the power storage device 4, the power storage devices 4 between the self systems 10. Is preferable for equalizing the amount of electricity stored.

  Therefore, as power interchange control, when the control device C uses the interconnect line 3 to exchange power between one self system 10 and another self system 10, the control device C configures the first interconnect line 3. The AC line 1 in each of the one self-system 10 and the other self-system 10 with respect to the connected inverter device 9 provided between the interconnection line 3a (3) and the second interconnection line 3b (3). Based on the target frequency at, power is accommodated from the self system 10 in which the power storage amount of the power storage device 4 is relatively large to the self system 10 in which the power storage amount of the power storage device 4 is relatively small.

  For example, as shown in FIG. 1, with respect to two self-systems 10A and 10B that are electrically connected through one linked inverter device 9 and are adjacent to each other, the one linked inverter device 9 Based on the target frequency determined according to the amount of power stored in the power storage device 4, the self system 10 in which the power storage amount of the power storage device 4 is relatively large changes to the self system 10 in which the power storage amount of the power storage device 4 is relatively small. And power interchange. Specifically, the linked inverter device 9 acquires information on the frequency fA of the AC line 1 of the own system 10A and information on the frequency fB of the AC line 1 of the own system 10B, compares the values, Electric power is accommodated from the self-system 10 in which the power storage amount of the power storage device 4 is relatively large, which is found by frequency comparison, to the self system 10 in which the power storage amount of the power storage device 4 is relatively small. Here, the information regarding the frequency of the AC line 1 acquired by the connected inverter device 9 is a value obtained by detecting the frequency (= target frequency) of the actual power in the AC line 1 of each of the own systems 10A and 10B. Alternatively, it may be a target frequency value transmitted from the self-supporting inverter device 5 that determines the target frequency.

Next, how the target frequency is determined in the power quality control described above will be described.
In the present embodiment, the self-supporting inverter device 5 performs control so that the frequency of power on the AC line 1 becomes a target frequency that is determined so as to increase as the amount of power stored in the power storage device 4 increases. As an example of this relational expression, a frequency fluctuation value determined by a function of the amount of power stored in the power storage device 4 (for example, a relationship in which the frequency fluctuation value increases as the power storage amount increases) is set to the reference frequency (for example, 60 Hz) of the AC line 1 In some cases, the target frequency is a value obtained by addition. In this case, the relationship between the target frequency: f, the reference frequency: f0, and the frequency fluctuation value: Δf can be expressed by the following (Formula 1). Further, the frequency variation: Δf can be expressed by the following (Equation 2) using the state of charge: [SOC] and constants A and B.

f = f0 + Δf (Equation 1)
Δf = A × [SOC] + B (Formula 2)

  The independent inverter device 5 stores the above relational expression in advance in an internal memory or the like so that the target frequency of the AC line 1 increases as the amount of power stored in the power storage apparatus 4 increases, and performs control according to the relational expression. Thus, the actual frequency of the AC line 1 (that is, the target frequency) reflects the amount of power stored in the power storage device 4 connected to the AC line 1 via the self-standing inverter device 5.

Next, the 1st charge control which charges the electrical storage apparatus 4 is demonstrated.
FIG. 2 is a diagram illustrating a schematic structure of the power storage device 4. As illustrated, the power storage device 4 is configured by connecting a plurality of cells 4a in series and in parallel. Note that the structure of the power storage device 4 shown in FIG. 2 is described for illustrative purposes, and can be changed as appropriate. For example, the number of series connections and the number of parallel connections of the cells 4a can be changed as appropriate. In addition, the power storage device 4 of the present embodiment includes a cell management unit 4b that detects the voltage and temperature of each cell 4a, a current sensor 4c that measures current flowing through all cells, a current sensor 4c, and a cell management unit 4b. And a control unit 4d for determining the state of the power storage device 4 based on the information (for example, the above-described power storage amount: SOC).

The cell management unit 4b has a function as voltage measuring means 4bv for measuring the voltage of each cell 4a and a function as temperature measuring means 4bt for detecting the temperature of each cell 4a.
Further, the control unit 4d can obtain information about the current measured by the current sensor 4c and information about the voltage measured by the voltage measuring unit 4bv (cell management unit 4b), and as a result, the power storage device An internal resistance of 4 can be derived. When power storage device 4 is deteriorated (the degree of progress of deterioration is large), its internal resistance increases. That is, the control unit 4d can know the degree of deterioration of the power storage device 4 based on the information about the internal resistance of the power storage device 4 derived as described above.

  Information on the voltage and temperature of each cell 4a obtained by the cell management unit 4b and information on the current measured by the current sensor 4c are transmitted to the control unit 4d. Further, it is transmitted from the power storage device 4 to the control device C as necessary. Information about the internal resistance of the power storage device 4 (information about the degree of deterioration of the power storage device 4) is also transmitted from the power storage device 4 to the control device C as necessary.

  FIG. 1 also shows the execution state of the first charging control performed in the power supply system. Specifically, FIG. 1 shows a state in which the first charging control is performed in the own system 10B. In the first charging control, when the control device C determines that the charging start condition for one power storage device 4 included in one self system 10B is satisfied, the control device C performs the following operation on one power storage device 4 included in the self system 10B. For the linked inverter device 9 connected using the first interconnection line 3a, the target charging power Pa to one power storage device 4 included in the own system 10B is transmitted from the second interconnection line 3b to the first mutual connection device 3B. The power is supplied to the connection line 3a to charge the one power storage device 4. In the present embodiment, for the electric power Pa and Pb shown in FIG. 1, the direction indicated by the arrow in the drawing is the positive direction.

In addition, while the first charging control for the power storage device 4 included in the self system 10 is performed, the power quality control described above is always performed in the one self system 10. And in this embodiment, the self-supporting inverter apparatus 5 changes the electrical storage apparatus 4 used for electric power quality control between when the first charging control is performed and when it is not performed.
Hereinafter, with reference to FIG. 1, power quality control in the own system 10B in which the first charging control is performed and power quality control in the own system 10C in which the first charging control is not performed will be described. .

