Control of active power factor corrector using a single current sensor

This paper presents the realization of a boost-type active power factor corrector (APFC) using a single current sensor to sense the inductor current for input current shaping and output voltage regulation. Neither input voltage nor output voltage sensing is needed. The sensed inductor current is used for two main functions. The first one is for comparison with a sawtooth signal in order to shape the input current waveform. The second is for determining the input and output voltages by processing the rates of change of the inductor current when the main switch is in on and off states, respectively. Compared to conventional APFCs, the proposed technique has several advantages. Firstly, no dissipative voltage divider is required. Secondly, electrical isolation between the power conversion stage and the control stage can be achieved inherently. Thirdly, no complicated or sophisticated digital sampling and numerical computations are needed. The applicability and accuracy of the proposed technique have been confirmed experimentally