This invention discloses a method for estimating the speed and position of a
permanent magnet synchronous motor (PMSM) based on a third-order switched extended
state observer. Specifically, based on the
mathematical model of the PMSM, a back-EMF
observer based on a sliding mode observer is constructed to obtain the estimated back-EMF. Further, the estimated back-EMF
signal is processed using a low-pass filter and amplitude normalization. The processed back-EMF is then used as the input
signal to a position
estimation scheme based on the third-order switched extended
state observer, achieving
accurate estimation of the PMSM's speed and position under different operating conditions. This invention is simple in principle and easy to implement. It combines the advantages of both third-order linear and third-order nonlinear extended state observers, improving
estimation accuracy and dynamic performance while reducing the adverse effects of
noise on the
estimation scheme. This solves the technical problems of low estimation accuracy, high
noise sensitivity, and difficulty in parameter tuning in existing estimation schemes.