1. State Key Laboratory of Power Transmission Equipment & System Security and New Technology (Chongqing University), Shapingba District, Chongqing 400044, China
2. Dongfang Electric Machinery Co., Ltd, Research and Test Center Sichuan, Deyang 618000, China
3. The Key Laboratory of Fluid and Power Machinery, Ministry of Education, Xihua University, Chengdu 610039, China