The Development Of High Power Aeronautical Static Inverter Based On Si And SiC Devices

Aerospace Static Inverter(ASI)is a kind of inverter which uses power semiconductor devices to convert DC power supply on aircraft into a fixed voltage and frequency.With the complexity,diversification and refinement of electrical equipment on aircraft,compared with the past,modern aircraft has higher and higher requirements on the function and performance of airborne power supply,which makes ASI develop towards the trend of miniaturization,lightweight,high efficiency and modularization.Compared with Si based power semiconductor devices,silicon carbide power semiconductor devices have a series of superior characteristics.Therefore,its application in ASI will have a very good development prospects,but there are relatively few related researches on applying Si C power devices to ASI.Making the development of two-stage 3k VA power-stage three-phase ASI as the goal,combining the design specifications of the static converter and the characteristics of Si C MOSFET,and aiming at the key issues of volume,weight,efficiency and modular design,this thesis starts from the topological structure,modulation strategy,sampling method,control algorithm and application of new power devices,and carries out the comparative study of Si MOSFET and Si C MOSFET-based aerospace inverter power supply,their design methods are introduced in detail.The research content of this thesis is as follows:1.In-depth understanding and analysis of ASI research status,combined with the characteristics comparison results of semiconductor power devices,it is pointed out that Si C devices are the preferred power switching devices in future aviation power supply,and provide a new idea for ASI miniaturization and lightweight.2.Based on the analysis of the research literature on ASI,this thesis determines the two-stage of three-phase combined inverters as the overall circuit topology of ASI,the push-pull forward circuit as the front-stage DC/DC converter topology,the traditional full-bridge inverters as the back-stage DC/AC inverters topology,and this thesis focuses on the in-depth study of the back-stage DC/AC inverters.3.According to the selected topology,the equivalent model of the DC/AC single-phase full-bridge inverter and three SPWM modulation methods are analyzed theoretically,the simulation models of SPWM driving pulse,single-phase full-bridge and three-phase combined open-loop and double-closed-loop control systems are built respectively,the feasibility of the inverter system control method and the accuracy of the parameter calculation are verified.4.Based on the simulation verification,the hardware and software design of the digitally controlled three-phase combined ASI is carried out,including the drive circuit,isolation circuit,auxiliary circuit,sampling circuit,DSP minimum system design and related SPWM generation,PI algorithm and other programs.5.The platform of a 3k VA power stage three-phase inverter power prototype based on Si device and a 1k VA power stage single-phase inverter power supply prototype based on Si C device are designed and built in the laboratory.After testing the two prototypes,the experimental results verify the correctness of theoretical calculation,simulation analysis and hardware and software parameter design.It also proves that Si C MOSFET has excellent switching performance and low loss characteristics compared with Si MOSFET,which can be effectively improved the power density of the inverter power supply in ASI applications,and provides a reference for expanding the application range of Si C power semiconductor devices in aviation power supply.