ZHANG Xiong1,2,ZHANG Yixuan1,ZHANG Ming1, WAN Shuting1,2?覮,HE Yuling1,2,DOU Longjiang1,2
(1. Hebei Key Laboratory of Electric Machinery Health Maintenance & Failure Prevention,Baoding 071003,China; 2. Department of Mechanical Engineering,North China Electric Power University,Baoding 071003 ,China)