دانلود رایگان مقاله محاسبه ظرفیت القاگری ماشین AC بر اساس تئوری تابع سیم پیچی

abstract

A numerical procedure for computing the inductances of ac machines is described. The procedure does not require that explicit expressions for airgap or winding functions be obtained therefore complicated integrations are avoided. The effects of stator slots are included in a manner in which all the harmonics are taken into account. The inductances obtained are subsequently transformed to d-q-0 reference frame and the results are seen to compare favorably with measurements. Significant differences exist in the computed inductances especially in the d-axis. Cross-coupling effects between the d-axis and q-axis inductances which are generally ignored when approximate expressions are used are also observed.

4. Conclusions

Significant differences exist between the two computed values especially in the d-axis inductances because the effect of slots is maximal in that axis (see Fig. 1b). The effect of slots reduces the quantity of iron (especially in the d-axis) and thus the inductances computed using the actual model are lower than those obtained from the sinusoidal model but it approximates the measured value. The rest of the d-axis inductances are distributed amongst the cross-couplings as can be seen in Fig. 3. This difference is much lower in the q-axis. It is seen from the results that the average values of d-q-0 inductances calculated are very close to the experimental ones. High values of cross coupling effects exist which are usually not observed when approximate sinusoidal expressions are used. This is because all spurious harmonics are included in the calculations by using the actual geometry of the airgap and winding layout. The outlined procedure can be applied to other ac machines having a simple rotor configuration.