Linear approximation * exponential function of T

Presentation

This model defines a B(H) behavior law:

• linear (without taking the saturation into consideration)
• for an isotropic material
• through a relative permeability μ_r which decreases in an exponential way when the temperature increases

It can be used for low magnetic fields as long as saturation is not reached.

Mathematical model

This model is a straight line whose μ_r slope varies with the temperature.

The corresponding mathematical formula is written:

B(H,T)= μ₀H+ μ₀( μ_r0 - 1)H.COEF(T)

where:

• μ₀ is the permeability of vacuum; μ₀ = 4 π 10^-7 [H/m]
• μ_r0 is the relative permeability of the material for T = 0°C
• COEF(T) is the previously described temperature coefficient

The shape of B(H) curve is presented in the figure below.