Distributed Maximum Power Point Tracking Architecture for Photovoltaic Systems
Photovoltaic to Virtual Bus Differential Power Processing
A. Nazer (TU Delft - Photovoltaic Materials and Devices)
M. Zeman – Promotor (TU Delft - Photovoltaic Materials and Devices)
O. Isabella – Promotor (TU Delft - Photovoltaic Materials and Devices)
P. Manganiello – Promotor (TU Delft - Photovoltaic Materials and Devices)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
This thesis introduces and develops advanced Differential Power Processing (DPP) architectures to enhance the performance and efficiency of photovoltaic (PV) systems by addressing mismatches among PV modules and strings. The work focuses on mitigating power losses due to voltage and current mismatches due to factors such as partial shading, panel misalignment, dust, and degradation. The research proposes novel architectures designed to reduce component voltage and power ratings, potentially lowering costs while maintaining high efficiency.
PV to Virtual Bus Parallel Differential Power Processing (PV2VB PDPP) Architecture: A new PV2VB PDPP architecture is introduced, leveraging a virtual bus as the input for string-level converters (SLCs). This design allows for reduced components’ voltage ratings by operating the virtual bus at a lower voltage than the main bus or PV strings. The architecture employs Dual Active Bridge converters connected to Bridgeless converters as SLCs to provide isolation and handle both positive and negative outputs. Experimental results demonstrate system efficiency ranging from 96.4% to 99%.
Dynamic Analysis and Stability: The thesis includes a comprehensive dynamic analysis of the PV2VB PDPP architecture, deriving small-signal models, transfer functions, and frequency responses. These analyses aid in understanding the system’s dynamic behavior, enabling effective controller design and stability studies. Experimental validation confirms fast stabilization of the virtual bus voltage (0.6 seconds) and intermediate bus voltages (15 milliseconds), ensuring efficient Maximum Power Point Tracking (MPPT) for each PV string.
Battery Integration in PV2VB PDPP Architecture: The work extends the PDPP architecture to include battery integration at the virtual bus, facilitating energy storage and management while performing MPPT. The battery integration reduces component voltage ratings and allows for efficient charging and discharging control by the central converter. Experimental evaluations show system efficiencies between 95.5% and 99%.
PV to Virtual Bus Series-Parallel Differential Power Processing (PV2VB SPDPP) Architecture: To address mismatches in both series-connected modules and parallel-connected strings, a PV2VB SPDPP architecture is proposed. This architecture uses a combination of SLCs and module-integrated converters (MICs), processing only a fraction of the total power. By leveraging virtual buses for both SLCs and MICs, the architecture reduces voltage and power stress on components, improving cost-effectiveness and reliability. Real-time simulations validate the system’s ability to balance power flow, ensure stable operation, and optimize PV module performance under mismatch conditions.