Novel Control of Doubly-Fed Induction Generators for Wind Energy Systems Connected to Weak Grids

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

Wind energy is the fastest growing renewable resource, much of it located in remote areas with weak transmission grids, where wind turbines are disconnected from the grid for their own protection, for example, beyond an unbalance of six percent in phase-phase voltages. The objective of this project is to develop a robust controller for wind generation systems capable of operating reliably on weak electric grids by riding through voltage abnormalities in a wide range. Doubly-fed induction generators allow an excellent opportunity to minimize torque pulsations due to voltage unbalances, and reactive power control for under/over voltage conditions by an integrated control over the currents injected by the rotor-side converter, and on the currents drawn by the line-side converter. This will be demonstrated by a hardware laboratory prototype. Wind measuring equipment will be installed at tribal colleges and data would be collected on the grid conditions. Yearly seminars will disseminate information regarding wind resources. Intellectual merits of this project are the novel control of doubly-fed induction generators that integrates minimization of torque pulsations and compensation of reactive power, and new discoveries are entirely possible. In terms of broader impacts, the proposed research will directly benefit other applications, such as in utility-scale inertial energy storage systems. This will be the PhD research of a graduate student interested in a teaching career. A strong component is to establish ties with tribal colleges to promote collaboration and dissemination of information, helping tribal communities regard wind as a significant economic resource.