Research Of Two Stage High Gain Soft-switching Inverter Based On GaN Device

The promotion of photovoltaic power generation technology is one of the effective measures to solve the energy crisis and environmental pollution problems.Photovoltaic grid-connected inverter is the core equipment of photovoltaic power generation system.The third generation semiconductor technology represented by GaN technology promotes the development of photovoltaic inverter in the direction of high frequency,high efficiency and high power density.In this paper,high gain DC/DC converter and single phase soft-switching inverter are studied,and the circuit efficiency is improved by combining GaN technology.Firstly,a dual-coupled inductor high gain DC/DC converter with ripple absorption circuit is proposed,which using the characteristics of ripple absorption and boosting of coupled inductor while combined with voltage doubler circuit and quadratic Boost circuit.The working principle and steady state characteristics of the converter are analyzed and verified by building simulation and experimental prototype.The experimental results show that the converter has the characteristics of low input current ripple,high voltage gain and low switching voltage stress.Secondly,based on the Boost-based switched capacitor circuit,a high gain DC/DC converter based on switched capacitor network is designed by introducing a quadratic circuit with ripple absorption circuit instead of Boost circuit.The working principle and steady state characteristics analysis of the converter show that it has the advantages of flexible topology,high voltage gain,low input current ripple and lower diode voltage stress.Finally,the correctness of the theoretical analysis is verified by simulation and experiment.Thirdly,a single phase GaN soft-switching inverter based on critical current continuous mode is designed.The working principle of the inverter working in the critical current modulation is analyzed,and the working characteristics of the inverter in three critical current modulation modes are compared.Three critical current modulation modes are simulated by Psim to verify analysis,meanwhile the loss of GaN device is simulated and analyzed.Finally,a two stage GaN inverter prototype is built.The experimental results show that inverter can realize zero voltage turn-on of switches.The use of GaN devices can effectively reduce the loss the circuit and make the inverter have the advantages of high frequency and high efficiency.There are 62 figures,8 tables and 80 references in this paper.