1. School of Electronic and Information Engineering, Tiangong University, Tianjin, China
2. Tianjin Key Laboratory of Optoelectronic Detection Technology and System, Tiangong University, Tianjin, China
3. Engineering Research Center of Ministry of Education for High Power Semiconductor Lighting Application System, Tianjin Polytechnic University, Tianjin, China
4. School of Control Science and Engineering, Tiangong University, Tianjin, China