Advanced Topology, Modulation, and Control for Achieving High-Performance Solar Microinverters
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Type
ThesisThesis type
Doctor of PhilosophyAuthor/s
Li, JinghangAbstract
Solar microinverter systems are classified into two-stage and single-stage topologies. Two-stage designs are constrained by the poor performance of the second-stage full bridge inverter (FBI), while single-stage dual active bridge (DAB) microinverters suffer from the lack of active ...
See moreSolar microinverter systems are classified into two-stage and single-stage topologies. Two-stage designs are constrained by the poor performance of the second-stage full bridge inverter (FBI), while single-stage dual active bridge (DAB) microinverters suffer from the lack of active power decoupling (APD). Chapter 2 proposes a DAB+FBI topology with an active auxiliary branch, achieving zero-voltage turn-on switching, fixed frequency, and continuous conduction mode (CCM) FBI operation. Simulations show a 60% loss reduction and 98.14% peak efficiency. Chapter 3 introduces an APD modulation that reuses the primary-side DC-blocking capacitor as a decoupling capacitor with a large-signal control loop, cutting capacitor volume by 75% and input current ripple by 96%. Chapter 4 develops a synergistic modulation extending APD to non-unity power factor. With an inner phase shift, secondary current is optimized, reducing RMS current by 27% and improving efficiency by 4.5%, reaching 93.8% full-load efficiency. Overall, the proposed topologies and modulation strategies enhance efficiency, power density, and MPPT accuracy, advancing high-performance solar microinverter systems.
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See moreSolar microinverter systems are classified into two-stage and single-stage topologies. Two-stage designs are constrained by the poor performance of the second-stage full bridge inverter (FBI), while single-stage dual active bridge (DAB) microinverters suffer from the lack of active power decoupling (APD). Chapter 2 proposes a DAB+FBI topology with an active auxiliary branch, achieving zero-voltage turn-on switching, fixed frequency, and continuous conduction mode (CCM) FBI operation. Simulations show a 60% loss reduction and 98.14% peak efficiency. Chapter 3 introduces an APD modulation that reuses the primary-side DC-blocking capacitor as a decoupling capacitor with a large-signal control loop, cutting capacitor volume by 75% and input current ripple by 96%. Chapter 4 develops a synergistic modulation extending APD to non-unity power factor. With an inner phase shift, secondary current is optimized, reducing RMS current by 27% and improving efficiency by 4.5%, reaching 93.8% full-load efficiency. Overall, the proposed topologies and modulation strategies enhance efficiency, power density, and MPPT accuracy, advancing high-performance solar microinverter systems.
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Date
2025Rights statement
The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.Faculty/School
Faculty of Engineering, School of Electrical and Information EngineeringAwarding institution
The University of SydneyShare