Research On Aeronautical Static Inverter Based On Current-Fed Half-Bridge Converter

Aeronautical Static Inverter is an important part of aircraft power supply system, so there is a higher requirement for ASI's reliability, volume, weight and conversion efficiency. In this paper, the research object is a two-stage ASI based on current-fed half-bridge converter, and most energy is spent on reducing volume and weight, improving conversion efficiency and reliability. The most significant research of study is the first DC/DC stage.Base on the understanding, analysis and comparision of common circuit topologies, the current-fed half-bridge(CFHB) converter which suitable for low input voltage and large input current situation is choosed as the DC/DC converter, and the half-bridge circuit is choosed as the DC/AC inverter. The typical structure scheme of ASI is analyzed, and an improvement plan is presented. At last, a scheme based on modula structureis proposed to solve the problems of typical scheme, such as centralized heat source, large volume and weight, low redundancy. At last the main technical parameters of DC/DC unit and DC/AC unit are given.The operation principle of current-fed half-bridge converter is analyzed, and the model of loss analysis is also deduced. The influence of the transformer's leakage inductancefor the converter is analyzed, and an improved scheme which can transfor energy of the leakage inductance to output side is proposed, so the improved scheme raises the efficiency of the converter directly. According to the requirement of later stage inverter, the control methods of the DC/DC stage are designed, which includes the control methods when the converter works on the condition of light load, continuous inductor current and converters in parallel. When the inductor current is continuous, the converter's stability is analyzed. At last the working principle of later stage is done. According to the requirements of the output, the modulation scheme and the control method are given.According to the main technical parameters, detailed calculation and optimized design to reduce the loss are given.To improve the efficiency, SiC MOSFETs are used in later stage and a SiC drive circuit which can works on a wide scope of duty ratio is given.Finally, simulation and a 500 VA ASI based on current-fed half-bridge converter are set up to prove the theory analysis. The efficiency curve of current-fed half-bridge converter is given and the highest efficiency is 95.36%, when the converter works on rated condition, the efficiency is 94.58%.