Offset compensation in the estimation of flux in induction machines

Pure integrators pose a problem in the flux estimation of induction motors. The performance of the induction machine control mainly depends on the accuracy of the estimated flux. Error in the flux estimation system comprises of a drift produced by the integrator as a consequence of initial conditions and a drift produced by an offset error present in the back electromotive force (emf) due to terminal voltage and/or phase current sensor measurement offset error. The method proposed in this paper provides a simple and effective solution to these problems. The method compensates the error produced by the inherent problem in the pure integrator and measurement error. It can easily be applied in a DSP based induction machine control system for flux estimation. The computation burden is light and as such execution time remains low.