Due to the parametric and structural uncertainty of the DC drive system, an adaptive control method is necessary. Therefore, an original model reference adaptive control (MRAC) for DC drives is proposed in this paper. MRAC ensures on-line adjustment of the control parameters with DC machine parameter variation. The proposed adaptive control structure provides regulating advantages: asymptotic cancellation of the tracking error, fast and smooth evolution towards the origin of the phase plan due to a sliding mode switching k-sigmoid function. The reference model can be a real strictly positive function (the tracking error is also the identification error) as its order is relatively higher than one degree. For this reason, the synthesis of the adaptive control will use a different type of error called augmented or enhanced error. The DC machine with separate excitation is fed at a constant flux. This adaptive control law assures robustness to external perturbations and to unmodelled dynamics.

In order to obtain an appropriate control for the electrical drive systems the real parameters values must be known accurately. Moreover, due to the parametric and structural uncertainty of the DC drive system, an adaptive control method is necessary. Therefore, a new model reference adaptive control (MRAC) for DC drives is proposed in this paper. MRAC ensures on-line adjustment of the control parameters with DC machine parameter variation. The adaptive control developed in this paper assures the asymptotic cancellation of the tracking error, fast and smooth responses of the DC drive without knowing a priory any information about the DC drive parameters. The simulation results show the validity of the proposed solution.

Grid-connected power converters are controlled by the current loop, the voltage being delivered by the grid. The proposed state feedback current control has three components: the state feedback, the forcing component to achieve the desired state x1 and the compensating feed forward of the perturbation. Moreover, the control of the power converter, through the external DC-link voltage loop, and internal current loop, assures zero steady state error, and power quality performances. In order to prove the quality of the proposed control, a regenerative load has been used, and the corresponding simulation results are provided.