Battery Energy Storage System for Grid Frequency Support Using the Virtual Synchronous Machine Strategy

Maintaining a constant frequency is vital for grid stability and reliability, especially during dynamic changes in load and generation, which are caused by the increasing incorporation of renewable intermittent energy sources such as solar and wind power. These energy sources decrease the system’s inertia, which compromises the primary frequency regulation, a process historically sustained by the speed regulators of conventional synchronous generators. In this study, to mitigate this issue, we investigate a battery energy storage system (BESS) operating with virtual synchronous machine (VSM) control to provide ancillary services of primary frequency control. A multilevel cascade H-bridge static converter with eleven levels is controlled to emulate the dynamic behavior of a conventional synchronous machine, allowing primary frequency control support. The case studies are evaluated using Matlab/Simulink R2024a software and tested under contingency scenarios involving load rejection and step-load insertion within an isolated power grid comprising other synchronous machines, alongside an analysis of the BESS-controlled power dispatch. Our simulation results demonstrate that the energy storage system, operating under a virtual synchronous machine (VSM) strategy, effectively emulates the dynamic behavior of a conventional synchronous generator, enabling controlled active and reactive power dispatch. Furthermore, the proposed control strategy provides virtual inertia support, mitigating the Rate of Change of Frequency (RoCoF) following disturbances, improves the damping of frequency oscillations, and ensures a smoother frequency recovery after load variations. These findings indicate that the proposed BESS can provide effective primary frequency control support in power systems characterized by a high penetration of converter-interfaced renewable energy sources. Nonetheless, further investigations into the influence of VSM parameters on the system’s dynamic response are needed to further optimize the performance of the proposed solution.