A Distributed Battery Pack Balanced Charging and Discharging Method and Distributed Micro-grid Structure

Abstract

The invention discloses a distributed equalization charge and discharge method for a storage battery and a distributed microgrid structure. Current-controlled voltage sources are serially connected in all distributed power supplies to change line impedance; the distributed microgrid structure comprises a plurality of distributed power supplies, the storage battery and the current-controlled voltage sources; the storage battery is connected with the distributed power supplies in parallel; the current-controlled voltage sources are serially connected with the distributed power supplies and are opposite to the distributed power supplies in polarity. According to the distributed equalization charge and discharge method and the distributed microgrid structure disclosed by the invention, the current-controlled voltage sources are adopted as virtual impedance and are serially connected in circuits of all the distributed power supplies, and the voltages of connected points are changed, so that charge and discharge current of all lines reaches balance, the problem that individual storage batteries is first aged due to overheavy charge and discharge current is avoided, and the cycle life of the storage battery is more balanced. Compared with the storage battery which is not controlled by adopting the virtual impedance, the storage battery adopting the method disclosed by the invention has the advantage that the cycle life is prolonged by 80 percent.

Description

technical field [0001] The invention relates to a method for equalizing charging and discharging of a distributed storage battery group and a distributed micro-grid structure, belonging to the technical field of micro-grids. Background technique [0002] Microgrid, also known as microgrid, is a concept relative to the traditional large power grid. It refers to a network composed of multiple distributed power sources and their related loads according to a certain topology, and is connected to the conventional power grid through static switches. [0003] In the microgrid, due to the long start-up time of the distributed power supply, the transient response to the load is poor, so when the load of the grid changes suddenly, it cannot provide energy supply to the load quickly and in time. Therefore, it is necessary to add energy storage devices such as batteries to the microgrid to meet the load demand. At present, most energy storage devices are connected to the microgrid in t...

AI Technical Summary

Problems solved by technology

Regardless of parallel or series connection, the closer the distributed power supply is to the load, the smaller its impedance value, that is, X 1 =0,X 2 3 n , the greater the pressure on the connected battery, the greater the discharge current, and the higher the peak temperature, which will inevitably lead to the aging of the battery first.

If it is not dealt with in time, the remaining batteries will quickly age and cannot meet the requirements of the load, and eventually the entire microgrid will not work properly

Images