Control of a Brushless Doubly-Fed induction generator via a matrix converter

The Doubly-Fed Induction Generator (DFIG) is one of the most widely used generators for wind energy applications and more of 50% of the installed Wind Energy Conversion Systems (WECS) are using this sort of variable speed technology. However, the machine requires brushes for the operation which increases the maintenance work. To overcome this drawback a Brushless Double Fed Induction Generator (BDFIG), composed of two cascaded doubly-fed machines with the rotor windings interconnected, could be used. In this work, the control of a BDFIG is presented using a matrix converter (MC). Matrix converters may be seen as suitable converter choice for this application instead of the standard back-to-back PWM voltage source converter topology. Results from an experimental rig are presented for operation of the BDFIG at variable speed with the machine driven by a commercial AC drive as a prime mover.