As renewable energy sources displace conventional power plants, electrical grids face mounting challenges maintaining frequency stability and system inertia. The StorInPlus grid-following inverter, integrated with a Virtual Energy Storage System platform, tackles this problem by providing multiple grid services simultaneously from a single device.
The system employs a sophisticated double-loop control architecture featuring a two-stage Phase-Locked Loop for precise grid synchronization and dedicated mechanisms for frequency estimation and Rate of Change of Frequency measurement. These components work together to detect grid disturbances rapidly and respond with appropriately scaled active power adjustments.
The inverter's control logic blends several service functions into a unified active power reference signal. Synthetic inertia mimics the inherent frequency support traditional generators provide, responding immediately to frequency deviations. Fast frequency reserve delivers sustained support over seconds to stabilize frequency. Secondary services including peak shaving and load leveling optimize energy dispatch and reduce demand spikes.
Hardware implementation includes a DC-link energy source, IGBT-based pulse-width modulation, an LCL output filter for harmonic mitigation, and a delta-star transformer for grid coupling. Researchers developed detailed simulation models in Simulink and validated their predictions against experimental measurements from a laboratory prototype.
Results demonstrate that StorInPlus tracks grid conditions accurately, responds to disturbances faster than conventional reserves, and stabilizes frequency excursions effectively. The technology shows particular promise for islanded microgrids and regions with very high renewable penetration where fast, coordinated frequency support becomes essential.
This work indicates grid-following inverters represent a scalable architectural approach for modern power systems. By consolidating multiple services into flexible, software-defined functions, operators can optimize grid support using distributed energy resources—a fundamental shift from the centralized generation model of past decades.
