Ultra-Fast Short-Circuit Detection for SiC-MOSFETs Using DC-Link Voltage Monitoring

Abstract

Power modules with silicon carbide (SiC) metal-oxide semiconductor field-effect transistors (MOSFETs) offer low losses through high switching speeds and optimized loop inductances to achieve the best possible performance. Increasing the switching speed while reducing the loop inductance leads to a rapid current rise in the event of a fault, e.g., a short circuit. Therefore, fast detection of overcurrent and short-circuit faults is essential for protecting the components from damage. Although recently published approaches are able to achieve a detection time of no more than 200 ns, this still does not fulfill the requirements of highly optimized switching cells with low loop inductances and high operating temperatures. This paper presents an ultra-fast short-circuit detection by monitoring the dc-link voltage of the converter. Compared to state-of-the-art methods, the proposed design has several advantages, e.g., lower component count and fastest possible detection times of less than 60 ns over the entire operating range of the converter. Both simulations and measurements verify the performance of the proposed short-circuit detection for an optimized inverter with embedded SiC MOSFETs.