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Permanent magnet synchronous machines are well suited for high speed applications due to their high efficiency, power density and dynamic response capability. The heat extraction area decreases as the speed increases, making thermal effects more dominant at high speed. The temperature dependent properties of permanent magnets necessitates high detail thermal models. This paper presents a two dimensional analytical model for a high speed permanent magnet synchronous machine magnet. The diffusion equation is solved where three of the permanent magnet boundaries experience convection heat flow; as the case is in radial flux machines. The heat generated on the rotor surface due to eddy currents is also taken into account. The model is verified using numerical techniques and shows good correlation (within 1.5 %). The model is also validated through experiments performed on a 4 kW, 30 000 r/min permanent magnet synchronous machine.

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There has been a considerable amount of research work on using the Taguchi method for electrical machine design in recent years. However, for the large community of electrical machine designers, this method is still less known. The purpose of this paper is to summarise the past and current research work of applying the Taguchi method in electrical machine designs. We attempt to give readers some insight into the advantages and disadvantages, challenges, current status and future perspective of the method.

Position sensing is one of the crucial parts of many systems, specifically in an active magnetic bearing. The position is used to control the magnetic forces within an active magnetic bearing to keep a rotor levitated. Sensors used in these systems must be very sensitive and are usually very expensive. In this paper a low cost printed circuit board position sensor is analysed. The sensor uses an excitation coil to establish a magnetic field. Four sensing coils are then used to measure the influence a conducting target has on the magnetic field to enable position sensing. The sensor's magnetic operation is analysed using finite element methods and very good correlation is found with measured results. The effects of the target material and the number of PCB layers are analysed. It is shown that a two layer sensor can produce acceptable sensitivity and linearity.

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