Comparing Switching and Conduction Losses of Uni- and Bidirectional SiC Semiconductor Switches for AC Applications

The presented research elaborates on the increase in conduction and switching losses when combining two regular SiC MosFETs to one bidirectional switch. The conduction losses are expected to double due to two semiconductors conducting the current while the switching losses should increase since the loop inductance is increased. Both effects are directly investigated through extensive double pulse tests and conduction loss measurements. The measured conduction losses are significantly lower than expected while no increase in switching losses can be measured. These directly measured losses are further verified through efficiency measurements with a 15 kW dc-dc converter prototype.