Study Of Inverter Employing SiC Schottky Diode

With the development of power electronic technology, inverters have been widelyused in various fields such as industry and civil fields. Now the emphasis is put on howto improve the performance of the inverter. Most researches improve the performanceby means of better circuit structure or control techniques. But the jumpingdevelopments of inverter technology always accompany the appearance of new powerdevices. Therefore, selecting new devices has become an effective way to improve theperformance of inverters. As a new semiconductor material, Silicon Carbide has wideband gap, high thermal conductivity and high breakdown field. The SiC Schottkydiode has not only higher breakdown voltage and working temperature but also moresuperior reverse recovery characteristics than the traditional Si p-i-n diode. The SiCSchottky diode, used as the freewheeling diode of the inverter, can effectively reducethe power loss of the diode and the switching device and improve the performance ofthe inverter.Firstly, the working principles of switching devices and freewheeling diodes areintroduced, the loss of power devices is analyzed, and the new devices such as SiCMOSFET and SiC Schottky diode are introduced. Secondly, the PSpice simulation ofthe SPWM full bridge inverter has been performed with the Si p-i-n ultra fast diodeand the SiC Schottky diode respectively used as the free wheeling diode under thesame condition. With their comparisons, the results show that the SiC Schottky diodecan greatly reduce the power loss of inverters. Further more, an inverter employingSiC Schottky diode as the freewheeling diode is designed and tested: With thecomparison of the Si p-i-n diode inverter, the inverter employing the SiC Schottkydiode can increase the efficiency with the output power of100W, and the workingtemperature of the SiC Schottky diode is lower. The tested results prove the validity ofthe design and the superiority of SiC Schottky diode over Si p-i-n diode.