Please use this identifier to cite or link to this item: http://hdl.handle.net/10266/6067
Title: Frequency Support of Micro-grid using Fleet of Electric Vehicles
Authors: Dhingra, Karanveer
Supervisor: Singh, Mukesh
Keywords: Electric Vehicles;Charging Station;Micro-grid;Distributed Energy Sources;Virtual Synchronous Generator
Issue Date: 11-Jan-2021
Abstract: In the today’s scenario, frequency deviation is a common issue in islanded microgrids (MG) due to the intermittent nature of renewable energy sources (RES). It generally occurs due to the mismatch between power generation and load demand of the MG. If the power generation by RES is more as compared to the load demand then frequency of the system increases on the contrary, if the load demand is more as compared to power generation then frequency of the system decreases. In order to overcome these deviations in frequency, it is very important to make the balance between load demand and power generation. This issue can be minimized by providing the inertia to the system. However, RES have low or no rotational mass and therefore, they are not able to provide the inertia to the system. On the other hand, it has been observed that virtual inertia to the system can be provided by using the energy storage system (ESS). Further, it has been found that electric vehicles (EVs) can behave as both storage and source of power for the MG. By considering these factors, concept of virtual synchronous generator (VSG) mechanism using a charging station (CS) is proposed to provide the inertia to the system where, a fleet of EVs parked in the CS acts as an ESS for MG. Case studies have been carried out to verify the frequency support of MG using VSG mechanism. In these case studies, irradiation level of the PV array and load of the MG system have been changed arbitrarily to induce the power mismatch in the system. Through simulation results, it has been verified that the frequency of the system can be supported by the bidirectional flow of power between the CS and MG using VSG control mechanism. Apart from this, sudden ingress and egress of EVs at the CS has been considered while providing the frequency support to the MG. However, the EVs which ingress and egress from the CS may have different battery voltage ratings with different charging needs. Moreover, the ingress and egress of EVs at the CS may be irregular. In such a case, support to MG’s frequency through EVs will be tough. In this work, a smart CS has been designed which can support the MG’s frequency, even during the sudden ingress and egress of different type of EVs. Simulations have been carried out in Matlab Simulink by taking into account the different cases like a sudden change of load on MG and sudden ingress/egress of EVs at the CS. The novelty of this work lies in catering to the sudden ingress and egress of EVs at the CS while providing the support to MG’s frequency through VSG mechanism. Moreover, novel handshaking process among multiple CS has been carried out by using VSG. These multiple CS co-ordinate with each other to accomplish the hand- shaking process by controlling the charging and discharging of EV batteries through VSG mechanism. Fleet of EVs placed at these CS act as an energy storage device for MG. Aggregator plays a role to collect the information from multiple CS about the charging requirements of the EVs. To accomplish the process of handshaking, simulations have been carried out in MATLAB simscape by considering the different case studies. In these case studies, diverse fleet of EVs are assumed to be deployed at the CS. From the simulation results, it has been observed that each individual EV deployed at the CS participate in the charging and discharging of their batteries to achieve the process of handshaking and hence to provide the support to MG’s frequency through VSG mechanism.
URI: http://hdl.handle.net/10266/6067
Appears in Collections:Doctoral Theses@EIED

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