Detection of EMI Issues Caused by Differential-Mode Voltages on an Electric Scooter

Typically, the most anticipated coupling to sensitive components of an electric scooter is through common mode. However, it is shown that such scooters can be susceptible to the differential mode voltage at the input of the controller, which is often neglected. In this paper, susceptible-to-electromagnetic-interference frequencies due to differential mode voltages are identified on a real case of an electric scooter. After an initial risk assessment using basic equations, the resonant frequencies are determined. Then the response is verified on the electric scooter using a VNA measurement with the direct injection technique.