Quasi-Fixed Switching Frequency Control of CRM Boost PFC Converter Based on Variable Inductor in Wide Input Voltage Range

With traditional constant on-time control, the switching frequency variation range of critical conduction mode boost power factor correction converter is large during a half line cycle, not to mention the wide range of input voltage's rms value. For this issue, this article puts forward a quasi-fixed switching frequency control, which combines the variable on-time and variable inductor technology together. Furthermore, a lower output voltage ripple and a higher efficiency are obtained. In spite of the power factor decrease, the input current harmonics still satisfy the IEC61000-3-2 Class D limits. The detailed theoretical analysis and experimental results are presented in this article.