Research On Speed Control And Torque Ripple Reduction In Outer-rotor Switched Reluctance Motor

The outer rotor switch reluctance motor(OSRM)can be used as wheel hub motors with the advantage of low-speed and high-torque,being suited to urban commuting and logistics vehicles.This paper researches five-phase OSRM,which is used in electric cars for wheel hub motors,and the main contents of this paper is that starting,regulating speed and reducing the OSRM torque ripples.A five-phase OSRM is analyzed by the finite element model—Magnet.The mechanism of the torque ripples is studied and a new step exciting current mode is suggested for solving the large torque ripples in traditional field current mode,which is verified by simulation model.The experiments are implemented by DSP TMS320F28335 from TI and the driving module is designed by an asymmetric half-bridge structure.This paper completes the speed adjustment experiment,including soft start,no-load speed adjustment,load speed adjustment and efficiency test.Experiments show that the OSRM can work regularly and be suited for electric cars.The influence of the reference current and the overlap angle of the excitation current mode on torque ripples are learned.The algorithm of the step exciting current mode is designed and the torque ripple of the step exciting current mode and traditional modes is analyzed.Experiments show that the new step exciting current mode can reduce the OSRM torque ripples and achieve the minimum torque ripples by adjusting excitation parameters.