Sensorless vector control in the presence of voltage and current measurement errors by dead-time [induction motors]

A sensorless vector control scheme for induction motors is proposed in the presence of voltage and current measurement error caused by dead-time. To overcome the pure integrator problem, the authors modified the stator flux observer through the injection of the current observation error so that poles lie in the left half complex plane. Further, upper bounds of the observation error and the speed estimation error are derived in the presence of voltage and current measurement errors. Experimental results show that the proposed scheme yields fairly good dynamic and steady-state performances irrespective of applied load torque at low speed.