Design of a Hybrid Common - Mode EMI Filter for Traction Inverters in Electrical Vehicles

Inhalt:
Higher power density due to silicon carbide switches, rising battery voltages up to 800 V and the mechanical benefits of unshielded battery cables require bigger EMI filters necessary for traction inverters in electrical vehicles. In order to counteract this trend, hybrid EMI filters, which are a combination of passive and active components, represent a promising opportunity to reduce the size of inductive filter elements. This paper presents a design approach and a first prototype of a hybrid filter for an automotive traction inverter. Different filter topologies are discussed in order to find the best match for the use case. Finally, the prototype’s attenuation is evaluated in a CISPR 25 standard test setup.