The WIND4GRID project, carried out from 2019 to 31 October 2022, aimed to create a novel inverter system for wind turbines that combines a grid‑side inverter, a multi‑source architecture, an integrated battery storage, and an advanced energy‑management system (EMS). The concept was designed specifically for unstable power grids, enabling the turbine to provide grid‑stabilising services such as peak shaving, synthetic inertia, and other ancillary services without the need for separate battery enclosures. By connecting one or more batteries to the DC bus of the turbine, the system can temporarily supply additional power during high demand periods, thereby reducing peak loads and improving overall grid utilisation.
The technical work of the consortium produced a comprehensive concept for deploying wind energy in Tunisia, including detailed aero‑elastic and electrical simulations of the turbine and its control system. A new inverter model was developed and used to generate simulation data that guided the design of the battery stack and the EMS. The battery stack itself was engineered to fit within the turbine tower, eliminating the requirement for external housing and simplifying installation. The EMS was tailored to manage the interaction between the turbine, the battery, and the grid, ensuring optimal power flow and compliance with grid‑code requirements. System‑level tests were conducted on a scaled prototype, demonstrating the feasibility of the integrated architecture and validating the EMS algorithms under realistic operating conditions. These tests confirmed that the system could deliver the intended grid services and that the battery could provide rapid response times necessary for synthetic inertia.
The project’s results also include a set of system‑service specifications that outline how the integrated turbine‑battery unit can support grid stability, frequency regulation, and voltage support. The EMS was shown to be capable of learning and executing control strategies that mimic the behaviour of conventional synchronous generators, thereby bridging the gap left by the absence of inherent inertia in inverter‑based resources. The overall outcome is a ready‑to‑deploy solution that enhances the reliability of renewable generation in regions with fluctuating supply and limited grid infrastructure.
Collaboration was organised in a 2 + 2 consortium structure. German partners LWET and Freqcon coordinated closely with Tunisian partners Quadan International and the National Engineering School Monastir. The project was funded by the German Federal Ministry of Education and Research, which provided 107 416 € for Freqcon’s portion. The consortium operated through seven work packages, with Freqcon focusing on the development of the multi‑source inverter, the EMS, and the scaled‑system tests. Regular project meetings were held, and due to the COVID‑19 pandemic, many of these were conducted remotely. The project was extended cost‑neutrally to accommodate pandemic‑related delays, ensuring that all milestones were met within the agreed timeframe. The collaborative effort produced a coherent, technically robust solution that advances the integration of battery storage into wind turbines and supports the broader goal of stabilising power grids with renewable resources.