Third harmonic compensation in bridgeless current sensorless PFC

Abstract

Single-phase Bridgeless power factor correction converters (PFCs) improve the conversion efficiency in comparison with the conventional PFCs, where a diode bridge plus a DC/DC boost converter are used, due to the absence of the input rectifier, but current sensing complexity increases. Its efficiency can be further increased, and its cost reduced by avoiding the input current sensor. This paper proposes a control strategy applicable to Bridgeless PFCs, implemented in a digital device (Field Programmable Gate Array, FPGA), where the grid current is not sensed. To compensate for the effect of the non-ideal operation of the converter, which result in current control errors, a third harmonic dependent function is introduced. The converter model is presented. Simulation and experimental results are used to assess the performance of the proposed method.