Research On Common-Mode Conducted EMI Suppression Strategy Of SiC Controller

In recent years,as the new energy vehicle industry continues to rapidly expand,the demand for advanced motor drive control solutions in this sector has grown considerably.,research on third-generation wide bandgap semiconductor technology has gradually deepened,and silicon carbide(SiC)has attracted more and more attention in the field of motor drive control due to its advantages of high breakdown voltage and fast switching speed.However,the ultra-high control frequency of SiC MOSFET controllers and their PWM control strategies can cause serious common mode conducted interference.In order to comply with the electromagnetic compatibility(EMC)standards in relevant industries,SiC MOSFET controllers must meet the basic functional requirements of motor control while addressing the electromagnetic interference they produce.Therefore,this thesis focuses on suppressing the common mode conducted interference generated by SiC MOSFET controllers.In this thesis,the principle of electromagnetic interference(EMI)caused by SiC controllers is studied in depth,and the sources of conducted EMI and the propagation path of common-mode conducted interference on SiC controllers are studied in detail,and a common-mode conduction high-frequency model under Matlab simulation software is built based on the above research,and the common-mode interference voltage at different switching frequencies is simulated and analyzed,which proves the importance of studying the suppression strategy of common-mode conducted interference of SiC controllers.Next,from the aspect of interference source suppression,this thesis proposes a random three-state pulse width modulation strategy for the EMI problem caused by switching high-frequency action and PWM modulation high-frequency harmonics,which suppresses common-mode conducted interference by changing the synthesis mode of vector voltage and carrier frequency,so that the common-mode voltage is reduced and the spectrum distribution of high-order harmonics is more uniform.According to the simulation analysis,it is verified that the random three-state pulse width modulation strategy has a good suppression effect on common-mode conduction interference.Furthermore,from the aspect of coupling path suppression,this thesis proposes an optimization design method for common-mode conducted EMI filters based on genetic algorithm SiC controller,which has excellent parameters and topologies and high degree of automation in view of the problem that it is difficult to obtain filters with excellent parameters and topology through empirical design in traditional filter design,and effectively shortens the time required to design common-mode conducted EMI filters.Overcome a series of problems in traditional filter design.According to the simulation analysis,the filter designed based on genetic algorithm can effectively suppress common-mode conducted interference.Finally,a common-mode conducted interference experimental platform is built to measure the initial common-mode conducted interference of the SiC controller,showing that the SiC controller has serious electromagnetic interference in the frequency range of 150 k Hz to 108 MHz.The proposed suppression strategies from the aspects of interference source and coupling path were experimentally verified,and finally the two suppression strategies were combined for double suppression experimental verification.The experimental results show that the common-mode conducted interference suppression strategy studied in this thesis can effectively reduce the common-mode conducted interference of SiC MOSFET controllers,and solve the problem of common-mode conducted interference exceeding the standard of SiC MOSFET controllers in the frequency range of 150 k Hz to 108 MHz,which has certain engineering significance.