  In the example illustrated in FIG. 1, in one self system 10 </ b> B, the first charge control for charging one power storage device 4 included in the self system 10 </ b> B is performed. At this time, as power quality control, the control device C is connected to one self-supporting inverter device 5 of one self-system 10 </ b> B by connecting the one self-supporting inverter device 5 using the crossover 11. Using the other power storage device 4 included in the own system 10A, the voltage of power in one AC line 1 of one own system 10B is set as a target voltage, and the one AC line 1 of the one self system 10B Control is performed such that the frequency of power is set to a target frequency determined according to the amount of power stored in one power storage device 4 of the one self-system 10B. Information on the amount of power stored in the power storage device 4 may be transmitted from the power storage device 4 to the self-supporting inverter device 5, or may be transmitted from the power storage device 4 to the control device C and further from the control device C to the self-supporting inverter device. 5 may be configured to be transmitted. Here, the self-standing inverter device 5 performs power quality control using the specific power storage device 4. For example, when power is supplied from the self-supporting inverter device 5 to the AC line 1, the supplied power is the specific power storage device 4. It means that the power is supplied from.

  On the other hand, in the example illustrated in FIG. 1, in one self system 10 </ b> C, the first charge control for charging one power storage device 4 included in the self system 10 </ b> C is not performed. At this time, as power quality control, the control device C uses one power storage device 4 included in one self system 10C for one self-standing inverter device 5 included in one self system 10C. One power storage device 4 having one self-system 10C having the voltage of power on one AC line 1 of the one self-system 10C as a target voltage and the voltage of power on one AC line 1 of the one self-system 10C. The control is performed so that the target frequency is determined according to the amount of electricity stored.

  By performing such control, each self system 10 can charge the power storage device 4 in parallel while performing power quality control. In addition, the control apparatus C is the electric current Pb supplied to the alternating current line 1 from the independent inverter apparatus 5 for electric power quality control, for example, the electric current value which flows into the alternating current line 1 from the independent inverter apparatus 5, and the alternating current line 1 It is possible to know by deriving the product of the voltage values.

In addition, the electric power Pb becomes negative electric power, that is, the electric power may go from the AC line 1 side to the power storage device 4 side via the self-supporting inverter device 5.
For example, in one self-system 10, the power supplied from the power generator 7 to the AC line 1 is greater than the power received by the power consuming device 6 from the AC line 1 (that is, the AC line 1 has excessive power generation). ), As described above, the control device C operates the independent inverter device 5 so as to draw power from the AC line 1 to the independent inverter device 5 (that is, from the AC line 1 to the independent inverter device). Power quality control is performed such that the power storage device 4 side is charged via 5). That is, the power Pb is negative power that goes in the direction opposite to the direction indicated by the arrow in FIG.

The charge start condition described above is a condition related to time, a condition related to the amount of power stored in the power storage device 4, or both of them.
Specifically, in the former case, the control device C determines that the charging start condition is satisfied when the set time is reached. In this manner, by adopting the time-related condition as the charge start condition, it is possible to determine that the charge start condition is periodically satisfied at the set time, and to charge the power storage device 4 by the first charge control. For example, if the set time is set before the time period in which the power demand increases during the day, it is determined that the charging start condition is satisfied prior to the time period in which the power demand increases, and the power storage device 4 is charged. As a result, the power supply capacity for the power consumer D can be increased prior to the time period when the power demand increases.
In the latter case, the control device C determines that the charging start condition is satisfied when the amount of power stored in the power storage device 4 is less than the lower limit power storage amount. The level of the lower limit storage amount can be set as appropriate. As described above, by adopting the condition related to the storage amount of the power storage device 4 as the charging start condition, the timing when the storage amount of the power storage device 4 becomes less than the lower limit storage amount, that is, the power from the power storage device 4 to the power consumer D It is determined that the charging start condition is satisfied at the timing when the supply surplus capacity decreases, and the power storage device 4 can be charged by the first charging control.

Next, the target charging power Pa to the power storage device 4 will be described.
FIG. 3 is a graph showing an example of the target charging power Pa. In the present embodiment, when the total voltage by the plurality of cells 4a constituting the power storage device 4 is less than the reference voltage, the control device C calculates the target charging power Pa to the power storage device 4 between the total voltage and a constant reference current. Constant current charging derived by product is performed, and when the total voltage is equal to or higher than the reference voltage, target charging power Pa to the power storage device 4 is performed by constant voltage charging derived by the product of the reference voltage and the target charging current. The current is determined by a current curve in which a constant reference current is set as an initial value and the current is decreased over time. The current curve is based on at least one of the temperature and the degree of deterioration of the cell 4a constituting the power storage device 4. To decide. The target charging power a (current and voltage) derived in this way is transmitted from the control device C to the connected inverter device 9.

  In this way, in a state where the total voltage by the plurality of cells 4a is less than the reference voltage, that is, in a state where the total amount of electricity stored by the plurality of cells 4a is relatively small, it is assumed that a relatively large constant reference current flows. Charging can be performed rapidly by performing current charging. On the other hand, in a state in which the total voltage by the plurality of cells 4a is equal to or higher than the reference voltage, that is, in a state in which the total amount of electricity stored by the plurality of cells 4a is relatively large, Overcharge can be suppressed by performing constant voltage charging to reduce the power consumption.

  In the present embodiment, the control device C stores four types of current curves (pattern A to pattern D) in storage means (not shown) such as an internal memory. Then, control device C determines a current curve used for determining the target charging current among the four types of current curves based on at least one of the temperature and the degree of deterioration of cell 4a constituting power storage device 4. That is, in the present embodiment, the current curve is determined according to at least one of the actual degree of deterioration of the cell 4a and the temperature of the cell 4a related to the ease of progress of the deterioration of the cell 4a. Setting that suppresses deterioration of the cell 4a during charging is possible. In any current curve (Pattern A to Pattern D), from the start of charging until time ta (that is, while the total voltage of the plurality of cells 4a constituting the power storage device 4 is less than the reference voltage Vr). The constant reference current Ir becomes the charging current. Then, by continuing such charging, the total voltage gradually increases. The reference current Ir and the reference voltage Vr are the same regardless of the current curve (pattern A to pattern D). From the start of charging to the time ta, the target charging power Pa is derived by the product of the total voltage V1 and the reference current Ir (= I1).

