As the world looks at cleaner mobility solutions, electric vehicle (EV) penetration is poised to grow, necessitating the setting up of a robust charging infrastructure
Bikash Sah, a student of Indian Institute of Technology (IIT), Guwahati has developed an EV charging system to source optimum performance out of EVs.
Internal Combustion Engine-powered vehicles have remained an indispensable part of our lives and it is certainly difficult to imagine lives without them. However, the presence of such vehicles has led to increasing pollution-related problems and this explains why leading economies in the world are experimenting with advanced technologies to develop cleaner mobility solutions, especially electric vehicles. EVs might continue to carry a heavier sticker price, but their usage is gradually picking up momentum based on unprecedented levels of collaboration among various industry stakeholders.
The increased usage of EVs has caused a paradigm shift in the transportation sector. EVs are replacing fossil fuel-powered conventional vehicles. According to data released by the International Energy Agency (IEA), more than three million EVs are on the roads today, with China and USA being the biggest buyers.
The widespread use of EVs demand an intelligent infrastructure, which can ensure the connected utility services are least affected. There are two significant challenges to this perspective. First, the grid to vehicle recharging (G2V) and then the vehicle to grid discharging (V2G) of EVs serve as an additional load as well as a distributed energy technology to the utility grid. Thus, there is a need for an overhaul of the existing power system (generation, transmission, and distribution) to meet the charging requirements.
Secondly, the adequate process of recharging and discharging EVs will require an intelligent controller to decide the amount of power to be exchanged between the utility grid and the EVs. The working of the controller will be dependent on the node voltage of the grid and the energy available in the EVs connected. The node voltage in the grid provides an idea of the load connected to the utility grid, and the amount of energy the EVs have to recharge or discharge. Hence, there is a requirement for a robust information exchange system that communicates data between various entities of a V2G system and a controller that can take intelligent decisions with data as inputs.
Bikash Sah, a student of IIT, Guwahati has worked on a charging infrastructure system, which has advanced features to recharge vehicles, considering the condition of electricity grid during peak load hours and the total energy available at public charging stations (PCS). The state of grid is a measure of node voltage, and the sum of energy available at each EV provides the total energy available at PCS. The recharging of vehicles takes place in a coordinated fashion, which is ensured using a communication system to exchange data signals between various entities of the infrastructure, including electricity grid, aggregator, intelligent controller, PCS and EVs, (1). This coordination is implemented using an intelligent controller.
The inputs to the controller are the data sampled at PCS and the sub-station. Based on the inputs, the controller decides the right amount of power to be exchanged. Here, the exchange in power corresponds to the following – the requirements of EVs at charging stations to recharge, and requirement of power by the electricity grid for support from EVs during peak load hours.
A significant innovation is the requirement of fewer data samples from the two ends – from the sub-station and the charging station. This work uses a fuzzy logic rule base controller. The number of rule base is varied by changing the number of membership functions and hence, improving the granularity in the decision-making process. This further leads to a reduction in data requirements on the input side. The decrease in the requirement of data leads to reduction in the cost of data collection, processing and sending. Since it is a step towards the future, the infrastructure with the mentioned functionality can be deployed to meet the requirements of EV charging and reducing the impact of EV charging on the grid.
Sah’s work is an innovative step towards reducing the requirements of data samples by the controller. The PCS should support the grid and recharge vehicles. The impact of variations in the number of input membership function develops an insight for deploying a charging infrastructure with required functionality at lower data transfer rates. This innovation will go a long way in integrating EVs to the electricity grid and help in the paradigm shift from conventional vehicles to battery-powered vehicles.
TEXT: Anirudh Raheja