Modeling and control of a two-switch asymmetrical half-bridge Boost Power Factor Corrector for single-phase rectifiers

In this paper, a single-phase Power Factor Corrector (PFC) based on a two-switch asymmetric half-bridge Boost converter is analyzed. This topology improves the source current shaping by avoiding the control detuning phenomenon from which suffers the conventional single-switch boost PFC, especially at very low input voltage. Pulse-Width-Modulated (PWM) multi-loops control schemes are proposed and developed in order to ensure a unity power factor at the AC-source side and a regulated voltage at the DC-load side. The first one uses the simple and robust hysteretic-based controller; the second one employs a conventional PI regulator, whereas the third one is based on the model nonlinearity compensation approach. The design of the last two control methods is based on the state-space averaged model of the converter. The performance of the different control strategies is evaluated through simulations carried out on a numerical version of the converter. The implemented model of the converter is obtained by using the switching function technique. The control system is tested under both rated and disturbed operating conditions. The system performance is evaluated in terms of source current Total Harmonic Distortion (THD), input power factor and DC voltage regulation.