Generation of high-frequency common mode currents in machines of inverter-based drive systems

The additional HF (high frequency) common mode current of inverter-based drive systems can cause parasitic effects such as HF bearing currents and wide band EMI (electro-magnetic interference). This paper presents a straightforward approach to prediction of the HF common mode current based on the dv_Lg/dt at the motor terminals. Only design parameters of the machine are used. No additional measurements are required. The HF common mode current generation is described by a distributed-parameter network. This model allows anticipation of the HF common mode current in order to better predict possible parasitic effects. For a given frame size, the number of parallel winding branches has a strong influence on the amplitude of the HF common mode current