A method to synchronize and control a system of parallel single-phase inverters without communication is presented. Inspired by the phenomenon synchronization in networks coupled oscillators, we propose that each inverter be controlled emulate dynamics nonlinear dead-zone oscillator. As consequence electrical coupling between inverters, they share load proportion their ratings. We outline sufficient condition for global asymptotic formulate methodology controller design such terminal...

Low-voltage distribution feeders were designed to sustain unidirectional power flows residential neighborhoods. The increased penetration of roof-top photovoltaic (PV) systems has highlighted pressing needs address quality and reliability concerns, especially when PV generation exceeds the household demand. A systematic method for determining active- reactive-power set points inverters in is proposed this paper, with objective optimizing operation feeder ensuring voltage regulation. Binary...

Virtual oscillator control (VOC) is a decentralized strategy for islanded microgrids where inverters are regulated to emulate the dynamics of weakly nonlinear oscillators. Compared droop control, which only well defined in sinusoidal steady state, VOC time-domain controller that enables interconnected stabilize arbitrary initial conditions synchronized limit cycle. However, oscillators elemental cannot be designed with conventional linear-control design methods. We address this challenge by...

This paper develops a real-time algorithmic framework for aggregations of distributed energy resources (DERs) in distribution networks to provide regulation services response transmission-level requests. Leveraging online primal-dual-type methods time-varying optimization problems and suitable linearizations the nonlinear AC power-flow equations, this work establishes system-theoretic foundation realize vision distribution-level virtual power plants. The controls output powers dispatchable...

This paper proposes a suite of algorithms to determine the active- and reactive-power setpoints for photovoltaic (PV) inverters in distribution networks. The objective is optimize operation feeder according variety performance objectives ensure voltage regulation. In general, these take form widely studied ac optimal power flow (OPF) problem. For envisioned application domain, nonlinear power-flow constraints render pertinent OPF problems nonconvex computationally intensive large systems. To...

A systematic framework for reliability assessment and fault-tolerant design of multiphase dc-dc converters deployed in photovoltaic applications is presented. System-level steady-state models allow a detailed specification component failure rates, turn establish the effects ambient conditions converter on reliability. Markov are derived to estimate mean time system failure. Case studies applied two- three-phase, 250-W demonstrate that topological redundancy does not necessarily translate...

Computationally efficient and scalable models that describe droop-controlled inverter dynamics are key to modeling, analysis, control in islanded microgrids. Typical developed from first principles this domain detailed of the power electronics inverters, as well network interactions. Consequently, these very involved; they offer limited analytical insights computationally expensive when applied investigate large microgrids with many inverters. This calls for development reduced-order capture...

This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate Van der Pol oscillators. The general strategy controlling behavior nonlinear oscillators presents a compelling time-domain alternative ubiquitous droop control methods which presume existence quasistationary sinusoidal steady state and operate on phasor quantities. We present two main results this paper. First, by leveraging method periodic averaging, we demonstrate laws...

Decentralized methods for computing optimal real and reactive power setpoints residential photovoltaic (PV) inverters are developed in this paper. It is known that conventional PV inverter controllers, which designed to extract maximum at unity factor, cannot address secondary performance objectives such as voltage regulation network loss minimization. Optimal flow techniques can be utilized select will provide ancillary services compute their according well-defined criteria economic...

A control scheme is proposed for an islanded low-inertia three-phase inverter-based microgrid with a high penetration of photovoltaic (PV) generation resources. The output each inverter programmed to emulate the dynamics nonlinear oscillator. virtual oscillators within controller are implicitly coupled through physical electrical network. asymptotic synchronization can be guaranteed by design, and as result, stable power system emerges innately no communication between inverters. Time-domain...

Sufficient conditions are derived for the global asymptotic synchronization of a class identical nonlinear oscillators coupled through linear time-invariant network. In particular, we focus on systems where connected to common node branch impedances. For such networks, it is shown that condition independent number and value load impedance node. Theoretical findings then leveraged control system parallel single-phase voltage source inverters serving an in islanded microgrid application. The...

