Abstract:In islanded DC microgrids with photovoltaic (PV) and energy storage systems, it is essential to maximize the utilization of PV generation, typically through maximum power point tracking (MPPT) techniques. However, traditional MPPT methods are often slow and imprecise, especially prone to failing into local optima under partial shadowing conditions. This paper proposes a hybrid MPPT control that combines the cuckoo search algorithm and the incremental conductance (INC) method. The cuckoo search algorithm is used for fast global optimization, followed by the INC method for accurate localization, enabling both rapid and precise tracking of the maximum power point. Energy storage units are crucial components in PV-storage DC microgrids, with key control objectives including equal output current sharing, state of charge (SoC) balancing, and DC bus voltage stability. However, current sharing is affected by differences in line resistance, which in turn affects the SoC balancing and DC bus voltage stability. Therefore, a novel voltage-current dual-loop control strategy is designed to achieve these objectives. The strategy uses the bus voltage as the feedback in the outer voltage loop and a control strategy based on the consistency algorithm is designed in the inner current loop, which combines the SoC with an exponential function and introduces an acceleration factor, enabling fast SoC balancing during charge/discharge cycles. The proposed control strategy eliminates the need for droop control and secondary compensation control, thus reducing communication burden. Finally, a DC microgrid system model is built in Matlab/Simulink to verify the effectiveness of the proposed hybrid MPPT and voltage-current dual-loop control strategy.