Inductive Analysis of a Multiconductor System Prototype

Broadband circuit models for electric machines are effective means to understand, predict, and control the phenomenon of conducted Electromagnetic Interference (EMI) from immunity/susceptibility perspective. These models should cover the capacitive and inductive coupling behavior of the component along the frequency band of interest. The circuit models when used under generic SPICE simulation softwares, are very helpful for design-related and troubleshooting activities. In this paper the inductive coupling for a winding on a laminated ferro-magnetic core prototype has been investigated and analyzed with aid of the freely available FEMM software package. Inductive coupling analysis resulted in the generation of a complex-numbered inductive coupling matrix expressing a certain wiring arrangement. This is achieved by automatically generating the desired geometry and assigning boundary conditions for the problem under FEMM through Lua scripting language and then solving for magneto-static and time-harmonic magnetic cases for both self- and mutual-inductances for every conductor in the multi-conductor system. Post-Processing of the solutions is performed and the results are linked back to MATLAB (R) and stored in a matrix format. The inductive coupling of the winding turns, along with the capacitive coupling, forms the resulting SPICE circuit model which is compared against prototype measurements taken by Rhode & Schwarz (R &) vector network analyzer.