Hardware-in-the-loop testing of brushless doubly fed reluctance generator under unbalanced grid voltage conditions

An extended vector control method for the operation of a brushless doubly fed reluctance generator-based wind energy conversion system under unbalanced grid voltage conditions is proposed. The modified scheme has the capability to control the positive and negative sequences of the inverter-fed winding (secondary) currents independently. The primary aim of this work is to evaluate the effectiveness of the control algorithm in case of asymmetrical grid voltages. Since large-scale generators of this type are not yet available, Hardware-in-the-Loop testing is considered the most suitable viable alternative to true experiments to validate the wind turbine performance using the optimized design parameters. The presented test results for different control targets have revealed the promising potential of the underlying control strategy and the controller itself to mitigate the oscillations and improve the quality of the grid-connected winding (primary) and secondary currents, electro-magnetic torque, reactive and active power waveforms, being of utmost importance for the grid integration of this emerging generator technology.