This paper will present two new Flux Switching Modulated Pole Machine (FS-MPM) topologies which have a similar structure to a Modulated Pole Machine. It aims to address the complexity of the rotor, by introducing a FS-MPM design in which the magnets are removed from the rotor and placed on the stator. Furthermore the number of magnets in the FS-MPMs is greatly reduced when compared to a standard MPM; reduction in component count and simplification of the rotor will offer a significant benefit in terms of cost and ease of production.

In recent years significant improvements in the field of Modulated Pole Machines (MPMs) have been achieved, especially in electric vehicles applications. MPMs such as Transverse Flux Machines (TFMs) are known for producing high torque densities; though further research and improvements are needed to reduce the inherently high cogging torque and torque ripple. This paper will present a method of reducing these undesirable features of TFMs through simple geometric changes, such as changing the tooth span of the stator teeth. It will be shown that a combination of varying tooth spans rather than a uniform tooth span for the whole machine helps to reduce the cogging torque and torque ripple of the machine without a significant effect on the overall torque output.

Modulated pole (transverse flux) machines are known for their torque density and can take advantage of mutual flux paths to further increase the torque density of this class of machine. This paper presents a retrospective design investigation into a combined phase machine conducted in order to reduce the harmonic content of the back EMF and the cogging torque of the machine; two common problems with modulated pole machines. A method is proposed and it is shown that by changing a simple geometry such as the tooth span, cogging torque, torque ripple and harmonic content can all be significantly reduced without a significant effect on the overall torque output.

This paper presents a method of reducing the cogging torque of transverse flux machines by shaping the poles of the rotor. A number of different techniques are presented and simulated. These simulations are verified by the construction of a number of rotors from which measured results have been obtained. Further to this, the rotors are applied to machines with different cogging torque reduction techniques applied to the stator. Measurements of cogging torque have been taken in order to assess the overall effectiveness of each technique.

Linear induction machines have been employed in the railways for several decades for traction and braking, using an additional “reaction” rail. Linear DC eddy current brakes have also been adopted to provide braking forces by inducing eddy currents in the existing running rails, but at the expense of considerable rail heating. This paper focuses on the concept design of an induction machine that operates at low slips to develop longitudinal braking forces as well as increased adhesion through vertical attractive forces with minimal rail losses. Several candidate topologies were compared using 2D finite element analysis (FEA), whilst 2D and 3D FEA as well as a static test rig were used to analyse and validate the static and dynamic performance of the final design. The simulation and physical test results showed reasonable agreement, and demonstrated that the concept is able to meet the vertical force target at a minimal rail loss.

This paper examines a method of AC copper loss reduction in a single-sided open slotted Axial Flux Machine (AFM) using a Soft Magnetic Composite (SMC) core and a steel lamination sheet to shield the coils from stray fields. This approach is easy to implement for this topology and does not require the use of more complex twisted and Litz type conductors. To improve performance, the machine has a steel lamination sheet placed between the coils and airgap which has been optimized using 3D finite element analysis (FEA) to minimize both coil AC loss and lamination eddy current losses. Concentrated windings are used. These are pre-wound and slide onto the open, parallel sided stator tooth. This method of construction ensures a very high slot fill factor. The 3DFE simulations are validated with experimental tests and this paper shows the method has reduced AC copper loss by harnessing the shielding effect of the lamination sheet. It is found that the higher the conductivity of lamination, the lower the AC copper loss and better efficiency.

Past decade has seen significant development in the field of Soft magnetic composite (SMC) materials and their application in electrical machines. This is due to their advantageous nature, isotropic magnetic and thermal properties as well as low eddy current loss specifically at medium and higher frequencies. SMC has opened the arena for innovative electrical machine designs with three-dimensional flux paths for mass production. The powder metallurgy process is cost effective, reduces post-production processes and drastically reduces yield losses in manufacturing. The process also has a lower energy consumption in comparison to other production technologies. The SMC materials are suitable for large-scale mass production of complex components with good tolerances, smooth surfaces, no secondary operations and almost no material waste. This paper reviews the material, its production, its application in electrical machines, discussing the existing advantages and difficulties while shedding light on the commercial success of SMC machines in industry.

This paper showcases design and comparison of a fractional-slot concentrated winding (FSCW) with an integral slot distributed winding (ISDW) interior permanent magnet (IPM) machine designed to meet FreedomCar traction machine specification. Both machines have been designed using the same IPM rotor and adjusted stack lengths to deliver the continuous output power, 30 kW and 55kW peak. The comparative study is carried out using Finite element analysis and provides a direct comparison between the two stator types for torque-speed curves, efficiency, power factor and losses at continuous and peak power. The results of the study indicate IPM machines with comparable torque and power densities can be designed with both stator types, though both stators have their own favourable features and the ultimate choice depends upon the target application.