A simple approach to flux and speed observation in induction motor drives

The stator-flux orientation concept allows very good transient and steady-state performances in induction motor drives. However, this central strategy can be conveniently implemented only if the stator flux is correctly observed in the entire speed range. The authors have developed a simple flux observer that gives very satisfactory results, especially near zero speed, and the approach which has been followed also allows a good speed estimation. The observer has been both simulated and implemented on an experimental system that uses a single chip to control the whole drive system. The experimental results show excellent performances, despite the low computational load.