Mathematical modeling, dynamic response analysis, and control of PMSG‐based wind turbines operating with an alternative control structure in power control mode

Abstract

Summary This paper deals with the detailed mathematical modeling, in-depth stability analysis, and control of PMSG-based wind turbine (WT), when PMSG works with an alternative control structure. In the alternative control structure, machine-side converter (MSC) is used for control of the dc-link voltage and grid-side converter (GSC) for control of the output power. In this way, full linearized dynamics of the dc-link model is achieved by using the equivalent current based model of the MSC and GSC. Based on the system detailed linearized representation, it is shown that the dc-link dynamics is non-minimum phase with a right half plane (RHP) zero, where the RHP zero depends on operating point and changes under wind speed variation. Hence, due to stability issue, careful considerations are considered for selection of the dc-link controller parameters, and necessary conditions are proposed to guarantee the closed-loop system stability at all operating conditions. Then, the dc-link control system is modified by introducing an auxiliary compensation block which virtually adds a positive damping resistor in parallel with the dc-link capacitor. Next design considerations for selection of the auxiliary compensation term are proposed, and finally response of the system is examined by the several time domain simulations.