Power Generation On The Rotating Frame For Helicopter Ice Protection Systems

Abstract

Helicopters operating in meteorological conditions that can lead to ice formation need an ice protection system (IPS). Current anti-icing technology relies on electrical heaters embedded in the rotor blades and the IPS shall ensure the reliable delivery of tens of kW of electrical power to the helicopter's rotors to melt the ice or prevent its accretion. The standard solution entails power generation on the airframe and subsequent distribution to the rotors by means of dedicated mechanical and electrical subsystems distributed within the rotorcraft. This solution is sub-optimal because the system's installation requires substantial modifications to the baseline helicopter, leading to higher weight, complexity, cost and maintenance. In the present work, we present an alternative "plug-in" approach where the IPS consists of self-contained modules that can be installed or removed with minimal impact, like a kit. Synchronous, brushless alternators generate the required power directly where needed, thus leading to overall system simplification. We developed, manufactured and rig-tested a demonstrator of this concept applied to a helicopter tail rotor. The chosen generator layout is a radial flux type, packaged with its electronics control and distribution sub-systems into a slip ring-type form factor. Preliminary tests were performed in a lab environment while full-scale validation took place on a tail rotor rig. We also conducted preliminary studies toward a main rotor application that represents a more challenging use case, mainly due to the need to speed-up the generator through a gearbox.