Maximum torque control with inductance setting of extended EMF observer

This paper presents maximum torque control with inductance settings in extended EMF observers for sensorless controls. The maximum torque control is defined on maximum torque control frame (f-t axes), whose f-axis is parallel to tangential lines of the constant torque curves in the d-q current axes. The angle between f-t axes and d-q axes denoted by ¿ is defined as the tangential angles of the constant torque curves. As position estimation error caused by inductance error can be calculated, the inductance is set so as to make the estimated position error equal to ¿. Since the maximum torque control is realized simply by making f-axis current component zero, complicated calculation is not required. Moreover, the proposed control is robust against magnetic saturation. The validity of the proposed system is confirmed by experiments.