Doubly-Fed Induction Generator Torque in Wind Turbines

Abstract

The field oriented doubly-fed induction generator (DFIG) is being increasingly used in variable speed wind turbines. It is therefore indispensable to become better acquainted with electrical and mechanical DFIG features in both stationary and dynamic modes of operation. Because of that, the DFIG torque is specifically discussed in this paper. A mathematical model of DFIG for steady-state modes in a known double-axis dq reference frame concerned with stator voltage vector has been made. Expressions concerning DFIG power from both the rotor and the stator side have been derived. Expressions regarding torque values have been obtained from the generator active power and mechanical rotational speed. Torque consists of asynchronous and synchronous torque components, whereas DFIG has been observed as a hybrid between an asynchronous and synchronous machines. For each particular torque characteristic analytical expressions have been derived.

Dinko Vukadinović

Full Professor | Department of Power Electronics and Control

Full professor at the Faculty of Electrical Engineering, Mechanical Engineering, and Naval Architecture in Split, specialized in modern control systems for power electronic converters, electric motors, and generators. At the Power Electronics Research Laboratory, he leads experimental projects and develops advanced methods for regulating electrical machines and converters, while supervising doctoral research in these areas.