Will the Dream Water Taxi Emerge? Development of Electric Propulsion Using Magnets

[Financial News] For the first time in the world, a high-efficiency counter-rotating propeller electric propulsion system using magnets has been developed. It is expected to be used not only in existing unmanned ships but also in water taxis. The Electric Power Research Center of the Korea Electrotechnology Research Institute (KERI), led by Dr. Hong Dogwan, announced on the 27th that they have developed the world's first 50kW-class 'Non-contact Magnetic Gear Applied Counter-rotating Propeller' technology.
The 'Counter-rotating Propeller' recovers rotational energy from the front propeller by rotating the rear propeller in the opposite direction and converts it back into thrust. It has over 10% higher propulsion efficiency and significant energy-saving effects compared to a single (1) propeller. Dr. Hong Dogwan's team proposed the 'Non-contact Magnetic Gear' as an alternative in 2022, which uses the repelling and attracting forces of the N and S poles of magnets to transmit power without contact and generate thrust with counter-rotating propellers. 
Subsequently, the research team successfully demonstrated the 'Non-contact Magnetic Gear Applied Counter-rotating Propeller' with outputs of 3kW (4 horsepower) and 10kW (13.5 horsepower) on an electric propulsion small unmanned ship (based on 48Vdc battery voltage). Particularly, the ship was equipped with the 'Autonomous Navigation Control System' developed by Dr. Cheon Jongmin's team at KERI's Precision Control Research Center, which also confirmed automatic route tracking, obstacle detection, and avoidance functions. This has been evaluated as opening the door to the 'Electric Propulsion Unmanned Ship Era' capable of performing missions such as marine surveys or reconnaissance in harsh conditions.
Furthermore, Dr. Hong Dogwan's team recently succeeded in achieving an output level of 50kW (67.5 horsepower) (with a peak of 65kW (87.8 horsepower)) through continuous research, which can accommodate about four adults. This level can drive a hydrofoil electric propulsion ship up to 8m in size (based on 600Vdc battery voltage), and it is expected to bring revolutionary changes in transportation and tourism sectors such as small-scale water taxis once the technology is commercialized.
The research team is currently aiming to achieve an output of over 100kW and ultimately plans to realize the 'DC Distribution Electric Ship System' technology by installing three 100kW-class units in marine mobility to transport dozens of people.
KERI's Dr. Hong Dogwan stated, “The 'Non-contact Magnetic Gear Applied Counter-rotating Propeller Electric Propulsion System', which boasts high propulsion efficiency, fuel cost savings, low noise and vibration, and a semi-permanent lifespan without the need for maintenance, will greatly change the landscape of eco-friendly marine mobility.”
KERI has completed patent applications related to the core technology, published research papers domestically and internationally, and plans to commercialize through technology transfer to related companies, seeing this achievement as a replacement for mechanical gears in various fields such as eco-friendly mobility (ships, aviation, automobiles), defense, and automation industries.




jiany@fnnews.com Reporter Yeon Jian