JP6333061B2 - Battery charge / discharge system - Google Patents

Description

  The present invention relates to a storage battery charge / discharge system.

  Conventionally, in a charge / discharge system that charges and discharges a storage battery, overcharge of the storage battery and overdischarge from the storage battery are prevented. As a method for preventing overcharge and overdischarge, there is a method for managing charge and discharge by monitoring the state of a storage battery (for example, Patent Document 1 below).

Japanese Patent Laid-Open No. 11-18317

  However, according to the above-described conventional technology, there is a problem that the life of the storage battery is shortened when charging and discharging are frequently repeated under conditions where the deterioration of the storage battery is a concern. Moreover, when the charging rate of the storage battery is lowered during normal use, there is a problem that it may not be used as an emergency power source in the event of a power failure.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the storage battery charging / discharging system which can use a storage battery reliably as an emergency power source at the time of a power failure, suppressing deterioration of a storage battery.

In order to solve the above-described problems and achieve the object, the present invention includes a storage battery that stores power, a monitoring device that monitors a charge state of the storage battery, and charges the storage battery with power and discharges the power from the storage battery. And a control device for controlling charging and discharging by the power conversion device based on a charging state of the storage battery according to a monitoring result of the monitoring device and an operating state of the power conversion device , In the operation mode representing the operation state of the power conversion device, when the control device has any one of a charge mode, a discharge mode, and a charge / discharge mode in which charging and discharging are combined, the control device, for each operation mode, the storage battery Different determination conditions are used in determining overcharge and overdischarge .

  According to the present invention, it is possible to reliably use a storage battery as an emergency power source during a power failure while suppressing deterioration of the storage battery.

FIG. 1 is a diagram illustrating a configuration example of a storage battery charging / discharging system. FIG. 2 is a diagram illustrating an operation state of the storage battery charging / discharging system in a steady state. FIG. 3 is a diagram illustrating an operation state of the storage battery charge / discharge system during overcharge. FIG. 4 is a diagram illustrating an operation state of the storage battery charge / discharge system during overdischarge. FIG. 5 is a diagram illustrating an operation in each operation mode for each charging rate in overcharging. FIG. 6 is a diagram showing the operation in each operation mode for each charging rate in overdischarge. FIG. 7 is a diagram illustrating the control contents of the control device at each charging rate.

  Embodiments of a storage battery charge / discharge system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a diagram illustrating a configuration example of a storage battery charge / discharge system 10 according to the present embodiment. The storage battery charging / discharging system 10 includes a power system 1, a switching device 2, a power generation device 3, a load 4, a power conversion device 5, a control device 6, a storage battery 7, and a monitoring device 8. In the following description, as an example, the storage battery 7 is a storage battery mounted on an electric vehicle. In the storage battery charging / discharging system 10, the switching device 2, the power generation device 3, the load 4, the power conversion device 5, and the control device 6 are installed in a house, and the storage battery 7 and the monitoring device 8 are installed in an electric vehicle. The power system 1 is a commercial system that supplies AC power from outside the house. In addition, the storage battery 7 is not limited to the storage battery mounted in the electric vehicle, For example, it is good also as a stationary storage battery.

  The power system 1 supplies AC power to the load 4 and the power conversion device 5 side in the storage battery charge / discharge system 10. In the storage battery charging / discharging system 10, the switchgear 2 opens or closes the connection between the power system 1 and the house side in the interconnected operation or the independent operation. The power generation device 3 is, for example, a solar power generation system installed in a house, but is an example and is not limited to the solar power generation system. Note that AC power is output from the power generation device 3. In the case of a solar power generation system, the generated DC power is converted into AC power and then output. The load 4 is a home appliance used by a user in a house. The power conversion device 5 converts AC power from the power system 1 and the power generation device 3 to DC power to charge the storage battery 7, and converts DC power from the storage battery 7 to AC power and supplies it to the load 4. . The control device 6 controls the operation of the power conversion device 5 based on the monitoring result obtained by monitoring the charging state of the storage battery 7 by the monitoring device 8. The control device 6 controls the opening or closing of the opening / closing device 2. The storage battery 7 stores the DC power converted into DC power by the power conversion device 5, and discharges the DC power to the power conversion device 5 during a power failure or the like. The monitoring device 8 monitors the state of charge (charge rate) of the storage battery 7 and notifies the control device 6 of the monitoring result.