  Specifically, as illustrated in Table 1 below, when the control device C selects a current curve based only on the temperature of the cell 4a, the temperature measured by the temperature measuring unit 4bt is relatively low ( When the deterioration of the cell 4a is relatively difficult to proceed), the current curve of the pattern A is selected. When the temperature is relatively high (when the deterioration of the cell 4a is relatively easy to proceed), the pattern C Select the current curve. As can be seen from the current curve of pattern A shown in FIG. 3 (a) and the current curve of pattern C shown in FIG. 3 (c), the current curve of pattern C is more time ta than the current curve of pattern A. Thereafter, the reduction rate of the target charging current with the passage of time is set to be large. That is, after the time ta, the target charging power is derived by the product of the reference voltage Vr (V2)) and the target charging current I2, and therefore the pattern C is charged with time as compared with the pattern A. The power reduction rate is set to be large. As described above, the power supply system includes the temperature measurement unit 4bt that measures the temperature of the power storage device 4, and the control device C selects the temperature among the plurality of current curves prepared in advance according to the temperature of the power storage device 4. A current curve corresponding to the temperature of power storage device 4 measured by measuring means 4bt is selected.

  Further, when the control device C selects a current curve based only on the degree of deterioration of the cell 4a (for example, the above-mentioned “internal resistance”), the degree of deterioration of the cell 4a is relatively low (the internal resistance is relatively low). If low, the pattern A current curve is selected, and if the degree of deterioration is relatively high, the pattern B current curve is selected. As described above, the power supply system includes the control unit 4d as a deterioration measurement unit that measures the degree of deterioration of the power storage device 4, and the control device C includes a plurality of preparations prepared in advance according to the degree of deterioration of the power storage device 4. Among the current curves, a current curve corresponding to the degree of deterioration of the power storage device 4 measured by the control unit 4d as the deterioration measuring means is selected.

  Alternatively, when the control device C selects a current curve based on the combination of the temperature and the degree of deterioration of the cell 4a, the current of the pattern A when the temperature of the cell 4a is relatively low and the degree of deterioration is relatively low. A curve is selected, and when the temperature of the cell 4a is relatively low and the degree of deterioration is relatively high, the current curve of the pattern B is selected, and the temperature of the cell 4a is relatively high and the degree of deterioration is relatively When the temperature is low, the current curve of the pattern C is selected, and when the temperature of the cell 4a is relatively high and the degree of deterioration is relatively high, the current curve of the pattern D is selected. As described above, the power supply system includes the temperature measurement unit 4bt that measures the temperature of the power storage device 4 and the control unit 4d that serves as a deterioration measurement unit that measures the degree of deterioration of the power storage device 4. Of a plurality of current curves prepared in advance according to the combination of the temperature and the degree of deterioration of the device 4, the temperature and the deterioration measuring means (control unit 4d) of the power storage device 4 measured by the temperature measuring means 4bt are measured. A current curve corresponding to a combination of deterioration degrees of the power storage device 4 is selected.

  As described above, the control device C determines the target charging power Pa that makes it difficult for the cell 4a to progress based on at least one of the temperature and the degree of deterioration of the cell 4a constituting the power storage device 4. Thus, it is possible to charge the power storage device 4 with the target charging power Pa while performing power quality control.

Second Embodiment
The power supply system of the second embodiment differs from the first embodiment in the method for determining the target charging power Pa. The power supply system according to the second embodiment will be described below, but the description of the same configuration as that of the first embodiment will be omitted.

  The power supply system of the present embodiment is the same as the configuration shown in FIG. 1, but the contents of the first charge control performed by the control device C (a method for determining the target charge power Pa) are different from those of the first embodiment. Yes. Specifically, in the present embodiment, the control device C stores the cell voltages of the plurality of cells 4a constituting the power storage device 4 (that is, the individual voltages of the cells 4a) in storage means (not shown) such as an internal memory. The relational expression between the highest cell voltage and the target charging current is stored. Then, the control device C determines a target charging current corresponding to the current highest cell voltage based on the relational expression, and multiplies the target charging current by the total voltage of the plurality of cells 4a constituting the power storage device 4. Is derived as the target charging power Pa to the power storage device 4. In the present embodiment, information on the voltage of each cell 4a obtained by the cell management unit 4b is transmitted to the control unit 4d, and further transmitted from the power storage device 4 to the control device C. The target charging power a (current and voltage) derived in this way is transmitted from the control device C to the connected inverter device 9.

  FIG. 4 is a graph illustrating an example of a relational expression between the highest cell voltage and the target charging current among the cell voltages of the plurality of cells 4 a constituting the power storage device 4. As shown in the figure, in this relational expression, a relationship is set such that the target charging current decreases as the maximum cell voltage increases. As described above, when the product of the target charging current and the total voltage of the plurality of cells 4a is used as the target charging power, the target charging current is set so that the target charging current decreases as the maximum cell voltage increases. It is determined according to the relational expression. That is, among the plurality of cells 4a, the cell with the highest cell voltage (the cell with the highest cell voltage) 4a is the cell with the largest amount of stored electricity, and is therefore intended to suppress overcharging of the cell. On the other hand, all the cells are charged. In other words, the fact that the target charging power Pa to the power storage device 4 is derived from the product of the target charging current determined based on the above relational expression and the total voltage of the plurality of cells 4a constitutes the power storage device 4. This means that the other cells 4a are also charged in accordance with the charging current to the cell 4a having the highest cell voltage (that is, the cell 4a having the largest amount of stored electricity) among the plurality of cells 4a.

