WOLFRAM SYSTEM MODELER
This information is part of the Modelica Standard Library maintained by the Modelica Association.
This model demonstrates the effects of non-linear magnetisation characteristics of soft magnetic materials (hysteresis neglected). A sinusoidal voltage is applied to an inductor with a closed ferromagnetic core of rectangular shape. Set the tolerance to 1e-7, simulate for 0.1 s and plot for example:
coil.i vs. time // non-harmonic current due to saturation of the core material r_mFe.mu_r vs. r_mFe.B // relative permeability vs. flux density inside core r_mFe.B vs. r_mFe.H // magnetisation curve B(H); hysteresis neglected
The magnetisation characteristics of the flux tube element representing the ferromagnetic core can easily be changed from simplified linear behaviour (nonLinearPermeability set to false and R_mFe.mu_rConst set to a positive value, preferably mu_rConst >> 1) to non-linear behaviour (e.g., selection of one of the electric sheets in Material.SoftMagnetic with nonLinearPermeability set to true). This enables for convenient initial design of magnetic circuits with linear material characteristics prior to simulation with non-linear behaviour.
If the supply voltage has a zero-crossing when applied to the inductor at time t=0 (i.e., source.phase set to zero instead of π/2), then the inrush current that is typical for switching of inductive loads can be observed.
Description: Voltage applied to inductor
Description: Inductor coil resistance
Description: Inductor coil
Description: Constant leakage reluctance
Description: Reluctance of small parasitic air gap (ferromagnetic core packeted from single sheets)
Description: Reluctance of ferromagnetic inductor core