Due to the rapid development of the power electronics industry in recent years, a large number of new power electronic devices have been increasingly put into the microgrid, which has improved the efficiency of power production and brought about power quality problems. In addition, there are many types of distributed power sources in the microgrid, and the complexity and uncertainty of its power production also seriously affect the power quality of the microgrid, thereby affecting the development and progress of the microgrid. The main power quality problems in the microgrid are voltage fluctuations, harmonics, three-phase unbalance (voltage, current), frequency fluctuations, etc. Because the microgrid contains more nonlinear loads, its harmonic problems are particularly prominent .