Strategies for smoothing power fluctuations in lithium-ion battery–supercapacitor energy storage systems

Abstract

Abstract Onshore wind power has received attention from governments, including China and Europe, as a renewable energy generation technology. Still, it is highly influenced by weather factors and often requires energy storage systems to smooth its power. The hybrid energy storage system (HESS), comprising a lithium-ion battery and a supercapacitor (SC), fully uses the advantages of both the lithium-ion battery and SC with high energy and high power density. The contribution of this paper is to give a control strategy for internal power coordination and smoothing power fluctuation in HESS. For internal power coordination, when the state of charge (SOC) of a lithium-ion battery and SC are not in the normal range simultaneously, the lithium-ion battery power limit must be adjusted to regulate their SOC. In contrast, for smoothing power fluctuation, a low-pass filter is used to reduce the charge/discharge depth of the lithium-ion battery and maintain the SOC of SC. The trigonometric factor is used to optimize the particle swarm optimization (PSO) to obtain a better power distribution value. The proposed strategy is optimized using onshore wind power generation and load 1-day power variation, and the results achieve the desired goal with superior application.