Torque Ripple Of Induction Motor Driving System And Its Control

On the basis of the magnetic circuit, the paper firstly developed the nonlinear dynamic model of asynchronous AC motor by curve fitting method, taking into account the main magnetic circuit saturation.The paper introduced the switch function and developed the models of the inverter, concerning dead-time or not, and analyzed the effect of dead-time on the output of inverter, under various modulation mode. The paper also integrated the inverter model and nonlinear dynamic model of asynchronous AC motor and obtained the asynchronous AC motor speed governing system model covering the dead-time. Based the model, stationary . torque ripple of system is simulated, under SPWM, SVPWM, MTPWM and THIPWM modulation mode respectively. The results show:1. On the aspect of DC voltage utilization factor, THIPWM is the highest of four, while SPWM is the lowest;2. On the aspect of stationary torque ripple, THIPWM is the best, and the THIPWM is second, taking into the dead-time;while concerning the dead-time, SVPWM and THIPWM also can reduce the torque ripple, but MTPWM is the best.