JP2016005390A - Charge/discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a charge/discharge device capable of effectively using photovoltaic power generation power by predicting a variation in system voltage.SOLUTION: A charge/discharge device comprises: charge/discharge circuits 2a, 2b for converting AC power from a commercial power system 7 and a photovoltaic power generation device to DC power to charge a lithium battery 1a and a fixed storage battery 6, and converting DC power stored in the lithium battery 1a and the fixed storage battery 6 to AC power to perform discharge; a system voltage prediction unit 2d for predicting a variation in system voltage of the commercial power system 7 caused by power selling of surplus power of the photovoltaic power generation device; and a control circuit 2c for controlling charge operation and discharge operation of the charge/discharge circuits 2a, 2b to perform control of delaying start of charge operation to the lithium battery 1a and the fixed storage battery 6 when the system voltage prediction unit 2d predicts that the value of the system voltage exceeds a prescribed voltage value.

Description

  The present invention relates to a charge / discharge device.

  Conventionally, the system voltage is predicted based on the reverse power flow of each customer predicted from the specifications of solar power generation devices of multiple customers, weather information, etc., and when the system voltage is expected to exceed a predetermined value, A technique relating to a system that requests an output of reactive power from a consumer is disclosed in Patent Document 1 below.

JP2012-253851A

  However, according to the above-described conventional technology, when an increase in the system voltage is expected, the increase in the system voltage can be suppressed by outputting reactive power. Is determined based on the active power. For this reason, there is a problem that the output of reactive power does not bring a financial merit to the installer of the photovoltaic power generation apparatus. In addition, there is a method of charging the storage battery in units of consumers when the reverse flow rate is equal to or higher than a predetermined value, but this is a burden on the consumers in terms of installation location and cost.

  This invention is made | formed in view of the above, Comprising: Change of system voltage is estimated and it aims at obtaining the charging / discharging apparatus which can utilize photovoltaic power generation effectively.

  In order to solve the above-described problems and achieve the object, the present invention is a charge / discharge device connected to a solar power generation device that sells surplus power of solar power generation in conjunction with a commercial power system, A charge / discharge circuit that converts AC power from the commercial power system and the photovoltaic power generator into DC power to charge the storage battery, converts DC power stored in the storage battery into AC power, and discharges the battery; A system voltage predicting unit that predicts a change in the system voltage of the commercial power system due to the sale of surplus power; and a charging operation and a discharging operation of the charge / discharge circuit are controlled, and the system voltage predicting unit And a control circuit that performs control to delay the start of the charging operation of the storage battery when it is predicted that the voltage value exceeds a prescribed voltage value.

  According to the present invention, it is possible to predict changes in the system voltage and effectively use solar power.

FIG. 1 is a diagram illustrating a configuration example of the charge / discharge device according to the first embodiment.

  Embodiments of a charge / discharge device 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 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of the charge / discharge device 2 of the present embodiment. The charging / discharging device 2 is connected to the electric vehicle 1 via a power line 4 for power transmission / reception and a signal line 5 for information transmission / reception. The charging / discharging device 2 is connected to a stationary storage battery 6 that is a storage battery installed in the house 3. In addition, the charging / discharging device 2 can be connected to the house 3 and can receive supply of AC power from the commercial power system 7 via the house 3. As shown in FIG. 1, the stationary storage battery 6 may be installed outside the house 3 instead of inside the house 3.

  The electric vehicle 1 includes a lithium battery 1 a that is a storage battery that serves as a power source, and an information communication device 1 b that communicates various types of information between the charge / discharge device 2 and the electric vehicle 1.

  The house 3 includes an operation panel 2e of the charge / discharge device 2 and various home appliances 3a to 3d in the house. Moreover, the solar cell 8 which performs solar power generation, and the power conditioner 9 which converts the direct current power of the solar cell 8 into alternating current power are installed in the house 3. Here, the solar battery 8 and the power conditioner 9 constitute a solar power generation device. The solar power generation apparatus is linked to the commercial power system 7 and sells surplus power generated by the solar battery 8.

  The charging / discharging device 2 includes charging / discharging circuits 2a and 2b, a control circuit 2c, and a system voltage prediction unit 2d.

  The charge / discharge circuit 2 a is a bidirectional converter that charges and discharges with the lithium battery 1 a of the electric vehicle 1. The charge / discharge circuit 2a converts the AC power of the commercial power system 7 into DC, charges the lithium battery 1a of the electric vehicle 1, and converts the DC power of the lithium battery 1a of the electric vehicle 1 into AC power. Then, discharging is performed by supplying AC power to the various home electric appliances 3a to 3d in the house 3.

