Characterization of Three-Phase Common-Mode Chokes at High Frequencies

This letter presents a method to characterize three-phase common-mode chokes at high frequencies. By performing a modal analysis of a high-frequency circuit model of the common mode choke regarded as a six-ports device, we demonstrate that when excited in a simple setup, the common-mode and differential-mode resonances of the three windings of the common mode choke can be plainly observed. This permits us to predict the response of the common mode choke to common mode and differential mode excitations with a simple measurement, i.e., two different setups are not required. Also it allows us to develop a method to determine the high-frequency parameters of the circuit model from the result of this simple measurement. Different commercial three-phase common-mode chokes have been measured and the predicted performance of the model has been compared with measured responses.