Investigation of Low Frequency Radiated EMI of the Three Phase Electric Motor System

In the realm of modern power electronics, motors find extensive application across various domains. To enhance energy density and facilitate miniaturization while achieving faster switching speeds, power electronic devices with such characteristics are widely employed for motor control. However, the adoption of these high-speed switching devices introduces a new set of challenges related to Electromagnetic Interference (EMI). Previous research has regarded radiated EMI (RE) from motors to be non-dominant in the presence of grounded motor casings. However, in certain circumstances, radiation generated by motors cannot be overlooked. In this paper, the radiation model is proposed to develop the LF radiated emissions for the motor. The mechanism of radiated emissions generated from the motor is analyzed in detail based on electrostatic theory. The developed model is validated via experiments. The impacts of different parameters on the radiated EMI are discussed.