Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Non-intrusive Enforcement of Decentralized Stability Protocol for IBRs in AC Microgrids

Tong Huang

TL;DR

This work presents a non-intrusive, decentralized stability protocol for inverter-based resources in AC microgrids by leveraging output-feedback passivity and a grid-edge protocol enforcement interface (PEI). It shows that if each IBR behaves OFP from input to output, the interconnected microgrid remains asymptotically stable, and provides a practical method for enforcing this via PEIs that require only the IBRs’ $L_2$-gain ($\gamma_n$). Case studies demonstrate that PEIs can suppress growth in interconnecting microgrids, with very small energy overhead (often a few percent of IBR energy) and without disclosing detailed controller designs. The approach enables plug-and-play operation, supports EMT-scale dynamics, and offers a path to scalable, IP-friendly stability certification in distributed energy resources.

Abstract

This paper presents decentralized, passivity-based stability protocol for inverter-based resources (IBRs) in AC microgrids and a non-intrusive approach that enforces the protocol. By "non-intrusive" we mean that the approach does not require reprogramming IBRs' controllers to enforce the stability protocol. Implementing the approach only requires very minimal information of IBR dynamics, and sharing such information with the non-IBR-manufacturer parties does not cause any concerns on intellectual property privacy. Enforcing the protocol allows for plug-and-play operation of IBRs, while maintaining microgrid stability. The proposed method is tested by simulating two networked microgrids with tie lines and two IBRs modeled in the electromagnetic transient (EMT) time scale. Simulations show that oscillations with increasing amplitudes can occur, when two stable AC microgrids are networked. Simulations also suggest that the proposed approach can mitigate such a system-level symptom by changing less than 2 percent of energy produced by IBRs.

Non-intrusive Enforcement of Decentralized Stability Protocol for IBRs in AC Microgrids

TL;DR

This work presents a non-intrusive, decentralized stability protocol for inverter-based resources in AC microgrids by leveraging output-feedback passivity and a grid-edge protocol enforcement interface (PEI). It shows that if each IBR behaves OFP from input to output, the interconnected microgrid remains asymptotically stable, and provides a practical method for enforcing this via PEIs that require only the IBRs’ -gain (). Case studies demonstrate that PEIs can suppress growth in interconnecting microgrids, with very small energy overhead (often a few percent of IBR energy) and without disclosing detailed controller designs. The approach enables plug-and-play operation, supports EMT-scale dynamics, and offers a path to scalable, IP-friendly stability certification in distributed energy resources.

Abstract

This paper presents decentralized, passivity-based stability protocol for inverter-based resources (IBRs) in AC microgrids and a non-intrusive approach that enforces the protocol. By "non-intrusive" we mean that the approach does not require reprogramming IBRs' controllers to enforce the stability protocol. Implementing the approach only requires very minimal information of IBR dynamics, and sharing such information with the non-IBR-manufacturer parties does not cause any concerns on intellectual property privacy. Enforcing the protocol allows for plug-and-play operation of IBRs, while maintaining microgrid stability. The proposed method is tested by simulating two networked microgrids with tie lines and two IBRs modeled in the electromagnetic transient (EMT) time scale. Simulations show that oscillations with increasing amplitudes can occur, when two stable AC microgrids are networked. Simulations also suggest that the proposed approach can mitigate such a system-level symptom by changing less than 2 percent of energy produced by IBRs.
Paper Structure (39 sections, 5 theorems, 43 equations, 37 figures, 1 table)

This paper contains 39 sections, 5 theorems, 43 equations, 37 figures, 1 table.

Table of Contents

  1. Introduction
  2. Microgrid Dynamics
  3. Dynamics of IBRs
  4. Dynamics of Microgrid Network
  5. A Feedback Perspective of Microgrid Dynamics
  6. Decentralized Stability Protocol
  7. Stability of Interconnected Systems
  8. Output Feedback Passivity of Microgrid Networks
  9. IBR-level Stability Protocol
  10. Non-intrusive Protocol Enforcement
  11. Basic Idea of Protocol Enforcement
  12. $\mathcal{L}_2$ Gain for IBRs
  13. Architecture of Protocol Enforcement Interfaces (PEI)
  14. Case Study
  15. Grid-connected Grid-following IBR
  16. ...and 24 more sections

Key Result

Lemma 1

(Corollary 1 in hill1977stability) The equilibrium point $\mathbf{o}$ of the closed-loop system in Figure fig:feedback is asymptotically stable, if both subsystems $\mathcal{F}$ and $\mathcal{B}$ are output feedback passive.

Figures (37)

  • Figure 1: Cyber and physical architecture of a grid-forming IBR.
  • Figure 2: Cyber and physical architecture of a grid-following IBR.
  • Figure 3: (a) Reference frame transformation; and (b) an input-output perspective of IBR dynamics
  • Figure 4: Branch $(i,j)_m$ in $\mathcal{E}_2$
  • Figure 5: A feedback perspective of microgrid dynamics
  • ...and 32 more figures

Theorems & Definitions (10)

  • Definition 1
  • Definition 2
  • Definition 3
  • Lemma 1
  • Theorem 1
  • proof
  • Theorem 2
  • proof
  • Lemma 2
  • Lemma 3