  The charge / discharge circuit 2 b is a bidirectional converter that charges and discharges with the stationary storage battery 6. The charging / discharging circuit 2b converts the AC power of the commercial power system 7 into DC and charges the stationary storage battery 6, and converts the DC power of the stationary storage battery 6 into AC power, It discharges by supplying alternating current power to household appliances 3a-3d.

  The control circuit 2 c controls the operation of the charge / discharge device 2. The control circuit 2 c controls the operation of the charge / discharge circuit 2 a to charge the lithium battery 1 a of the electric vehicle 1 or discharge from the lithium battery 1 a of the electric vehicle 1. The control circuit 2 c controls the operation of the charge / discharge circuit 2 b to charge the stationary storage battery 6 or discharge from the stationary storage battery 6.

  The system voltage prediction unit 2d obtains weather forecast information every specified time, and predicts a change in the system voltage of the commercial power system 7. The system voltage prediction unit 2d obtains weather forecast information indicating that the weather is sunny from 10:00 to 15:00, for example. When the time zone from 10 o'clock to 15 o'clock is fine, other solar power generators installed in houses around the house 3 also flow a large amount of power back to the commercial power system 7, so the system voltage prediction unit 2d Then, the rise of the system voltage of the commercial power system 7, for example, a time zone in which the system voltage exceeds the specified voltage value can be predicted. The system voltage prediction unit 2d may predict whether the system voltage exceeds a specified voltage value for a specified time based on weather forecast information.

  In the charging / discharging device 2, the control circuit 2 c uses the charging / discharging circuit 2 a to exchange the DC power stored in the lithium battery 1 a in the time period up to 10 o'clock with respect to the prediction of the system voltage prediction unit 2 d. It converts into electric power, supplies alternating current power to the various household electrical appliances 3a-3d in the house 3, and discharges. Further, the control circuit 2c converts the DC power stored in the stationary storage battery 6 into AC power by the charge / discharge circuit 2b, and supplies the AC power to the various household electrical appliances 3a to 3d in the house 3 to discharge them. At this time, the control circuit 2c displays to the user via the operation panel 2e that the system voltage is being discharged because an increase in the system voltage is predicted.

  In the charging / discharging device 2, the control circuit 2 c charges and discharges the AC power generated by the photovoltaic power generation device when it enters the time zone from 10:00 to 15:00 where the increase in the system voltage of the commercial power system 7 is predicted. The circuit 2a is converted into DC power, and charging of the lithium battery 1a of the electric vehicle 1 is started. The control circuit 2c receives information on the remaining capacity of the lithium battery 1a from the electric vehicle 1 via the signal line 5, and performs charging until the battery is fully charged. Moreover, the control circuit 2c converts the AC power generated by the photovoltaic power generator into DC power by the charge / discharge circuit 2b, and starts charging the stationary storage battery 6. The control circuit 2c monitors the charging voltage and the charging current of the stationary storage battery 6, and performs charging until the full charge determination is made such that the charging voltage is equal to or higher than the specified voltage value and equal to or lower than the specified current value.

  In addition, in the charging / discharging apparatus 2, although discharge operation is performed before the time slot | zone when the raise of the system voltage of the commercial power system 7 is estimated, it is not limited to this. For example, when the charging rates of the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 are both low at the predicted time, the charging / discharging device 2 may not perform the discharging operation. In the charging / discharging device 2, charging is not performed until a time zone in which an increase in the system voltage of the commercial power system 7 is predicted, that is, charging is delayed until a time period in which an increase in the system voltage of the commercial power system 7 is predicted. Thus, compared with the case where the charging of the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 is started from the time when the increase of the system voltage of the commercial power system 7 is predicted, the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 are The time until full charge can be postponed. In the charging / discharging device 2, it is possible to avoid a situation where the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 are fully charged at an early stage in a time zone in which an increase in the system voltage of the commercial power system 7 is predicted.

  In recent years, electric vehicles 1 have been widely used. A system has been developed in which the DC power of the lithium battery 1a of the electric vehicle 1 is converted into AC power and used in the house 3. By using the lithium battery 1a of the electric car 1 for supplying power to the house 3, a new system is developed. There is no need to install a storage battery, and the problems of installation location and cost can be solved. In addition, in preparation for a large-scale disaster, the use of stationary storage batteries 6 in houses 3 is also progressing. The stationary storage battery 6 has been reduced in size and cost, and the problems of installation location and cost can be solved. When the system voltage is expected to rise, the charging / discharging device 2 charges each of these storage batteries with the power generated by the solar power generation device, the electric power for running the electric vehicle 1, and various home appliances in the house 3 By using it as the power of 3a to 3d, it is possible to effectively use the photovoltaic power.

