Development of ESS for Regenerative Energy of Electric Vehicle

초록

The electric railway is a clean and energy saving system, because it requires relatively less energy than automobiles by transporting the same passengers or goods. Six thousands of vehicles are operated on Korean urban transit system. This system is 95% of regeneration system. Especially, the VVVF-Inverter vehicle has a merit of the highest regeneration rate. Energy consumption is 90% for traction and 10% for auxiliary supply. Braking energy is about 30% of energy consumption. Up to 30% of the tractive power of vehicles capable of returning energy to the power supply can be regenerated during braking and that this energy can be used to feed vehicles which are accelerating at the same time. The energy generated by braking vehicle would simply be converted into waste heat by its braking resistors if no other vehicle is accelerating at exactly the same time. Such synchronized braking and accelerating can not be coordinated, the ESS(energy storage system, here after) stores the energy generated during braking and discharges it again when a vehicle accelerates. The ESS creates optimum conditions for energy regeneration in urban transit system. The ESS is able to store and discharge energy extremely quickly, consequently enabling a complete exchange of energy between vehicles, even if they are not braking and accelerating at precisely the same time, as is most frequently the case in everyday service. The ESS reduces primary energy consumption without affecting transport capacity and punctuality. In addition, the ESS can stabilize the system voltage. The ESS is considered to be one of the useful devices for energy storing and recycling. This paper presents the development of the ESS. Namely, effect of the ESS for energy saving, applying the electric double layer capacitor(EDLC, here after) as the storage unit of the ESS, The ESS design, installation and field tests.