An adaptive limiter for unbalanced operation of doubly fed induction generator-based wind energy system

Abstract

Actual limits on parameters of type-3 wind generation unit, i.e., doubly fed induction generator (DFIG), are in terms of peak values of phase quantities but enforcement of limits in DFIG is achieved by positive and negative sequence controllers. The limits are generally enforced considering the scenario where positive and negative sequence vectors are collinear. However, this restricts the capability regions of the DFIG. The objective of this paper is to implement an adaptive limiter which conforms to all possible variations in phase angle between positive and negative sequence components. This will improve the range of operation irrespective of the level of unbalance of the connected distribution system. An adaptive limiter for voltage and current, considering different pulse width modulation (PWM) techniques for the voltage source converters (VSC), is implemented for unbalanced operation of DFIG and compared with generalised collinear technique.