Study of nonlinear-carrier control stability for PFC boost converters

Abstract

Nonlinear control considers an elegant technique for boost PFC converters. Switch duty cycle is determined by comparing a signal derived from the main switch current with a periodic, nonlinear carrier waveform that forces the input current to follow the input line voltage. That results in a near unity power factor. However, nonlinear phenomena have been detected in PFC circuits resulted in low power factor. In this paper, a study of the stability of nonlinear control in pre-regulator PFC converter with resistive load and two-stage PFC converter where DC-DC has replaced the load. Both circuits have been tested to determine the practical limitation for stable and unstable regions. Lastly, some design guidelines have been made clear for stable operation using stability maps.