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Recent Developments of Electrical Drives - Part 32

Recent Developments of Electrical Drives - Part 32. 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 | 308 Di Gerlando et al. Figure 1. Left basic structure of a PM synchronous machine with tooth coil armature winding. Right coil winding senses around teeth. cycle-phase referring to a layer portion of one cycle including adjacent coils belonging to the same phase parent coil in each layer the first coil of every cycle-phase its succession assignment defines the winding the no. of teeth cycle Ntc and the no. of coils cycle Ncc must be multiple of the no. of phases Nph links about no. of teeth cycle-phase Ntcph and no. of coils cycle-phase Nccph Ntc NphNtcPh Ncc NphNccph in case of controverse coils the no. of coils cycle-phase Nccph coincides with the no. of teeth cycle-phase Ntcph the optimal no. of PMs cycle Nmc differs by one with respect to Ntc Nmc Ntc 1 highest winding factor the optimal displacement among layers equals a no. of teeth Nts nearest to Nccph 2 low harmonic distortion the no. of cycles Nc equals the maximum no. of parallel paths a of each phase the total no. of PMs Nm NmcNc of a rotating machine must be even thus if Nmc is even the no. of cycles Nc can be any integer if Nmc is odd Nc must be even the no. of coils cycle-phase Nccph can be any integer Figure 2. Double layer winding two coils tooth with controverse tooth coils Ntc 12 Ncc 12 Nph 3 Ntcph Nccph 4 Nts 2. III-1.2. High Pole Number PM Synchronous Motor 309 it can be shown that the winding factor kw of a three-phase tooth coil machine with two-layer windings equals the product of a distribution factor kd times a displacement factor ks for the phase winding e.m.f. of the jth order harmonic j 1 3 5 . we have kwj kdj ksj with 1 k sin j n 6 Nccph sin j NCCph n 6 ks cos j Nsp Ndcf n 6 3 a traditional machine with two-layer distributed windings q slots pole-phase and coil pitch shortening of ca slots exhibits a winding factor fa equal to the product of a distribution factor fd times a pitch factor fp faj fdj-fpj with 4 f sin j n 6 dj q sin j q n 6 fpj cos j ca q n 6 6 these expressions and the .