Design Of GaN HEMT-based MHz Boost PFC

With the continuous improvement of living standard,people are more and more inseparable from a variety of electronic devices.And switching mode power supply plays a significant role in all power electronic equipment,but its harmonic pollution not only affects the operation of itself,but also endangers the security of power grid.Therefore,almost all AC/DC converters need the ability of power factor correction to meet the related harmonic standards.Meanwhile,the volume and weight of power supply are relatively large,such as personal computers,which mainly caused by passive devices,such as capacitors,inductors,etc.Therefore,increasing power density and reducing volume of power supply have become one of the development directions of power electronics.For switching mode power supply,the most direct way to reduce their volume is to increase the frequency.Accordingly,the research of high frequency power factor correction circuits,which is widely used in power electronics,is becoming a hot research topic in the field of power electronics.However,the silicon-based semiconductor devices,which are widely used in switching power supply,are difficult to adapt to the high frequency(MHz)environment due to the limitation of their own material properties.The wide band gap semiconductor power devices,such as gallium nitride(GaN)devices,have the characteristics of high withstand voltage,high working temperature and faster switching speed,which can achieve lower system cost and higher power density.There is a tendency to replace the original silicon power devices in some fields of high frequency,medium and small power,It provides the possibility for realizing high frequency miniaturization power supply.Based on studying the principle of commercial Boost PFC controller,this thesis puts forward the optimization proposal and scheme for the current boundary conduction mode Boost PFC design under the MHz.Finally,a 200W high frequency Boost PFC with GaN HEMT is designed,and the correctness of the system is verified by PSpice simulation and experiment.Meanwhile,the cause of the oscillation in experiment is analyzed systematically.