1. Hebei University of Science and Technology, School of Electrical Engineering, No.26 Yuxiang Street, Shijiazhuang, Hebei 050018, P.R. China
2. Hebei University of Science and Technology, School of Electrical Engineering, No.26 Yuxiang Street, Shijiazhuang, Hebei 050018, P.R. China (Corresponding author), e-mail: xzh@hebust.edu.cn, https://orcid.org/0000-0002-5456-2610