Abstract
This paper proposes a new method of sensorless vector control for induction motors, in which the motor speed is estimated by both instantaneous reactive power and variation of magnetizing current. The proposed system is constructed in a synchronously rotating reference frame and is very simple. Another advantage is that the proposed system can work in regenerating mode without any special technique. A linear model is deduced to analyze system stability. According to the trajectories of poles and zeroes, the system gain is selected to be suited for operating in a wide speed range and in motoring or regenerating mode. The feasibility of the proposed system is verified by digital simulation.
