Research On Single-stage Resonant Isolated AC-DC Power Factor Correction Converter

With the rapid development of the economy,a large number of power electronic device are widely used in industrial production and daily life.The large-scale application of these power supply devices will inject a large amount of harmonics into the power grid,which may cause unstable operation of other electrical equipment or even damage the electrical equipment.Power Factor Correction(PFC)technology came into being.The traditional two-stage boost-type isolated PFC converter has the disadvantages of many components,low conversion efficiency and large volume of the converter.Aiming at the problems of traditional two-stage converters,a new single-stage resonant isolated bridge PFC converter topology based on active-clamping soft switching technology is presented in this paper,the working principle of soft switch and the operation characteristics are also analyzed in detail.The characteristics and analysis results show that it s voltage gain is only related to the transformer’s ratio and duty cycle,and has nothing to do with the resonance parameters and switching frequency.The converter has similar boost characteristics as the traditional Boost converter.Compared with the traditional isolated two-stage converter,the new single-stage PFC converter only requires single-stage control,and the control method is simple.With active clamping technology,zero-voltage soft-switching of the main and the auxiliary power tubes can be achieved,and fewer components are required,and the conversion efficiency is higher.In order to further improve the conversion efficiency and improve the input current harmonics and power factor,an improved bridgeless single-state isolated PFC converter based on the new bridge PFC converter was proposed,and its soft switching operation principle was also analyzed,and state-space averaging method is used to establish state-space and small-signal mathematical models for the proposed bridgeless converters.The amplitudefrequency and phase-frequency characteristics of the transfer function with input current and duty cycle under different input voltage conditions are analyzed.Based on the onecycle control method,the two PFC converter topologies are also analyzed in detail.Finally,the simulation models were built with MATLAB and PSIM software,and the topologies and control methods of the proposed two single-stage isolated PFC converters were simulated and studied.A experimental prototype based on Si C Mosfet power tube of 3k W single-stage bridge PFC converter and the experimental prototype of a low-power single-stage bridgeless PFC converter are designed and built respectively.Experimental results show that the two new single-stage isolated PFC converters based on soft switching technology proposed in this paper can achieve zero-voltage switching of the main and the auxiliary power tubes,and both of them have the advantages of high input power factor,low harmonic content of grid-side input current,and high conversion efficiency.The analysis result based on the comparison of the two topologies shows that the bridgeless converter topology has better performance.