The proposed thesis aims to develop innovative isolated DC-DC power converter topologies that enhance efficiency and scalability for sustainable energy technology applications. The research begins by optimizing the parallel differential power processing (PDPP) architecture in photovoltaic (PV) systems by replacing two dual active bridge (DAB) converters with a single optimized DAB. This first phase focuses on simplifying the PDPP architecture, reducing hardware redundancy, and improving system cost-effectiveness while maintaining high performance in mitigating mismatch losses among PV strings. The insights gained from this optimization will inform the second phase by adapting the DAB topology. In this phase, the conventional full-bridge design of the DAB will be replaced with a Packed U-Cell (PUC5) converter to meet the bidirectional power flow and high-power density requirements. This unified project bridges renewable energy domains by leveraging the fundamental principles of efficient power processing while addressing the unique challenges of sustainable energy applications. Through detailed real-time simulations or experimental validations and performance evaluations, the thesis will contribute to developing scalable, cost-effective, and high-performance solutions that advance sustainable energy technologies. My thesis aligns closely with my study programme in Sustainable Energy Technology, particularly in Electric Mobility Systems. It integrates key aspects of power engineering, snd energy storage, by focusing on advanced power converter architectures. The academic aspect of my thesis lies in advancing the state of the art in power converter technology through theoretical analysis, real-time simulation, or experimental validation. It contributes to existing knowledge by proposing novel designs—replacing dual DAB converters with a single optimised DAB in PV systems and introducing a new DAB converter using the PUC5 topology.