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Your search keyword '"Bahrani, Behrooz"' showing total 91 results
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91 results on '"Bahrani, Behrooz"'

1. A Complex-Coefficient Voltage Control for Virtual Synchronous Generators for Dynamic Enhancement and Power-Voltage Decoupling

Author

Xu, Jingzhe, Zhou, Weihua, and Bahrani, Behrooz

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

As electric power systems evolve towards decarbonization, the transition to inverter-based resources (IBRs) presents challenges to grid stability, necessitating innovative control solutions. Virtual synchronous generator (VSG) emerges as a prominent solution. However, conventional VSGs are prone to instability in strong grids, slow voltage regulation, and coupled power-voltage response. To address these issues, this paper introduces an advanced VSG control strategy. A novel analysis of the VSG control dynamics is presented through a second-order closed-loop complex single-input single-output system, employing a vectorized geometrical pole analysis technique for enhanced voltage stability and dynamics. The proposed comprehensive controller design mitigates issues related to control interacted subsynchronous resonance and $dq \leftrightarrow 3\phi$ transformation-induced voltage-coupled power transients, achieving improved system robustness and simplified control tuning. Key contributions include a two-fold design: optimized voltage transition characteristics through direct pole placement and transient power overshoot correction via a compensator. Validated by simulation and experiments, the findings offer a pragmatic solution for integrating VSG technology into decarbonizing power systems, ensuring reliability and efficiency., Comment: 13 pages, 26 figures. Preparing for journal submission

Published
2024

26. Rapid Admittance Measurement of Power Converters Using Double-PLL Grid-Following Inverters

Author

Zhou, Weihua, Ravanji, Mohammad Hasan, Mohammed, Nabil, and Bahrani, Behrooz

Abstract

The increasing use of inverter-based resources (IBRs) in power systems highlights the need for a deep understanding of their stability and dynamics. Traditional analytical models, limited by the black-box nature of IBRs, underscore the importance of frequency-domain methods through measured admittance. Facing challenges in real-world admittance measurement, such as the absence of ideal voltage or current sources, the use of measurement inverters as perturbation sources has emerged as a promising approach, despite drawbacks like reduced system stability and increased measurement time. This article introduces a novel control strategy for measurement inverters, elucidating the impact of abc/dq and dq/abc transformations on admittance measurement. The key advancements are an analysis of the admittance contributions from these transformations and the implementation of double phase-locked loops in the measurement inverters, aimed at improving stability and decreasing measurement duration.

Published
2024
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27. Grid-Forming Inverter-Based Resource Research Landscape: Understanding the Key Assets for Renewable-Rich Power Systems

Author

Bahrani, Behrooz, Ravanji, Mohammad Hasan, Kroposki, Benjamin, Ramasubramanian, Deepak, Guillaud, Xavier, Prevost, Thibault, and Cutululis, Nicolaos-Antonio

Abstract

The shift to net zero energy systems has changed the face of our power grid. Traditional large-scale synchronous generators found inside coal and natural gas plants are being replaced with inverter-based resource (IBR) technologies. This transition to an IBR-dominant power grid introduces new characteristics, altering how our grid operates. Therefore, the role of IBRs has expanded, requiring them to provide a range of essential services to keep our grid reliable, resilient, and secure.

Published
2024
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36. Transient Stability Analysis of Virtual Synchronous Generator Equipped With Quadrature-Prioritized Current Limiter

Author

Me, Si Phu, Ravanji, Mohammad Hasan, Leonardi, Bruno, Ramasubramanian, Deepak, Ma, Jin, Zabihi, Sasan, and Bahrani, Behrooz

Abstract

A current limiter (CL), which protects virtual synchronous generators (VSGs) from overcurrents, may significantly alter the operation of the VSGs when activated. In this letter, a transient stability analysis of VSGs equipped with quadrature (q-)prioritized CL is performed. This study shows that in addition to the instability caused by the positive feedback of the primary controller, a VSG could become unstable after large disturbances due to the failure of the inner voltage controller. In this study, a stability criterion is provided for the voltage control loop.

Published
2023
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44. Multivariable Control Design for Grid-Forming Inverters With Decoupled Active and Reactive Power Loops.

Author

Rathnayake, Dayan Bandara and Bahrani, Behrooz

Abstract

Grid-forming inverters (GFMIs) are recognized as a prominent driver toward achieving renewable energy-rich power grids. Unlike grid-following inverters (GFLIs), which are controlled as current sources, GFMIs are controlled as voltage sources. In GFMIs, dynamic control of the magnitude ($V_{\mathrm{c}}$) and angle ($\theta$) of the point of common coupling (PCC) voltage is used to achieve active ($P$) and reactive ($Q$) power transfer across a line. However, independent control of $P$ and $Q$ via $V_{\mathrm{c}}$ and $\theta$ becomes challenging due to the coupling between $P$ and $Q$ loops. The coupling becomes severe as the resistance-to-reactance ratio of the grid impedance and the power angle between the GFMI and the grid voltages are increased. This article proposes a novel multivariable controller to completely decouple $P$ and $Q$ loops in GFMIs. The proposed multivariable controller could be designed based on the prevalent control structures for GFMIs such as droop controller, swing equation-based virtual synchronous generator (VSG) controller, zero steady-state error reactive power controller, and fixed steady-state error reactive power controller. The additional cross-channel decoupling controllers in the proposed multivariable controller provide superior decoupling action over the existing decoupling methods, such as the virtual inductor-based method. An $\mathcal {H}_\infty$ -based method is adopted to tune the proposed multivariable controller parameters, where the straightforward formulation of the desired closed-loop dynamics based on the open-loop system is clearly shown. The decoupling performance of the controller is experimentally validated extensively. The experimental results show that the proposed controller results in superior performance over the prevalent decoupling methods, such as the virtual-inductor decoupling method. [ABSTRACT FROM AUTHOR]

Published
2023
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48. Demand response cybersecurity for power systems with high renewable power share

Author

Haes Alhelou, Hassan and Bahrani, Behrooz

Abstract

Cybersecurity is crucial for modern power systems due to their high digitization. The open information and communication technology, that is (ICT) being used for the operation of such systems, is highly vulnerable to cyber threats. The adopted smart grid concept around the globe enables the utilization of demand-side for providing ancillary services based on well-known demand response (DR) programs. These programs aggregate smart appliances in homes and electric vehicles (EVs) for providing vital services such as frequency regulation and voltage support. Since the aggregation is based on cyber layer, any cyber threat could affect the ancillary services that are being delivered from the aggregators, which might lead to stability and security issues resulting in brownout or massive blackouts. This chapter discusses the cybersecurity in DR program and shows its importance for modern and future smart power systems due to their stability and security margins. Furthermore, the cyberattack case study is implemented in a power system with demand side program responsible for providing primary frequency support ancillary service, where the results confirm the high vulnerability of modern power systems to cyber threats on DR-active power reserve providers. Moreover, technical suggestions are provided for enhancing the cybersecurity in DR programs in power systems with high power share from renewable energy sources.

Published
2022
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