Design and Controllability of Plug-in Hybrid Electric Vehicle (PHEV) Charging Facilities Integrated with Renewable Energy Resources

Electricity generation and transportation account for most of the global primary energy demand. The majority of the world’s coal demand is for electricity generation and the majority of the world’s oil demand is for transportation. This has triggered an increase in the deployment of renewable energy sources such as photovoltaic (PV) and wind throughout the globe. Likewise, alternative vehicle technologies, such as plug-in hybrid electric vehicles (PHEVs), are being developed to reduce the world’s dependence on oil for transportation and to limit transportation-related greenhouse gas emissions. A major barrier for the wide penetration of PHEVs in the market is the underdeveloped charging infrastructure. Another emerging issue is that a large number of PHEVs connected to the grid simultaneously may pose a huge threat to the quality and stability of the overall power system. Since the initial penetration of PHEVs is expected to be confined to a particular neighborhood, charging them simultaneously might cause serious issues to the distribution transformers. In view of the above issues this dissertation proposes a PHEV charging station architecture for workplace-based parking facilities using renewable energy sources (wind and/or PV) coupled with smart grid technologies. The proposed control algorithm will reduce the stress imposed on the grid at the distribution level during peak load hours. The proposed architecture consists of a DC microgrid that allows three-way interaction between the distributed energy sources, PHEVs and the grid, ensuring optimal usage of available power, charging time and grid stability. It consists of a photovoltaic and/or wind power source, power conditioning unit (PCU) along with an energy storage unit (ESU). The PCU consists of power converters with an intermediate DC-link. A unique control algorithm, based on the variation in DC link voltage level and the priority charging levels of PHEVs, facilitates the energy management and scheduling of PHEVs in the charging facility. As the DC link voltage is the only criterion used for switching between various modes, the overall complexity of the system is reduced in comparison to other existing methods.