A Hybrid Renewable Energy System (HRES) with a Proportional-Resonant (PR) Controlled Inverter

Abstract

This paper investigates the effectiveness of Proportional-Resonant (PR) controllers in Hybrid Renewable Energy Systems (HRES), which integrate solar and wind components to optimize energy reliability and efficiency. The study addresses the research question regarding the extent to which PR controllers enhance performance and efficiency in managing power quality, system stability, and frequency-specific control in grid-connected applications. Experimental evaluations further validate that variations in load conditions, such as those from RL loads, have minimal impact on output performance, underscoring the robustness of the PR approach. Additionally, the development and testing of a small-scale hybrid wind-solar microgrid, including tailored power electronic converters, control algorithms, and an energy management system, illustrate the practical applicability of these advanced control strategies in both standalone and dynamic operational environments.

Introduction

The global push for sustainable, independent energy has accelerated the use of hybrid renewable energy systems (HRES), which combine sources like solar and wind to improve reliability and reduce intermittency. Effective operation of these systems depends on advanced control strategies to manage the complex interactions between energy sources, converters, and varying loads. Key challenges include maintaining power quality, stability, and frequency regulation, especially in grid-connected setups.

Recent research highlights adaptive energy management and coordinated control architectures for standalone microgrids to maintain power balance amid fluctuating generation and demand. However, optimizing harmonic suppression and frequency control remains a challenge.

This study focuses on Proportional-Resonant (PR) controllers, demonstrating their effectiveness in enhancing power quality, stabilizing grid interactions, and reducing frequency deviations in a small-scale wind-solar microgrid. Experimental results under resistive-inductive load fluctuations show PR controllers’ robustness, supporting their use in both standalone and grid-connected systems. This work bridges theory and practice, advancing scalable control methods for resilient, efficient HRES.

The system consists of solar PV and wind turbine energy sources connected via DC-DC boost converters to a DC bus, feeding a single-phase inverter and load. The wind system uses a permanent magnet synchronous generator (PMSG) and variable speed turbine, while the solar system employs a PV panel with a closed-loop boost converter. An energy management system regulates power flow to maintain load supply.

Conclusion

A simulation model of a hybrid solar–wind energy system was successfully developed to reflect real-world scenarios involving variable renewable inputs and dynamic load demands. The system employs a closed-loop PI-controlled DC-DC boost converter to regulate the DC bus voltage under fluctuating wind and solar power inputs. This regulated DC voltage is then converted to AC using a PR-controlled inverter, which supplies power to a variable load. The simulation results confirm that the system maintains a stable DC bus and steady AC output, demonstrating effective handling of practical variations. The Total Harmonic Distortion (THD) of the inverter output voltage was found to be within acceptable limits—typically less than 5%, as recommended by IEEE Standard 519. The Power Factor (PF) of the system remained high—above 0.95, which is generally considered acceptable for grid-connected and standalone applications. These results validate the effectiveness of the chosen control strategies and confirm the system\'s capability to operate efficiently under dynamic real-life conditions. This work offers a foundation for further development, real-time implementation, and testing of hybrid renewable energy systems.

References

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Copyright

Copyright © 2025 Dipak Khachane, Prof. M.F.A.R. Satarkar, Pankaj Banswal, Vaibhavi Bhostekar, Shubhankar Vadke. 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.