The use of electric vehicles (EV) is becoming more widespread as a response to global warming. The major issues associated with EV are the annoyance represented by charging the vehicles and their limited cruising range. In an attempt to remove the restrictions on the cruising range of EV, the research discussed in this paper developed a dynamic charging EV and low-cost infrastructure that would make it possible for the vehicles to charge by receiving power directly from infrastructure while in motion.
Based on considerations of the effect of electromagnetic waves, charging power, and the amount of power able to be supplied by the system, this development focused on a contact-type charging system. The use of a wireless charging system would produce concerns over danger due to the infiltration of foreign matter into the primary and secondary coils and the health effects of leakage flux. Because of this, a contact-type charging system was judged to also present advantages from the perspective of safety. With regard to fixing the positioning of the power collection equipment, pushing the twin rollers of the power collection arm horizontally against positive and negative conductor rails arranged in a V-shaped configuration fixes the power collection unit at the height of the rails.
Driving tests have already been conducted using the system to supply 180 kW of power (DC 600 V, 300 A) at vehicle speeds of more than 156 km/h during charging. Development is proceeding, with a view toward supplying 450 kW of power (DC 750 V, 600 A) at a vehicle speed of 200 km/h during charging.
If the system were introduced to expressways, the supply of 450 kW of power would represent a ratio of vehicle cruising range to charging lane length of 25:1. This would mean that the restrictions on EV cruising range could be removed by the installation of approximately two kilometers of charging lane per 50 km. It is estimated that the infrastructure installation cost in this case would be around 1/20 that of the cost for installation of wireless charging equipment.
The authors’ previous report, published in 2014, discussed a dynamic charging system supplying 100 kW of power (DC 375 V, 300 A) at a vehicle speed of 70km/h during charging, and presented the results of driving tests (1).
This report will discuss the results of driving tests conducted using 180 kW of power (DC 600 V, 300 A) supplied at a higher vehicle speed (156 km/h) and the future outlook for the system.
Tajima, T., Tanaka, H., Fukuda, T., Nakasato, Y. et al., "Study of High Power Dynamic Charging System," SAE Technical Paper 2017-01-1245, 2017, https://doi.org/10.4271/2017-01-1245.
