Research on Speed Sensorless Control of Induction Motor Based on Back EMF

This article mainly uses the reduced-order model of induction motor (IM) to study the speed identification. Since the traditional voltage model (VM) and current model (CM) each have certain limitations, a general reduced-order model obtained by combining VM and CM is proposed for flux observation. This method is more conducive to analyzing system stability and determining gain, so that the entire induction motor vector control system reaches complete stability. In addition, for the full-order observer, according to the rapidity of current convergence, the back EMF can also be used to convert the full-order observer into an equivalent reduced-order observer. In this way, state feedback matrix can be avoided, which can greatly reduce the complexity of calculation and be more convenient to analyzing the stability of the system. Through the simulation of this novel back EMF reduced-order model, the feasibility of the system can be verified.