Sensorless Variable Speed Operation of Doubly-Fed Reluctance Wind Generators

A flux vector orientated control scheme for gridconnected applications of an emerging doubly-fed reluctance generator without a shaft angular position or velocity sensor has been proposed and experimentally verified. This brushless machine technology is inherently medium-speed and as such is an attractive solution for the compromised reliability and high maintenance costs associated with the presence of brushes and the failures prone 3-stage gearbox of conventional slip ring doublyfed induction generators, traditionally used in wind energy conversion systems. The test results produced have undoubtedly shown the sensorless controller effectiveness both in terms of speed and reactive power response for typical variable loading profiles and speed ranges of geared wind turbines.