An Ultra-Fast and Non-Invasive Short Circuit Protection Strategy for a WBG Power Electronics Converter with Multiple Half-Bridge Legs

This paper presents a novel short circuit protection strategy for a wide-band gap power electronics converter composed of multiple half-bridge legs. The main approaches of the proposed strategy are a single point of monitoring (SPM) indicating the short circuit events occurred in a multiple switching legs and a non-invasive implementation of an ultra-fast short circuit current detection strategy. Ultra-high frequency (UHF) AC current, tens or hundreds of MHz, flowing through the decoupling capacitor represents the short circuit current flowing through the multiple switching legs. To capture the UHF AC current, a noninvasive MHz bandwidth magnetic current sensor is applied to the PCB conduction path of the converter. In this paper, simulation results of the short circuit current representation through the DC- link network, especially through DC capacitors, a non-invasive approach for the measurement of the decoupling capacitor current, and experimental results showing the UHF AC current sensing performance are presented.