Predictive digital control of power factor preregulators with input voltage estimation using disturbance observers

The paper presents 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 PFPs with an internal deadbeat current control and a conventional outer voltage control, possibly with fast dynamic response. The resulting control algorithm is simple, accurate, and robust with respect to parameter mismatch. The digital control has been implemented both in a field programmable gate array and in a digital signal processor (TMS320F2812), to test the proposed algorithm with different control delays. Experimental results on a single-phase boost PFPs show the effectiveness of the proposed solution.