Advances in electromagnetic interference modeling and noise reduction for adjustable speed motor drive systems

With the PWM techniques widely applied in motor drive systems, the impact of the electromagnetic interference (EMI) in adjustable speed drive (ASD) system cannot be ignored. EMI noise in motor drive systems could bring electromechanical damages to the motors as well as reduce the stability of the ASD system. Since the high frequency noises propagate paths are quite complicated compared with fundamental frequency components, the high frequency EMI noise coupled through system's parasitic parameters is difficult to analyze and eliminate. In this paper, the EMI modeling techniques for different function units, such as induction motors and rectifier-inverters, in ASD systems, are reviewed and evaluated in terms of applied frequency range, parameterization of the model and the accuracy of the model. The motor's EMI models are categorized based on modeling techniques and model's topologies. Furthermore, the modeling techniques for conventional rectifier-inverter systems are summarized. Based on the models of ASD system, the EMI noise suppression techniques including passive filter techniques, Wheatstone bridge balance technique, active filter techniques and optimized modulation techniques are reviewed and compared.