SiC MOSFET在航空静止变流器中的应用研究

摘要

The aeronautic static inverters(ASIs)which convert the airborne DC bus voltage to constant 400 Hz AC voltage are critical to the requirements of power density, efficiency, environment adaptability, reliability and electrical properties. The SiC semiconductor devices with high switching speed and good performance under high temperature have good promise to be applied in ASIs, but now there is still less research on using the wide range band gap power switches in ASIs. First, the key issues of applying SiC MOSFETs to ASIs is analyzed based on the typical ASI topology in this paper. Then considering the inverter cascaded by two half bridges, the losses of Si MOSFET-based and SiC MOSFET-based are compared. The comparison results show that the SiC MOSFET inverter’s total loss is less even though its on-state loss is high and the efficiency merit of SiC MOSFET inverters is more prominent with the switching frequency increasing. Finally, to meet the requirements of high switching frequency SiC MOSFET inverters, a drive circuit which adapts to high switching frequency and wide range PWM signals is designed. a two-stage cascaded 115 V/400 Hz half-bridge inverter rated at 500 VA is developed to validate the feasibility of the ASI with SiC MOSFETs.%航空静止变流器实现机载直流电到交流电的转换，对功率密度、效率、环境适应性、可靠性和电气性能等有较高的要求。碳化硅（SiC）半导体器件的开关速度快、高温特性好，在航空静止变流器中有很好的应用前景，但目前关于宽禁带器件在航空静止变流器中应用的研究比较少。首先结合现有的典型航空静止变流器电路拓扑分析了SiC MOSFET 应用的关键问题；然后针对航空静止变流器逆变级的两级级联半桥逆变器，对比分析了应用SiC MOSFET 与Si MOSFET 的损耗大小，分析结果表明在现采用的开关频率下，即使现有 SiC MOSFET导通损耗较大，但总损耗仍较小；且开关频率越高，SiC MOSFET的效率优势越明显，最后为适应高开关频率SiC MOSFET 逆变器的需要设计了一种适应高开关频率和宽占空比变化信号的 SiC MOSFET 驱动电路,搭建了1台500 VA、115 V/400 Hz两级级联半桥逆变器实验样机，并验证了应用SiC MOSFET 的航空静止变流器逆变级的可行性。