Design and Comparison of Output Filter Configurations for SiC-MOSFET-Based Automotive DC-AC Inverters

This paper investigates and analyzes different configurations of three-phase EMI filter for SiC-MOSFET-based automotive DC-AC inverters. Different configurations, such as single- and two-stage output filters (CM, dv/dt, dv/dt-CM, and sine-CM), are developed to investigate their performance at the output of SiC inverters. Filter performances are measured by their attenuation with respect to system requirements. The attenuation strongly depends on the mutual couplings between the filter components and their parasitic parameters. The parasitic parameters of the components and the electromagnetic couplings between the components are determined using ANSYS Q3D (FEM-MoM). In addition, a comparison is made between different filter configurations, considering the filter sizes, weights, and prices. It is found that proper selection of components, optimized placement of components, and suitable PCB design can significantly reduce the sizes, weights, and costs of EMI output filters. Finally, a measurement setup with different filter configurations is constructed for the EMI experiment. It is shown that two-stage optimized output filters attenuate EMI interference levels more.