Parallel connection of SiC MOSFET modules for future use in traction converters

Silicon (Si) IGBTs are widely used in railway traction converters. In the near future, Silicon Carbide (SiC) technology will push the limits of switching devices in three directions: higher blocking voltage, higher operating temperature and higher switching speed. The first SiC MOSFET modules are available on the market and look promising. Although they are still limited in breakdown voltage, these wideband-gap components should improve traction-chain efficiency. Particularly, a significant reduction in the switching losses is expected which should lead to improvements in power-weight ratios. Nevertheless, because of the high switching speed and the high current levels required by traction applications, the implementation of these new modules is critical. In this paper, the authors focus on the parallel connection of Dual-SiC MOSFET modules. The key points are underlined and an original approach is proposed to design the bus-bar and the gate drive circuit. Experimental results performed on an Opposition Method test-bench, valid the good operation of three Dual-SiC MOSFET modules in parallel.