Photovoltaic based electric and plug-in hybrid electric vehicle battery charging infrastructure using a modified z-converter topology

摘要

There currently exist numerous uncertainties about the future of energy consumption in the industrialized world. It is safe to claim with confidence that fossil fuel reserves are proving to be inadequate, highly difficult to extract and refine, and less attractive to the community, given their environmental and socio-political impact. More recently, this has lead to the natural conclusion that renewable energy technologies should be preferred over more traditional ones. Replacing carbon as an economic engine can be achieved in numerous ways. However, it is still not clear, as to which renewable options will be more successful. On the other hand, it is quite safe to expect that the trend towards distributed and local power generation, using wind and photovoltaic sources will continue. At the same time, the enormous transportation sector will rely more heavily on electricity and related infrastructure needed for storage and distribution. All the above issues point towards the realization of public and private facilities to generate electricity locally, to recharge electric and plug-in hybrid electric vehicles. In this thesis, a photovoltaic (PV) source is proposed for electric/plug-in hybrid electric vehicle battery charging, due to the fact that solar panels can be conveniently placed above the vehicle parking space and can double as a shade provider. In fact, such a feature is so desirable that indeed, several installations exist today, that use a carport PV array to generate power for purposes other than EV recharging. Determining the technical goals for such facilities and discussing some relevant solutions is, broadly, the scope of this thesis. More particularly, the thesis aims at establishing application oriented technical differences between regular PV-grid-tied systems and PV systems that are specifically adapted to public or semi-public EV charging, noting that the former arrangement has enjoyed much attention in literature. This goal will be accomplished by presenting the design process for one such system, starting with the definition of technical specifications that take into account all the real constraints dictated by the state of the art in PV and battery technologies, grid interface requirements, safety standards, and market demands. The second part of this thesis focuses on the power converter topology, with strong emphasis on the analysis of the Z-loaded/sourced converter, as a fairly suitable and practical topology. At the same time, other possible topologies will also be considered for comparison purposes, especially with regards to reliability, efficiency, and cost.