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Special Issue on Electromagnetic Fields in Electrical Engineering
Edited by Slawomir Wiak
1 Introduction
Recently many research teams started to explore the possibilities of using soft magnetic composite (SMC) materials in electrical machines ([6] Guo et al. , 2003; [8] Kapelski et al. , 2011; [14] Wang and Howe, 2005). SMC materials are basically iron powder particles separated with an electrically insulated layer ([7] Hultman and Andersson, 2009). This technology has many advantages to classical laminated core solutions, i.e. reduced size and weight, fewer parts and lower manufacturing costs. Presently the Somaloy technology - the (SMC) concept brand from Swedish company Höganäs - is one of the most commonly used type of SMC materials in area of the electrical machines. In the paper authors present the elaborated design of the 18,000 rpm and 0.75 kW PM motor with core made of Somaloy 500+0.6% LB1 material. This motor is dedicated to operate with single phase supply BLDC converter. Low power (below 1 kW) high speed drives are widely used for home appliance purposes.
In the paper the four pole permanent magnet high speed motor is considered. The structure of motor is shown in Figure 1 [Figure omitted. See Article Image.]. The analyzed motor consists of stator with 15 coils made of stranded copper wire, rotor with rare-earth magnets (VAC 669AP) and aluminium sleeve. Stator windings are symmetrical and wound in fractional slot winding arrangement with q equals 1¼, where q is number of coils by pole and phase. The magnetic circuit of the motor has been made of powder material - Somaloy 500 ([7] Hultman and Andersson, 2009). For the calculation of magnetic field distributions and main parameters of the considered motor, a special computer program has been elaborated. The authors used their experience got in developing such a software before ([8] Kapelski et al. , 2011; [9] Maciejuk and Jedryczka, 2007; [15] Wojciechowski et al. , 2009). In the elaborated software the finite element method and A formulation have been applied. It is known that the finite element equations may be described using the language of circuit theory ([2] Demenko and Sykulski, 2006; [10] Ren and Qu, 2010). The finite element equations arising from vector potential A for the system described by edge elements...