Permeance Function Analysis And Electromagnetic Noise Analysis Of Double-stator Field-modulation Machine

Recently,field-modulation machines have gained more and more attention due to its merits of high torque density and ability of low-speed direct drive.The abundant magnetic field harmonics in the air-gap of the field-modulation machine can result in high torque and high radial electromagnetic force on the core as well,which will cause great radial vibration displacement on the core and hence,the great electromagnetic noise.As the quality of living improves,people have raised the awareness of noise suppression in both living and working circumstances.Therefore,to prompt the application of field-modulation machines,the noise analysis of the field-modulation machine is essential.This thesis takes field-modulation double-stator electrical-excitation synchronous machine(FM-DSEESM)as an example to be analyzed.Considering the special configuration of the dual air-gaps,permeance function is used to investigate the radial electromagnetic force on the inner surface of the outer stator in FM-DSEESM.Then the radial electromagnetic force is coupled with the modal analysis to investigate the electromagnetic noise responses in both no-load mode and on-load mode.This thesis mainly consists of the following aspects:1.Based on the configuration of the dual air-gaps and the distribution of the magnetic flux lines,the permeance functions of FM-DSEESM are deduced and the magnetic field densities in the dual air-gaps are calculated.By the application of Maxwell tensor method,the harmonic components of the radial electromagnetic force on the inner surface of the outer stator are calculated and classified by their sources.The electromagnetic finite element model of FM-DSSESM is built.The simulation results,along with the prototype experiment results,are compared with the analytical results for validation.2.Modal test platform for FM-DSEESM is set up and the modal tests for FM-DSEESM are carried out.Based on the test results of modal shapes and their corresponding modal frequencies,the modal finite element model is built.3.The radial electromagnetic force distribution on the inner surface of the outer stator is coupled with the modal model to investigate the vibration response of FM-DSEESM in both no-load mode and on-load mode.Acoustic response is further investigated by boundary element acoustic model and modal participating factor(MPF)is used to find the most prominent contributor in modal modes during the vibration and noise responses.