Tmeic Corporation

Benjamin D Rudolph

Paul S Bixel

Methods, systems, controller devices, and computer program products for reactive power control at a renewable energy site are provided. Embodiments address dynamic performance problems associated with control loop delay and the changing modes of operation for meeting utility voltage and reactive power constraints. Provided is a method for reactive power control involving: (a) determining a site-wide reactive power command comprised by a sum of a reactive power feedforward or compensation term and an integrator term; and (b) distributing the site-wide reactive power command among inverters. Embodiments can include a reactive power control term based on the sum of a single integrator and reactive power compensation term, an integrator anti-windup mechanism based on the status of individual inverters, a means for decreasing detrimental effects of loop delay during reactive power reference changes, and/or a means of implementing voltage and power factor limits with smooth transfer between reactive power operating regions.

Renewable energy site reactive power control

The present invention provides methods, systems, computer program products, and devices for renewable energy site power limit control that address conditions of plant saturation and loop delay. In an exemplary embodiment, power limit control of the present invention is broken into two levels of control: a site-wide real power limit control that produces a single site-wide command, SitePlimCom, for all inverters, and inverter-level power limit control that outputs a command, Inv[x].PlimCom[k], for individual inverters. In some embodiments, the invention has one or more of the following features: an integrator with nonlinear gains, limit based anti-windup, a power limit control term based on the sum of both integrator and feed-forward terms, and an inverter-level controller designed to meet slew rate and site power overshoot constraints. The invention can be used at any renewable energy site employing inverters wherein improved dynamic control performance is needed, including solar, wind, and tidal energy sites.

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Roanoke, VA, United States of America

Benjamin D Rudolph