Plant-Level Coordinated Frequency Support for Renewable Power Plants with Wind, PV, and Hybrid Energy Storage Using Model Predictive Control

High penetration of inverter-interfaced renewable generation reduces power system inertia and increases the demand for fast plant-level frequency support. This paper proposes a model predictive control (MPC)-based coordinated frequency support strategy for renewable power plants integrating wind power, photovoltaic (PV) generation, and hybrid energy storage systems (HESSs). An equivalent grid frequency response model is first established and combined with aggregated dynamic models of wind, PV, and heterogeneous HESS units to develop a unified control-oriented state-space formulation. In this framework, renewable reserve limits, storage power constraints, and state-of-charge (SoC) dynamics are explicitly incorporated to characterize the time-varying feasible support capability of the plant. On this basis, the coordinated frequency support problem is formulated as a constrained receding-horizon optimization problem, in which frequency deviation suppression, plant-level supplementary power coordination, and HESS energy-state management are considered simultaneously. Simulation studies under step-change and random load disturbances demonstrate the effectiveness of the proposed strategy. Under the representative step-change disturbance, the maximum frequency deviation is limited to approximately 4.5×10−4 p.u., and the frequency rapidly recovers to a steady operating region. Under random load disturbances, the frequency deviation remains bounded within approximately ±1.0×10−3 p.u. Moreover, the SoC values of all heterogeneous storage units remain within the prescribed range of 0.3–0.7 p.u. throughout the support process. These results demonstrate that the proposed strategy achieves effective transient frequency support while maintaining coordinated active power allocation and feasible HESS energy-state operation.