<Third Embodiment>
The power supply system of the third embodiment is different from the above embodiment in the method for determining the target charging power Pa. Hereinafter, the power supply system of the third embodiment will be described, but the description of the same configuration as that of the above embodiment will be omitted.

FIG. 5 is a diagram illustrating a schematic structure of the power storage device 4.
As illustrated, in the present embodiment, the power storage device 4 includes a plurality of cell units 4u. The cell unit 4u is connected in parallel with the cell main body 4e and the bypass circuit 4f that adjusts the amount of current that flows by bypassing the cell main body 4e out of the current flowing through the cell unit 4u. Have In addition, the structure of the electrical storage apparatus 4 shown in FIG. 5 was described for the purpose of illustration, and can be changed suitably. For example, the number of series connections and the number of parallel connections of the cell units 4u can be changed as appropriate.

  Also in the present embodiment, the power storage device 4 includes the cell management unit 4b that detects the voltage and temperature of each cell body 4e, the current sensor 4c that measures the current flowing through all the cells, the current sensor 4c, and the cell management unit 4b. And a control unit 4d that determines the state of the power storage device 4 (for example, the above-described power storage amount: SOC) based on the information from. The operation of the bypass circuit unit 4f is controlled by, for example, the control unit 4d and the cell management unit 4b that have received a command from the control device C. When charging the power storage device 4, the control device C derives the product of the total voltage of the plurality of cell units 4 u constituting the power storage device 4 and the total current flowing through the power storage device 4 as the target charging power Pa. To do.

  The total current passed through the power storage device 4 is a current measured by the current sensor 4c, but the control device C determines the total current passed through the power storage device 4 as follows, and then the connected inverter device 9 Let me control.

FIG. 6 is a graph showing an example of a relational expression between the voltage (cell voltage) of the cell body 4e and the temporary charging current. Since the voltage of the cell body 4e corresponds to the amount of electricity stored in the cell body 4e, it can be said that this relational expression is the relation between the amount of electricity stored in the cell body 4e and the temporary charging current. In this relational expression, when the cell voltage (storage amount) of the cell main body 4e is less than the reference voltage Vs (reference storage amount), a constant reference current Is as a temporary charging current is determined, and the cell main body 4e When the cell voltage (storage amount) is equal to or higher than the reference voltage Vs (reference storage amount), a provisional charging current that decreases as the cell voltage (storage amount) of the cell body 4e increases is determined. As described above, the cell main body 4e in the state where the cell voltage (power storage amount) of the cell main body 4e is less than the reference voltage Vs (reference power storage amount), that is, the power storage amount is relatively small, A large constant reference current is determined as the temporary charging current, and rapid charging with the relatively large charging current is expected. On the other hand, in the state where the cell voltage (storage amount) of the cell body 4e is equal to or higher than the reference voltage Vs (reference storage amount), that is, the cell body 4e in which the storage amount is relatively large, With the reference current as an initial value, a temporary charging current that decreases as the cell voltage (charged amount) of the cell body 4e increases, and charging while suppressing overcharging by the charging current according to the charged amount Is expected to be implemented.
The relational expression shown in FIG. 6 is shown for illustrative purposes, and the shape of the graph does not accurately reflect the relationship between the charged amount (cell voltage) and the temporary charging current.

  The control device C acquires information about the storage amount (cell voltage) for each cell unit 4u (cell main body portion 4e) from the storage device 4. Then, according to the relational expression illustrated in FIG. 6, the control device C determines a temporary charging current corresponding to the amount of storage (cell voltage) of the cell body 4 e for each of the plurality of cell units 4 u included in the power storage device 4. .

  Next, the control device C compares the first temporary target charging current and the second temporary target charging current. The first temporary target charging current is a value derived by adding the upper limit bypass current, which is the upper limit value of the bypass current, to the smallest temporary charging current among the temporary charging currents for each of the plurality of cell units 4u. The second temporary target charging current is the largest temporary charging current among the temporary charging currents for each of the plurality of cell units 4u. And the control apparatus C determines the temporary target charging current of the smaller one of both as the target charging current which flows through every several cell unit 4u. Then, the control device C supplies the target charging current for each of the plurality of cell units 4u, and each of the plurality of cell units 4u includes the cell main body 4e out of the target charging current supplied to the cell unit 4u. Control is performed so that a current exceeding the provisional charging current determined according to the amount of stored current flows through the bypass circuit portion 4f and the other current flows through the cell main body portion 4e. In the present embodiment, the total current, which is the sum of the target charging currents that flow through each of the plurality of cell units 4u constituting the power storage device 4, is the target charging current [number of parallel connections of the cell units 4u] times. Then, the control device C transmits the total voltage of the plurality of cell units 4u constituting the power storage device 4 and the total current flowing through the power storage device 4 to the connected inverter device 9, and the target charging power Pa, which is the product thereof. Is supplied from the connected inverter device 9 to the power storage device 4.

  Next, with reference to FIGS. 7 and 8, a specific example of a method for determining the target charging current It flowing to each cell unit 4u will be described. FIG. 7 is a diagram schematically illustrating a target charging current that flows to the cell unit 4u, a current that flows to the cell body 4e, and a current that flows to the bypass circuit 4f. In FIG. 7, the charged amount of the cell main body 4 e is shown in dark color, and the level of the reference charged amount is indicated by a broken line. FIG. 8 is a diagram for explaining a method for determining the target charging current It to be passed through the cell unit 4u. 7 and 8 show a circuit in which three cell units 4u are connected in parallel for the purpose of illustration. Also, the three cell units 4u are given X, Y, and Z symbols in order from the left side in the drawing, and in the following description, the x, y, and z symbols are also assigned to correspond to each cell unit 4u. Use. In this example, the reference current Is is 5 A, and the upper limit bypass current is 2 A.

