Comparative efficiency analysis for silicon, silicon carbide MOSFETs and IGBT device for DC-DC boost converter

In present study, a comparative efficiency analysis for silicon (Si), silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) and insulated gate bipolar transistor (IGBT) device based DC- DC boost converter is performed. Due to different gate-drive characteristics of power semiconductor devices such as Si, SiC MOSFETs and IGBT device, different voltage levels are required to drive aforementioned devices. A 500 W boost converter for wide input voltage range (30-72 V) and 110 V output voltage is designed having a single gate driver circuit for Si, SiC MOSFETs and IGBT. A single gate driver provides the gate-source (or base-emitter in case of IGBT) signal for all the devices which eliminates the use of separate gate driver circuit. Si MOSFET and IGBT are driven by 12 V gate-source voltage whereas SiC MOSFET is operated by 18 V gate-source voltage using the gate driver circuit. An experimental study is performed for the comparative efficiency analysis for Si, SiC MOSFETs and IGBT device based converter for 20 and 50 kHz switching frequencies. It is found that SiC based converter provides highest efficiency approximate to 97.8%, whereas the lowest efficiency approximate to 94% is found for IGBT based converter at 20 kHz switching frequency. SiC based converter gives higher efficiency because lower conduction loss owning to lower on-state resistance as compared to Si MOSFET. Besides this, SiC application has another advantage such as low switching loss at higher frequency resulting compact size of converter. However, use of IGBT at higher switching frequency results in higher switching losses, hence lower efficiency of the converter.