Synchronization and power sharing for droop-controlled inverters in islanded microgrids

By John William Simpson-Porco, Florian Dörfler, Francesco Bullo. at - Automatisierungstechnik, 2012

845 citations recorded by the source corpus.

Motivated by the recent and growing interest in smart grid technology, we study the operation of DC/AC inverters in an inductive microgrid. We show that a network of loads and DC/AC inverters equipped with power-frequency droop controllers can be cast as a Kuramoto model of phase-coupled oscillators. This novel description, together with results from the theory of coupled oscillators, allows us to characterize the behavior of the network of inverters and loads. Specically, we provide a necessary and sucient condition for the existence of a synchronized solution that is unique and locally exponentially stable. We present a selection of controller gains leading to a desirable sharing of power among the inverters, and specify the set of loads which can be serviced without violating given actuation constraints. Moreover, we propose a distributed integral controller based on averaging algorithms, which dynamically regulates the system frequency in the presence of a time-varying load. Remarkably, this distributed-averaging integral controller has the additional property that it preserves the power sharing properties of the primary droop controller. Our results hold without assumptions on identical line characteristics or voltage magnitudes.

Subfields: Computer Networks and Communications, Control and Systems Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/efd921de7ee8980a7240bbe52caeff270db1de1a

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Citations in the corpus

Secondary Frequency and Voltage Control of Islanded Microgrids via Distributed Averaging (2015, methodology): “In this paper, we build on our previous theoretical and experimental works [15], [16] and introduce a general and fully distributed framework for secondary frequency and voltage control in islanded microgrids.”
Event-Triggered Consensus Control for Multi-Agent Systems Against False Data-Injection Attacks (2019, background): “applications in various areas, for instance, formation con-trol for unmanned vehicles [6], power management in power networks [7], and distributed sensor networks [8].”
A Survey on Model-Based Distributed Control and Filtering for Industrial Cyber-Physical Systems (2019, background): “Lately, stability and convergence properties receive considerable research efforts, see, e.g. [131], [133].”
An Overview of Recent Advances in Event-Triggered Consensus of Multiagent Systems (2018, neutral): “In a microgrid, a fundamental concern is how to efficiently dispatch power supply of DGs to distributed loads, which refers to power sharing issues including economic dispatch [118]–[120] and proportional power sharing [12], [13].”
Breaking the Hierarchy: Distributed Control and Economic Optimality in Microgrids (2014, background): “(7)-(10)], and (by continuity) networks with sufficiently uniform R/X ratio lines.”
On the Secondary Control Architectures of AC Microgrids: An Overview (2020, methodology): “techniques, the following distributed protocol is used [14], [55], [88], [166], [167]:”
Understanding Small-Signal Stability of Low-Inertia Systems (2021, background): “3, with the former mode potentially differentiating between several representative classes of control such as droop control [43], [44], Virtual Synchronous Machine (VSM) control [45], [46], Virtual Oscillator Control (VOC) [47], [48] and matching control [49], [50].”
A Survey of Distributed Optimization and Control Algorithms for Electric Power Systems (2017, background): “To alleviate this shortcoming, distributed averaging-based integral control can be implemented [197], [198], [201]–[206].”
Voltage Stability and Reactive Power Sharing in Inverter-Based Microgrids With Consensus-Based Distributed Voltage Control (2016, methodology): “This protocol has been applied previously in inverter-based microgrids to the problems of secondary frequency control [12], [29]–[31], as well as secondary voltage control [30]–[33].”
Transient Stability Analysis and Control Design of Droop-Controlled Voltage Source Converters Considering Current Limitation (2019, background): “The P-f droop control can also achieve power sharing autonomously in islanded ac microgrids, which makes the VSCs have similar primary frequency responses to that of synchronous generators [12].”
Synchronization in complex networks and its application - A survey of recent advances and challenges (2014, methodology): “Owing to the emergence of microgrids in nowaday power grids, it becomes more important to utilize the droop controller to avoid circulating currents among the converters without using any critical communication (Guerrero et al., 2011; Schiffer et al., 2014; Simpson-Porco et al., 2013).”
Distributed Secondary Voltage and Frequency Restoration Control of Droop-Controlled Inverter-Based Microgrids (2015, background): “As far as we know, relevant results are only available in [13]–[16].”
Synchronous Instability Mechanism of P-f Droop-Controlled Voltage Source Converter Caused by Current Saturation (2016, methodology): “1 [1], [2] is used in VSC and the following assumptions are made: 1) The Q-V droop control, the dynamics of inductances, and the dynamics of voltage and current control loop are neglected [4], as the synchronous stability is mainly dominated by the droop control in large time scale; 2) The VSC is at”
Conditions for stability of droop-controlled inverter-based microgrids (2014, methodology): “In Section 6 we propose a selection of the droop gains and setpoints, similar to the one given in Simpson-Porco et al. (2013a), that ensures the DG units share (in steady-state) the active power according to a specified pattern.”