Efficient in reducing charging time, which is a commercialization issue

The Korea Advanced Institute of Science and Technology (KAIST) showcased smart wireless charging technology applicable to various fields at 'EV Trend 2018,' which opened on the 12th.

Wireless charging electric buses save 38% on fuel costs compared to diesel and 33% compared to CNG. They are attracting attention because the battery weighs only one-third as much as plug-in or battery swapping charging methods.

Wireless charging methods for electric vehicles can also be applied to railways, ships, trams, drones, and home appliances. After successfully commercializing the electric vehicle wireless charging method (OLEV), the Korea Advanced Institute of Science and Technology (KAIST) is applying it to bus routes 180 and 195 in Gumi City.

Until now, electric buses have faced issues regarding weight and cost due to the inclusion of batteries weighing over 1 ton. Charging also required a long time, and the short driving range was a stumbling block to commercialization. Wireless charging is a method designed to solve these existing battery problems by charging while passengers are boarding and alighting at bus stops. It is advantageous for commercialization because it allows for charging in a short period of time.

It is a principle that utilizes Magnetic Resonance Imaging Technology (SMFIR) to efficiently collect magnetic fields generated from power lines buried beneath the road through a current collector mounted on the underside of the vehicle, converting them into electrical energy for charging. For commercial operation, a separation distance of 20 cm, power transmission efficiency of 85%, current collection capacity of 100 kW, and electromagnetic safety for the human body of up to 62.5 mG must be secured.

To apply this to buses, power supply rails must be installed in sections of approximately 5% of the entire route, including the starting point, terminal, bus stops, intersections, and parking lots. It is also necessary to install batteries and a current collector on the vehicle's undercarriage.

Starting with the operation of an elephant train at Seoul Grand Park in 2011, the Korea Advanced Institute of Science and Technology (KAIST) has been operating wireless charging electric buses in Gumi City in 2014 and Sejong City in 2015. In 2016, the number of buses was increased and continues to be used to this day.

In addition to applications in buses, research is being conducted on technologies such as wireless charging railway technology, trams, buildings, and wireless charging systems using drones.