Modular Multilevel Converter based Grid connected DC Microgrid Integrating Wind Energy

The global adoption of energy storage systems and wind energy conversion systems has expanded significantly in recent years. In this context, this paper discusses the enhanced operation and control of a DC microgrid system, which integrate AC grid, wind energy conversion system, battery storage system, and DC load. An enhanced Modular Multilevel Converter (MMC) is utilized for efficient AC to DC conversion for AC grid and wind energy system, while a Sensing and Balancing Control strategy already proposed by the authors ensures capacitor voltage balancing, contributing to DC voltage stability within the microgrid. The battery storage system system integrates a Bidirectional DC-DC Converter (BDC) to ensure consistent voltage output in both buck and boost modes, making it adaptable to varying load requirements. The performance of proposed DC microgrid system is compared with identical system using MMC with conventional capacitor voltage balancing technique. The effectiveness of MMC and its control algorithms in maintaining a stable DC bus link voltage has been analyzed using MATLAB/Simulink simulations. A detailed comparison of Total Harmonic Distortion (THD), DC bus voltage, and battery voltage has been conducted to evaluate the system's performance. The results demonstrate significant improvements in voltage stability and harmonic reduction, highlighting the efficiency of the control strategy. Additionally, the analysis reveals a consistent performance of MMC, ensuring reliable operation of the DC microgrid. Key advantages of the proposed system include high efficiency, modularity, stability and scalability, making it suitable for modern energy storage and grid integration applications.