Small-Signal Stability Analysis and MOSMA-Based Optimization Control Strategy of OWF with MMC-HVDC Grid Connection

Area of Science:

• Electrical Engineering
• Power Systems
• Renewable Energy Integration

Background:

• Offshore wind farms (OWFs) connected via modular multilevel-converter-based HVDC (MMC-HVDC) systems are experiencing oscillation events across a wider frequency band.
• This phenomenon complicates small-signal interaction analysis and stability control.
• Existing methods struggle to address these wideband oscillations effectively.

Purpose of the Study:

• To investigate the wideband dynamic interaction mechanism in MMC-HVDC connected OWFs.
• To develop an improved control strategy for enhancing small-signal stability and mitigating oscillation risks.
• To improve the wideband damping ability and adaptability of grid-connected systems.

Main Methods:

• Detailed impedance models of the grid-connected system were established, incorporating submarine cable characteristics, control delay, and frequency coupling.
• Active damping control and impedance stability criteria were employed to analyze wideband resonance and derive stability constraints.
• An improved multi-objective slime mold algorithm (MOSMA) was utilized for coordinated optimization of control parameters.

Main Results:

• The study successfully analyzed the wideband dynamic interaction mechanism and resonance phenomena.
• Stability constraints for controller parameters were determined using impedance analysis.
• The proposed MOSMA-based control strategy demonstrated enhanced adaptability and wideband damping capabilities.

Conclusions:

• The developed impedance models and stability analysis provide a robust framework for understanding wideband oscillations.
• The MOSMA-based coordinated optimization control strategy effectively improves the wideband stability of MMC-HVDC connected OWFs.
• Simulation and experimental results validate the efficacy of the proposed control strategy in enhancing system performance and reliability.