Extending Winding Capacitance Cancellation to Three-Phase EMC Input Filter Networks

Techniques have been presented in the literature for canceling stray capacitances for inductors in single-phase power filters. With the same aim, the flexibility of three-phase networks is here explored. A thorough theoretical analysis is presented, where pros and cons of parasitic cancellation networks are highlighted and improvements are proposed. A systematic mathematical procedure to evaluate impedances for different noise modes in three-phase circuits is presented. The influence of parasitic effects is accessed and asymmetrical capacitance cancellation is proposed, facilitating applications in switched power circuits. Experimental results are presented, which prove the feasibility of the presented techniques.