中文说明：
单相BOOST PFC仿真电路，输入电压220V/50Hz，输出电压400V直流，采用闭环控制，实现功率因数校正功能，输入电流THD小于5%
English Description：
Single phase boost PFC simulation circuit, with input voltage of 220 V / 50 Hz and output voltage of 400 V DC, adopts closed-loop control to realize power factor correction function, and input current thd is less than 5%