Propagation Paths and Filter Methods for Common Mode (CM) Currents in WPT systems for Electrical Vehicles (EV)

Inhalt:
Wireless Power Transfer (WPT) systems for electrical vehicles transfer energy by magnetic field over an air gap of several centimeters. Beside the limits for magnetic field strength, mainly caused by the stray fields of the open structure with loosely coupled coils, there is a request to measure and limit the common mode currents on the power line between the primary power electronics and resonant circuit. The common mode currents are expected to cause additional emissions at high frequencies. In this work the propagation paths of common mode currents in WPT systems are investigated and possible filter methods are evaluated.