Active flux based full-order discrete-time sliding mode observer for position sensorless IPMSM drives

To improve the control performance of the position sensorless interior permanent magnet synchronous motor (IPMSM) drives, an active flux model based full-order discrete-time sliding mode observer (DT-SMO) is proposed. Bearing in mind the modeling uncertainties and external disturbances, the observer design and the stability analysis are given. To reduce the inherent chattering problem of the sliding mode control, the sigmoid function is used. To enhance the position estimation accuracy, the quadrature phase-locked loop (PLL) is adopted to track the position information form the equivalent back electromotive force (EMF) obtained through DT-SMO. Experiments on a 2.2kW sensorless IPMSM vector controlled drive have been carried out to verify the proposed scheme.