A Simplified Input Filter Capacity Current Compensation Scheme for 360–800 Hz CRM Totem-Pole PFC with Si MOSFETs

The critical conduction mode (CRM) totem-pole power factor correction (PFC) converter is widely used in low-to-medium power applications of airborne instrument power generation system due to its advantages of less power stage components and low switching loss. The leading phase of the input current caused by input filter capacity (IFC) current comes into unnegligible for high line frequency (360–800 Hz) grid, which deteriorates the PF value. In order to improve the PF, either a high-performance MCU or the look-up table (LUT) method is required for direct compensation of IFC current. However, for the purpose of matching the high and wide frequency (360–800 Hz) input voltage and input RMS voltage fluctuation ranges, the MCU with large storage capacity is needed for storing the LUT data. In this paper, a simplified IFC current compensation algorithm is proposed with low-cost commercial MCU and without any additional external storage component. Furthermore, in order to decrease the current distortion caused by the reverse recovery of body diode of MOSFET and the resonance between the boost inductor and output junction capacitances of switches, a variable on-time (VOT) control compensating the reverse current in the switching cycle, which can reduce the input current THD and further improve the PF. With the proposed control schemes, the input current THD and PF meet the RTCA DO-160G Std in the entire line frequency range in a 300W CRM totem-pole PFC prototype.