  Next, in the storage battery charge / discharge system 10, an operation in which the power conversion device 5 charges and discharges power with the storage battery 7 will be described. In the present embodiment, there are two types of operation modes of the storage battery charging / discharging system 10, namely, an interconnection operation in a state connected to the power system 1 and a self-sustained operation in a state disconnected from the power system 1. In the interconnected operation, the power conversion device 5 charges the storage battery 7 with a charging mode, the power conversion device 5 discharges the power from the storage battery 7, and the power conversion device 5 charges the power with the storage battery 7. Three modes are defined: a charge / discharge mode for discharging. In the self-sustained operation, a charge / discharge mode in which the power converter 5 charges and discharges power with the storage battery 7 is defined.

  In the charging mode of the interconnected operation, the power conversion device 5 converts the AC power from the power system 1 into DC power and charges the storage battery 7. At this time, in the storage battery charging / discharging system 10, the switchgear 2 is closed and connected to the power system 1.

  In the discharge mode of the interconnection operation, the power conversion device 5 converts the DC power from the storage battery 7 into AC power and supplies it to the load 4 to control the trading power to the power system 1. Note that, in the interconnection regulations, since reverse flow from the storage battery 7 to the power system 1 is prohibited, the power conversion device 5 outputs the power from the storage battery 7 only to the load 4. At this time, in the storage battery charging / discharging system 10, the switchgear 2 is closed and connected to the power system 1.

  In the charge / discharge mode of the interconnected operation, the power conversion device 5 supplies power from the storage battery 7 to the load 4 to control the trading power to the power system 1. Further, the power conversion device 5 supplies surplus power obtained by subtracting the power consumption of the load 4 from the power generated by the power generation device 3 to the storage battery 7. At this time, in the storage battery charging / discharging system 10, the switchgear 2 is closed and connected to the power system 1.

  In the charge / discharge mode of the self-sustained operation, the power conversion device 5 operates as a constant voltage source that simulates the voltage of the normal power system 1 and supplies power from the storage battery 7 to the load 4. Further, the power conversion device 5 supplies surplus power obtained by subtracting the power consumption of the load 4 from the power generated by the power generation device 3 to the storage battery 7. At this time, in the storage battery charging / discharging system 10, the switchgear 2 is opened and disconnected from the power system 1.

  Next, in the storage battery charging / discharging system 10, the monitoring device 8 monitors the state of charge of the storage battery 7, and the control device 6 overcharges or overdischarges the storage battery 7 based on the monitoring result of the state of charge of the storage battery 7 by the monitoring device 8. The operation | movement which determines this and controls the power converter device 5 is demonstrated.

  When it determines with overcharge, the control apparatus 6 controls and stops the power converter device 5 in the charge mode of interconnection operation. At this time, in the control device 6, as a threshold value for determining overcharge, an upper limit value that is limited by the monitoring device 8 that monitors the storage battery 7, or a set value if the user can set the minimum value, is set. The overcharge determination threshold is used. Here, the upper limit value restricted by the monitoring device 8 may be, for example, the upper limit value of the charging rate notified from the electric vehicle side when the storage battery charging / discharging system 10 is a system using an electric vehicle. When the monitoring device 8 and the control device 6 manage operation / stop individually, the system may be stopped if the upper limit value restricted by the monitoring device 8 is not observed. The threshold value may be set with a margin for the upper limit value to be limited.

  When it determines with overcharge, in the charging / discharging mode of interconnection operation, the control apparatus 6 controls the power converter device 5, prohibits charging operation, and continues discharge operation. At this time, in the control device 6, as a threshold value for determining overcharge, an upper limit value limited by the monitoring device 8 that monitors the storage battery 7, a level at which deterioration of the storage battery 7 is not a concern (not deteriorated), or a user sets If possible, the minimum value of the set values is set as an overcharge determination threshold. Here, the level at which the deterioration of the storage battery 7 is not concerned (is not deteriorated) is the value of the charging rate at which the storage battery 7 does not deteriorate even if charging and discharging are frequently repeated. However, when it is desired to prioritize the amount of power that can be used over the deterioration of the storage battery 7, the level at which the storage battery 7 does not deteriorate may be excluded in setting the overcharge determination threshold. In particular, in the case of a self-sustained operation described later, it is assumed to be excluded because it is used as an emergency power source.

