Research On High Efficiency Two-Stage Aeronautical Static Inverter

Aeronautical Static Inverter(ASI) converts the generator or battery power to constant voltage and constant frequency AC power. ASIs provide high quality power for critical equipments on the plane, and they are the important parts of the power supply system.With the requirements of power supply is more and more high, aeronautical static inverter is developing toward the direction of high efficiency and high power density. This paper uses the two-stage aeronautical static inverter as the research object, learning how to improve the efficiency of DC/DC converter and decrease the volume and weight of dual buck full bridge inverter.Flyback converter due to its compact structure, simple control, and electrical isolation, is widely used in medium and small power applications. This paper adopts a double voltage output flyback converter, can achieve high voltage gain with lower turn ratio. Flyback transformer leakage will cause large voltage spikes on the primary side switch, reduce the efficiency of the converter. In order to solve this problem, a leakage energy absorption circuitt is proposed, which can recovery leakage inductance energy and released directly to the output side of the load.In order to reduce the volume of inverter filter inductor, dual buck full bridge inverter(DBFBI) with the carrier phase shifted SPWM(CPS-SPWM) control is used in this paper. In the control mode, filter inductor equivalent frequency is twice of the switching frequency, reducing the volume and weight of filter inductance. Through the inverter loss calculation, the influence of the switching frequency on the loss of inverter is analysised, and improve the switching frequency of the inverter to further reduce the size of filter inductor and weight.The GJB requirements: ASI can produce three times the rated current under the condition of short-circuit, and the duration of the program is not less than 5s. It is necessary to analysis the working principl of short-circuit, finding out the key factors which affect short-circuit loss. Through the theoretical analysis of short circuit loss, the method of reducing the short circuit loss with lower bus voltage is proposed. Finally, the simulation shows that the method of reducing short-circuit loss scheme is feasible.A 1KVA aeronautical static inverter is developed, and the experimental results have verified the correctness of the theoretical analysis.