Power converters play a pivotal role in renewable energy power generation systems,
with their significance increasing utilization and broad application in areas such as
photovoltaics, fuel cells, uninterruptible power supplies, and electric vehicles. The
advent of sustainable charging methodologies derived from renewable energy sources
paves the way for future interfaces that are not only sustainable but also render
distributed energy resources eco-friendly. An optimal converter is characterized by a
wide conversion ratio, cost-effectiveness, minimal voltage stress on switches,
simplicity, galvanic isolation, and high-efficiency performance. These attributes enable
the converter’s economic viability in various systems, including charging systems,
inversion, and green energy resources like solar energy conversion. This research aims
to explore these aspects in depth, contributing to the body of knowledge in this rapidly
evolving electric power conversion field.
This study introduces an electrically isolated D2 dc to dc converter; an innovative
derivation from the traditional single switch D2 converter, designed to fulfil the
requirements of sustainable distributed systems. Comprehensive models of the
proposed converter, including circuit and mathematical models, a simulation model,
and a hardware platform, confirm these aspects. The converter topology is implemented
in a photovoltaic system for maximum power point tracking and energy storage device
charging. It accommodates three dc/dc application scenarios: low power conversion,
input-parallel output-series cascaded and interleaved parallel connections, each
governed by their respective modulation strategies and control methods. This research
exploration of these aspects contributes to the evolving field of sustainable energy
conversion.
This thesis presents three variations derived from the isolated D2 converter, for active
power factor correction, namely, the isolated D2 converter, the bridgeless isolated D2
converter, and the interleaving isolated D2 converter. Each of these converters
successfully achieves the power factor correction objectives of maintaining a stable
output voltage, ensuring a near unity factor, and minimizing harmonic current. After analysis and comparison, the interleaving converter emerges as a superior choice,
demonstrating the most advantageous characteristics among the three power factor
correction converters.
A single-phase inverter is derived from the proposed isolated D2 converter for inversion
applications. The inverter is sinusoidally modulated with second-order generalized
integrator phase lock loop, generating a standard sinusoidal voltage waveform. The
output voltage and current from the inversion process align with the requirements of
distributed resources. This innovative approach to inversion offers the potential for
efficient energy conversion in distributed systems, including both single and three phase
system.
This research encompasses the realization of dc/dc application converters, power factor
correction converters, and inverters on both software and hardware platforms. The
features and characteristics of these elements are observed, compared, and analysed.
The isolated D2 converter, the focus of this research, demonstrates wide and effective
applicability in isolated dc/dc, ac/dc, and dc/ac applications, exhibiting commendable
performance when properly utilized. Given its robustness, the isolated D2 converter
with continuous input and output current converter, is posited as a promising converter
topology for future energy resources.
Keywords: An isolated D2 converter; dc/dc applications; Active power factor
correction; Single-phase inversion
| Date of Award | 12 Sept 2024 |
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| Original language | English |
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| Awarding Institution | - University Of Strathclyde
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| Sponsors | University of Strathclyde |
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| Supervisor | Barry Williams (Supervisor) & Khaled Ahmed (Supervisor) |
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