Design and build of novel electric machines for transport electrification
: (Alternative Format Thesis)

  • Boyuan Yin

Student thesis: Doctoral ThesisPhD


Decarbonisation has been a worldwide target to achieve global emissions reduction. The electrification of transportation has been proposed not only for sustainable and net-zero targets but also to provide a more energy-efficient solution. Electric propulsion has been widely considered in ship systems and aviation. An integrated full electric propulsion (IFEP) system removes the direct mechanical coupling between a prime mover and a propeller, which is replaced by an all-electric onboard network to supply both the ship services such as the domestic/hotel loads (navigation, lighting, air-conditioning, etc) and also the propulsion systems, which can subsequently reduce fuel consumption, increase system reliability and reduce maintenance costs. To help achieve these goals during this PhD research project a magnetically decoupled dual wound generator and a novel fast-operation moving coil actuator were designed, built and experimentally tested.

A dual wound generator, designed as the power supply for an IFEP system, provides power simultaneously for the ship services and propulsion systems. The main challenge of the design of a dual wound generator for an IFEP system is the decoupling of the two outputs. A fully magnetically decoupled dual wound generator with 2-pole and 6-pole windings for ships power requirements is developed in this thesis. The harmonics calculation using an algebraic method is described in detail for the winding design. A 2D finite element model is built and simulated in COMSOL, to investigate the magnetic field distributions and machine dynamical performance. A prototype dual wound generator is manufactured and tested to further validate the decoupling of the two outputs. Different load conditions are tested considering the practical operations. The experimental results demonstrate that the two outputs including the end-windings are fully decoupled under complex load conditions.

Hydrogen-powered all-electric aircraft, developed for the requirements of sustainability and decarbonisation, have higher energy efficiency, less fuel consumption and potential weight reductions. One of the key limitations to improving the reliability of onboard DC networks is the design of fast operating DC circuit breakers to isolate high and fast-rise DC fault currents. A novel design of a moving coil actuator with compensation coils topology for hybrid DC circuit breakers is also presented in this thesis. The actuator topology is designed and simulated by 2D finite element modelling in COMSOL. A prototype moving coil actuator is built and experimentally tested with a vacuum interrupter. Mechanical latching springs and other supporting structures are also included in the prototype to eliminate the effect of bouncing, rebounding and welding. The experimental results demonstrate that the compensation coils can eliminate the saturation, reducing the coil equivalent inductance and improving the operating speed.
Date of Award12 Dec 2022
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorXiaoze Pei (Supervisor) & Vincent Zeng (Supervisor)

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