This paper proposes an improved digital deadbeat current controller for single-phase shunt active power filters. The main advantages of the suggested control technique are simplicity, fast dynamics, low computational burden, high accuracy and direct digital implementation. A straightforward modelling of system and design procedure is described in this paper. The stability analysis of the current control system, especially under parameter uncertainties, is studied. Also, a comprehensive comparison between the proposed technique and the conventional deadbeat controller is provided. In order to generate the reference compensating current, a second order generalized integrator-based PQ technique is used and the effect of integrator discretization in terms of dynamic response, accuracy and real-time computational burden is investigated. Simulation and experimental results on a real prototype system under steady-state and transients are reported to demonstrate the validity of theoretical analyses.

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