  When it is determined that the battery is overcharged, the control device 6 controls the power conversion device 5 to prohibit the charging operation and continue the discharging operation in the charge / discharge mode of the independent operation. In the case of self-sustained operation, the power conversion device 5 basically operates as a constant voltage source. Therefore, as a method of prohibiting the charging operation, a switching device is inserted into the output of the power generation device 3 and disconnected when charging is prohibited. There is a way. At this time, in the control device 6, as a threshold for determining overcharge, an upper limit value that is restricted by the monitoring device 8 that monitors the storage battery 7, a level at which the storage battery 7 does not deteriorate, or a setting that can be set by the user The minimum value among the values is set as an overcharge determination threshold. This is the same as the charge / discharge mode during the interconnected operation.

  On the other hand, when it determines with overdischarge, the control apparatus 6 controls the power converter device 5 to be stopped in the discharge mode of the interconnection operation. At this time, in the control device 6, as a threshold value for determining overdischarge, the lower limit value limited by the monitoring device 8 that monitors the storage battery 7 or, if the user can set, the maximum value among the set values. A value with a margin is set as an overdischarge determination threshold. Here, the lower limit value limited by the monitoring device 8 may be, for example, the lower limit value of the charging rate notified from the electric vehicle side when the storage battery charging / discharging system 10 is a system using an electric vehicle. When the monitoring device 8 and the control device 6 manage operation / stop individually, the system may be stopped unless the lower limit value restricted by the monitoring device 8 is observed. The threshold value may be set with a margin for the lower limit value to be restricted.

  When it determines with overdischarge, in the charging / discharging mode of interconnection operation, the control apparatus 6 controls the power converter device 5, prohibits discharge operation, and continues charging operation. At this time, in the control device 6, as a threshold for determining overdischarge, a lower limit value that is restricted by the monitoring device 8 that monitors the storage battery 7, a level at which the storage battery 7 does not deteriorate, or a setting that can be set by the user Among the values, a value obtained by adding a margin to the maximum value is set as an overdischarge determination threshold value.

  When it determines with overdischarge, the control apparatus 6 controls and stops the power converter device 5 in the charging / discharging mode of self-sustained operation. In the case of self-sustained operation, the power conversion device 5 operates as a constant voltage source. Therefore, as a method of prohibiting the discharge operation, there is a method of inserting a switching device at the input of the load 4 and disconnecting it when prohibiting discharge. In this case, power is not supplied to the load 4 and a power failure occurs. Therefore, in the present embodiment, it is not assumed that the discharge operation is prohibited and the operation is continued. At this time, in the control device 6, as a threshold for determining overdischarge, a lower limit value that is restricted by the monitoring device 8 that monitors the storage battery 7, a level at which the storage battery 7 does not deteriorate, or a setting that can be set by the user Among the values, a value obtained by adding a margin to the maximum value is set as an overdischarge determination threshold value. Assuming that charging is performed from the power generation device 3 in an emergency, the control device 6 provides another threshold before the charging rate falls below the threshold and stops, and the charging rate falls below the threshold. In this case, the operation of the power conversion device 5 is continued when the charging rate has increased at the specified time, but the power conversion device 5 may be controlled to stop when the charging rate has decreased. . The control device 6 may control the power conversion device 5 to stop even when the charging rate has not increased in a prescribed time. Moreover, in the control apparatus 6, when the change of the charging rate of the storage battery 7 is smaller than the defined change rate, you may control so that the power converter device 5 may be stopped.

  The operation state of the storage battery charging / discharging system 10 during normal operation, overcharge, and overdischarge will be described with reference to FIGS.

