New control method stabilizes power grids as renewable energy surges
Engineers have developed a more precise way to control inverters that convert renewable energy onto the power grid, addressing a critical bottleneck as utilities worldwide shift away from coal and gas. The advance could reduce grid instability and allow utilities to integrate far more solar and wind capacity without expensive infrastructure upgrades.
Originaltitel: Precise Virtual Admittance Synthesis for Enhanced Grid-Forming Performance
Virtual admittance control has emerged as an effective approach to enhance the performance and exploit the capabilities of grid-forming converters (GFMs) in terms of system robustness, stability, and flexibility. Shaping GFM admittance/impedance (immittance) at low frequencies enables outer-loop power regulation and stable operation under varying grid strengths. To further support synchronous-machine-like behavior, shaping GFM immittance at higher frequencies is also important, as e.g., it can help prevent destabilizing interactions in the harmonic range. In this regard, wide-band frequencydomain analysis not only provides a practical means to verify compliance with grid codes, but also enables the demonstration of sophisticated GFM functionalities, particularly those related to stability. To this end, this article addresses frequency-domain accuracy characterization and presents a virtual admittance controller design approach that, unlike the conventional approach, ensures that the GFM's output immittance accurately matches the target across a wide frequency range. Consequently, the GFM's admittance passivity properties are enhanced with the proposed approach, which can be considered a solid base for enabling advanced grid-forming performance, especially from the stability perspective.