| With the continuous development of power electronics technology and the improvement of performance requirements,permanent magnet synchronous motor(PMSM)drivers are developing towards high integration,high power density,and high-frequency.The high-frequency pulse signals generated by the internal power device switches contain large dv/dt and di/dt,leading to severe common-mode and differential-mode electromagnetic interference(EMI).Common-mode EMI,as the main component of conducted EMI and radiated EMI,has become one of the most severe interferences in PMSM drive systems.Therefore,this article focuses on the study of common-mode EMI filter for PMSM drive systems,and proposes a hybrid active common mode filter for three-phase PMSM drive systems to suppress common-mode EMI caused by power devices.The research content of this article mainly includes four parts:(1)The vector control model of three-phase PMSM based on Space Vector Pulse Width Modulation(SVPWM)is established,and the mechanism of commonmode EMI generation in the driving system is analyzed.On this basis,highfrequency parasitic parameters are extracted,the main circuit topology and time-domain model of the driving system with high-frequency impedance characteristics are established,and the conduction path of common-mode EMI is analyzed.(2)The topology types and working principles of passive and active EMI filters are analyzed,and corresponding insertion loss expressions and impedance characteristics are derived for different types of filters.Finally,the current limitations of different filters are analyzed.(3)To suppress common-mode EMI in PMSM drive systems,a hybrid active common mode filter based on passive and active EMI filters is proposed.Simulation has verified that this filter can improve insertion loss by changing the impedance characteristics of the filtering capacitor,achieving the goal of suppressing common-mode EMI,and has better insertion loss and frequency domain characteristics than traditional passive EMI filters.(4)Experimental platform of three-phase PMSM drive system used by testing hybrid active common mode filters is built.The results of indicate that the proposed filter has better common-mode EMI suppression effect and stability,compared to traditional passive EMI filters,and the effectiveness of the proposed filter are verified. |