  In the example shown in FIG. 7A, in all the cell units 4u (X, Y, Z), the charged amount of the cell body 4e is less than the reference charged amount. Therefore, as shown in FIG. 8A, the cell voltages Vx, Vy, Vz corresponding to the charged amount of each cell body 4e are also less than the reference voltage Vs corresponding to the reference charged amount. As a result, the control device C determines the temporary charging current Ipx corresponding to the storage amount (cell voltage Vx) of the cell body 4e (X) as the reference current Is, and stores the storage amount (cell of the cell body 4e (Y) (cell The temporary charging current Ipy corresponding to the voltage Vy) is determined as the reference current Is, and the temporary charging current Ipz corresponding to the charged amount (cell voltage Vz) of the cell body 4e (Z) is determined as the constant reference current Is. .

  Next, the control device C uses the smallest temporary charging current (5A) among the temporary charging currents Ipx, Ipy, Ipz of the three cell units 4u (X, Y, Z) as the first temporary target charging current. Is set to a value (7A) derived by adding the upper limit bypass current (2A). Further, the control device C uses the largest temporary charging current (5A) among the temporary charging currents Ipx, Ipy, Ipz of the three cell units 4u (X, Y, Z) as the second temporary target charging current. Set. Then, the control device C supplies the smaller temporary target charging current (5A) of the first temporary target charging current (7A) and the second temporary target charging current (5A) to the three cell units 4u ( X, Y, Z) is determined as a target charging current It to be passed. In this case, three times the target charging current It (5A) (the number of cell units 4u connected in parallel) is the total current (15A) that flows through the power storage device 4. FIG. 7A shows a state where a total current of 15 A is supplied to the power storage device 4 and a target charging current It of 5 A is supplied to each cell unit 4 u. Further, in each cell unit 4u, since the determined target charging current It (5A) is equal to the original temporary charging current (5A), it is not necessary to pass the bypass current to the bypass circuit unit 4f, and the target charging current It ( 5A) flows into the cell body 4e.

  FIGS. 7B and 8B show a state after the amount of power stored in each cell unit 4u has increased. In this case, the charged amount of the cell unit 4u (X) exceeds the reference charged amount, and as shown in FIG. 8B, the temporary charging current Ipx of the cell unit 4u (X) = 1A. On the other hand, the storage amount of the cell unit 4u (Y, Z) is less than the reference storage amount, and as shown in FIG. 8B, the temporary charging currents Ipy, Ipz of the cell unit 4u (Y, Z) = 5A. In this case, the first temporary target charging current is 3A (= 1A + 2A), and the second temporary target charging current is 5A. Then, the smaller 3A is determined as the target charging current It flowing through each cell unit 4u (X, Y, Z). In this case, the target charging current It (3A) is three times (the number of parallel connections of the cell units 4u). ) Is the total current (9 A) that flows through the power storage device 4. FIG. 7B shows a state in which a total current of 9 A is supplied to the power storage device 4 and a target charging current It of 3 A is supplied to each cell unit 4 u. In the cell unit 4u (Y, Z), since the determined target charging current It (3A) is smaller than the original temporary charging current (5A), it is not necessary to pass the bypass current to the bypass circuit unit 4f, and the target charging A current It (3A) is passed through the cell body 4e. On the other hand, in the cell unit 4u (X), since the determined target charging current It (3A) exceeds the original temporary charging current (1A), the cell of the target charging current It (3A) A current (2A) that exceeds the temporary charging current (1A) determined according to the amount of power stored in the main body 4e is passed through the bypass circuit 4f, and another current (1A) is passed through the cell main body 4e. It is.

  FIGS. 7C and 8C show a state after the amount of power stored in each cell unit 4u has increased. In this case, the storage amount of the cell unit 4u (X, Z) exceeds the reference storage amount and is in a fully charged state, and as shown in FIG. 8C, the cell unit 4u (X, Z) ) Provisional charging current Ipx, Ipz = 0A. On the other hand, the storage amount of the cell unit 4u (Y) is less than the reference storage amount, and as shown in FIG. 8C, the temporary charging current Ipy of the cell unit 4u (Y) is 5A. In this case, the first temporary target charging current is 2A (= 0A + 2A), and the second temporary target charging current is 5A. Then, the smaller 2A is determined as the target charging current It flowing through each cell unit 4u (X, Y, Z). In this case, the target charging current It (2A) is three times (the number of cell units 4u connected in parallel). ) Is the total current (6 A) flowing through the power storage device 4. FIG. 7C shows a state in which a total current of 6A is supplied to the power storage device 4 and a target charging current It of 2A is supplied to each cell unit 4u. In the cell unit 4u (Y), the determined target charging current It (2A) is smaller than the original temporary charging current (5A), so there is no need to pass the bypass current through the bypass circuit unit 4f, and the target charging current It (2A) flows into the cell body 4e. On the other hand, in the cell unit 4u (X, Z), since the determined target charging current It (2A) exceeds the original temporary charging current (0A), the target charging current It (2A) The current (2A) exceeding the temporary charging current (0A) determined according to the amount of electricity stored in the cell main body 4e is passed through the bypass circuit 4f, and no current is passed through the cell main body 4e.

  As described above, in the present embodiment, the cell unit 4u is connected in parallel with the cell body 4e, and the amount of bypass current that flows by bypassing the cell body 4e out of the current flowing through the cell unit 4u is determined. A bypass circuit unit 4f for adjustment is provided. Therefore, at least an upper limit bypass current can be passed through each cell unit 4u regardless of the amount of electricity stored in the cell main body 4e. That is, since at least a part of the target charging current flowing through the cell unit 4u can be passed through the bypass circuit unit 4f, even if the target charging currents flowing through the plurality of cell units 4u are the same, Thus, the charging current passed through the cell body 4e can be varied. For example, even if there is a cell unit 4u that is fully charged, it is only necessary to pass a current through the bypass circuit unit 4f. Therefore, it is possible to perform balance charging in which a charging current is continuously supplied to the cell unit 4u that is not fully charged. Furthermore, since the target charging current supplied to each cell unit 4u is the sum of the provisional charging current and the upper limit bypass current for itself, the current exceeding the upper limit bypass current should not be passed through the bypass circuit unit 4f. In addition, it is possible to prevent a current exceeding the temporary charging current for the cell body portion 4e from flowing.

