Sensorless position and speed control of induction motors using high frequency injection and without off-line pre-commissioning

This paper addresses the sensorless speed and position control of induction motors using high frequency injection at zero and low frequencies. A novel algorithm is presented which allows the rejection of saturation and nonlinear inverter effects without the need for an off-line pre-commissioning process. The method is based on a set of synchronous filters to identify the disturbance waveforms, and a memory algorithm, which refines the quality of the disturbance waveforms as the motors operational history is increased. The algorithm is entirely sensorless. Experimental results show sensorless low frequency operation with and without the memory algorithm.