Simulation Study of Three-level DTC Based on Torque Predictive Control

In stator flux linkage estimator based on the flux amplitude and phase compensation,traditional direct torque control scheme of three-level inverter based on synthesizing voltage vectors,a new predictive control method was proposed to reduce the large torque ripple caused by discontinuity of the voltage vectors in a work period.Reference voltage space vector which will be added to the inverter next period can be determined by calculating the errors of the flux and torque by the last sample period.Vector is then synthesized by a space vector pulse width modulation(SVPWM) algorithm to keep a constant switch frequency.The simulation shows that the control method can lessen the torque ripple and maintain the waveform of stator flux nearly round and the sine character of current is nicer.