International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 12 Issue: 09 | Sep 2025
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p-ISSN: 2395-0072
TRANSFORMERLESS PHOTOVOLTAIC: OPTIMIZING RESIDENTIAL GRID INTERFACE WITH REDUCED HARMONICS Akshay Giramallayya Mathapati1, Prof.R.T. Bansode2 Fabtech Technical Campus College of Engineering and Research Sangola
---------------------------------------------------------------------***--------------------------------------------------------------------ABSTRACT The increasing demand for efficient and sustainable energy solutions has led to the development of transformerless photovoltaic (PV) systems, which are designed to optimize the integration of solar power with residential grid interfaces while minimizing harmonic distortion. This study focuses on the design, analysis, and optimization of a transformerless PV system aimed at improving energy conversion efficiency, reducing harmonic distortion, and ensuring grid compliance for residential applications. The proposed system utilizes a novel inverter topology that eliminates the need for traditional transformers, significantly reducing power losses and system costs while maintaining high performance. The key solution implemented is an inverter with a total harmonic distortion (THD) of 2-3%, well below the IEEE 1547 standard of 5%, ensuring that the output current meets grid quality standards. To further reduce harmonics and improve power quality, the system employs an LCL filter and bipolar sinusoidal pulse-width modulation (SPWM) switching. The results of simulations show that the inverter produces a sinusoidal current and voltage that are perfectly in phase, yielding a unity power factor and stable output, which is critical for seamless integration with the residential grid. Additionally, the system integrates a battery storage solution that dynamically compensates for variations in solar generation, maintaining stable power output even during periods of low irradiance. The battery storage also helps in optimizing energy utilization and reducing voltage fluctuations. Control strategies, including maximum power point tracking (MPPT) and battery management, have been implemented and successfully validated, with the system showing fast response times (within 0.1-0.2 seconds) to environmental changes such as fluctuating solar irradiance. The results confirm that the transformerless PV system not only achieves high efficiency and low THD but also offers a cost-effective solution for residential solar power generation. Furthermore, the simulation model is modular and scalable, allowing for future expansion and the incorporation of advanced grid features, such as reactive power control and fault ride-through, ensuring longterm adaptability and compliance with grid requirements. This study highlights the potential of transformerless PV systems as a reliable, efficient, and cost-effective solution for residential energy needs, contributing to the broader goals of energy sustainability and grid modernization. Keyword- Maximum Power Point Tracking (MPPT), Compliance, Unity Power Factor, Residential Solar Power I. INTRODUCTION With the growing demand for clean, renewable energy, photovoltaic (PV) systems have become an integral part of residential electricity generation. However, the challenge lies not only in harnessing solar energy efficiently but also in ensuring that the generated power is seamlessly integrated into the residential electrical grid while minimizing disruptions[1]. One significant issue that can arise during this integration is the production of harmonics—distortions in the normal waveform of the electrical current[2]. Harmonics are typically caused by nonlinear loads, such as inverters that convert DC (Direct Current) electricity from solar panels into AC (Alternating Current) electricity for residential use. These harmonic distortions can interfere with the proper functioning of household appliances, cause overheating of transformers and other electrical components, and degrade the overall power quality[3]. In response to these challenges, transformer less photovoltaic (TL-PV) systems have emerged as an innovative solution to optimize the interface between residential PV systems and the electrical grid[4]. Unlike conventional PV systems that utilize a transformer to step up or step-down voltage levels, transformer less inverters use more compact and efficient designs that reduce system costs and improve overall energy efficiency. The elimination of the transformer, however, introduces potential concerns related to harmonic distortion[5]. Transformer less inverters are known to generate higher harmonic content compared to their transformer-based counterparts, primarily due to the absence of isolation between the grid and the PV system[6]. The main objective of optimizing the residential grid interface with reduced harmonics is to ensure the efficient and smooth integration of solar energy into the power grid while maintaining power quality and compliance with regulatory standards[7]. Advances in power electronics, modulation techniques, and grid synchronization algorithms are helping to mitigate harmonic distortions and ensure that the output from transformer less PV systems is as clean as possible.
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