<Fourth embodiment>
The power supply system of the fourth embodiment is different from the above-described embodiment in that the self-system includes a charging inverter device that connects the external power system. The power supply system according to the fourth embodiment will be described below, but the description of the same configuration as that of the above embodiment will be omitted.

  FIG. 9 is a diagram illustrating a configuration of a power supply system according to the fourth embodiment. As shown in the figure, the power supply system of the present embodiment connects the power storage device 4 of one self-system 10B of the plurality of self-systems 10 and an external power system 20 using an external connection line 22. The charging inverter device 21 is provided. The power system 20 is, for example, a system that is used for power supply by a power company that conducts power supply business. Further, as will be described later, the control device C causes the self-standing inverter device 5 to perform power quality control, causes the linked inverter device 9 to perform power interchange control, and causes the charging inverter device 21 to perform power interchange control. On the other hand, the second charging control is performed. The external connection line 22 includes a first external connection line 22a for connecting the charging inverter device 21 and the power system 20, and a second external connection line 22b for connecting the charging inverter device 21 and the power storage device 4. It consists of. Also in this embodiment, another power storage device 4 included in another self system 10 is connected to the self-supporting inverter device 5 included in each self system 10 via a crossover 11.

  Also in the present embodiment, the control device C performs power quality control on the AC line 1 of the one self-system 10 with respect to the self-supporting inverter device 5 of the one self-system 10 as power quality control. The control is performed such that the voltage of the power is a target voltage, and the frequency of the power on the one AC line 1 is set to a target frequency determined according to the amount of power stored in the power storage device 4 included in the one self-system 10, and As power interchange control, when power is interchanged between one self system 10 and another self system 10 using the interconnect line 3, the first interconnect line 3a and the second interconnect line constituting the interconnect line 3 are used. Based on the target frequency on the AC line 1 in each of one self system 10 and another self system 10 with respect to the connected inverter device 9 provided between the interconnect lines 3b. From its own system 10 storage amount is relatively large of power storage device 4, the power storage quantity of the power storage device 4 and to interchange power to a relatively small self-system 10.

Next, the second charging control will be described.
FIG. 9 also shows the execution state of the second charging control performed in the power supply system. Specifically, FIG. 9 shows a state in which the second charging control is performed in the own system 10C. In the second charging control, when the control device C determines that the charging start condition for one power storage device 4 included in one self system 10C is satisfied, the control device C supplies the second power storage device 4 included in the self system 10C to the second power storage device 4. For the charging inverter device 21 connected using the interconnection line 22b, the target charging power Pa to one power storage device 4 of the self system 10C is supplied from the second interconnection line 3b to the first interconnection. The power is supplied to the line 3a to charge the one power storage device 4. Also in this embodiment, the direction indicated by the arrow in FIG. 9 is the positive direction for each of the electric power Pa and Pb. And the electric power Pb may become negative electric power similarly to having demonstrated in the said 1st Embodiment.

In addition, while the second charging control is being performed on the power storage device 4 included in the self system 10, the power quality control described above is always performed in the one self system 10. And in this embodiment, the self-supporting inverter apparatus 5 changes the electrical storage apparatus 4 used for electric power quality control between when the 2nd charge control is performed and when it is not performed.
Below, with reference to FIG. 9, the power quality control in the own system 10C in which the second charging control is performed and the power quality control in the own system 10B in which the second charging control is not performed will be described. .

  In the example illustrated in FIG. 9, in one self system 10 </ b> C, the second charge control for charging one power storage device 4 included in the self system 10 </ b> C is performed. At this time, as the power quality control, the control device C is connected to one independent inverter device 5 included in one self system 10 </ b> C by connecting the one independent inverter device 5 using the crossover 11. Using the other power storage device 4 included in the own system 10B, the voltage of the power in one AC line 1 of one self system 10C is set as a target voltage, and the power in one AC line 1 of the own system 10C Is controlled to be a target frequency determined according to the amount of power stored in one power storage device 4 of the self system 10C.

  On the other hand, in the example illustrated in FIG. 9, the second charging control for charging one power storage device 4 included in the self system 10 </ b> B is not performed in one self system 10 </ b> B. At this time, as power quality control, the control device C uses one power storage device 4 included in one self system 10B for one self-inverted inverter device 5 included in one self system 10B. The voltage of power on one AC line 1 of 10B is set as a target voltage, and the frequency of power on AC line 1 of self system 10B is determined according to the amount of power stored in one power storage device 4 of the self system 10B. Control to be performed at the target frequency. This control is the same when the second charge control is not performed in the own system 10C.

  By performing such control, each self system 10 can charge the power storage device 4 in parallel while performing power quality control. In addition, the control apparatus C is the electric current Pb supplied to the alternating current line 1 from the independent inverter apparatus 5 for electric power quality control, for example, the electric current value which flows into the alternating current line 1 from the independent inverter apparatus 5, and the alternating current line 1 It is possible to know by deriving the product of the voltage values.

In the second charge control of the present embodiment, the method for determining the target charge power Pa is the same as the method for determining the target charge power Pa described in the first to third embodiments.
That is, according to the method for determining the target charging power Pa described in the first embodiment, the control device C is such that the total voltage by the plurality of cells 4a (or the cell body 4e) constituting the power storage device 4 is less than the reference voltage. Then, constant current charging for deriving the target charging power Pa to the power storage device 4 by the product of the total voltage and a constant reference current is performed. Constant voltage charging is performed by deriving the power Pa by the product of the reference voltage and the target charging current, and the target charging current is determined by a current curve with a constant reference current as an initial value and decreasing with time. The curve is determined based on at least one of the deterioration degree and the temperature of the cell 4a (or the cell main body 4e) constituting the power storage device 4.

