Design and implementation of decoupled controller for interlinking converter in hybrid microgrid

A hybrid microgrid is an interconnected system of an AC and DC subgrid using an interlinking converter (IC). The main concerns for the stable operation of a hybrid microgrid are primarily related to the control of the DG, ICs, and loads. The small perturbation instability associated with the stability of the control loops affects the performance of the IC. The linearized model of the IC has the cross-coupling of axes d and q that adds to the effective impedance at the output side of the filter section. This needs to be addressed, as it affects the power-sharing capability of the IC. In this work, structural decoupling is directly derived from the linearized state-space model. It ensures a mathematically rigorous decoupling strategy that is precisely aligned with the system’s dynamics, ensuring a more accurate and effective control framework and offering a more scalable framework for decoupling. Unlike conventional d-q decoupling strategies, which rely on empirical separation of the control loops in a rotating frame, this decoupling approach based on the linearized state-space model of the interlinking converter is less complex and a perfect decoupled is obtained. MATLAB simulation results and the experimental results are also verified.