1. State Key Laboratory of Power Transmission Equipment Technology, School of Electrical Engineering, Chongqing University, Chongqing 400044, China
2. National Innovation Center for Industry-Education Integration of Energy Storage Technology, School of Electrical Engineering, Chongqing University, Chongqing 400044, China
3. MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China