A new flux observer of induction motor by H/spl infin/ optimization

Field-oriented control has emerged as an important approach to the control of induction motors, and rotor flux estimation from the terminal variables is a key step in most popular implementations of such a system. Based on the analysis of disturbance and parameter variations of a vector controlled induction motor system driven by a three-level inverter, a reduced order flux observer is presented according to the H/spl infin/ theory, which can minimize the estimation error. Simulation and experimental results are given which show that this flux observer gives better performance during steady state and transient process than the traditional current-based and voltage-based method. It is more robust against parameter variations and converges faster.