Integration of Parasitic Cancellation Techniques for EMI Filter Design
Cancellation techniques have been developed to cancel both self and mutual parasitic parameters. The question is if it is possible to integrate them into one EMI filter so as to improve the performance of both CM and DM filters. The studies are carried out in CPES to investigate the possibilities and implementations of the integration of parasitic cacnellations. It is found that CM inductor's EPC cancellation, DM inductor's winding 90 degree rotation (to reduce the mutual inductance between inductors and capacitors) and the cancellation turn integrated with capacitor (to reduce the mutual inductance between two capacitors) can be integrated without any conflicts and performance degrade. Prototype is built for both one-stage and two-stage EMI filters. The insertion gain measurement verified the integrated cancellation techniques. Other cancellation techniques may conflict with each other so that they may be inefficient on filter performance improvement.