Phase leading input capacitor compensation using variable inductor with high efficiency in a CRM boost PFC

Abstract

In low-to-mid power supplies, a critical mode (CRM) boost power factor corrector (PFC) converter is a popular topology due to its simple control and no reverse recovery problem. In a CRM boost PFC, the poor power factor due to phase leading input current (PLIC) by input capacitor (Cin) has been pointed out. There has been an effort to compensate PLIC in a CRM boost PFC by digital control. However, digital control is rarely used due to its high cost under 300W application, where the cost is the one of the key factors. In this paper, a new analog control method is proposed to compensate PLIC in a CRM boost PFC. It is achieved by making a lagging current using a variable inductor. The proposed method uses a few components which are very small and cheap. The feasibility of the proposed converter is validated with an 90-264 VRMS input and 390 V/0.5 A output prototype.