An Isolated Three-Phase Induction Generator System With Dual Stator Winding Sets Under Unbalanced Load Condition

This paper presents a stand-alone wind-based dual-stator-winding induction generation (DWIG) system under unbalanced load conditions. The DWIG consists of a cage-rotor and a stator with two sets of three-phase windings with the same number of pole-pairs. The first winding is fed by a three-phase STATCOM and is used to excite the machine. The STATCOM main frequency is chosen to be equal to generator load frequency. Since two stator windings share the same working frequency, the output frequency is independent of the generator load power demand, and its prime mover speed. The second stator winding is connected to the load. Assuming a three-phase unbalanced load, the main aim of this paper is to use conventional proportional-integral (PI) controllers for three different control targets. In the first target, the PI controllers are used to regulate the load positive-sequence-voltage while simultaneously removing the load negative-sequence-voltage. In the second and third control targets, the positive-sequence-voltage is regulated while simultaneously removing either the load negative-sequence-current or the load active power double-frequency-component. A separate PI regulator is used to regulate the STATCOM dc-link voltage by obtaining the rotor reference speed. Some simulation and experimental results are presented to prove the validity and effectiveness of the proposed system.