Performance Analysis of Fast Charging Stations for G2V and V2G Microgrid Systems

In recent years, the potential scarcity of fossil fuels and increasing environmental challenges have motivated widespread study on electric vehicles (EV). Plugged-in EVs use the energy available in the distribution grid to charge their batteries. This shows the inevitability of the charging element and calls for an efficient network of fast charging stations. However, the developing EV charging infrastructure poses quite a lot of challenges for the existing distribution system. In this paper a photovoltaic (PV) generator integrated, three-phase fast charging station which also facilitates vehicle-to-grid (V2G) power exchange is modelled. The battery charger station aims at the regulation of the grid voltage level by varying the reactive power flow. The renewable source integration can prove as a means to reduce the power demand on the grid. The PV generation integrated EV charging station is connected to a microgrid system and the performance and operation of the system is analyzed by simulating different operating conditions.

I. Introduction

The 21rst century has witnessed increased population growth rates and rapid advancements in technology. This has led to a tremendous hike in worldwide energy consumption rates. The automobile and transportation industry can be accounted for a major contribution to the increased energy demand as a significant part of today’s automobile industry is owned by vehicles which work on internal combustion engines (ICE) which rely on fossil fuels like petroleum, diesel, and natural gas to meet their energy demands.. Moreover, it is a known fact that such ICE vehicles are an obstacle to a healthy and sustainable environment on account of the enormous amount of tailpipe emissions which contain particulate matter pollution and greenhouse gases. Electric vehicles have proven themselves as attractive alternatives for ICE vehicles. The advantages of EVs over ICE vehicles include environment friendly operation and zero emissions. The main factor that differentiates EVs from ICE vehicles is that EVs utilize rechargeable batteries energized from the power grid as the propulsion source of the vehicle. Consequently, many countries are now targeting the widespread replacement of ICE vehicles by EVs and the number of EVs on road are predicted to multiply in the coming years. The major obstacles to achieving these numbers are prolonged charging durations and range anxiety. Therefore, in order to ensure a smooth transition into battery powered electrified transportation we have to ensure an efficient as well as a widespread network of fast charging stations [1]. A lot many charger topologies have been proposed in the current literature. In [2] a review of the proposed topologies for battery charging. The charging station infrastructures and levels for hybrid vehicles and plug-in EVs are analysed. Bidirectional and unidirectional charger topologies, on-board charger and off-board charger topologies, integrated EV charger setups, etc., are presented. The different topologies for fast charging stations that have been presented in the literature are reviewed in [3]. A detailed study of the charging and control strategies of EV charging systems is presented in [4]. It also models an EV charger system for low duty and high duty vehicles.