Understanding rotor flux behaviour of a multi-megawatt DFIG in wind energy conversion

Rotor flux of a doubly-fed induction generator (DFIG) mainly depends on torque developed by the machine and reactive power interaction with the grid. Evaluation of the rotor flux of the machine is critical since lower value results in reactive power consumption from the grid, whereas higher value in unstable operation of the DFIG system. If rotor flux requirement is evaluated beforehand, the machine operation can be made more economical and stable. This paper presents an analytical study for the evaluation of rotor flux of a multi-mega watt DFIG. The analysis is carried out by deriving generalised expressions and rotor flux requirement is evaluated for various operating conditions on a 2 MW machine. Further, a simulation study using rotor voltage vector-based direct torque control (DTC) on the DFIG is carried out in MATLAB Simulink and the analytical results are compared with simulation results. Copyright © 2024 Inderscience Enterprises Ltd.