Digital Control of Single-phase Power Factor Preregulators with Input Voltage Estimation

This paper proposes a fully digital control of boost Power Factor Preregulators (PFPs) with input voltage estimation. The proposed solution is based on a conventional multi-loop structure for PFP with an internal current control and an outer voltage control possibly with fast dynamic response. Instead, input voltage sensing is avoided by using a conventional PI (proportional-integral) current regulator for the estimation of the rectified input voltage. The use of the estimated rectified input voltage for the generation of current reference introduces an additional control loop which, however, increases the stability margin of the current regulator. The digital control has been implemented using the TMX320F2812 DSP, which has been proven to be an effective hardware for rapid prototyping. Experimental results on a single-phase 400W boost PFP show the effectiveness of the proposed approach.