Modelling and development of a fault tolerant permanent magnet machine for helicopter tail rotor applications

Abstract

With environmental and energy issues becoming increasingly prominent, environmentally friendly transport is receiving progressively more attention and research. This thesis concentrates on a study of the motor used in the electric tail rotor of helicopters. The concept of ‘More Electric Aircraft’ (MEA) has gained attention because of the many advantages it brings, such as enhanced aircraft performance, increased reliability, decreased operating and maintenance costs and reduced greenhouse gas emissions. All these advantages it brings have attracted a lot of attention to it. Helicopter technology has also been influenced by this conceptual approach. This study proposes a Permanent Magnet (PM) motor design for a helicopter electric tail rotor with fault-tolerant performance. The performance of this type of motor was analysed using Finite Element (FE) simulation, paying particular attention to rotor losses and their mitigation, along with topologies which offer fault tolerance. Due to the harsh working environment of motors, it is essential to prevent damage caused by high temperatures, such as insulation failure, demagnetisation of PMs. Losses were minimised and the heat dissipation performance of the motor was obtained by Computational Fluid Dynamics (CFD) simulation based on the finite element simulation results. A new hybrid cooling design was proposed that showed excellent cooling results in simulations. Finally, considering the complexity of the model, part of the stator winding was manufactured with the hybrid cooling design and tested in a wind tunnel. The experimental and simulation results were compared, and the design was validated. The predicted and measured results showed some consistency in the cooling performance.