Seite - 65 - in Hybrid Electric Vehicles

High share of PHEV and BEV results in high demand of electricity due to charging; hence, it strongly correlates to the supply and balancing of electrical grid. Unmanaged charging of PHEVs and BEVs potentially results in several grid problems includ- ing over and under voltage and frequency in distribution networks, especially when individ- ual charging of PHEVs and BEVs takes place in large number and capacity [11]. Some methods to minimize the impact of unmanaged charging of PHEVs and BEVs have been proposed and developed by some researcher. They include coordinated charging [12], demand response [13], battery-assisted charging [14] and appropriate charger distribution [15]. In addition, an integrated vehicle to grid (V2G) is also potential to avoid the concentrated charging, as well as facilitate the other services [16]. In the coordinated charging, the charging behaviour of PHEVs and BEVs are controlled by certain entities; therefore, the electrical grid can be maintained stable and balance. Further, this charging behaviour control is then correlated strongly with the V2G services, especially for load-shifting or valley filling strategy [17]. However, the algorithm for valley filling under large- scale vehicles deployment is very sophisticated; hence, computational complexity becomes a very crucial factor [18]. Demand response encourages the users or drivers of PHEVs and BEVs to manage their charging demand during peak-load hours or when the electrical grid system is at risk [19]. Therefore, it is usually divided into two types: time-based and incentive-based. The former deals strongly with the real-time pricing and critical peak pricing. On the other hand, the lat- ter is related to the incentive due to utilization of PHEVs and BEVs for frequency regulation and spinning reserve [20]. Pricing system in the electrical grid requires accurate prediction on both supply and demand sides. Therefore, the uncertainties clarification and their impacts minimization become the major concern in demand response. Although they are promising methods, both coordinated charging and demand response require further theoretical developments and demonstrations on to ensure the system and standard in a relatively massive control system. On the other hand, the battery-assisted charging is consid- ered simple and applicable, due to its simplicities and convenience in structure and control. This chapter discusses the charging system for both PHEV and BEV including the recently developed battery-assisted charger. At the beginning, available charging levels and systems for PHEVs and BEVs are explained initially in terms of charging rate and standards. In addi- tion, the charging behaviour of the PHEV and BEV in different ambient temperature (seasons) are also described, clarifying the effect of ambient temperature to the charging rate. At the last, an advanced charging system with battery assistance is also explained including their quick- charging performance during simultaneous charging of electric vehicles. 2. Charging system for PHEV and BEV Charging of PHEVs and BEVs correlates strongly with some parameters including charging devices, cost, charging rate, location, time and grid condition. Therefore, relevant selection Advanced Charging System for Plug-in Hybrid Electric Vehicles and Battery Electric Vehicles http://dx.doi.org/10.5772/intechopen.68287 65