Optimal Control of a Doubly Fed Induction Generator of a Wind Turbine in Island Grid Operation

Abstract

Great significance is given to the use of energy from renewable sources, especially in industrial and municipal applications. The present article is devoted to the optimal control of a DFIG generator with the help of a rotor-side converter (RSC). Its aim is to ensure the delivery of the voltage of a three-phase network with appropriate parameters while operating in an islanded grid. Such a grid is usually characterized by an uneven loading of each phase. Additionally, the load of these phases changes randomly in time. In order to ensure the assumed parameters of line voltages, the optimal control is applied with a square cost function. This ensures the shape of voltage that is in accordance with the referential voltage. Moreover, higher harmonics with a given number are detected and reduced. The simulations that were executed confirm compliance with the conditions of the parameters of the output voltage in the islanded grid. Attention was paid to oscillations in the power flowing through the rotor-side converter (RSC). The methods to accelerate the suppression of these oscillations are presented.

Fabrication and Mathematical Modeling of the Brushless Doubly Fed Induction Generator-Based Wind Electric Conversion System

“…e design of a 2/6 pole, 400V, 3.5 kW BDFIM with star connection for SPW, delta-star connection for APW, and nested loop rotor was carried out using BDFIM design equations and standard output equations (15)(16)(17). Table 1 lists the machine's specifications [7].…”

“…e converter rating typically ranges between 25% and 35% of the rated power, allowing a wind turbine operation speed range of 50% to 120% of the rated speed. e authors present a control for the rotor-side converter (RSC) developed to provide symmetrical and three-phase voltage with minimal harmonic content at the islanded load terminals in [15]. e operation of an island is characterised by the uneven load on each phase and random behaviour.…”

Archives of Control Sciences

“…10. Thus, in contrast to similar studies [30,31], the model takes into account the dependences of self and mutual inductances on the angular rotor position that increases its accuracy.…”