Research Of Soft-Switching Bridgeless Boost PFC Technology

PFC(Power Factor Correction)has become one of the most important research aspects in power electronics field. It can shape line current and eliminate the undesirable effects on power net work by the line current harmonics. Consequently it increases the performance of switching mode power supply(SMPS)and improves the quality of power net work as well.The topology employed in power factor correction single-phase supplies often consists of a front-end full-bridge diode rectifier.At any given instant, there are relatively more on-state semiconductors in the circuit. The total conduction losses always include two diode losses from the front-end bridge rectifier.In rather high power applications, the circuit usually operates in CCM mode. The diode conduction losses have influenced on the improvement of power efficiency. High power density and fast transient response of the circuit can be achieved by increasing switching frequency. However, the switching losses increase in direct ratio.The power supply suffers from high electromagnetic interferences produced in the switching transition and the reverse recovery in power diode.From these, An improved minimum voltage stress of bridgeless Boost PFC topology is proposed in this dissertation. The bridgeless boost PFC with soft-switching uses bi-directional switches as substitutes for rectifier diodes. It not only can achieve rectification in the primary circuit but also high power factor is obtained simultaneously. For both the conduction and commutation losses are reduced in the bridgeless boost PFC with soft switching, simulation results show it is a high efficiency power factor correcting approach.Based on one-cycle control chip IR1150,a 300W bridgeless Boost PFC prototype with 80-264VAC input voltage and 400VDC output voltage has been made.The experimental results satisfy design requirment and the proposed bridgeless PFC circuit has good performance.