Wireless power transfer system using a Helmholtz coil for electromagnetic suspension carrier system

An electromagnetic suspension carrier system has carriers with on-board batteries. The carrier stops to charge the batteries when the battery energy runs out. In order to omit the charging stop, we have developed a power transmission system using wireless power transfer (WPT) system with the magnetic resonance coupling. To design the suitable arrangement of feeding and receiving antennas for feeding to the carrier of the electromagnetic suspension carrier system, power transmission efficiency was measured with resonance antennas arranged parallel and vertical to the carrying direction. Experimental results shew that resonance antennas arranged parallel to the carrying direction realizes high and stable power transmission efficiency. Also, the Helmholtz-coil-type loop antenna coupled with the feeding and receiving antennas gave robustness against variations in the height of the receiving antenna to the WPT system.