Enhanced Sliding Mode Control for Dual MPPT Systems Integrated with Three-Level T-Type PV Inverters

Bagheri, Farzaneh; Bonaldo, Jakson; Guler, Naki; Rivera, Marco; Wheeler, Patrick; Lima, Rogerio

Abstract

Dual Maximum Power Point Tracking (MPPT) inverters are essential in residential and small commercial solar power systems, optimizing power extraction from two independent solar panel arrays to enhance efficiency and energy harvesting. On the other hand, the Three-Level T-Type Voltage Source Inverter (3L T-Type VSI) is known for its reduced switching losses, improved harmonic distortion, and reduced part count in comparison to other three-level topologies. In this paper, a novel architecture is proposed to integrate the dual MPPT structure directly to each DC-side split capacitor of the 3L T-Type VSI, taking advantage of the intrinsic characteristics of the inverter’s topology. Further performance enhancement is achieved by integrating a classical MPPT strategy to the control framework to make it feasible for a real-case grid integration. The combination of these methods ensures faster and stable tracking under dynamic irradiance conditions. Considering that strategies dedicated to balancing the DC-link capacitor’s voltage slightly affect the AC-side current waveform, an enhanced sliding mode control (SMC) strategy tailored for dual MPPT and 3L T-Type VSI is deployed, combining the simplicity of conventional PI controllers used in the independent MPPT-based DC-DC converters with the superior robustness and dynamic performance of SMC. Real-time results obtained using the OPAL-RT Hardware-in-the-Loop platform validated the performance of the proposed control strategy under realistic test scenarios. The current THD was maintained below 4.8% even under highly distorted grid conditions, and the controller achieved a steady state within approximately 15 ms following perturbations in the DC-link voltage, sudden irradiance variations, and voltage sags and swells. Additionally, the power factor remained unitary, enhancing power transfer from the renewable source to the grid. The proposed system was able to achieve efficient power extraction while maintaining high power quality (PQ) standards for the output, positioning it as a practical and flexible solution for advanced solar PV systems.

Citation

Bagheri, F., Bonaldo, J., Guler, N., Rivera, M., Wheeler, P., & Lima, R. (2025). Enhanced Sliding Mode Control for Dual MPPT Systems Integrated with Three-Level T-Type PV Inverters. Energies, 18(13), Article 3344. https://doi.org/10.3390/en18133344

• Journal Article Type: Article
• Acceptance Date: Jun 21, 2025
• Online Publication Date: Jun 26, 2025
• Publication Date: Jul 1, 2025
• Deposit Date: Jul 10, 2025
• Publicly Available Date: Jul 10, 2025
• Journal: Energies
• Electronic ISSN: 1996-1073
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 18
• Issue: 13
• Article Number: 3344
• DOI: https://doi.org/10.3390/en18133344
• Keywords: Dual Maximum Power Point Tracking (MPPT); grid-connected inverters; photovoltaic systems; sliding mode control (SMC); Three-Level T-Type inverters
• Public URL: https://nottingham-repository.worktribe.com/output/50975666
• Publisher URL: https://www.mdpi.com/1996-1073/18/13/3344