Robust speed sensorless induction motor drive

A speed sensorless induction motor (IM) drive with robust control characteristics is introduced. First, a speed observation system, which is insensitive to the variations of motor parameters, is derived based on the concept of sliding mode. Next, an integral-proportional (IP) speed controller using the estimated speed signal is designed to stabilize the speed loop. Then, to preserve the robust control performance under parameter variations and external load disturbance, an adaptive uncertainty observer with feedforward control is proposed. The adaptive uncertainty observer is implemented to estimate the lump of uncertainty of the controlled plant. To increase the accuracy of the estimated values, the speed observation system is implemented using a digital signal processor (DSP) with a high sampling rate