Speed-sensorless tracking control of a DC-motor via a double Buck-converter

This article deals with the sensor-less trajectory tracking control of a double-buck-converter/dc-motor combination. We simultaneously regulate, both, the output voltage of the first buck-converter and the angular velocity of the dc-motor shaft so that it tracks a pre-specified reference trajectory. The main result of our proposed control scheme is a linear time-varying controller that is based only on measurements of converter currents and voltages. The control law is derived using the exact tracking error dynamics from which a static linear passive output feedback is derived. All variables of the reference trajectories are generated exploiting the differential flatness property of the combined multi-variable system. The discrete switching control realization of the designed continuous feedback control law is accomplished by means of a Sigma-Delta scheme. Experimental results are provided