A distributed control scheme with cost optimization and capacity constraints

Abstract

This paper proposes a novel distributed control scheme for DC microgrids to acquire minimum generation cost and recover the global average voltage with consideration of capacity constraints. Our main focus is on constrained problems where the power of each distributed generator (DG) is restricted to lie in the feasible region. In this paper, a global load observer (GLO) is introduced that uses neighbor's data to estimate the total load across the microgird. To achieve minimizing generation cost, an alternative control strategy is proposed based on the specific characteristics of the optimum solution. When the total load which can be obtained by the GLO is less than the critical point, it generates power according to equal incremental cost rate (ICR) criteria; otherwise, it generates power maintain the maximum output point. To achieve voltage recovery, a voltage regulator is designed. The proposed controller on each DG communicates with its neighbor DGs on a sparse communication graph. The performance of the proposed scheme is validated and tested through MATLAB simulation.