A frequency-separated strategy for the integration of different types of electric vehicles into grid frequency regulation

Electric vehicles with different types of energy sources would have different performance when participating in grid frequency regulation. Batteries and supercapacitors are two booming concepts for electric vehicle energy sources. Supercapacitors are able to provide temporary power surge and charge or discharge frequently with less cost of lifetime compared to batteries. This paper first develops the mathematic model of electric vehicle battery and supercapacitor energy sources to differentiate these two types of electric vehicles. Then, the performance of different types of electric vehicles during the frequency regulation process is studied. According to different working characteristics, a frequency-separated strategy for grid frequency regulation is proposed, where supercapacitors deal with the high-frequency signals while batteries deal with the medium-frequency signals. By applying this strategy, the advantages of these two types of electric vehicles are taken and the cost of lifetime loss becomes less.