Zero-voltage switching current-fed flyback converter for power factor correction application

Previous research on flyback power factor correction (PFC) converters exposes some inherent shortcomings, such as high-voltage spike on the metal oxide semiconductor field effect transistor (MOSFET), frequency variation, pulsating input current and hard switching operation. This study presents a new topology for PFC applications named zero-voltage switching (ZVS) current-fed flyback converter to not only achieve spike-free voltage, ZVS on the MOSFETs, but also improve the input current quality. By utilising quasi-z-source configuration, the voltage spikes on the MOSFET are effectively eliminated using only a capacitive clamper, resulting in no-loss consumption. Low-voltage MOSFETs with low on-resistance R_ds(on) are used to improve the efficiency. In addition, by taking advantage of the average current mode control with the continuous conduction mode operation, the input current perfectly tracks the input voltage. To demonstrate the circuit´s feasibility, a 100-140 V input, 28 V/5 A output laboratory prototype was built. The experimental results showed that the proposed topology completely eliminated the voltage spikes on the MOSFETs. The efficiency was improved using low R_ds(on) MOSFETs, and ZVS was achieved. In summary, the proposed topology meets the high efficiency and high-input current quality requirements.