Grid Integration of Smart Inverters for Resilient Energy Systems

With the rapid expansion of photovoltaics, the demands placed on inverters are growing: They must no longer merely convert electricity efficiently, but also ensure the stability of the energy system. The EU project “IN.SPIRE” is developing and demonstrating two prototypes of smart inverters for low- and medium-voltage systems, ranging from innovative power electronics and grid-forming control to novel reflex functions in the context of cybersecurity. Thirteen partners from industry and research are using this project to implement forward-looking solutions. These solutions make PV systems more technically efficient, more compatible, and more resource-efficient, thereby enabling a secure European energy transition.

Initial Situation

The rapid expansion of photovoltaics is presenting growing challenges for grid and plant operators, particularly for inverters as the central interface between PV, storage, and the grid. Many of today’s systems still operate primarily in grid-following mode and can only actively support the stability of the power grid to a limited extent. In large PV systems, current 1,500-V architectures also limit power density and material savings. Failures, thermal stress, and operational data that is difficult to analyze drive up maintenance costs and yield losses, while additional communication interfaces simultaneously introduce new cyber risks.

Objective

The goal of “IN.SPIRE” is to develop, test, and demonstrate two market-ready prototypes: a scalable low-voltage hybrid inverter for commercial and industrial applications, and a 3-kV medium-voltage inverter with 3 MVA for large PV systems. In addition, we are developing solutions that ensure safe and stable operation throughout the entire grid lifecycle, ranging from control technology and condition monitoring to IT security. Their performance and grid compliance are verified up to TRL 6-7 using practical testing methods in the laboratory and in the field. This is intended to reduce costs, material usage, and downtime while increasing energy yield and grid stability.

Approach

The prototypes are implemented through a phased development and testing process: Simulation models support the design phase before components, firmware, and control systems are integrated and validated in the laboratory. Fraunhofer ISE is developing the high-level control system for the medium-voltage inverter. It translates future grid requirements into control strategies and includes reflex functions that compare external commands with local measurement values and the inverter’s operating limits before executing them. The prototype is then tested under simulated grid events in the institute’s medium-voltage test infrastructure.

• Th!nk E
• Katholieke Universiteit Leuven
• Solar Power Europe
• CE+T
• Silicon Austria Labs GmbH 
• Vlaamse Instelling voor Technologisch Onderzoek
• Infinion Technologies AG
• Dresden University of Technology 
• SMA Solar Technology AG
• Zelena Energetska Zadruga Za Usluge ZEZ 
• SolarDefend
• 3E

The “IN.SPIRE” project is funded by the European Union.