High penetration of renewable energy sources such as wind generation in microgrids (MGs) causes fluctuations of power flow and significantly affects the power system (PS) operation. This can lead to severe problems, such as system frequency oscillations, and/or violations of power lines capability. With the proper control, superconducting magnetic energy storage (SMES) is able to significantly enhance the dynamic security of the PS. In an SMES system, the power conditioning system (PCS) is the crucial component that directly influences the validity of the SMES in the dynamic control of the PS. This paper proposes the use of an improved SMES controller for the stabilization and control of the power flow of wind-hybrid MGs. In this sense, the design and implementation of a novel high-performance PCS scheme of the SMES is described. Moreover, a detailed model of the SMES unit is derived and a novel three-level control scheme is designed, comprising a full decoupled current control strategy in the d-q reference frame and an enhanced PS frequency controller. The dynamic performance of the proposed systems is fully validated by computer simulation.Index Terms-Distributed energy storage, microgrids (MGs), power conditioning system (PCS), superconducting magnetic energy storage (SMES).

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The connection of wind power generation into ac microgrids (MGs) is steadily increasing. This incorporation can bring problems onto the power quality and dynamics of the electrical grid due to the lack of controllability over the wind. In this work, a flywheel energy storage (FES) is used to mitigate problems introduced by wind generation into MGs. A dynamic model of the FES device is briefly presented and a technique to control the power exchanged between the device and the power system is proposed. The control technique has three modes, namely: voltage control (VC), frequency control (FC), and active power stabilization (APS). Simulation tests on the behavior of the FES device are analyzed when it works in combination with wind generation in the electrical microgrid. Results show an acceptable performance of the proposed control techniques along with a high effectiveness to smooth the active power fluctuations of wind generation. Index Terms-Distributed generation (DG), flywheel energy storage (FES), frequency control, fuzzy logic controller (FLC), microgrid (MG), voltage control, wind power generation.

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