Analysis Of Electromagnetic Torque Mechanism And Torque Ripple Suppression Strategy Of Flux-modulation Double-stator Machine

Recently,field-modulation machines have attracted widespread attention due to their excellent characteristics of low speed and large torque.Based on the magnetic field modulation effect of the air-gap,there is a very complex harmonic magnetic field in the air-gap of field-modulation machines,which breaks the design law of the same number of pole pairs of the stator and rotor in conventional machines.While bringing large torque,the abundant magnetic field harmonics may cause severe torque pulsation,which will cause severe speed pulsation,and greatly limits the application of field-modulation machines in high-precision servo systems.Therefore,it is very necessary to study the torque mechanism and torque ripple suppression of field-modulation machines.This thesis will research a Flux-Modulation Electrically-Mathematical Double-Stator Machine(FMEE-DSM)with double stator and double air gap structure based on the following:1.Combined with the basic structure of FMEE-DSM,the no-load air gap magnetic field and armature reaction air gap magnetic field are analyzed based on the principle of magnetic field modulation,the effective working harmonics are determined according to the order and rotation speed of the obtained air-gap magnetic density harmonics,and the FMEE-DSM electromagnetic torque generation mechanism is clarified.2.Based on the finite element analysis(FEA)and mathematical model,the ontology simulation modeling of FMEE-DSM is built,and the field-oriented control(FOC)of FMEE-DSM is first realized.In view of the large torque ripples of FMEE-DSM under traditional FOC,the main components of torque ripple are analyzed,and the dominant harmonic components of torque in FMEE-DSM are accurately identified.3.In order to effectively suppress torque ripple,a second-order iterative learning control(Second-Order ILC)strategy was proposed.The period of iterative and the number of iteration were considered comprehensively to shorten the iteration time,so as to accelerate the convergence speed of ILC.4.To verify the feasibility of proposed control strategy,a test bench of the FMEE-DSM control system was built based on d SPACE 1103.Accordingly,both the static and dynamic performances of the FMEE-DSM were investigated under the conditions of no-load and rated load.The theoretical analysis,computer simulation and hardware experimentation are given to verify the proposed second-order ILC.