An improved active disturbance rejection control for voltage stabilization and performance enhancement in hybrid photovoltaic battery based DC microgrids via red-tailed hawk algorithm

Traditional electrical power generation is undergoing a major transformation as renewable energy sources (RESs) become increasingly prevalent in modern power systems, where DC microgrids (DCMGs) play a pivotal role. Among these, hybrid systems combining photovoltaic (PV) generation as solar power with battery energy storage systems (BESS) offer improved overall power conversion efficiency and optimize energy distribution. The BESS balances generation and consumption by serving a dual function: supplying energy during generation deficits and absorbing excess power, thereby ensuring voltage stability within the DCMG. However, the interaction between DCMG voltage, PV system outputs, and BESS current introduces nonlinear behavior, making control design difficult under varying conditions such as radiation changes, load shifts, and parameter uncertainties. This paper introduces an adaptive active disturbance rejection control (ADRC) approach to overcome these challenges, implemented across the four control loops of the PV/BESS-based DCMG. The ADRC is enhanced with an extended state observer (ESO) optimized by the Red-tailed Hawk Optimization (RTH) algorithm. The RTH adaptively tunes the ESO parameters, effectively resolving the gain-coupling problem in ESO-based ADRC loops and enabling coordinated optimization across all four interconnected control loops. This adaptive tuning significantly improves DCMG voltage stability, disturbance estimation accuracy, dynamic response, steady-state performance, and power balance, while achieving an optimal trade-off among disturbance estimation speed, noise rejection, and steady-state performance. Detailed mathematical models of the PV–BESS DCMG components, incorporating system uncertainties and external disturbances, ware developed to support the proposed control approach. The controller's efficacy is validated through extensive simulations and Control Hardware-in-the-Loop (CHIL) testing. The results prove superior voltage stability, disturbance attenuations, current quality, and power balance, confirming the robustness and reliability of the suggested control scheme for PV–BESS-based DCMGs.