Wireless Power Transfer with Temperature Monitoring Interface for Helicopter Rotor Blade Ice Protection

Traditional ice protection systems for helicopters convey electrical power from generators to blade heaters through flimsy carbon contacts embedded in “slipring” devices. However, the harsh vibratory environment combined with the high speed/current typically results in sparkling, powder and a very short life of sliprings themselves. In order to eliminate friction, the use of a rotary transformer assisted by power electronics is considered. For this purpose, a suitable transformer topology is investigated from first principles and paired with a resonant inverter. Preliminary finite element method analysis followed by experimental validation on a reduced scale transformer prototype show that a suitable full scale unit could transfer the necessary power to protect a medium class helicopter tail rotor, with a weight/size comparable to that of a legacy slipring but at a fraction of its maintenance and downtime cost. Beyond shrinking the size and the weight of the transformer, the use of power electronics brings some other interesting advantages, including the possibility to correct the load power factor and to interface with resistance temperature detectors, to avoid blade overheating.