Small-signal modeling and linear control of a dual boost power factor correction circuit

In this paper, a small-signal modeling of a single-phase AC-DC dual boost power factor correction (PFC) pre-regulator is presented. The circuit consists of two interleaved boost converters. A high rated main boost, used for current wave-shaping and energy control, operates at low frequency; whereas an auxiliary boost uses a low rated device operating at high frequency and is controlled to compensate the low frequency ripple generated by the main boost. The control scheme proposed for the dual PFC is based on a small-signal model, which is developed using the average modeling technique along with the small-signal linearization process. The linear controllers are designed in the frequency domain, and are adjusted in order to ensure high dynamic performance of the PFC. Experimental results based on a laboratory 1 kW prototype validate the proposed control approach.