PSEUDO-DIRECT DRIVE FOR BLADE PITCH CONTROL ACTUATION

This paper presents an investigation into the design and control of a fault tolerant magnetically geared Pseudo Direct Drive (PDD®) motor as part of a propeller blade Pitch Control Mechanism (PCM) of an Open Rotor Engine (ORE). This type of engine offers significant fuel savings over incumbent technology and is the subject of significant research. As the blades are rotating, the actuation mechanism must by necessity also rotate. This presents challenges in the transfer of electrical power and results in highly mechanically stressed electrical and electromagnetic components. It was found that the PDD motor has significant advantages for this application, where continuously high levels of holding torque to react the aerodynamic loads require high torque density to meet mass targets, whilst the intrinsic magnetic gear provides a passive torque fuse to protect the actuator mechanism in the case of a fault.