Resonant frequency design for EMI filters to avoid current harmonic bands in electric vehicle traction motor drives

This study analyzed the problems occurring in the electromagnetic interference (EMI) filter used in electric vehicle (EV) systems and proposed a filter design to solve them. This study focused on the problems that occur when the DC link current harmonic component generated by the traction inverter coincides with the resonance frequency of the EMI filter connected in parallel with the DC bus. The DC link current harmonic was generated by the switching operation of the inverter, and the harmonic components were mathematically analyzed with a double Fourier series by considering the switching modulation technique. In addition, the EMI filter was equivalently analyzed and converted in consideration of the power network and harmonic component of the EV system. In this way, an appropriate resonant frequency band of the EMI filter was proposed, and the EMI filter with the proposed resonant frequency was manufactured and verified through experiments. In addition, the important factors to consider when designing the EMI filter were identified by comparing the harmonic characteristics applied to the EMI filter according to the DC link capacitor size of the traction inverter. KCI Citation Count: 0