A Modified Compensation Strategy of Flux Linkage Observer in PMSM Sensorless Control Based on Augmented Disturbance Observer

Flux linkage observers have been widely employed in the permanent magnet synchronous motors (PMSM) sensorless drives. In order to improve the accuracy of rotor position estimation and suppress the effects of multiple disturbances including current sampling error and inverter nonlinearity, a modified compensation strategy for the position estimation error of the flux linkage observer based on the augmented disturbance observer (ADO) is proposed in this paper. Considering the current sampling error and the inverter nonlinearity, a new voltage model of PMSM is formulated, and a disturbance modeling approach based on a non-cascaded structure is proposed. Based on this model, an ADO is developed to accurately estimate multiple types of disturbances and extract the back electromotive force (BEMF) signal to detect and compensate errors in position estimation of the flux linkage observer. Experimental results demonstrate that the proposed method can effectively suppress multiple disturbances and significantly enhance the accuracy of position compensation.