Z-Source Flyback PFC Rectifier for Energy Storage Systems

This paper proposes a wide range high step-down gain flyback power factor correction rectifier (PFC) based on the flyback DC-DC converter. The proposed rectifier is composed of a step-down Z-source network at the AC to DC stage, followed by a flyback chopper. The proposed PFC rectifier offers better input and output waveform qualities in comparison to the conventional buck-boost and flyback PFC rectifiers, because of continuous input current. Also, it ensures high power factor (PF) operation and low harmonic contents over a wide range of load and source variations with galvanic isolation. These features are practically of interest for a battery charging system. Furthermore, the proposed PFC rectifier allows for increasing the switching frequency due to a higher duty cycle possible for the same voltage gain than the competitors. Finally, the unity power factor operation is simply possible by just using a simple single loop voltage controller. A test bench of the proposed PFC rectifier is designed for performance evaluation in PLECS software. Also, the performance of the converter is experimentally confirmed by tests on a 230 Vrms to 48 Vdc rated at 200-W laboratory prototype.