  Alternatively, according to the method for determining the target charging power Pa described in the second embodiment, the control device C is the highest cell among the cell voltages of the plurality of cells 4a (or the cell main body 4e) constituting the power storage device 4. Based on the relational expression between the voltage and the target charging current, a target charging current corresponding to the current highest cell voltage is determined, and the plurality of cells 4a (or cell main body portions 4e) constituting the target charging current and the power storage device 4 are determined. Is derived as a target charging power Pa to the power storage device 4, and in the above relational expression, a relationship is set such that the target charging current decreases as the maximum cell voltage increases.

  Alternatively, according to the method for determining the target charging power Pa described in the third embodiment, when the control device C charges the power storage device 4 with the target charging power, the amount of power stored in the cell body 4e is the reference. When the charged amount is less than the charged amount, a constant reference current as a temporary charging current is determined, and when the charged amount of the cell main body 4e is equal to or greater than the reference charged amount, the temporary charged current decreases as the charged amount of the cell main body 4e increases. Using the relational expression in which the charging current is determined, a temporary charging current is determined for each of the plurality of cell units 4u according to the amount of power stored in the cell body 4e, and the temporary charging current for each of the plurality of cell units 4u is determined. The first temporary target charging current derived by adding the upper limit bypass current that is the upper limit value of the bypass current to the smallest temporary charging current, and the largest temporary charging among the temporary charging currents for each of the plurality of cell units 4u. Current Compared with the second temporary target charging current, the smaller temporary target charging current of the two is determined as a target charging current that flows for each of the plurality of cell units 4u, and the target charging current is determined for each of the plurality of cell units 4u. In each of the plurality of cell units 4u, the target charging current supplied to the cell unit 4u bypasses the current that exceeds the temporary charging current determined according to the amount of electricity stored in the cell body 4e. The total current that is the sum of the target charging currents that are supplied to each of the plurality of cell units 4 u that constitute the power storage device 4 and the plurality of currents that constitute the power storage device 4. The product of the total voltage by the cell unit 4u is set as the target charging power.

<Another embodiment>
In the said embodiment, the number of the self systems with which an electric power supply system is provided can be changed suitably. For example, the number of self systems can be set as appropriate, such as 2, tens, hundreds, etc., and can be freely added / deleted.

  In the above embodiment, the relational expression (Formula 2) for deriving the frequency variation value: “Δf = A × [SOC] + B” is described for the purpose of illustration, and can be changed as appropriate. Moreover, in the said embodiment, the relationship where the frequency of the electric power in the alternating current line 1 becomes high as the electrical storage amount of the electrical storage apparatus 4 becomes large (that is, when the coefficient A takes a positive value in Formula 2) in the said embodiment. ), The self-sustained inverter device 5 decreases the frequency of power on the AC line 1 as the power storage amount of the power storage device 4 increases. Control may be performed so that the target frequency is determined by the following relationship (that is, when the coefficient A takes a negative value in Equation 2).

In the said embodiment, the timing of the charge stop in 1st charge control and 2nd charge control can be set suitably.
For example, the control device C performs control such that charging by the first charge control or the second charge control is stopped when the total voltage by the plurality of cells 4a constituting the power storage device 4 reaches the upper limit total voltage. Can do. Alternatively, the control device C is charged by the first charge control or the second charge control when the highest cell voltage among the individual cell voltages of the plurality of cells 4a constituting the power storage device 4 becomes the upper limit individual cell voltage. It is possible to perform control to stop the operation.
Alternatively, the control device C indicates that all the cell voltages of the cells 4a (or the cell main body portion 4e) constituting the power storage device 4 indicate that the cell 4a (or the cell main body portion 4e) has a fully charged amount. When it becomes, control which stops the charge by 1st charge control or 2nd charge control can be performed.

  In the above embodiment, the relational expression between the maximum cell voltage and the target charging current shown in FIG. 4 can be changed as appropriate. For example, FIG. 4 shows an example in which the maximum cell voltage and the target charging current are set in a non-linear relationship, but both may be set in a linear relationship. Similarly, the relational expression between the cell voltage and the temporary charging current shown in FIG. 6 can be changed as appropriate.

  INDUSTRIAL APPLICABILITY The present invention can be used for a power supply system that can charge a power storage device while performing power quality control that maintains the power quality of an AC line using the power storage device.

1: AC line 2: Self-connection line 3: Interconnection line 4: Power storage device 4a: Cell 4b: Cell management unit 4bt: Temperature measurement means 4bv: Voltage measurement means 4c: Current sensor 4d: Control unit 4e: Cell body 4f : Bypass circuit unit 4u: Cell unit 5: Independent inverter device 6: Power consuming device 7: Power generation device 9: Linked inverter device 10: Self system 10A: Self system 10B: Self system 10C: Self system 11: Crossover 20: Power System 21: Charging inverter device 22: External connection line 22a: First external connection line 22b: Second external connection line C: Controller D: Electric power consumer

Claims (7)

