Recent Advances of Control Technologies for Brushless Doubly-Fed Generators

The brushless doubly-fed generator (BDFG) is a kind of dual-electrical-port field-modulated electrical machine containing two sets of stator windings with different pole pairs. The stator power winding undertakes most of the power inflow and outflow, and the stator control winding connected to the power converter can be utilized to regulate the machine operation status. Consequently, the rotor no longer needs to be supplied by the power converter, so that the brushes and slip rings can be removed. The BDFG can be used for grid-connected power generation as well as standalone power generation. This paper reviews recent advances of control technologies for BDFGs under different operation conditions, e.g., grid-connected ac power generation with normal and faulty grids, standalone ac power generation with normal and special loads, and dc power generation. The progresses of sensorless control technologies for BDFG-based power generation systems are also discussed. The classification and comparison are carried out to discover the similarities and differences between theses control technologies. This paper is in the hope of inspiring new, ground breakings and progresses for high-performance BDFG power generator applications.