This paper considers future distribution networks featuringinverter-interfaced photovoltaic (PV) systems, and addresses the synthesis offeedback controllers that seek real- and reactive-power inverter setpointscorresponding to AC optimal power flow (OPF) solutions. The objective is tobridge the temporal gap between long-term system optimization and real-timeinverter control, and enable seamless PV-owner participation withoutcompromising system efficiency and stability. The design of the controllers isgrounded on a dual epsilon-subgradient method, and semidefinite programmingrelaxations are advocated to bypass the non-convexity of AC OPF formulations.Global convergence of inverter output powers is analytically established fordiminishing stepsize rules and strictly convex OPF costs for cases where: i)computational limits dictate asynchronous updates of the controller signals,and ii) inverter reference inputs may be updated at a faster rate than thepower-output settling time. Although the focus is on PV systems, the frameworknaturally accommodates different types of inverter-interfaced energy resources.
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