Optimizing the inductance cancellation behavior in an EMI filter design with the help of a sensitivity analysis

A novel algorithm for the iterative geometric optimization of EMI filters is presented. The two step approach of an equivalent electric circuit extraction, followed by a sensitivity analysis in the circuit as well as the 3D model domain drives the shape optimization. This allows for a deeper insight into coupling paths and their cause in the model, and their effect in the circuit domain. The concept of inductance cancellation in an EMI filter will be used to demonstrate the individual steps. Intermittent results provide insight into the physical relationship of parasitics and their effect on the transmission coefficient. The sensitivity analysis will ultimately drive the geometric modifications with the aim to find the design with the optimal filter performance.