Common-Mode EMI Noise Analysis and Reduction for AC–DC–AC Systems With Paralleled Power Modules

In this article, the common-mode (CM) noise model is developed for an ac-dc-ac system with paralleled power modules. The CM noise contributions from both rectifiers and motor drives are analyzed. The interaction between the ac/dc rectifiers and dc/ac motor drives is explored. The CM noise reduction techniques which include a decoupling inductor technique and a CM noise balance technique are proposed to reduce the CM noise on the ac input side. Experiments and simulations were conducted to validate the developed CM noise model, rectifier and inverter interaction theory and CM noise reduction techniques.