Predictive digital control of power factor preregulators using disturbance observer for input voltage estimation

The paper present a fully digital control of single-phase boost power factor preregulators (PFPs) based on inductor (or switch) current and output voltage measurements. Input voltage sensing is avoided using a disturbance observer, which provides a waveform proportional to the rectified input voltage. The proposed solution is based on a multiloop structure for PFP with an internal deadbeat current control and an outer voltage control with fast dynamic response. The resulting control algorithm is simple, accurate and robust respect to parameter mismatch. The digital control has been implemented both in a field programmable gate array (FPGA) and in a DSP (TMS320F2812), so as to test the proposed algorithm with different control delays. Experimental results on a single-phase 500 W boost PFP show the effectiveness of the proposed solution.