Fuzzy-Adaptive ESO Control for Dual Active Bridge Converters

Area of Science:

• Electrical Engineering
• Control Systems
• Power Electronics

Background:

• Converter-dominated DC microgrids face voltage instability due to load transients.
• Energy storage systems and bidirectional dual active bridge converters are key components for mitigation.
• Robust controller performance is crucial for handling step-load conditions.

Purpose of the Study:

• To propose an active disturbance rejection control (ADRC) framework for DC microgrid voltage regulation.
• To enhance transient performance and mitigate voltage deviations under load steps.
• To address the trade-off between transient speed and noise sensitivity in Extended State Observer (ESO) control.

Main Methods:

• Implementation of an ADRC framework utilizing fuzzy logic for adaptive Extended State Observer (ESO) bandwidth tuning.
• The ESO bandwidth is dynamically adjusted based on estimation error: increased during transients for faster compensation, decreased in steady-state to reduce noise.
• Validation through hardware experiments under various load-step conditions.

Main Results:

• The proposed adaptive ESO controller significantly reduced peak voltage undershoot and settling time during load increases compared to PI and fixed-bandwidth ESO controllers.
• For load decreases, the adaptive ESO controller demonstrated substantial reductions in peak overshoot and settling time versus the PI controller and fixed-bandwidth ESO.
• Adaptive bandwidth tuning effectively balances transient response speed and noise suppression.

Conclusions:

• The fuzzy-logic-tuned adaptive ESO framework provides superior transient performance in DC microgrids compared to conventional methods.
• This approach effectively mitigates voltage deviations during severe load transients, enhancing grid stability.
• The adaptive strategy overcomes limitations of fixed-bandwidth controllers, offering improved overall regulation.