Analysis And Reduction Of Vibration In Switched Reluctance Motor

This dissertation is devoted to " Research on theory and control strategy of nonlinear vibration in switched reluctance motor ", which is supported by the National Natural Science Fund(59977005).A nonlinear function of inductance against rotor position is constructed. Based on the model, the effect of controlled parameters of SRM in APC and voltage-PWM on vibration is studied in time domain and frequency domain respectively. Research in time domain indicates that the effect of turn-on angular on phase current , shearing force and radial force is more significant than that of turn-off angular in APC and that if chopping frequency and speed is increased and duty is reduced in voltage-PWM, then phase current, shearing force and radial force are reduced, resulting in the reduction of vibration and acoustic noise. Research in frequency domain indicates that in APC and voltage-PWM, little modulation of controlled parameter can modify the spectrum of phase current, shearing force and radial force. So the spectrum can be modified to avoid the harmonic with inherent frequency of stator conveniently.Two-steps commutation in course of voltage-PWM is studied in the dissertation. The conclusion is that vibration of phase current, shearing force and radial force are reduced by use the two-steps commutation. Assorted control of controlled parameter are researched. The conclusion is that if quotient of chopping frequency and speed is confirmed, the shape of phase current, shearing force and radial force are identical. So in practical use, chopping frequency can be modified according with the speed.Nonlinear model of inductance against rotor position and phase current is constructed. Based on the model, formulae of nonlinear phase current, shearing force and radial force are calculated. Simplify the nonlinear phase current formula is done and the condition of using the simplified formula is studied according to the error analyses.Dynamic nonlinear simulation model of switched reluctance drives is constructed. Based on the model, torque ripple minimization based on torque observation is studied. Adaptive fuzzy PID is adopted in the closed speed loop in the model. Theconclusion is that the effect of torque ripple minimization is significant.