Study On The Drive Technology Of Srm With Modular Converter Based On Limited Feedback

In recent years,the more/all electric aircrafts(M/AEAs),electric vehicles(EVs)and hybrid EVs are becoming a viable transportation option due to the increasing energy crisis and environmental concerns.Switched reluctance machine(SRM),which has several attractive features,such as simple structure without permanent magnet,good performance over wide speed range,high reliability and strong applicability for harsh environment,has attracted extensive attention,and it also has broad application prospects and huge potential for aerospace and electrified transportation.However,the topologies of converter of SRM are different from the ones of ac machine,so the standard switch modules cannot be used which makes the converter low-integrated.In addition,the doubly salient structure and highly non-linearity of magnetic field lead to serious torque ripple,which have constrained the application of SRM deeply.In order to obtain high performance,each phase needs current and voltage sensors.These requirement yields more expensive and larger size,which limits its application.In this paper,theoretical research and experimental verification were adopted to raise integration of the converter,reduce the number of current sensors and decrease the torque ripple of SRM.Adopting the standard and commonly used switch modules is base of improving the system integration.For a 3-phase SRM,the modular converter adopted is composed of a dual and a 3-phase full bridge switch module,which are standard industrial switch modules,and the windings of the SRM are in star-connection.In this paper,novel operating modes were proposed and the dynamic performances of the SRM and converter efficiency were compared with the conventional asymmetric half-bridge converter.According to the modular power converter and the proposed operating modes,this paper proposed a novel phase current reconstruction method for 3-phase SRM with single bus current sensor.Depending on the special operating modes and one PWM signal injection,the bus current is processed to reconstruct the phase currents in both magnetization and demagnetization regions.With the reconstructed phase currents,the conventional control schemes of the SRM,for instance,single-pulse voltage(SPV)and hysteresis current control(HCC)method,are implemented,and both open-loop and closed-loop conditions are involved.Advanced control methods,such as direct instantaneous torque control,was also presented,where the instantaneous torque was estimated based on the reconstructed phase current.SRM drive system with modular converter was built,and the effectiveness of the proposed method was verified by experiments under various operating conditions.