说明：  根据对Boost电路工作原理和有源功率因数校正(APFC)控制方案的研究分析，设计了一款采用Boost电路的APFC变换器。输入电压为220V±10% (198VAC～242VAC)，输入频率为50Hz，输出的直流电压为400V，输出功率为500W。
(According to the research and analysis of the working principle of Boost circuit and the active power factor correction (APFC) control scheme, a APFC converter using Boost circuit is designed. The input voltage is 220V + 10% (198VAC to 242VAC), the input frequency is 50Hz, the output DC voltage is 400V, and the output power is 500W.)