I. Introduction
Energy is the core driving force for contemporary social production, development and progress. With the continuous emergence of resources and environmental problems, traditional fossil energy is gradually giving new energy such as wind energy, solar energy [1]. In September 2020, China made the “carbon peak” to the world in 2030. In 2060, the “carbon neutrality” commitment will be more important in my country's energy consumption structure, such as photovoltaic power generation system. In recent years, with the significant improvement of the performance of band gap devices [2], the development of high performance magnetic materials [3] has promoted the development of electric transformers towards high efficiency and high power density into possible.