Validation of Virtual Synchronous Machine (VSM) Technology for Solar Energy Applications

The rapid adoption of photovoltaic (solar) energy is driving a fundamental shift from centralized generation toward decentralized Distributed Energy Resources (DERs) integrated through power electronic converters, known as inverter-based resources (IBRs). Solar energy has emerged as a crucial component in addressing climate change, meeting global sustainability targets, and providing reliable, affordable, and modern energy access to all. However, integrating IBRs capable of operating in both off-grid and grid-tied modes presents significant technical challenges, primarily due to the need to replicate the physical properties and control behaviors of traditional synchronous machines used in centralized power plants. Virtual Synchronous Machine (VSM) technology represents a promising solution to these challenges by embedding the dynamic behaviors and inherent synchronization capabilities of synchronous machines within IBRs, offering enhanced control flexibility and enabling autonomous operation. This study investigates the application, integration, and rigorous experimental validation of VSM technology across solar energy systems, from individual off-grid units to large-scale grid-integrated scenarios. Experimental validation began with the design, simulation, and field testing of a portable off-grid solar generation unit employing a VSM-based power converter coupled with energy storage. Further experimental studies demonstrated effective parallel operation, precise power sharing, and self-synchronization mechanisms among multiple off-grid solar systems enhanced with plug-and-play capabilities. The scalability and versatility of VSM technology were then evaluated through the development and validation of the TTU 108-Converter Autonomous Smart Grid Testbed, which integrates physical solar panels, wind turbine emulators, battery storage systems, and flexible loads. This testbed emulates an autonomous, large-scale community power system capable of operating entirely on renewable sources while seamlessly transitioning between grid-tied and off-grid modes. Experimental results confirm that VSM-enabled converters effectively maintain strict voltage and frequency regulation compliant with utility standards, achieve accurate power sharing among interconnected IBRs, support seamless transitions between off-grid and grid-tied operation modes, and exhibit robust black-start and self-synchronization capabilities. Overall, this research provides rigorous experimental validation of an advanced power electronics control approach to addressing key challenges in integrating solar energy systems within modern energy infrastructure, significantly enhancing their reliability, scalability, resilience, and safety.