Research Projects

In recent years, the integration of solar photovoltaic (PV) systems into the electrical grid has increased substantially, driven by global efforts to reduce carbon emissions and promote energy sustainability. Despite advancements, challenges persist in improving the efficiency, reliability, and cost-effectiveness of PV systems, particularly in power conversion stages. Conventional PV inverters with transformers often suffer from limitations in size, weight, cost, and efficiency. Transformerless multilevel inverters (MLIs) utilizing switched capacitor (SC) techniques, known as switched capacitor multilevel inverters (SCMLIs), have emerged as a promising alternative. SCMLIs use capacitors for voltage boosting and generate multilevel output voltage waveforms without relying on bulky magnetic components. Initially conceptualized in low-power DC-DC converters like the Makowski boosting network, SCMLI technology has evolved since its introduction in 1998. Over the last decade, numerous SCMLI configurations have been developed, focusing on reducing component counts, improving voltage-boosting capabilities, and increasing output voltage levels. A major drawback of transformerless designs is the issue of common-mode leakage current, which can compromise safety and efficiency in PV applications. To address this, researchers introduced common-grounded SCMLIs (CG-SCMLIs). By connecting the PV source ground to the load or grid ground, leakage currents are effectively eliminated, enhancing safety and efficiency. However, these designs face challenges such as higher component counts, the need for high-voltage-rated capacitors, and increased voltage stress on components, which affect cost and efficiency. On the other hand, SiC devices, such as SiC MOSFETs, offer better performance compared to conventional silicon-based counterparts. Combining SC topologies with SiC devices enables CG-SCMLIs to achieve high voltage gain, reduced switching losses, and improved thermal performance. This project aims to develop a novel CG-SCMLI topology leveraging SiC devices. The objectives are to achieve high voltage gain, a reduced number of components, and a common-grounded structure to minimize leakage current. The proposed inverter will be analyzed and validated using advanced control methods, including Finite Control Set Model Predictive Control (FCS-MPC) technique. Performance evaluations will focus on generating high-quality output waveforms with minimized filter sizes and ensuring robust dynamic responses under varying load conditions. Additionally, the system will be tested in both grid-connected and standalone scenarios. Overall, the integration of SiC-based CG-SCMLIs addresses critical challenges in PV power conversion, offering compact, efficient, and safer solutions. These innovations have the potential to greatly improve PV system performance and energy efficiency, advancing the overarching objective of a more sustainable and cleaner energy future.