A SiC-Si Hybrid Module for Direct Matrix Converter With Mitigated Current Spikes

Reliable and affordable ac/ac power conversion plays a key role in supplying various electrical equipment. Among the options available, the direct matrix converter (DMC) outperforms its counterparts (e.g., ac/dc/ac), in terms of lifespan and compactness, due to its omission of fragile and bulky dc-link capacitors. However, most off-the-shelf DMC modules suffer from high input current spikes, which if unresolved can noticeably increase current stresses and lower efficiency. Origin of the spikes and a mechanism for reducing them are hence studied in this article, before developing a low-cost silicon carbide (SiC)-Si hybrid module for implementing DMC reliably and compactly. The developed module consists of 18 Si insulated gate bipolar transistors (IGBTs) and 18 SiC junction barrier Schottky (JBS) diodes connected in a common-collector structure. The improved reverse recovery property of the SiC JBS diodes then permits the hybrid module to operate with mitigated current spikes. To demonstrate, the hybrid module has been fabricated, tested, and compared with two counterparts in terms of their input current spikes and power losses over different output voltages and switching frequencies. Experimental results have proved the expected performances of the hybrid DMC module, which collectively can accelerate large-scale emergence of small all-semiconductor drives for industrial pumps, cooling and refrigeration systems, and others widely needed in developing economies.