In this paper, we present a virtual oscillator control (VOC) strategy for power inverters to operate in either grid-connected or islanded settings. The proposed controller is based on the dynamics of nonlinear Andronov-Hopf and it provides voltage regulation, frequency support mode. It also features potential respond real- reactive-power setpoints dispatchability contrast early VOC incarnations which exhibit undesirable harmonics, offers sinusoidal ac limit cycle as well improved dynamic...

Federated Learning (FL) has become a popular paradigm for learning from distributed data. To effectively utilize data at different devices without moving them to the cloud, algorithms such as Averaging (FedAvg) have adopted "computation then aggregation" (CTA) model, in which multiple local updates are performed using data, before sending models cloud aggregation. However, these schemes typically require strong assumptions, identically independent (i.i.d), or size of gradients bounded. In...

Virtual oscillator control (VOC) and droop are distinct methods to ensure synchronization power sharing of parallel inverters in islanded systems. VOC is a strategy where the dynamics nonlinear used derive states modulate switch terminals an inverter. Since time-domain controller that reacts instantaneous measurements with no additional filters or computations, it provides rapid response during transients stabilizes volatile dynamics. In contrast, regulates inverter voltage measured average...

This paper explores solutions to linearized power-flow equations with bus-voltage phasors represented in rectangular coordinates. The key idea is solve for complex-valued perturbations around a nominal voltage profile from set of linear that are obtained by neglecting quadratic terms the original nonlinear equations. We prove lossless networks, where real part perturbation suppressed satisfies active-power balance system result motivates development approximate improve over conventional DC...

We propose a framework to study the impact of stochastic active/reactive power injections on system dynamics with focus time scales involving electromechanical phenomena. In this framework, evolve according continuous-time Markov chain (CTMC), while are described by standard differential algebraic equation (DAE) model. The DAE model is linearized around nominal set injections, and combination CTMC forms process known as hybrid (SHS). extended generator SHS yields ordinary equations that...

This paper develops an approach to enable the optimal participation of distributed energy resources (DERs) in inertial- and primary-frequency response alongside conventional synchronous generators. Leveraging a reduced-order model description frequency dynamics, DERs' synthetic inertias droop coefficients are designed meet time-domain performance objectives overshoot steady-state regulation. Furthermore, optimization-based method centered around classical economic dispatch is developed...

This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is bridge temporal gap between long-term system optimization real-time control, enable seamless PV-owner participation without compromising efficiency stability. design grounded on a dual ε-subgradient method, while...

This paper focuses on power distribution systems with inverter-interfaced renewable energy sources (RESs), and develops a distributed control framework to steer the RES output powers solutions of ac optimal flow (OPF) problems. The design algorithm is based suitable linear approximation power-flow equations, leverages so-called alternating direction method multipliers (ADMM). Convergence RES-inverter approximate OPF problem established under conditions mismatches between commanded setpoints...

Grid-forming (GFM) control offers promising performance features for inverter-based resources (IBRs) across scales. However, design, analysis, and benchmarking of GFM IBRs during unbalanced faults remains largely unexplored. In this article, we outline a stationary-reference-frame nested-loop architecture integrate the same with novel current-limiting strategies. The improves on virtual-impedance current-reference-saturation limiting as well state-of-the-art methods voltage-source inverters....

Virtual oscillator control (VOC) is a time-domain strategy that leverages the dynamics of nonlinear circuits for synchronizing and regulating grid-forming inverters. In this article, we examine class second-order composed harmonic state-dependent damping has found extensive interest in context VOC. We center our analysis on Van der Pol, Dead-zone, Andronov-Hopf oscillators; these are characterized by several distinguishing attributes but they all share common structure noted above....

A framework to integrate reliability and performance analysis of grid-tied photovoltaic (PV) systems is formulated using Markov reward models (MRM). The allows the computation metrics such as capacity energy yield, availability. paper also provides an analytical method compute sensitivity MRM-parameter variations. approach demonstrated be particularly useful formulate optimal operational policies, e.g., repair strategies, impact variations in model parameters on system can rapidly evaluated....