Investigation on Multi-Physics Modelling of Fault Tolerant Stator Mounted Permanent Magnet Machines

This thesis investigates the stator mounted permanent magnet machines from the point of view of fault
tolerant capability. The topologies studied are switched flux (and its derivatives C-Core, E-Core and
modular), doubly salient and flux reversal permanent magnet machines. The study focuses on fault mode
operation of these machines looking at severe conditions like short-circuit and irreversible
demagnetization. The temperature dependence of the permanent magnet properties is taken into account.
A complex multi-physics model is developed in order to assess the thermal state evolution of the switched
flux machine during both healthy and faulty operation modes. This model couples the electro-mechanical
domain with the thermal one, thus being able to consider a large range of operating conditions. It also
solves issues such as large computational time and resources while still maintaining the accuracy.
Experimental results are also provided for each chapter. A hierarchy in terms of fault tolerant capability
is established. A good compromise can be reached between performance and fault tolerant capability.
The mechanism of the magnet irreversible demagnetization process is explained based on magnetic
circuit configuration. It is also found that the studied topology are extremely resilient against the
demagnetizing influence of the short-circuit current and the magnet demagnetization is almost only
affected by temperature.