  FIG. 2 is a diagram illustrating an operation state of the storage battery charging / discharging system 10 in a steady state. For example, in the connected operation charging mode, charging is possible and discharging is impossible, indicating that the operation is possible, and in the connecting operation discharging mode, charging is not possible and discharging is possible, indicating that the operation is possible.

  FIG. 3 is a diagram illustrating an operation state of the storage battery charge / discharge system 10 during overcharge. The colored column is the difference from the steady state. For example, in the charge mode of the interconnected operation, it indicates that the operation is stopped because charging is impossible and cannot be discharged, and in the discharge mode of the interconnected operation, it is indicated that the operation is possible because charging is not possible and discharge is possible. Here, in any of the operation modes, the charge control column cannot be charged.

  FIG. 4 is a diagram illustrating an operation state of the storage battery charge / discharge system 10 during overdischarge. The colored column is the difference from the steady state. For example, in the connected operation charging mode, charging is possible and discharging is impossible, indicating that the operation is possible, and in the connecting operation discharging mode, charging is not possible and discharging is not possible, indicating that the operation is stopped. Here, in any operation mode, the discharge control column cannot be discharged.

  In the storage battery charging / discharging system 10, the control device 6 controls the operation according to the operation mode of the power conversion device 5 when the storage battery 7 is overcharged or overdischarged based on the charging rate of the storage battery 7. .

  As a case where the power conversion device 5 supplies power to the storage battery 7 to charge it, there are two modes, a charging mode and a charging / discharging mode. In the charging mode, since the power conversion device 5 only charges the storage battery 7, the charging rate increases. However, in the charge / discharge mode, the power conversion device 5 charges the storage battery 7 and also discharges from the storage battery 7, so that the charging rate does not change in one direction but increases and decreases.

  Here, as described above, the storage battery 7 has a range of a charging rate that deteriorates by frequently repeating charging and discharging. In the charge / discharge mode, the storage battery 7 is deteriorated when charge / discharge is repeated in a range where the storage battery 7 deteriorates. Therefore, in the charge / discharge mode, it is desirable not to perform any operation of charging or discharging within a range where the storage battery 7 deteriorates due to repeated charging / discharging. On the other hand, since no discharge occurs in the charging mode, even if the storage battery 7 is deteriorated, the storage battery 7 is not affected by the amount of charging. Therefore, in the charging mode, charging can be continued even in a range where the operation is limited in the charging / discharging mode.

  In addition, the control device 6 may change the determination of overdischarge depending on the charging rate in the charge / discharge mode of the interconnection operation or the independent operation. The control device 6 prohibits discharging (with a higher charging rate) with respect to the charging rate during interconnected operation, and continues discharging at a lower charging rate than during interconnected operation during independent operation. To control. The case of autonomous operation is an emergency operation such as a power failure. The control device 6 can use the storage battery 7 as an emergency power source in the event of an emergency such as a power outage by prohibiting the discharge early if the charging rate of the storage battery 7 decreases during the interconnected operation.

  In this Embodiment, the control apparatus 6 of the storage battery charging / discharging system 10 uses the storage battery 7 efficiently by changing the threshold value (determination level) which determines whether it is overcharge or overdischarge in each operation mode. However, deterioration of the storage battery 7 can be suppressed. Moreover, the control apparatus 6 can utilize the storage battery 7 as an emergency power supply reliably at the time of a power failure by controlling with each operation | movement restriction | limiting which differs for every operation mode in each threshold value.

  FIG. 5 is a diagram illustrating an operation in each operation mode for each charging rate in overcharging. It is assumed that the charging rate A is larger and the charging rates B and C are smaller in this order.

  The charging rate A is, for example, an upper limit value limited by the monitoring device 8 of the storage battery 7. When the charging rate of the storage battery 7 exceeds the upper limit value, there is a possibility that the storage battery charge / discharge system 10 cannot return. In the operation shown in the present embodiment, the upper limit value is not exceeded, but it is assumed that the charging rate of the storage battery 7 exceeds the upper limit value when the storage battery 7 is connected. Conventionally, overcharge is determined as the overcharge determination threshold only by the charge rate A. The charging rate B is set to a level with a margin to the charging rate A. The charging rate C is set to a level at which the storage battery 7 does not deteriorate when charging and discharging are repeated in the storage battery 7. When charging / discharging the storage battery 7 in a state where the charging rate C is exceeded, it is assumed that the storage battery 7 is likely to be deteriorated compared to the case where charging / discharging is repeated for the storage battery 7 at a charging rate C or less. However, if there is no such problem, the charging rates B and C may be the same. The charge rates B and C may be set by the user within a range of the charge rate A or less. Moreover, in order to prevent chattering, the threshold value for resetting the determination result of overcharge determined by each threshold value may be set with a hysteresis with respect to the charging rates B and C.

