Multivariable Robust Grid Currents Control of a Squirrel Cage Induction Generator Connected to a Wind Turbine

Abstract

In this paper, a multivariable robust control strategy of a variable speed wind energy conversion system based on a squirrel cage induction generator (SCIG) is presented. Optimal speed control of the SCIG is achieved by a conventional PI controller combined with a Maximum Power Point Tracking (MPPT) strategy. The Indirect Field Oriented Control (IFOC) technique based on a simple Park (d-q) reference model is used to implement the proposed controller. Active and reactive power flow between the grid and the inverter is controlled via simultaneous H-infinity control of active and reactive currents of the grid and the DC link voltage. The switching technique of the inverter which is connected directly to the grid is controlled by a programmed PWM look-up table wave shaping. The robustness and performance of the proposed control scheme is evaluated on a comprehensive model of the wind energy conversion system using Matlab/Simulink.