Research On The Control System Of A Novel Power Converter For Seven-phase Switched Reluctance Motor

Switched Reluctance Motor(SRM)has a series of advantages,such as simple and sturdy structure,low manufacturing cost,flexible and convenient control,good fault tolerance performance,and suitability for high temperature and high speed.However,it also has shortcomings such as large torque ripple and low power density.Multiphase SRM has a series of advantages of traditional SRM,as well as lower torque ripple and higher power density,as well as higher reliability and fault tolerance performance.However,the increase in the number of motor phases will lead to an increase in the cost and complexity of multiphase SRM power converters.Therefore,the research on lowcost and high-performance SRM new power converters is of great significance.This thesis mainly studies a new type of power converter,the seven phase N+1type power converter,for the seven phase 14/8 structure U-shaped segmented rotor SRM(referred to as the "seven phase SRM").It improves the performance of existing SRM power converters,allowing them to simultaneously meet the requirements of a small number of power devices,flexible and convenient control,good fault tolerance performance,and high reliability.It also requires the topology,working mode,and load operation of the new power converter The fault-tolerant performance was studied and compared with the performance of traditional power converters in start-up,rated,and other states under load operation.Firstly,the output performance and required topology of eight commutation methods,namely,the few phase commutation method and the multi-phase commutation method,for the seven phase SRM were analyzed.The most suitable commutation method with superior output performance and simple required topology structure,the two phase commutation method,was selected.Based on this,the traditional SRM power converter was improved to make it suitable for the seven phase SRM.The seven phase asymmetric half bridge power converter,the four phase full bridge power converter,were analyzed The characteristics of the seven phase common switching power converter and the seven phase C-dump power converter are summarized,and the selection requirements of the SRM power converter are summarized.The characteristics of the new seven phase N+1 power converter are studied.Secondly,the working mode of the new seven phase N+1 power converter was analyzed.Based on the two phase commutation method,the flow paths of excitation current,demagnetization current,and continuous current of the seven phase N+1 power converter in the two phase conduction mode,four phase conduction mode,and six phase conduction mode were analyzed.And a seven phase SRM finite element model was established in Ansys/Maxwell,a seven phase N+1 power converter model was established in Ansys/Simplorer,and a control system model was established in Matlab/Simulink.Based on this,a joint simulation system was established to analyze the output performance of the seven phase N+1 power converter under medium to low speed load operation and rated speed load operation,and the operational performance of the new power converter under switch circuit failure was studied and analyzed,By comparing and analyzing the load operation of the seven phase asymmetric half bridge power converter at medium to low speeds and rated speeds,it is concluded that the performance of the seven phase N+1 power converter is similar to that of the seven phase asymmetric half bridge power converter,with lower costs.Finally,based on the seven phase N+1 power converter studied in this thesis,the software and hardware system of the seven phase SRM controller was completed using TMS320F28335.The performance of the seven phase N+1 power converter under different control strategies was experimentally verified using the seven phase SRM as the control object.There are 71 figures,14 tables and 110 references in the thesis.