  When the operation mode is the charging mode, the control device 6 continues the operation at the charging rate C, but performs control to stop the operation at the charging rate B. Further, when the operation mode is the charge / discharge mode of the interconnected operation, the control device 6 prohibits the charging operation at the charging rates C and B, and continues the operation only by the discharging operation. When the operation mode is the self-sustaining operation charge / discharge mode, the control device 6 continues the operation at the charge rate C, but at the charge rate B, the charge operation is prohibited and the operation is continued only by the discharge operation. Further, when the operation mode is the discharge mode, the control device 6 continues the discharge operation at the charge rates C and B.

  FIG. 6 is a diagram showing the operation in each operation mode for each charging rate in overdischarge. It is assumed that the charging rate D is larger and the charging rates E, F, and G become smaller in this order. The charging rate D is a value smaller than the charging rate C shown in FIG.

  The charging rate D is set to a level at which the storage battery 7 does not deteriorate when charging and discharging are repeated in the storage battery 7. When charging / discharging the storage battery 7 in a state of a charging rate lower than the charging rate D, it is assumed that the storage battery 7 is likely to be deteriorated as compared with the case where charging / discharging is repeated on the storage battery 7 at a charging rate D or higher. However, if there is no such problem, the charging rates D and E may be the same. Here, when the operation mode is the charge / discharge mode, two values to be set by the user are prepared in order to change the control content between the interconnected operation and the independent operation. The charging rate G is, for example, a lower limit value limited by the monitoring device 8 of the storage battery 7. When the charging rate of the storage battery 7 is lower than the lower limit value, there is a possibility that the storage battery charge / discharge system 10 cannot return. In addition, in the operation | movement shown to this Embodiment, although it does not become lower than this lower limit, the case where the charging rate of the storage battery 7 is lower than a lower limit at the time of connecting the storage battery 7 is assumed. Conventionally, overdischarge is determined as an overdischarge determination threshold only by the charging rate G. The charge rates D, E, and F may be set by the user within a range equal to or higher than the charge rate G. Further, in order to prevent chattering, threshold values for resetting the overdischarge determination results determined by the respective threshold values may be set with hysteresis for the charging rates D, E, and F.

  When the operation mode is the charging mode, the control device 6 continues the charging operation at the charging rates D, E, and F. Further, when the operation mode is the charge / discharge mode, the control device 6 prohibits discharge in the interconnected operation and continues the operation only by charging, and continues the operation by charging / discharging in the independent operation. When the operation mode is the charge / discharge mode, the control device 6 stops the operation in the grid operation at the charging rate E, and continues the operation by the charge / discharge in the independent operation. When the operation mode is the charge / discharge mode, the control device 6 stops the operation at the charge rate F in the interconnected operation and the independent operation. Further, when the operation mode is the discharge mode, the control device 6 stops the discharge operation at the charge rates D, E, and F.

  FIG. 7 is a diagram illustrating the control contents of the control device 6 at each charging rate. The control shown in FIG. 5 and FIG. 6 is shown. In the determination of overcharge, the control device 6 continues to be charged to a range equal to or lower than the charge rate B in the charge mode, but in the charge / discharge mode of the interconnected operation, the charge rate in consideration of deterioration of the storage battery 7. Charging / discharging is performed in a range of C or lower, and charging / discharging is performed in a range of charging rate B or lower in the charge / discharge mode of the self-sustaining operation. Further, in the determination of overdischarge, the control device 6 performs discharge in the range of the charge rate D or more in the discharge mode, and performs charge / discharge in the range of the charge rate D or more in the charge / discharge mode of the interconnected operation. In the charge / discharge mode of the independent operation, the charge / discharge is stopped at the charge rate F. In the charge / discharge mode, particularly in the case of the interconnected operation, the operation is performed in a narrow range as compared with the other operation modes.

