Simulation on Wireless Power Transfer based Battery Pack Equalization with SOC Quantitative Regulation

Abstract

This paper proposes a battery pack equalization method based on wireless power transfer (WPT). Compared with the traditional wired equalization method, the proposed method can realize the physical isolation between the power supply and the battery, which makes the equalization safer and more convenient. Firstly, this paper studies the battery equalization method aiming at the balance of state of charge (SOC). Secondly, in order to ensure the stability of equalization current and facilitate the SOC estimation based on equalization, a closed-loop feedback control is adopted on the primary side of the wireless equalization system. Thirdly, simulation is conducted to verify the wireless equalization system. The simulation results show that constant current equalization can be achieved using the proposed wireless equalization system with single battery, or battery pack of 2 or 3 batteries connected in series. Besides, all the SOCs equal in 1080 seconds with maximum 0.15 initial SOC imbalance.