Power quality conditioning system based on Lithium-Ion Ultracapacitors for Electric Vehicles Quick Charging Stations

Abstract

Power Conditioning Systems (PCSs), also known as Active Filters or Custom Power, are innovative devices based on Power Electronics widely used on Medium Voltage (MV) and Low Voltage (LV) power transmission networks to improve the quality of power distribution and compensate local disturbances. Some of common features are improving the quality of the power supply of particularly sensitive loads to network disturbances, such voltage sag compensation or short interruptions, peak shaving, active power factor correction. Such type of devices, especially with the primary function of peak-shaving, are very suitable coupled with Electric Vehicle Quick Charging Stations (EVQCS) due the considerable power absorbed by them from the three-phase network (in our case 400 V-50 Hz) especially at the beginning of the charging (several kW for some minutes). In this way, the network will be relieved of high power peaks need that would cause an impact on utilities and necessary investments by the distributor. This paper describes an innovative power conditioning system with energetic storage based on Lithium-Ion Ultracapacitors which have high performance in terms of specific energy and long service life. The device is designed and built to be a support for an EVQCS. The prototype is actually installed in the experimental area of Enel Ingegneria e Ricerca, located in Livorno, where a series of tests has proven its functionality and benifts for the grid. Future tests will be dedicated on interaction with a Li-ion storage system to improve energy services.