Aggregation of EVs for Primary Frequency Control of an Industrial Microgrid by Implementing Grid Regulation & Charger Controller

 ABSTRACT:

 After nearly a century with internal combustion engines dominating the transportation sector, it now appears that electric vehicles (EVs) are on the brink of enjoying rapid development due to numerous useful features they possess, such as less operational cost and reduced carbon emissions. EVs can act as load as well as source, by utilizing the technique known as Vehicle-to-Grid (or Grid-to-Vehicle technique if EVs are used as a load). This technique adds key features to an industrial microgrid in the form of primary frequency control and congestion management. In this paper, two controllers (grid regulation and charger controller) are proposed by considering different charging profiles, state of charge of electric vehicle batteries, and a varying number of electric vehicles in an electric vehicle fleet. These controllers provide bidirectional power flow, which can provide primary frequency control during different contingencies that an industrial microgrid may face during a 24-hour period. Simulation results prove that the proposed controllers provide reliable support in terms of frequency regulation to an industrial microgrid during contingencies. Furthermore, simulation results also depict that by adding more electric vehicles in the fleet during the vehicle-to-grid mode, the frequency of an industrial microgrid can be improved to even better levels. Different case studies in this article constitute an industrial microgrid with varied distributed energy resources (i.e. solar and wind farm), electric vehicles fleet, industrial and residential load along with diesel generator. These test cases are simulated and results are analyzed by using MATLAB/SIMULINK.

 KEYWORDS:

1.      Industrial Microgrid

2.      Vehicle to Grid

3.      Electric Vehicle

4.      Grid to Vehicle

5.      Primary Frequency Control

6.      State of Charge

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

This paper studies the impact of EVs’ charging on an industrial microgrid. The control scheme is implemented through grid regulation and charger controllers which provide bidirectional power flow. This dual power flow not only provides charging power to EVs but also ensures frequency regulation through active and reactive power support. The charging station consists of a central AC/DC VSC station that injects power into an industrial microgrid and minimizes frequency deviations. Different contingencies have been simulated and their impact on primary frequency is observed. Simulation results prove that the proposed bidirectional charging strategy contributes effectively towards frequency regulation. The frequency is well regulated within the acceptable margin when V2G mode is enabled for EVs’ charging/discharging as compared to when V2G mode was disabled. Frequency regulation improves even further by increasing the number of EVs in the fleet as more vehicles contribute to grid regulation mode. Hence, simulation results prove the robustness of the proposed controllers.

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