The UNIFI Annual Meeting 2025 on January 29-30 at Arizona State University, Tempe, AZ, hosted by Dr. Vijay Vittal and Dr. Raja Ayyanar, brought together industry leaders, researchers, and system operators to shape the future of grid-forming (GFM) inverters. With inverter-based resources rapidly reshaping power grids, discussions centered on standardization, industry collaboration, and advancing UNIFI’s technical roadmap to ensure GFM technology is both scalable and reliable.
The meeting opened with a reflection on UNIFI’s 2024 accomplishments, the introduction of new members, and GFM Specifications Version 2, paving the way for Version 3. A key question emerged: What does success look like for UNIFI? Members explored how to incentivize collaboration, attract manufacturers, and create a clear industry pathway for GFM adoption. One major challenge is the lack of common ground between manufacturers and utilities—should GFM be defined by its performance or by standard models? The consensus leaned toward performance-based standardization, ensuring that different technologies can coexist while meeting essential performance requirements.
Discussions around industry-academia collaboration also took center stage. Beyond data and model sharing, members emphasized the need for PhD dissertation collaborations, where academia could tackle industry-defined challenges while strengthening the future workforce. Discussions also turned to UNIFI’s long-term sustainability, with a roadmap outlining strategies to transition into a self-sustaining organization ensuring continued leadership in GFM research, standardization, and integration.
During the meeting, four cross-cut teams shared updates. A key discussion centered on the categorization of GFM control approaches, proposing classifications such as GFM Core, GFM, and GFM+ to better define their role and expected functionalities. Other critical discussions explored balancing computational efficiency and model fidelity, lack of generic secondary control frameworks, sub-synchronous oscillations, scalable control, dc side modeling, and the need for analytical approaches for large signal stability. Another major discussion was on which responsibilities will be passed to GFM inverters in future grid scenarios. There remains no clear industry consensus on expected fault responses, and stakeholders debated whether fault ride-through (FRT) requirements should be explicitly defined or left flexible. Additionally, the ongoing EMT vs. phasor model debate continued, with a lack of agreement on where each modeling approach is sufficient or necessary, highlighting the need for further research on hybrid methodologies.
Industry representatives shared insights on real-world grid integration, with ERCOT reporting that IBRs accounted for 75% of their generation mix in 2024, raising concerns about grid strength and wide-area event impacts. Other stakeholders, including GE, Tesla, KIUC, eXUS renewables, SMA, and Hitachi Energy, highlighted challenges in market adoption, regulatory uncertainty, and the lack of cohesive standards for GFM certification.
The final session of the meeting focused on refining UNIFI specifications and gathering feedback for Version 3 of the UNIFI specifications. While Version 2 has made significant progress, more detailed specifications are needed to accelerate its adoption as an industry standard. As the discussion on UNIFI Specifications Version 3 unfolded, a familiar tension emerged—should the standards include specific quantified requirements for GFM performance, or should they allow room for flexibility? Some argued that clear, quantifiable benchmarks would provide much-needed guidance for manufacturers and system operators. Others pushed back, warning that overly rigid requirements could stifle innovation and limit real-world applicability.
Along the line of standardization, one promising pathway discussed was leveraging the Industry Affiliate Network (IAN) to fast-track UNIFI GFM specifications into IEEE standards within the next 6-9 months, a significantly shorter timeframe than conventional processes. Discussions on certification frameworks and performance testing methodologies also took center stage, aiming to ensure GFM performance validation across diverse grid conditions. The meeting concluded with a call for suggestions on ongoing cross-cut teams and brainstorming new potential research topics.
Thanks to the graduate students at ASU, UNIFI members toured the power electronics and power systems labs, gaining insight into cutting-edge research and experimental work shaping the future of grid-forming technology.
Students joined industry members over dinner, continuing the exchange of ideas in a more informal setting, fostering connections and future collaborations.
Congrats to Debjyoti Chatterjee from UT Austin for winning the best poster award for his work: “Is Equal Area Criterion Applicable for Grid-forming Inverters.”
