Enhancing the Dynamic Performance of a Standalone DFIG Under Variable Speed Operation Using an Effective Control Technique

Abstract

The paper aims at introducing an efficient control algorithm which enhances the dynamic performance of a standalone doubly fed induction generator (DFIG) operating at variable speeds. To illustrate the effectiveness of the proposed controller, the performance of the DFIG is also evaluated using other control strategies. The control approaches which are used for the comparison purpose are the stator voltage-oriented control (SVOC) and the model predictive direct torque control (MPDTC). At first, the performance of the DFIG under each control technique is analyzed in details, showing the principle of operation of each strategy; then, a comprehensive dynamic performance comparison is performed among the three controllers; through which the merits and defects of each technique are clarified. The results confirm the validation and superiority of the proposed predictive voltage control (PVC) strategy over the other control techniques. This is illustrated through the faster dynamics, the simplicity, the reduced computational efforts and reduced ripples content. Moreover, the numerical results are showing a reduction in the total harmonic distortion (THD) with a percentage of 1.72% compared to MPDTC, and also showing a faster dynamic response in the power and torque profiles with percentage of 0.98% and 0.7% compared to SVOC; and with percentage of 0.1% and 0.52% compared to MPDTC, respectively.