ANALYSIS AND DESIGN OF A DC-DC QUADRATIC POWER CONVERTER WITH PARTIAL POWER PROCESSING ARCHITECTURE FOR PHOTOVOLTAIC APPLICATIONS

The increasing adoption of photovoltaic (PV) systems demands innovative DC-DC power conversion solutions. This thesis focuses particularly on micro-grid systems and standalone PV modules, where traditional array connections are unavailable, generating the need for high step-up requirements with wide input voltage variations. The analysis, design, and simulation of a novel DC-DC power converter with a Partial Power Processing (PPP) architecture is presented, designed to operate over a wide input voltage range (15–43 V) and deliver constant output voltage (350 V) across a broad power range (50–680 W), accommodating the variability of PV energy sources. To overcome efficiency bottlenecks in DC-DC stages for single-phase grid-tied PV systems, this thesis introduces the exploitation of Partial Power Processing through a dual stage quadratic converter with Input-Parallel Output-Series (IPOS) topology, offering high performance by allowing part of the power to flow directly to the load, bypassing the converter stages. This approach achieves high efficiency, reduces component stress, and ensures reliable performance under various conditions. Simulation results reveal a California Energy Commission (CEC) weighted efficiency of 97.2% and a European (EURO) weighted efficiency of 96.8% at the rated power of 680 W. By providing a comprehensive framework for addressing wide input voltage ranges, high step-up gains, and partial power processing, this work contributes to advancing the state of the art in PV power conversion. The methodologies and findings offer practical insights for improving efficiency in renewable energy systems while addressing challenges posed by Partial Power Processing load balancing. Building on these innovations, this work also contributes to the DC-DC power converter design workflow by presenting developed methodologies and tools tailored to address the challenges of achieving high step-up gain values with large input voltage variation in circuit topologies highly dependent on load conditions. A detailed efficiency measurement approach, leveraging LTSpice and MATLAB integration, is introduced alongside innovative techniques for magnetic loss estimation through simulation. These contributions provide valuable insights to assist designers in optimizing converter performance for renewable energy applications.