Accurate Consensus-Based Distributed Averaging With Variable Time Delay in Support of Distributed Secondary Control Algorithms

Du, Yuhua; Tu, Hao; Yu, Hui; Lukic, Srdjan

doi:10.1109/tsg.2020.2975752

Cited by 36 publications

(15 citation statements)

References 30 publications

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“…As stated in ref. [30], the observer of the scheme can accurately track the average dynamic states (i.e., x i = ∑ N i=1 z i /N) only when τ remains unchanged, otherwise it would lead to convergence error from the exact solution. In contrast to the unchanged τ, the asynchronous sampling case considered in this paper is notoriously complex because the probability distribution of timeslot for information exchange is time-varying during the sampling procedure, which poses challenge to the ratio consensus algorithm in accurate average.…”

Section: Ratio Consensus Algorithmmentioning

confidence: 99%

Distributed Secondary Voltage Control for DC Microgrids with Consideration of Asynchronous Sampling

Lou

Hong

2021

Processes

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This paper studies the distributed secondary control of DC microgrids (MGs) in the case of asynchronous sampling, including both the stability condition and accurate consensus algorithm. The asynchrony means that the update actions of each distributed generation (DG) based on the local information and information received from neighbors are independent of the actions of others at sampled discrete times, which would cause deviation from the accurate convergence and even lead to instability in the worst case. First, a small-signal model of MG installed with secondary voltage control is established to include the individual sampling periods. A stability criterion based on the periodic continuity of sampling instant offset is thus formulated to reveal a stability mapping of multiple sampling. By quantifying the accuracy deviations caused by the asynchrony, an improved ratio consensus strategy is proposed that allows the deviation to be estimated accurately via an auxiliary signal and compensated with respect to the eventual equilibrium to produce an exact solution. Our approach customizes the stability and accuracy for distributed secondary control considering asynchronous sampling in MG, which has been ignored in most existing literature. The effectiveness of the proposed methodology is verified by simulations.

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Section: Ratio Consensus Algorithmmentioning

confidence: 99%

Distributed Secondary Voltage Control for DC Microgrids with Consideration of Asynchronous Sampling

Lou

Hong

2021

Processes

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“…This implies that the asynchronous distributed average consensus may end up with an inexact average. As proposed in [5], [6], [7], [8], this issue can be obviated by augmenting auxiliary algorithms that require extra computing, possibly delaying the time to obtain the average. Sometimes it is beneficial in terms of computational speed and easiness of implementation to proceed with distributed averaging asynchronously, which necessitates rigorous analysis on how far the asynchronous average is deviated from the exact average.…”

Section: Average Error Analysismentioning

confidence: 99%

“…Although an asynchronous algorithm, a counterpart of the synchronous one, naturally takes into account the above issues and hence more practical, it has been reported in [1], [2], [3], [4] that asynchronous information exchanges may lead to inaccuracy in solutions. Therefore, robust communication protocols have been studied (see [5], [6], [7], [8] to list a few) to correct biased averages. These protocols serve as a compensator to induce an exact average while allowing asynchronous communications between connected nodes.…”

Section: Introductionmentioning

confidence: 99%

Asynchronous Distributed Averaging: A Switched System Framework for Average Error Analysis

Lee

2020

Preprint

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This paper investigates an expected average error for distributed averaging problems under asynchronous updates. The asynchronism in this context implies no existence of a global clock as well as random characteristics in communication uncertainty such as communication delays and packet drops. Although some previous works contributed to the design of average consensus protocols to guarantee the convergence to an exact average, these methods may increase computational burdens due to extra works. Sometimes it is thus beneficial to make each agent exchange information asynchronously without modifying the algorithm, which causes randomness in the average value as a trade-off. In this study, an expected average error is analyzed based on the switched system framework, to estimate an upper bound of the asynchronous average compared to the exact one in the expectation sense. Numerical examples are provided to validate the proposed results.

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“…Due to the increasing number of DGs, it is impractical to implement a fully connected communication network among all DGs to make the system states globally accessible for regulations. However, consensus-based algorithms can calculate the average of locally measured parameters in a distributed way using a sparse communication network [19] . The conventional consensus-based algorithm, called average consensus, is only applicable to a group of static inputs.…”

Section: Introduction1mentioning

confidence: 99%

Distributed control framework and scalable small-signal stability analysis for dynamic microgrids

Men

Liu

2021

Chin. J. Electr. Eng.

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As a growing number of microgrids (MGs) has been integrated into the modern power grids, the interconnection and applicable cooperation among multiple MGs motivate the development of networked MGs. Dynamic MGs, as an advanced networked MGs structure, can not only integrate multiple MGs into the distribution system but also fulfill the requested system network reconfiguration with improved flexibility. A general distributed control approach for networked MGs is reviewed. A distributed control framework for dynamic MGs operation is developed, along with an extensible architecture with considerations of large-scale distributed energy resources (DERs) integration. A scalable small-signal stability analysis is conducted per the proposed distributed control strategies and the conditions under which the system is exponentially stable are derived. At last, the effectiveness of the proposed control framework and stability analysis are verified using a 6-bus test feeder.

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Accurate Consensus-Based Distributed Averaging With Variable Time Delay in Support of Distributed Secondary Control Algorithms

Cited by 36 publications

References 30 publications

Distributed Secondary Voltage Control for DC Microgrids with Consideration of Asynchronous Sampling

Distributed Secondary Voltage Control for DC Microgrids with Consideration of Asynchronous Sampling

Asynchronous Distributed Averaging: A Switched System Framework for Average Error Analysis

Distributed control framework and scalable small-signal stability analysis for dynamic microgrids

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