  As described above, according to the present embodiment, in the charging / discharging device 2 connected to the house 3 including the solar power generation device, when the system voltage of the commercial power system 7 is predicted to increase by solar power generation, By starting charging of the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 at the time when the increase of the system voltage is predicted, the increase of the system voltage of the commercial power system 7 in the house 3 can be suppressed. When the system voltage is predicted to be higher than the specified voltage value, the charging / discharging device 2 charges the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 until the time when the system voltage is expected to rise. Is not performed, and the start of charging is delayed. As a result, it is possible to prevent the power conditioner 9 from suppressing solar power generation due to the increase in the system voltage and to avoid outputting reactive power during the time when the increase in the system voltage is predicted. The power generation device can be operated efficiently, and as a result, the generated power of the solar power generation device can be used for charging each storage battery, and the solar power generation power can be used effectively.

  Moreover, in the charging / discharging device 2, the DC power stored in the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 is converted before the time zone in which the system voltage of the commercial power system 7 is expected to rise, and the house 3 By using it as the power of various household electrical appliances 3a to 3d in the house, it is possible to suppress the amount of power purchased during this time period. Furthermore, the capacity | capacitance for charging each storage battery at the time of the system voltage rise of the commercial power grid | system 7 can be ensured. Further, in the charging / discharging device 2, a display indicating that discharging is in progress is performed via the operation panel 2e, and the operation of the vacuum cleaner, the washing machine, etc. is urged to the user during the discharging period, so that the solar stored in each storage battery Photovoltaic power can be used effectively, and purchased power can be reduced.

  In the present embodiment, the charging / discharging device 2 includes two charging / discharging circuits 2a and 2b, and based on the prediction of the system voltage prediction unit 2d, the lithium battery 1a and the stationary storage battery 6 of the electric vehicle 1 are used. Although charging / discharging operation | movement was performed between storage batteries, the number of charging / discharging circuits and storage batteries is not limited to two. One or three or more charge / discharge circuits and storage batteries may be used.

Embodiment 2. FIG.
The configuration of the charging / discharging device 2 of the present embodiment is the same as that of the first embodiment shown in FIG. In the first embodiment, the system voltage prediction unit 2d obtains weather forecast information, but information for predicting a change in the system voltage of the commercial power system 7 is not limited to this. For example, the grid voltage prediction unit 2d uses the cloud to generate the amount of solar power generated and the amount of power sold by a solar power generation device installed in other houses in the surrounding area including the area where the charging / discharging device 2 is installed. Alternatively, the reverse power flow rate or the like may be monitored in real time, and the change in the system voltage of the commercial power system 7 may be predicted from the absolute value and increase rate of the amount of photovoltaic power generation, the amount of power sold, and the reverse power flow. Even in this case, the same effect as in the first embodiment can be obtained.

  As described above, the charging / discharging device according to the present invention is useful for charging / discharging a storage battery of an electric vehicle, and is particularly suitable when a solar power generation device is installed in a house.

  DESCRIPTION OF SYMBOLS 1 Electric vehicle, 1a Lithium battery, 1b Information communication apparatus, 2 Charging / discharging apparatus, 2a, 2b Charging / discharging circuit, 2c Control circuit, 2d System voltage prediction part, 2e Operation panel, 3 House, 3a-3d Various household appliances in house 4, power line, 5 signal line, 6 stationary storage battery, 7 commercial power system, 8 solar battery, 9 power conditioner.

Claims (5)

A charge / discharge device connected to a solar power generation device that sells surplus power of solar power generation in conjunction with a commercial power system,
A charge / discharge circuit that converts AC power from the commercial power system and the photovoltaic power generator into DC power to charge the storage battery, converts DC power stored in the storage battery into AC power, and discharges the battery; ,
A system voltage prediction unit that predicts a change in system voltage of the commercial power system due to the sale of surplus power; and
The charging operation and the discharging operation of the charging / discharging circuit are controlled, and when the system voltage predicting unit predicts that the system voltage exceeds a specified voltage value, a control to delay the start of the charging operation to the storage battery is performed. A control circuit;
A charge / discharge device comprising: The system voltage prediction unit predicts a time zone in which the system voltage exceeds a specified voltage value based on the acquired weather forecast information,
The control circuit starts charging the storage battery after the start of the time period,
The charge / discharge device according to claim 1. The control circuit discharges the storage battery until the start of the time zone,
The charge / discharge device according to claim 2. The system voltage prediction unit predicts whether the system voltage exceeds a specified voltage value for a specified time based on the weather forecast information.
The charge / discharge device according to claim 2 or 3. The system voltage prediction unit acquires information on the amount of power sold by other solar power generation devices installed in an area including a point where the charge / discharge device is installed, and information on the amount of power sold by the other solar power generation devices Predicting a change in the grid voltage based on
The charge / discharge device according to any one of claims 1 to 4.

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