In the ever-evolving landscape of energy systems, the transition to renewable sources is reshaping how electricity is generated and managed. However, this transformation comes with inherent challenges, primarily revolving around system stability and complexity. Recent groundbreaking research from Tsinghua University, published in the journal iEnergy, illuminates a revolutionary method to inject greater reliability and simplicity into renewable power grids through an innovative control strategy for grid-forming converters (GFM).
At the heart of modern power system complexity lies the integration of converter-interfaced generators (CIGs), such as solar panels and wind turbines, which differ fundamentally from traditional synchronous generators (SGs). Unlike SGs, whose dynamics are dictated by physical rotating masses, CIGs operate through power electronics and control algorithms, introducing intricate nonlinear behaviors. This complexity engenders dynamic instability risks, a hurdle for secure and reliable power delivery. Professor Yong Min of Tsinghua University highlights this, emphasizing the need to curtail the complexity by isolating or decoupling system dynamics, such as through DC asynchronous interconnections, which leverage power electronics’ flexibility to reduce grid interdependence and dynamic feedback.
This need for simplification and control inspired the research group to reconceptualize GFM control design, focusing on drastically reducing the dynamic footprint of CIGs within power systems. Conventionally, GFM converters attempt to emulate synchronous machines, inheriting rotor angle and frequency stability challenges while introducing converter-specific instabilities. However, the new methodology diverges fundamentally by treating each GFM converter as a constant voltage source operating strictly within its physical and operational limits. Under this paradigm, dynamic control actions are minimized, only invoked when necessary for device protection or when operating constraints are exceeded. Consequently, this approach curtails system oscillations and interactions that typically cascade into instabilities.
The team’s frequency-fixed grid-forming (FF-GFM) control strategy represents a seismic shift in renewable energy management. With FF-GFM implemented, the grid’s frequency becomes effectively immutable, pinned to its rated value under normal operation. This stability removes the classical frequency synchronization dynamics and eliminates traditional rotor angle stability concerns that plague SG-based systems. The system thus behaves as a static network governed solely by power flow equations, sidestepping the latent threats that arise from dynamic interactions among conventional generators and converters.
Furthermore, this method is not just theoretical. Crucially, it allows for compatibility with existing power sources, including conventional synchronous generators and grid-following CIGs. This interoperability is essential for transitioning existing infrastructure toward fully renewable-based grids without necessitating complete overhauls, allowing phased integration. Professor Lei Chen, a co-author of the study, underscores this gradual adoption pathway as vital, noting that the FF-GFM control mechanism can enable 100% renewable systems without compromising grid stability or requiring extensive re-engineering.
The implications of such a control scheme extend beyond stability. By transforming the power system from a complex dynamic network into a static entity, operational predictability and safety can reach unprecedented levels. The model dismisses the often unpredictable dynamic responses inherent to traditional power systems, opening doors to simplified grid operation, enhanced cybersecurity due to fewer dynamic control points, and easier integration of diverse renewable resources without risk of destabilizing interactions.
Technical underpinnings of the FF-GFM control involve sophisticated algorithms that maintain voltage constancy via control loops designed to avoid introducing frequency variations or phase swings typical in synchronous systems. When power generation or loading fluctuates, the system does not react by shifting frequency but rather adjusts power flows statically. To manage longer-term changes and power balancing, a secondary, slower active power control layer modulates power setpoints, subtly directing power flows without disturbing the foundational frequency stability. This two-tiered control—fast frequency-fixed response combined with slow secondary active power control—ensures the system remains stable and responsive.
This innovative approach effectively redefines grid-forming converter roles, emphasizing device safety and operational limits over dynamic emulation of physical machines. The team’s research, published in the fully open-access journal iEnergy, showcases experimental validates and comprehensive simulations demonstrating reduced dynamic variability and robust stability under various operating conditions, including high renewable penetration scenarios. Such results herald promising prospects for future grids transitioning toward fully renewable generation.
The broader impact of this research aligns with global decarbonization goals and the increasing drive toward sustainable energy. As countries worldwide accelerate renewable adoption, ensuring grid stability without reliance on fossil-fuel-based synchronous generators becomes a top priority. The FF-GFM control offers researchers, utility companies, and policymakers a concrete tool to optimize grid architectures accordingly, mitigating blackout risks while enabling seamless integration of renewables.
Tsinghua University’s State Key Laboratory of Power System Operation and Control spearheaded this research, capitalizing on cross-disciplinary expertise in power electronics, control theory, and system dynamics. Ph.D. candidate Zhenyu Lei elaborates on the paradigm shift, stressing that reducing control-induced dynamics in converters marks a fundamental advance over existing emulation strategies, which often carry forward legacy issues from traditional machines into future grids.
The research is published in iEnergy, a journal renowned for disseminating pioneering studies in power and energy systems from top-tier institutions across the globe. Since its inception in 2022, iEnergy has fostered an impressive portfolio of articles, garnering citations from premier journals like Nature Materials and Joule, further reflecting the importance and relevance of advances such as FF-GFM control.
Looking forward, the implications of adopting frequency-fixed grid-forming control span technology, policy, and economics. The enhanced stability and simplicity pave the way for more resilient and flexible grids capable of adapting to variable renewable output. This can reduce reliance on ancillary services, simplify grid codes, and lower operational costs. Moreover, the static operation model inherent to FF-GFM may facilitate novel applications in microgrids, islanded systems, and cross-border power exchanges via DC interconnections, aligning with global energy transition objectives.
In conclusion, the frequency-fixed grid-forming control strategy introduced by the Tsinghua University research team stands as a beacon for the future of renewable power systems. By minimizing dynamic complexity and providing robust frequency stabilization, this approach promises to solve some of today’s most daunting challenges in power system operation. As renewable energy scales to meet global demand, innovations like FF-GFM are crucial to creating safer, more reliable, and sustainable grids capable of supporting the energy needs of tomorrow.
Subject of Research: Frequency-fixed grid-forming control strategy for converter-interfaced generators in renewable power systems
Article Title: Frequency-fixed grid-forming control for less-dynamic and safer renewable power systems
News Publication Date: 27 October 2025
Web References:
- Study Link: https://ieeexplore.ieee.org/document/11218760/authors#authors
- Journal iEnergy: https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=9732629
- DOI: http://dx.doi.org/10.23919/IEN.2025.0024
Image Credits: iEnergy
Keywords
Grid-forming control, Frequency-fixed control, Converter-interfaced generators, Renewable power systems, Power system stability, Dynamic reduction, Static power networks, Power electronics, Synchronous generators, Renewable energy integration, System reliability, Secondary active power control