  In the present embodiment, an example in which the storage battery 7 and the monitoring device 8 are mounted on an electric vehicle has been described as the storage battery charging / discharging system 10. However, at this time, the control device 6 always communicates with the monitoring device 8. Instead, the information of the storage battery 7 is acquired by communicating only during charging and discharging. Moreover, the electric vehicle can be disconnected from the system, and the connection between the power conversion device 5 and the storage battery 7 and the control device 6 and the monitoring device 8 can be disconnected. In this case, the control device 6 may hold information on the storage battery 7 including the determination result of overcharge / overdischarge until the storage battery 7 and the monitoring device 8 are disconnected in a storage unit (not shown). Thereby, in the control apparatus 6, even if it is not communicating with the monitoring apparatus 8 until an electric vehicle is disconnected from a system, it controls the operation | movement of the power converter device 5 using the information of the storage battery 7 hold | maintained. Can do.

  Further, in the case of interconnected operation, when charging operation or discharging operation is prohibited due to overcharge / overdischarge, charging to the storage battery 7 is also performed according to the power consumption of the load 4 or the generated power of the power generation device 3. There is a case where the state where there is no discharge from the battery continues. At this time, since the loss of the power conversion device 5 is supplied from the power system 1, the control device 6 desirably stops the power conversion device 5. Further, after stopping the power conversion device 5, the control device 6 monitors the power sale / purchase state of the power passing through the switchgear 2, and can discharge in the power purchase state and charge in the power sale state. Operation may be resumed.

  Further, in the charge / discharge mode of the grid operation, the control device 6 stops the charging operation in the overcharge state, but restarts the charging operation according to the state of the storage battery charging / discharging system 10 after the stop. Also good. For example, after stopping the charging operation, the control device 6 monitors the switchgear 2 to monitor the power buying and selling state. In the power purchase state, it is considered that power is consumed by the load 4 or the like. Therefore, the control device 6 controls the power conversion device 5 to convert the power from the storage battery 7 and supply it to the load 4 side in the power purchase state. Thereby, even if the control apparatus 6 stops the charge operation to the storage battery 7, it can restart the charge to the storage battery 7 by reducing the charging rate of the storage battery 7 using the electric power of the storage battery 7. .

  Similarly, in the charge / discharge mode of the interconnection operation, the control device 6 stops the discharge operation in the overdischarge state, but restarts the discharge operation according to the state of the storage battery charge / discharge system 10 after the stop. May be. For example, after stopping the discharging operation, the control device 6 monitors the switchgear 2 to monitor the power buying and selling state. If the power is being sold, it is possible that the power generator 3 generates power. Therefore, the control device 6 controls the power conversion device 5 to convert the power from the power generation device 3 and supply it to the storage battery 7 in the power sale state. Thereby, even if the control apparatus 6 stops the discharge operation from the storage battery 7, it can restart the discharge from the storage battery 7 by charging the storage battery 7 and raising the charging rate of the storage battery 7.

  As described above, according to the present embodiment, in storage battery charging / discharging system 10, control device 6 controls the operation of power conversion device 5 based on the state of charge of storage battery 7 by monitoring device 8. Specifically, in overcharge determination, the control device 6 stops the charging operation in the charge / discharge mode at a charging rate lower than the charging rate at which the charging operation is stopped in the charging mode. Thereby, the economic effect by a storage battery can be utilized in steady state, suppressing the deterioration of the storage battery 7 by repeating charging / discharging in a state with a high charging rate. Further, in the determination of overdischarge, the control device 6 stops the discharge with a sufficient charge rate in the discharge mode of the interconnected operation, and is lower than the charge rate of stopping the discharge in the charge / discharge mode of the interconnected operation. Even at the charging rate, the discharging operation in the charge / discharge mode of the independent operation is continued. Thereby, in the independent operation at the time of a power failure, the storage battery 7 can be reliably used as an emergency power source.