A plurality of self-systems including an AC line to which a plurality of power consumers are connected, a power storage device, and a self-standing inverter device that connects the power storage device and the AC line using a self-connection line,
The power storage device of one of the self systems and the AC line of the other self system are connected using an interconnection line so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device between the self systems,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
A control device is provided that performs power quality control on the independent inverter device, and performs power interchange control and first charge control on the linked inverter device,
To the self-supporting inverter device, the other power storage device of the other self-system is connected with a jumper,
The controller is
As the first charging control, when it is determined that a charging start condition for one power storage device included in one self-system is satisfied, the first power connection device is connected to the one power storage device using the first interconnection line. The connected inverter device is supplied with target charging power for the one power storage device from the second interconnect line to the first interconnect line to charge the one power storage device. Let
As the power quality control, when the first charge control for charging the one power storage device in the one self-system is not performed, the one self-inverter device included in the one self-system Then, using the one power storage device of the one self-system, the power voltage on the one AC line of the one self-system is set as a target voltage, and the frequency of the power on the one AC line is set. Is controlled to be a target frequency determined according to the amount of power stored in the one power storage device, and the first charge control is performed to charge the one power storage device in the one self-system. The one self-standing inverter device is connected to the one self-standing inverter device included in the one self-system using the crossover. The other power storage device included in the other self-system is used to set the voltage of power on the one AC line of the one self-system as a target voltage and the power of the power on the one AC line. Control the frequency to be a target frequency determined according to the amount of power stored in the one power storage device, and
As the power interchange control, when power is interchanged between the specific self-system connected to each other using the interconnect line and another self-system using the interconnect line, the interconnect line is used. For the connected inverter device provided between the first interconnection line and the second interconnection line that constitute the first interconnection line, the specific self system and the other self system in the alternating current line A power supply system configured to allow power to be accommodated from a self-system having a relatively large power storage amount of the power storage device to a self-system having a relatively small power storage amount of the power storage device based on a target frequency. A plurality of self-systems including an AC line to which a plurality of power consumers are connected, a power storage device, and a self-standing inverter device that connects the power storage device and the AC line using a self-connection line,
The power storage device of one of the self systems and the AC line of the other self system are connected using an interconnection line so that a plurality of the self systems are electrically connected in series. A power supply system comprising a connected inverter device between the self systems,
The interconnect line includes a first interconnect line for connecting the linked inverter device and the power storage device, and a second interconnect line for connecting the linked inverter device and the AC line. ,
An inverter device for charging that uses an external connection line to connect one power storage device of one of the plurality of self systems and an external power system; and
A control device for performing power quality control on the self-supporting inverter device, performing power interchange control on the linked inverter device, and performing second charge control on the charging inverter device; With
The external connection line includes a first external connection line for connecting the charging inverter device and the power system, and a second external connection line for connecting the charging inverter device and the one power storage device. And consists of
To the self-supporting inverter device, the other power storage device of the other self-system is connected with a jumper,
The controller is
When it is determined that the charging start condition for the one power storage device connected to the charging inverter device using the second external connection line is satisfied as the second charging control, the charging inverter device In contrast, the target charging power to the one power storage device is supplied from the first external connection line to the second external connection line to charge the one power storage device,
As the power quality control, when the second charging control for charging the one power storage device in the one self system is not performed, the one self-inverted inverter device included in the one self system Then, using the one power storage device of the one self-system, the power voltage on the one AC line of the one self-system is set as a target voltage, and the frequency of the power on the one AC line is set. Is controlled to be a target frequency determined according to the amount of power stored in the one power storage device, and the second charge control is performed to charge the one power storage device in the one self-system. The one self-standing inverter device is connected to the one self-standing inverter device included in the one self-system using the crossover. The other power storage device included in the other self-system is used to set the voltage of power on the one AC line of the one self-system as a target voltage and the power of the power on the one AC line. Control the frequency to be a target frequency determined according to the amount of power stored in the one power storage device, and
As the power interchange control, when power is interchanged between the specific self-system connected to each other using the interconnect line and another self-system using the interconnect line, the interconnect line is used. For the connected inverter device provided between the first interconnection line and the second interconnection line that constitute the first interconnection line, the specific self system and the other self system in the alternating current line A power supply system configured to allow power to be accommodated from a self-system having a relatively large power storage amount of the power storage device to a self-system having a relatively small power storage amount of the power storage device based on a target frequency. The controller is
When the total voltage by a plurality of cells constituting the power storage device is less than a reference voltage, the target charging power to the power storage device is subjected to constant current charging derived by a product of the total voltage and a constant reference current,
When the total voltage is equal to or higher than the reference voltage, the target charging power to the power storage device is subjected to constant voltage charging derived by a product of the reference voltage and the target charging current,
The target charging current is determined by a current curve in which the constant reference current is set as an initial value and the current is decreased over time, and the current curve is determined by at least one of a deterioration degree and a temperature of a cell constituting the power storage device. The power supply system according to claim 1, wherein the power supply system is determined based on one of the two. The control device determines a target charging current corresponding to the current highest cell voltage based on a relational expression between a highest cell voltage and a target charging current among cell voltages of a plurality of cells constituting the power storage device. The product of the target charging current and the total voltage of a plurality of cells constituting the power storage device is derived as the target charging power to the power storage device,
3. The power supply system according to claim 1, wherein in the relational expression, a relationship is set such that the target charging current decreases as the highest cell voltage increases. The power storage device is configured by a plurality of cell units,
The cell unit includes a cell main body and a bypass circuit portion that is connected in parallel with the cell main body and adjusts the amount of bypass current that flows through the cell main body while bypassing the cell main body. Have
When the control device causes the power storage device to be charged with the target charging power,
When the charged amount of the cell main body is less than the reference charged amount, a fixed reference current as a temporary charging current is determined, and when the charged amount of the cell main body is equal to or greater than the reference charged amount, the cell main body Using a relational expression in which a provisional charging current that decreases as the amount of electricity stored increases is determined for each of the plurality of cell units, determines a provisional charging current according to the amount of electricity stored in the cell main body,
A first temporary target charging current derived by adding an upper limit bypass current, which is an upper limit value of the bypass current, to the smallest temporary charging current among the temporary charging currents for each of the plurality of cell units; The second temporary target charging current which is the largest temporary charging current among the temporary charging currents of each cell unit is compared, and the smaller temporary target charging current is compared with the plurality of cell units. It is determined as the target charging current that flows every time,
The target charging current is supplied for each of the plurality of cell units, and each of the plurality of cell units is determined according to the amount of power stored in the cell main body portion of the target charging current supplied to the cell unit. The amount of current exceeding the provisional charging current is passed through the bypass circuit portion, the other portion of the current is passed through the cell body portion,
A product of a total current, which is a sum of the target charging currents flowing for each of the plurality of cell units constituting the power storage device, and a total voltage of the plurality of cell units constituting the power storage device is set as the target charging power. The power supply system according to claim 1 or 2, which is configured as follows.   The power supply system according to any one of claims 1 to 5, wherein the control device determines that the charging start condition is satisfied when a set time is reached.   The power supply system according to any one of claims 1 to 6, wherein the control device determines that the charging start condition is satisfied when a storage amount of the power storage device is less than a lower limit storage amount.

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