A balanced switching method for battery packs in a hybrid energy storage system

Abstract

The invention discloses a balance switching method for storage battery sets in a hybrid energy storage system. The balance switching method includes the steps that the charge state of a super capacitor and the charge states of all the storage battery sets in the hybrid energy storage system are monitored, and according to the different charge states of the super capacitor, the storage battery sets are selectively switched. According to the balance switching method for the storage battery sets, the charge state of the super capacitor in the smoothing process of the wind power is adjusted, the charge state of the super capacitor is kept the optimal state accordingly, and adjusting capacity is high; meanwhile, the charge states of all the storage battery sets in the charging process and the discharging process can be balanced, the discharge depth of the storage battery sets is reduced, and therefore the cycling life of the storage battery sets is prolonged. By means of the balance switching method, the high power density of the super capacitor and the high energy density of the storage battery sets can be effectively combined, and the redundancy rate of a device is decreased, fluctuation of a wind power plant is improved, and the high-performance hybrid energy storage system is formed.

Description

technical field [0001] The invention relates to a method for balanced switching of battery packs in a hybrid energy storage system. The state of charge (SOC) of a supercapacitor and the state of charge of a battery pack are used as feedback quantities to selectively switch and switch a battery pack, which belongs to the hybrid energy storage system. energy and wind power technologies. Background technique [0002] In a wind farm, the cooperation between wind energy and energy storage system can effectively balance wind power fluctuations, and a single energy storage system is difficult to meet the energy density and power density requirements of the wind farm for the energy storage system. In addition, the combined use of various energy storage technologies can maximize the performance of the energy storage system while optimizing the system structure and reducing equipment redundancy. Therefore, using the characteristics of high power density and fast charging and discharg...

AI Technical Summary

Problems solved by technology

However, if this method is directly applied to the switching control of the battery pack, there are still the following defects: although the cycle switching method can ensure the balance of the running time of each battery pack, it cannot guarantee the balance of the state of charge of each battery pack

To be precise, the cycle switching method will cause a large difference in the depth of discharge (DOD) of each battery pack. If the depth of discharge exceeds 30% to 50% for a long time, its cycle life will be adversely affected. Therefore, the above method is not suitable for Switching of battery packs in wind farm hybrid energy storage system

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