Grid-connected quasi-Z-source PV inverter for electricvehicle charging station

The use of electrical vehicle (EV) as a more environmentally friendly transportation option compared to the conventional internal combustion engine vehicle (ICE) has increased the demand on the utility grid energy. As a solution, other alternative energy source such as photovoltaic (PV) becomes increasingly applied in the EV charging station infrastructure. However as the energy that can be harvested from the PV is constrained, among others by the sun irradiation availability and space for system installation, integration with utility grid still need to be considered to ensure a smooth charging operation. In this paper, a new method of integration between PV inverter system with utility grid for vehicle charging station based on the quasi-Z-source (qZSI) topology is proposed. The proposed system realizes a bidirectional power flow management between PV sources, energy storage unit and the utility grid which is very suitable for small to mid size business infrastructure. The main advantage is the flexibility of the proposed topology with various voltage levels of the inverter DC link and the battery storage, with no circuit modification requirement. All the design and configuration for each component in the system are detailed and the operation is verified through simulation. The results demonstrate the proposed system meets the requirement.