Investigation of Doubly-Fed Machine in Variable Speed Applications: Final Technical Report

摘要

Renewable energy sources have long been recognized as attractive alternatives to the conventional generation of electric power. One of the great challenges is to convert the intermittent and varying energy of these renewable sources into electric power in an efficient and effective way. Some of the emerging technologies involve mechanical to electrical energy conversion, which has usually been accomplished through the use of synchronous machines operating at a constant input speed and constant frequency. The requirement for constant input speed is often incompatible with the desire for efficient energy capture and imposes difficult control problems on the conversion equipment. A more natural approach to the conversion of intermittent and varying energy sources is a conversion system which accepts a variable mechanical input speed and produces the grid required constant frequency and voltage directly. This program has investigated the doubly-fed machine as a potential candidate to convert a varying input speed to a constant frequency, constant voltage output. Although this work is applicable to all rotating generation configurations with speed dependent efficiency, special emphasis was placed on hydro and wind power sources. 20 figs., 8 tabs.