Small-signal modelling and linear control of a high efficiency dual boost single-phase power factor correction circuit

In this study, a small-signal model-based linear control design of a single-phase AC-DC dual boost power factor correction (PFC) pre-regulator is presented. The converter 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 averaged model of the converter, which is developed using the state-space average modelling technique along with the small-signal linearisation process. The linear controllers are designed in the frequency domain, and are adjusted in order to ensure the required performance of the PFC, namely a close-to-unity input power factor and a regulated DC voltage. Experimental results based on a laboratory 1 kW prototype validate the proposed theoretical approach.