Experimental EMI study of a 3-phase 100kW 1200V Dual Active Bridge Converter using SiC MOSFETs

This paper presents a system-level EMI investigation in a new 3-phase 1.2kV 100kW insulated DC/DC converter. In this prototype, achieving full operation was prevented by false triggering of semiconductors due to large common-mode current through gate drivers. A passive filter embedded into the structure of the transformer to connect it to the ground is proposed as a corrective and cost effective solution to mitigate the electromagnetic interferences. New grounding layout enabled to reduce the common-mode current through gate drivers by up to 75% without decreasing the switching rate. This allowed to proceed to measurements on the prototype at nominal operation. The method is validated in simulation and extensive experimental results have been obtained from the considered prototype. This proved the feasibility of the proposed solution and showed the effect of the transformer design in EMI behavior of insulated DC/DC converters.

Introduction

Proper electromagnetic compatibility (EMC) design during development process of any type of electronic device is necessary to ensure the stable operation. The proper EMC design is a challenge when power semiconductors generate high-speed voltage and current transients. In switched mode power converters, the high switching speed of power semiconductors constitutes an important source of electro-magnetic interference (EMI). This means that the interference can disturb other devices in the close common electromagnetic environment. Therefore, electromagnetic compatibility (EMC) of the converter is a must to ensure not only its operation but also the proper function of other electronic equipment in its vicinity [1].