Simulation Model of Common-Mode Chokes for High-Power Applications

Linear and nonlinear Cauer-network models for nanocrystalline inductor cores are developed and used for circuit simulations of common-mode chokes for inverter-based drive systems of several hundred kW. Experimental measurements of the chokes´ performance in a high-power test bed are compared to the model results. When the model is based on measured characteristics of the material used, the match to measured behavior is good. Damping inherent in the material characteristic is adequate, such that additional damping is not useful. The primary limitation to accurate prediction of loss in practice is the tolerance on specifications of core characteristics, particularly at high frequency where limits are not specified.