  As described above, the storage battery charge / discharge system according to the present invention is useful for a power supply system including a storage battery, and is particularly suitable for a system that can be operated in a plurality of operation modes.

  DESCRIPTION OF SYMBOLS 1 Power system, 2 Switchgear apparatus, 3 Electric power generation apparatus, 4 Load, 5 Power converter device, 6 Control apparatus, 7 Storage battery, 8 Monitoring apparatus, 10 Storage battery charging / discharging system.

Claims (12)

A storage battery for storing electric power;
A monitoring device for monitoring the state of charge of the storage battery;
A power converter for charging the storage battery with power and discharging the power from the storage battery;
A control device for controlling charging and discharging by the power conversion device based on a charging state of the storage battery according to a monitoring result of the monitoring device and an operation state of the power conversion device;
Equipped with a,
In the operation mode representing the operating state of the power converter, when having any one of a charge mode, a discharge mode, and a charge / discharge mode combining charging and discharging,
The control device uses different determination conditions in the determination of overcharge and overdischarge of the storage battery for each operation mode.
A storage battery charging / discharging system. The control device performs different control on the power conversion device under each determination condition.
The storage battery charging / discharging system according to claim 1 . The control device performs control for prohibiting charging in the charging / discharging mode at a charging rate lower than a charging rate of the storage battery that can be charged in the charging mode in the charging operation of the power conversion device to the storage battery.
The storage battery charging / discharging system according to claim 1 or 2 , wherein In the operation state of the power converter, further, there is a connected operation connected to a power system capable of supplying AC power to the power converter, and a self-supporting operation disconnected from the power system,
The control device performs control for prohibiting discharge in the grid operation and charge / discharge mode at a charge rate higher than the charge rate of the storage battery that can be discharged in the charge / discharge mode of the independent operation.
The storage battery charging / discharging system according to claim 1 , 2, or 3 . In the overdischarge determination condition in the charge / discharge mode of the self-sustained operation, when the charging rate of the storage battery does not increase at a specified time,
The control device stops the power converter;
The storage battery charging / discharging system according to claim 4 . The determination conditions for the overcharge and the overdischarge can be set by the user.
The storage battery charging / discharging system according to any one of claims 1 to 5 , wherein Provide hysteresis for the overcharge and overdischarge determination conditions,
The storage battery charging / discharging system according to any one of claims 1 to 6 , wherein When it is possible to disconnect the storage battery and the monitoring device,
The control device holds information on the storage battery including determination results of the overcharge and the overdischarge until the storage battery and the monitoring device are disconnected.
The storage battery charging / discharging system according to any one of claims 1 to 7 , wherein If the change in the charging rate of the storage battery is smaller than the specified rate of change,
The control device stops the power converter;
The storage battery charging / discharging system according to any one of claims 1 to 8 , wherein further,
A power system capable of supplying AC power to the power converter;
A load that consumes AC power;
A power generator capable of supplying AC power;
With
The control device monitors the power between the load, the power generation device, and the power conversion device and the power system, and resumes operation according to the conditions of power selling power and power purchasing power,
The storage battery charging / discharging system according to claim 9 . further,
An open / close device capable of opening and closing a connection between the power system and the power system capable of supplying AC power to the power converter;
A load that consumes AC power;
With
The control device monitors the switchgear when the charging operation is stopped due to overcharge determination, and discharges power from the storage battery to the power converter when the switch is in a power purchase state due to consumption of the load. And the charging operation of the storage battery is restarted after the charge rate of the storage battery falls below the determination condition for overcharging.
The storage battery charging / discharging system according to any one of claims 1 to 8 , wherein further,
An open / close device capable of opening and closing a connection between the power system and the power system capable of supplying AC power to the power converter;
A power generator capable of supplying AC power;
With
The control device monitors the switchgear when the discharge operation is stopped due to overdischarge determination, and when the power generation device generates power, the control device supplies power to the storage battery with respect to the power conversion device. Performing charging control, and restarting the discharge operation after the charge rate of the storage battery is increased from the overdischarge determination condition,
The storage battery charging / discharging system according to any one of claims 1 to 8 , wherein

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