Modeling of the propagation of high-frequency currents in AC motors

This paper describes the phenomena of propagation of common mode high-frequency currents (HF) in the metallic parts of AC machines supplied by pulse width modulation (PWM) inverters. After identifying the privileged paths of these HF currents by means of finite elements (FE) analysis method, an equivalent electric model based on geometric parameters, electromagnetic and dielectric characteristics of the studied structure is proposed. This model makes possible to predict the HF currents in the different metallic parts of the studied structure and the total common mode current in the ground.