Bhowmik Biddut, Acquah Moses Amoasi, Kim Sung-Yul
Electrical Engineering, School of Electrical and Biomedical Engineering, College of Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Department of Electrical and Computer Engineering, School of Engineering, University of Connecticut, Storrs, CT, 06269, United States of America.
Sci Rep. 2025 Aug 16;15(1):29996. doi: 10.1038/s41598-025-11367-2.
The rapid displacement of synchronous generators (SGs) by renewable energy sources has resulted in low-inertia power systems that are increasingly vulnerable to frequency instability, poor power-sharing coordination, and limited fault recovery. In this context, this paper proposes a comprehensive control and system-level realization of Hybrid-Compatible Grid-Forming Inverters (HC-GFIs)- a novel inverter framework designed to emulate synchronous generator behavior while enhancing interoperability in mixed-generation systems. The control architecture of the HC-GFIs is designed as a multi-layered cascaded structure incorporating active power-frequency droop control, voltage regulation loops, a current-limiting regulator, and a dynamic current control layer. Additionally, two novel contributions- a saturation-based DC current controller and an AC current regulator- are introduced to overcome known limitations of overcurrent vulnerability and fault ride-through challenges in conventional GFIs. Extensive time-domain simulations were conducted in both the IEEE 9-bus and 39-bus systems to evaluate scalability and dynamic performance. In the 9-bus system, subjected to a 33.33% step load disturbance, HC-GFIs reduced frequency nadir deviations by up to 0.43 Hz and improved settling time by over 90% compared to all-SG systems. Voltage deviation was maintained within 0.02 p.u. with oscillations damped within 5 s, contrasting sharply with the prolonged instability in SG-only networks. In the 39-bus system, under a severe three-phase-to-ground bolted fault, the HC-GFIs maintained voltage regulation near faulted buses and mitigated high RoCoF transients. Furthermore, the proposed HC-GFIs demonstrate compliance with IEEE Std. 2800 - 2022 RoCoF thresholds and outperform SGs in power-sharing, transient damping, and voltage ride-through performance. This study establishes HC-GFIs as a technically robust, scalable, and standards-compliant solution for stabilizing low-inertia grids, offering a critical pathway for enabling the reliable integration of renewable energy resources into future power systems.
可再生能源迅速取代同步发电机（SGs），导致电力系统惯性降低，使其越来越容易受到频率不稳定、功率分配协调不佳以及故障恢复能力有限的影响。在此背景下，本文提出了一种混合兼容型并网逆变器（HC-GFIs）的综合控制及系统级实现方案——这是一种新型逆变器框架，旨在模拟同步发电机的行为，同时增强混合发电系统中的互操作性。HC-GFIs的控制架构设计为多层级联结构，包括有功功率-频率下垂控制、电压调节回路、限流调节器和动态电流控制层。此外，还引入了两项新成果——基于饱和的直流电流控制器和交流电流调节器，以克服传统并网逆变器在过流易损性和故障穿越挑战方面的已知局限性。在IEEE 9节点和39节点系统中进行了广泛的时域仿真，以评估其可扩展性和动态性能。在9节点系统中，在受到33.33%的阶跃负载扰动时，与全SG系统相比，HC-GFIs将频率最低点偏差降低了高达0.43Hz，并将稳定时间缩短了90%以上。电压偏差保持在0.02标幺值以内，振荡在5秒内得到抑制，这与仅由SG组成的网络中长时间的不稳定形成鲜明对比。在39节点系统中，在严重的三相接地短路故障情况下，HC-GFIs维持了故障母线附近的电压调节，并减轻了高变化率频率（RoCoF）瞬变。此外，所提出的HC-GFIs符合IEEE Std. 2800−2022 RoCoF阈值，并且在功率分配、暂态阻尼和电压穿越性能方面优于SGs。本研究将HC-GFIs确立为一种技术上稳健、可扩展且符合标准的解决方案，用于稳定低惯性电网，为可再生能源可靠接入未来电力系统提供了关键途径。
