Abstract
In this paper, the operating principle and basic structure of the drive are introduced. An electromechanical coupled dynamic model of the drive is presented by means of electromagnetic theory and mechanical principle. The electromechanical coupled dynamic equations of the drive system are given. The concept of the electromagnetic mesh stiffness is presented and their calculating equations are obtained. Then, the natural frequencies and mode shapes of the electromechanical coupled dynamic system are analyzed. Finally, Changes of the natural frequencies of the electromechanical system along with the mechanical and electric parameters of the drive are analyzed, respectively.