Analysing integrated renewable energy and smart-grid systems to improve voltage quality and harmonic distortion losses at electric-vehicle charging stations

Due to environmental impacts of fossil fuels, a move towards using Electric-Vehicles (EV) to reduce carbon emissions and fossil fuels is regarded as a good solution to the climate change problem. In recent years, a dramatic increase of EV and charging stations has raised voltage quality and harmonic distortion issues that are affecting the electrical grid network. To address these issues there is a need to redesign the integrated renewable energy and smart grid network by applying new methodologies. The aim of this work is to propose an isolated smart micro grid, which connects renewable energy generation units to the electric vehicles charging station without degrading voltage quality or causing harmonic distortion losses. A topology has been identified for the smart grid that is simulated with the intention of implementing it with the integration of modern communication technologies that enables the components to produce and reflect data in an efficient way to assist better regulation in the power flow. The power flow is investigated by simulating unpredictable renewable energy and by using car batteries at the electric vehicle charging station. It is investigated how micro grid parameters are affected in the presence of super capacitors, car batteries and the use of larger power electronic converters. In the simulations, an electrical power control system is implemented at power conversion units which generates the correct duty cycle of the converter switches and controls the power flow operation at the smart grid. Then the proposed electrical power control system is compared with other systems such as maximum power point tracking (MPPT) algorithm and space vector pulse width modulation (SVPWM). A smart sensor system and smart protection are connected to protect the grid and to maintain system stability over a long time. The research focuses on developing a smart grid that performs the communication among the converters, performs power sharing, and does preventive management. It also monitors the energy efficiently and balances the energy in the grid irrespective of load or power generation variations. A mathematical model is developed to predict grid behaviour and is validated via MATLAB simulation of the grid. It is noticed that an improvement is made in the efficiency of renewable energy transmission to the electric-vehicle charging station.