A Proportional and Weight Based Decentralized Charge Controller of Electric Vehicles for the Improvement of Local Voltage Profile

Abstract

The market for electric vehicles has been gradually increasing. Despite several advantages, incorporating electric vehicles (EVs) on a large scale into the distribution grid is a challenging task. Feeder overloads, system power losses, and voltage violations could all arise because of the unregulated charging of EVs. A centralized and coordinated control approach can monitor and manage the large number of EVs; however, it requires high bandwidth and a reliable communication channel. Also, proportional based decentralized EV charging control approach automatically reduces charging current to improve the grid voltage profile, downstream EV encounters higher reduction of charging current due to their position in the grid. As a result, this study developed a decentralized modified proportional-based control approach for EV battery charging that can improve the grid voltage under heavy load conditions and ensure fair charging among EVs, regardless of their position in the grid. The battery’s state of charge (SOC), constant current (CC), and constant voltage (CV)-based charging are all considered by the proposed controller. The proposed method was also compared with proportional and voltage-sensitivity-based decentralized EV charging control methods. A SiC-MOSFET switch-based H-bridge converter is utilized to experimentally validate the grid-connected EV system. The proposed system was initially developed in MATLAB Simulink, and a laboratory prototype was constructed to verify the results experimentally.

Keywords

• Decentralized charge controller
• proportional charge controller
• voltage sensitivity-based charge controller
• weight based fair charging