New orientation technique of aligned D-Q reference frame for controlling doubly-fed induction generators

Area of Science:

• Electrical Engineering
• Power Systems
• Control Systems

Background:

• Doubly-Fed Induction Generators (DFIG) control necessitates precise d-q reference frame orientation.
• Conventional methods rely on Phase-Locked Loop (PLL) schemes to align the d-axis with the grid voltage vector.
• PLLs exhibit instability under grid frequency and phase angle disturbances, impacting DFIG control performance.

Purpose of the Study:

• To propose and validate a novel DFIG orientation method independent of PLL schemes.
• To demonstrate the effectiveness and reliability of the proposed method under frequency and phase angle disturbances.
• To ensure stable and independent active and reactive power control in DFIG systems.

Main Methods:

• Development of a new orientation technique for DFIG control, eliminating the need for a PLL.
• Implementation of a small-scale DFIG experimental test bench using dSPACE DS1104 and DS1102 controllers.
• Evaluation of the proposed orientation method's performance under various operating conditions, including grid disturbances.
• Comparative analysis between the proposed orientation technique and the conventional PLL-based approach.

Main Results:

• The proposed orientation method provides stable and effective DFIG control without a PLL, even during frequency and phase angle disturbances.
• Experimental validation confirms the reliability and robustness of the new orientation technique.
• Independent active and reactive power control is successfully achieved under diverse operating scenarios.
• The proposed method outperforms the conventional PLL technique in terms of stability and disturbance rejection.

Conclusions:

• The proposed PLL-independent orientation method offers a superior alternative for DFIG control, enhancing stability and performance.
• This approach effectively mitigates issues associated with PLL instability in dynamic grid conditions.
• The validated experimental results underscore the practical applicability and efficacy of the novel orientation technique for DFIG systems.