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1. A Corrective Scheme to Prevent Adverse Dynamic Interaction of Grid-forming Inverters

   Muhammad F. Umar; Mohsen Hosseinzadehtaher; Mohammad B. Shadmand; Hanif Livani; Mohammed Ben-Idris (January 2023, Innovative Smart Grid Technologies)

   This paper proposes a control scheme that prevents the adverse dynamic interactions between the heterogeneously controlled grid-forming inverters (GFMI) in power electronics dominated grid (PEDG) towards a resilient self-driving grid. The primary controller of GFMIs in a grid cluster can vary based on their manufacturers such as virtual synchronous generation, droop control, power synchronization control, etc. Therefore, this can introduce heterogeneity among the network of GFMIs in PEDG. Resultantly, during the interconnection of GFMIs that are based on heterogenous primary controller poses various synchronization and dynamic interaction challenges in PEDG. For instance, severe fluctuations in frequency and voltage, high ROCOF, unintended reactive power circulation that poses a threat on the overall transient stability of the PEDG. Therefore, to mitigate these adverse dynamic interactions among the heterogeneously controlled GFMIs, a force enclaved homogenization (FEH) control is proposed in a supervisory level controller. This will autonomously adjust inertia coefficients of the each GFMI to have homogenous transient response and will enforce coherency among the heterogenous DGs. This will prevent the PEDG from the adverse dynamic interactions during an interconnection and load disturbance. Various case studies are presented that validates the effectiveness of the proposed FEH control. 

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2. A Novel Discrete-Time State-Space Model for Decentralized Dynamic State Estimation of Grid-Forming Inverters

   https://doi.org/10.1109/TPWRS.2025.3647604  

   Zhao, Xingyu; Netto, Marcos; Zhao, Junbo (December 2025, IEEE Transactions on Power Systems)

   Stiff dynamics continue to pose challenges for power system dynamic state estimation. In particular, models of inverters with control schemes designed to support grid voltage and frequency, namely, grid-forming inverters (GFMs), are highly prone to numerical instability. This paper develops a novel analytical modeling technique derived from two cascading subsystems, namely synchronization and dq-frame voltage control. This allows us to obtain a closed-form discrete-time state-space model based on the matrix exponential function. The resulting model enables a numerically stable and decentralized dynamic state estimator that can track the dynamics of GFMs at standard synchrophasor reporting rates. In contrast, existing dynamic state estimators are subject to numerical issues. The proposed algorithm is tested on a 14-bus power system with a GFM and compared with the standard algorithm whose process model is discretized using well-known Runge-Kutta methods. Numerical results demonstrate the superiority of the proposed method under various conditions. 

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3. On the Analytical Modeling and Discretization of Grid-Forming Inverters

   https://doi.org/10.1109/PESGM52009.2025.11225006  

   Zhao, Xingyu; Netto, Marcos; Zhao, Junbo (July 2025, IEEE)

   The stiff dynamic model of grid-forming inverters (GFMs) presents numerical challenges in time discretization for real-time simulation, estimation, and control. To address this challenge, this paper proposes modeling GFMs as two cascading subsystems: a reference-frame-synchronization system and an in-reference-frame system. This paper demonstrates that these two subsystems are approximately linear, allowing their time discretization to be derived in closed form using the matrix exponential. The proposed discretization method is tested on the IEEE 14-bus power system with a GFM connected and compared with second- and fourth-order Runge-Kutta methods. The numerical results validate the proposed method and demonstrate its potential for discretization with longer step sizes. 

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4. Performance Evolution of Combined Grid-Forming and Grid-Following Inverters with Different Filtering Mechanisms

   https://doi.org/10.23919/ICPE2023-ECCEAsia54778.2023.10213884  

   Nurunnabi, Md; Li, Shuhui; Mondal, Hahnemann; Hong, Yang-Ki; Choi, Minyeong; Won, Hoyun (May 2023, 2023 11th International Conference on Power Electronics and ECCE Asia (ICPE 2023 - ECCE Asia))

   This paper discusses the challenges faced by electric power systems due to the increasing use of inverter-based renewable energy resources (IBRs) operating in grid-following mode (GFL) and the limited support they provide for the grid’s reliability and stability. With increased IBRs connected to the grid, electric utilities are increasingly requiring IBRs to behave like traditional grid-forming (GFM) synchronous generators to provide support for inertia, frequency, voltage, black start capability, and more. The paper focuses on developing GFM inverter technologies with L, LC, and LCL filters and investigates the performance of combined GFM and GFL inverters with different filtering mechanisms when supplying different types of loads. It also emphasizes achieving voltage controllability at the point of common coupling of the GFM with the rest of an AC system. EMT simulation is utilized to investigate the interaction of combined GFM and GFL inverters with different filtering mechanisms. The research results will assist electric utilities in ensuring the reliability and stability of electric power systems in the future. 

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5. Tutorial on Dynamics and Control of Grid-Connected Power Electronics and Renewable Generation

   https://doi.org/10.1109/CDC49753.2023.10383826  

   Groß, Dominic (December 2023, IEEE Conference on Decision and Control)

   Electrical power systems are transitioning from fuel-based generation to renewable generation and transmission interfaced by power electronics. This transition challenges standard power system modeling, analysis, and control paradigms across timescales from milliseconds to seasons. This tutorial focuses on frequency stability on timescales of milliseconds to seconds. We first review basic results for grid-following (GFL) and grid-forming (GFM) control of voltage source converters (VSCs), typical renewable generation, and high voltage direct current (HVdc) transmission. In this context, it becomes apparent that GFL and GFM control functions are needed to operate emerging power systems. However, combining GFL resources, GFM resources, and legacy generation on the same system results in highly complex dynamics that are a significant obstacle to stability analysis. The remainder of the tutorial provides an overview of recent developments in universal GFM controls that bridge the gap between GFL and GFM control and provide a pathway to a coherent control and analysis framework accounting for power generation, power conversion, and power transmission. 

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