Speed-controlled Electrical Drive with Novel Disturbance Observer Udc 621.313 62-83 621.396.965.8

This paper presents the design of a digitally-controlled speed electrical drive in the presence of arbitrary external immeasurable load disturbances. The extraction of a known class of external disturbances is achieved by using the novel DOB (Disturbance Observer), in which the discrete-time model of external disturbance is included implicitly. It is shown, analytically, by simulation, and experimentally, that the proposed modification of disturbance observer enables the entire rejection of a known class of immeasurable external disturbances, in the steady-state, regardless of the DOB filter cutoff frequency. Thus the speed of disturbance extraction and quality of closed-loop system set-point transient response can be achieved independently. The proposed design procedure is carried out by the speed-controlled drive with a vectorcontrolled induction motor. Both the simulation and experimental results illustrate the effectiveness and robustness of the proposed technique.