Hybrid SiC-Si DC–AC Topology: SHEPWM Si-IGBT Master Unit Handling High Power Integrated With Partial-Power SiC-MOSFET Slave Unit Improving Performance

Abstract

Based on partial power conversion concept, this article proposes a hybrid silicon carbide (SiC)-silicon (Si) dc–ac topology to improve performance in high power application. First, master unit (MU) uses Si-IGBT working in low frequency to handle main high power because of its high rated current capacity and high switching loss, whereas the low power quality of MU is induced by the low switching frequency. And SiC-MOSFET suffers from high cost and high conduction loss at high power level. To solve these problems, the partial-power slave unit (SU) based on SiC-MOSFET is connected with MU in series through line-frequency transformer, whereas SU works in high frequency to compensate the harmonic of MU and adjusts the total output voltage. In this new topology, the corresponding hybrid modulation strategy and multiple quasi-proportional-resonance control for single-phase system are introduced in detail to ensure the reliable operation. In the end, a 4.5-kW converter prototype was implemented and tested. Simulation and experiment results are given to verify the performance of the proposed hybrid dc–ac topology.