Summary

In EMSolution, the self- and mutual inductance of an air-core COIL (external current field source) must previously be entered in the CIRCUIT or NETWORK. Now the inductance of the COIL can be calculated within EMSolution, instead of having to calculate it separately.

Explanation

Inductance calculations are performed for the GCE, ARC and LOOP elements. The self and mutual inductances of the other elements are not calculated and are set to zero. The mutual inductance between GCE, ARC and LOOP and the other elements is also calculated. As an example, consider an axisymmetric two-dimensional, ac steady-state analysis as shown in Fig. 1. Assume that two series of LOOP coils are wound on an iron core, with voltage applied to Coil 1 and Coil 2 short-circuited.

Fig.1　Analysis model

The calculated inductance of the air core is output to the output file and is also used in the analysis. The coil is assumed to be 100T with a radial width of 1 cm and an axial width of 10 cm.

************ Inductance between COIL series *************************** Series No. 1 — No. 1 : 2.60611e-04 (H) *** Series No. 2 — No. 1 : 2.53315e-04 (H) *** Series No. 2 — No. 2 : 5.55665e-04 (H) ***

A comparison of the same analysis with an analysis using ELMCUR (internal current source) is shown in Fig. 2. When ELMCUR is used, the inductance of the air core is included in the analysis domain, and the results of the internal calculation of the inductance of the air core using ELMCUR and COIL are in good agreement, as shown in Fig. 2.

Fig.2　Comparison between COIL and ELMCUR (internal current source)