Design and Implement a Digital <em>H∞ </em>Robust Controller for a MW-Class PMSG-Based Grid-Interactive Wind Energy Conversion System

A digital <em>H∞</em> controller for a permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS) is presented. Wind energy is an uncertain fluctuating resource which requires a tight control management. So, it is still an exigent task for the control design engineers. The conventional proportional-integral (PI) control is not ideal during high turbulence wind velocities, and the nonlinear behavior of the power converters. These are raising interest towards the robust control concepts. The robust design is to find a controller, for a given system, such that the closed-loop system becomes robust that assurance high-integrity and fault tolerant control system, robust <em>H∞</em> control theory has befallen a standard design method of choice over the past two decades in industrial control applications. The robust <em>H∞</em> control theory is also gaining eminence in the WECS. Due to the implementation complexity for the continuous <em>H∞</em> controller, and availability of the high speedy micro-controllers, the design of a sample-data or a digital <em>H∞</em> controller is very important for the realistic implementation. But there isn’t a single research to evaluate the performance of the digital <em>H∞</em> controller for the WECS. In this paper, the proposed digital <em>H∞</em> controller schemes comprise for the both generator and grid interactive power converters, and the control performances are compared with the conventional PI controller and the fuzzy controller. Simulation results confirm the efficacy of the proposed method Energies 2013, 6 2085 which are ensured the WECS stabilities, mitigate shaft stress, and improving the DC-link voltage and output power qualities.