The transition to an inverter-dominant, renewable power grid is driving new developments in power converter controls technology that aim to offer the speed and flexibility of power electronic equipment in combination with the stabilizing characteristics of synchronous machines.
Today, the vast majority of all installed inverter-based resources (like wind, solar PV, and battery) interface to the grid through inverters that operate under a “grid following” control approach, in which the inverter measures the AC voltage waveform of the grid and responds by injecting current in order to achieve its active and reactive power setpoints. This approach requires that the grid already be present, and the measure-then-respond approach poses practical limits to the provision of grid services that operate in the fastest timeframes, like inertia and grid strength.
In contrast, “grid forming” technology refers to the inverter control paradigm in which the inverters synthesize a voltage phasor, which is controlled relative to the grid’s voltage phasor to achieve the desired current and power flow. This approach borrows attributes from synchronous machine technologies, which enable it to energize equipment and to provide services like inertia and grid strength.
Though grid-forming control concepts are not new to the industry, they’ve received renewed attention with the proliferation of inverter-based resources in recent years. While the industry and many inverter manufacturers have made tremendous progress in the space and many vendors are offering and have installed grid-forming inverters, there is a lot more work to be done around development of the technology, applications, and the impact on operations and transmission planning.
To learn more & get involved, please check out the IEEE PES Electric Machinery Committee (EMC) website
Electric Machinery Committee’s Renewable Energy Machines and Systems Subcommittee is planning panel sessions for IEEE PES General Meeting 2022, including: Grid-Forming Converter Technology and Applications
IEEE Power & Energy MagazineThe 2021 Nov/Dec issue of P&E Magazine is devoted to integrating PV and Wind systems into the grid using inverter-based technology. Grid-forming inverters are a large part of that discussion. You can cite the issue or this article from it.
- A Future with Inverter-Based Resources, Matesvosyan, et al. IEEE P&E Magazine. (The issue is not yet available on the PES website, but can be accessed in Xplore).
- Influence of Inverter-Based Resources on Microgrid Protection, Part I. Reno, et al. IEEE P&E Magazine, Volume: 19, Issue: 3. May/June 2021.
- Practical Microgrid Protection Solutions, Manson et al, P&E Magazine, Volume: 19, Issue: 3. May/June 2021.
- Grid-Forming Inverters: Are They the Key for High Renewable Penetration? Julia Matevosyan, et al. IEEE P&E Magazine, Volume: 17, Issue: 6. November/December 2019.
IEEE Electrification Magazine
- AC Microgrid Small-Signal Modeling: Hierarchical Control Structure Challenges and Solutions. Y. Wu, J. M. Guerrero, J. C. Vasquez and J. Li. IEEE Electrification Magazine, Volume: 7, No. 4, pp. 81-88. December 2019. doi: 10.1109/MELE.2019.2943980.
- A Controller Hardware-in-the-Loop Testbed: Verification and Validation of Microgrid Control Architectures. S. Nigam, O. Ajala and A. D. Dominguez-Garcia. IEEE Electrification Magazine, Volume: 8, No. 3, pp. 92-100. September 2020. doi: 10.1109/MELE.2020.3005740.
IEEE Open Access Journal of Power and Energy (OAJPE)
- Generalized Formulation of Steady-State Equivalent Circuit Models of Grid-Forming Inverters. V. C. Cunha et al. IEEE Open Access Journal of Power and Energy, Volume: 8, pp. 352-364. August 2021. doi: 10.1109/OAJPE.2021.3108680.
IEEE PES Webinars (Panel)
Grid forming capability for HVDC and FACTS: definitions and applications, IEEE PES General Meeting 2021 (Transmission and Distribution). Grid forming capability is at present being considered as a key feature for the future generation of converters to enable a higher penetration of renewables in future power systems with a lower system inertia coming from conventional generation employing synchronous machines. This panel session discusses the needs for grid forming capability from converters, with the focus on HVDC and FACTS, and the consequences of particular choices in controls. Different proposals from vendors and system operators alike will be discussed.
- Grid Forming Capability for HVDC & FACTS: Definitions and Applications‘, panel session video hosted by the Power and Energy Society (PES), held on July 26th-29th, 2021 during the 2021 IEEE PES General Meeting.
[Panel available here]