Power Conversion Using Silicon Carbide

Silicon carbide(SiC)semiconductors offer revolutionary improvements in power electronics due to much lower conduction and switching losses, higher switching frequencies, higher voltage capability, higher operating temperatures and other superior properties relative to standard silicon devices. In Phase I, SiC MOSFETs were tested and characterized, confirming lower losses. It is projected that losses will be no more than one-fifth of that with silicon devices and, when combined with an operating temperature of 300 degrees C, the power semiconductor block of an inverter will be dramatically smaller and can be cooled with natural air convection (no fan). A power block for a 5 kW inverter has been estimated to be approximately a 1-inch cube. It will be constructed of entirely new materials that can withstand 300 degrees C with frequent thermal cycling. The output filter elements will be extraordinarily small also due to PWM switching at 100 kHz. In Phase II, a SiC-based inverter will be designed, fabricated and tested using the compact, high temperature power block developed in Phase I, along with a high frequency output filter and appropriate control system.