Optimization and Control of Hybrid Renewable Energy Source DC Micro-Grid Via Advance Control Strategies Using Matlab/Simulation

Abstract

The growing need for sustainable energy solutions has made DC micro-grids a key part of modern power distribution. However, keeping a stable DC bus voltage during unpredictable weather and changing load conditions is still a major challenge. This research presents a new DC micro-grid design that integrates Solar Photovoltaic (PV) and Wind Energy systems. The main innovation in this work is the use of a Zeta Converter as the primary AC-DC interface. This setup provides a non-inverting output and significantly lower current ripples compared to traditional Buck-Boost or SEPIC designs. To deal with the inconsistent nature of renewable energy, a Hybrid Energy Storage System (HESS) combines a Lithium-ion battery bank with an Ultracapacitor. This combination supplies both high energy density and quick responses. Simulation studies done in MATLAB/Simulink confirm that the system can maintain a steady DC link voltage, ensuring smooth power delivery to AC and multi-level DC loads

Introduction

This paper proposes a DC Smart Micro-grid System for efficient and sustainable energy delivery by integrating renewable energy sources, energy storage systems, and advanced power electronic converters. Unlike conventional power systems, the proposed DC micro-grid reduces conversion losses, improves energy efficiency, and supports reliable power delivery to both AC and DC loads.

Literature Review

Recent research highlights DC micro-grids as an effective solution for integrating renewable energy sources such as solar (PV) and wind energy with energy storage devices including batteries, ultracapacitors, and electric vehicles (EVs). Hybrid renewable energy systems improve reliability by combining complementary energy sources, while smart energy management strategies optimize power flow. Previous studies also emphasize the importance of simulation tools like MATLAB/Simulink for evaluating voltage stability, efficiency, and converter performance. However, many existing systems lack advanced converter designs and practical smart energy management.

Proposed Methodology

The proposed system is modeled and simulated using MATLAB/Simulink. It integrates:

• 415 V AC utility supply
• Photovoltaic (PV) system
• Wind energy conversion system
• Battery and supercapacitor hybrid energy storage system
• Advanced power electronic converters

The main objective is to maintain a stable DC bus voltage under varying load and renewable energy conditions while maximizing renewable energy utilization.

System Components

Photovoltaic (PV) System

• Converts solar energy into DC electricity.
• Uses a Maximum Power Point Tracking (MPPT) algorithm to maximize power extraction.
• Supplies power directly to loads or stores excess energy.

Wind Energy System

• Uses a wind turbine coupled with a Permanent Magnet Synchronous Generator (PMSG).
• Converts wind energy into electrical power under varying wind conditions.
• Integrates seamlessly with the DC micro-grid.

Zeta Converter

• Acts as the primary DC-DC converter between the utility supply and DC bus.
• Provides both step-up and step-down voltage regulation.
• Produces lower voltage ripple, continuous output current, reduced Total Harmonic Distortion (THD), and better efficiency than conventional converters.

Buck-Boost Converter

• Regulates the PV output voltage.
• Operates in both buck and boost modes using the Perturb and Observe (P&O) MPPT algorithm.
• Ensures maximum power extraction from the PV array.

Hybrid Energy Storage System

• Battery: Stores excess renewable energy and supplies power during high demand through a bidirectional DC-DC converter.
• Supercapacitor: Provides rapid power support during sudden load changes, reducing voltage fluctuations and improving DC bus stability.

Simulation and Results

The complete DC micro-grid was simulated in MATLAB/Simulink. Results demonstrate:

• Stable DC bus voltage under changing operating conditions.
• Reliable integration of PV, wind, battery, and supercapacitor systems.
• Efficient power delivery to DC loads.
• Improved voltage regulation and reduced ripple.
• Higher efficiency and better power quality using the Zeta converter compared to the conventional Buck converter.

Conclusion

The proposed DC micro-grid system has been designed and simulated by combining multiple energy sources such as solar photovoltaic (PV), wind energy, and the utility grid. It also includes power electronic converters and energy storage systems to improve performance, flexibility, and reliability. Components like the Zeta converter, Buck-Boost converter, and bidirectional DC-DC converters are crucial for efficient power management and voltage regulation. The system can maintain a stable DC bus voltage of about 170V, even with changing load and source conditions. This stable DC link ensures proper power distribution to various types of loads. The system successfully provides 110V AC through an inverter for household applications. It also delivers regulated 100V DC and 48V DC outputs using buck converters for DC loads. This multi-level power distribution shows the versatility of the proposed micro-grid.The Zeta converter, used to connect to the utility grid, offers advantages like non-inverted output voltage, continuous current, and reduced ripple content. This leads to better power quality and lower Total Harmonic Distortion (THD). The Buck-Boost converter paired with the PV system ensures maximum power extraction through MPPT (Perturb and Observe algorithm), improving the efficiency of solar energy use.A key feature of this system is its hybrid energy storage system, which includes both a battery and a supercapacitor. The battery handles long-term energy storage and backup, while the supercapacitor responds quickly to sudden load changes and transient conditions. This combination greatly improves system stability, reduces voltage fluctuations, and ensures uninterrupted power supply. The simulation results show smooth power flow, effective load sharing among different energy sources, and minimal voltage variations. The system operates reliably during changes in renewable generation and load demand, demonstrating the effectiveness of the control strategy.In conclusion, the proposed DC micro-grid system provides a reliable, efficient, and scalable solution for modern energy needs. It is suitable for smart grids, renewable energy integration, and sustainable power systems. It offers improved performance, better power quality, and enhanced operational stability. The proposed DC micro-grid system effectively integrates multiple energy sources, including AC utility supply, renewable energy (PV and wind), energy storage systems, and electric vehicle support. The system operates under different modes such as AC mode, renewable mode, hybrid mode, and standby mode, ensuring uninterrupted power supply under various conditions.The DC link voltage is maintained at a stable level, ensuring efficient power sharing and minimizing power quality issues. The system successfully supplies both AC and DC loads, highlighting its flexibility and reducing conversion losses. Simulation results demonstrate smooth power flow, minimal voltage fluctuations, and effective load management. Overall, the proposed system provides a reliable, efficient, and sustainable solution for modern smart grid applications, validating its suitability for future energy systems.

References

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Copyright

Copyright © 2026 Abhay M. Halmare , Uday kumar Shende, Aditya Madhav Kothare, Yash Pramod Nanotkar, Vishal Surendrakumar Dhurve, Ankita Pundlik Dukse, Rachi Mahendra Sadavarte. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.