Impedance interaction and power flow enhancement in DC microgrids by using interval type-2 fuzzy logic and active voltage stabilizer-based hybrid damping controller

Abstract

In DC microgrids the impedance interaction takes place due to the cascaded connection of a Permanent Magnet Synchronous Generator -Voltage Source Converter and a Dual Active Bridge converter. This impedance interaction adversely degrades system stability and transient response, resulting in oscillations and voltage deviations and affecting power flow in the DC microgrid. To mitigate these challenges, a modified control strategy is proposed, that integrates an interval type-2 fuzzy logic controller (IT2FLC) with an active voltage stabilizer (AVS) and active damping (AD). The modified controller regulates voltage, current transients, and power flow more effectively than a conventional controller. The IT2FLC enhances microgrid stability by handling system uncertainties, non-linearities, and impedance interactions of cascaded systems. The AVS ensures rapid and accurate voltage regulation during transient conditions, helping to maintain a consistent voltage despite sudden changes in load. At the same time, AD suppresses oscillations, preventing resonance and ensuring smooth operation. The modified controller (IT2FLC+AVS+AD) is also compared with different controllers like PI, (PI+AD), and (PI+AVS+AD) in terms of transient parameters that reveal the modified controller is better in terms of rise time, overshoot, undershoot, and settling time.