Conservative power theory: application in a wind system with DFIG to compensate harmonic currents and unbalance electric current

Abstract

This paper presents the application of the conservative power theory (CPT) in the current loop control of the grid side converter (GSC) in a wind energy conversion system (WECS) with doubly fed induction generator (DFIG). The active and reactive power control of DFIG is performed using vector control by orientation of the stator magnetic flux and the analysis of the system is based on simulation results performed in Simulink. The CPT is a technique that allows to decompose the electric current in a given section of the electrical grid in components that represent the behavior of non-linear loads, unbalanced loads and reactive loads connected to the electrical systems. Therefore, the objective of this work is to present the possibility of compensating harmonic currents, unbalances of electric current and to improve the power factor using the CPT in the control of a WECS with DFIG. From the analysis of the obtained results it was observed that adding multiple functionalities to the WECS with DFIG allowing it to operate in order to improve the quality of the electric energy seen by the electric grid. The behavior of the electric current drained by the non-linear and unbalanced load was compensated by the wind system at different points of operation of the DFIG as the results show.