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Recent Developments of Electrical Drives - Part 35

Recent Developments of Electrical Drives - Part 35. The book stating the recent developments of electrical drives, can be useful for engineers and researchers investigating and designing electrical and electronic devices as well as for students and young researchers dealing with electrical and electronic engineering, computer sciences (advanced computer modelling, sophisticated control systems with artificial intelligence tools applied, optimal design bye use of classical and genetic algorithms employed), applied mathematics and all the topics where electromagnetic, thermal, mechanical phenomena occur | 338 Martinez-Munoz et al. Design 3 is a radial machine that could be entirely built from iron laminations. However using iron powder allows both the stator yoke and the teeth tips to be extended above the teeth body which leaves more space for the winding and reduces the amount of copper 2 . For the same reason iron powder was used in the stator core in Design 2 where the flux flow is only radial. It can be argued that the massive yokes in the stator core in Design 2 and the rotor core in Design 3 could be built from iron laminations. However it was tested in FEM that the difference in the torque response was negligible since the linking flux is still constrained by the lower permeability of the iron powder used in the teeth. The inner and outer radius are the same in the three designs 19 and 100 mm respectively. The axial length of the body of the stator teeth is also the same as well as the tip length. The total length of the machines is 76 mm in Design 1 43 mm in Design 2 and 50 mm in Design 3. Design 1 was optimized using the magnetic-equivalent-circuit model described in 4 . Designs 2 and 3 were optimized directly using FEM and adjusting the dimensions obtained for the stator top and the claw-pole rotor in Design 1. The number of turns in the a.c. windings was calculated for a d.c. link voltage in the converter of 310 V giving a peak phase voltage of 179 V and for a nominal speed of 1500 rpm. The voltage for the d.c. winding was provided by a 12 V source. Iron losses The iron losses in a rotating electrical machine consist of an alternating and a rotating component 5-7 and can be expressed as in 1 . For pure alternation and rotation the trajectory of the flux density loci describes a line and a circle respectively. But in general alternating and rotating effects interact yielding an elliptical trajectory and Bmajor and Bm n ir represent the major and minor axis of the ellipse. Their ratio Rb Bminor Bmajor determines the contribution of the alternating and .