Simulation Service

During the development of a magnetic product, electromagnetic simulation plays a more important role than ever. By repeatedly optimizing the geometric and magnetic structure, the development cycle will be dramatically reduced. However, the non-linear property of hard magnetic material makes the problem more complicated, when the anisotropic orientation is expected as space-variated. Hence, it is quite difficult to estimate the saturation and final open/closed loop magnetic field distribution.

Simulation service provides:  

  • hard magnetic material saturation analysis

  • open/closed loop magnetic field analysis

  • accurate modelling of hard magnetic material

Application

Assigned by our client, W-testing shall analyze the saturation and orientation of hard magnetic material as well as the final open loop magnetic field strength density, based on a given non-linear magnetic property. Therefore, this task shall solve the following problems:

  • modelling of non-linear material property

  • saturation analysis of magentization

  • open loop magnetic field analysis of hard magnetic material

Modelling of non-linear material property

A magnetization curve of a typical hard magnetic material starts from the origin and along the hysteresis in the first quadrant until it reaches the saturation point.  After this point, the permeability of the material can be approximated as µ0.

B = J + µ0H

J is the magnetization of the hard magnetic material.

Magnetization of a typical hard magnetic material 

Saturation analysis of magnetization

from the equation above,  it is quite easy to convert the magnetic field to the saturation of each point inside the material.

J = B - µ0H

X-axis is the angle position around circumference [°]; Y-axis is the radial position [mm]; on the right side, the scale indicates magnetization(saturation) [T];

this application is a radial ring magnet with 3-pole-pairs.

Open loop magnetic field analysis of hard magnetic material

Based on the result in the last process, the same operation can be applied to each component of vector field to obtain the orientation of magnetization.

Jx = Bx - µ0Hx

Jy = By - µ0Hy

At last, the results of orientation and strength of magnetization are converted to the vector of Hc to apply in the FEM simulation model. After solving the problem:

On the left side, the graphic is the distribution of flux lines; and on the right side, the graphic is the vector field distribution.

Distribution of magnetic field strength density B

Comparison of simulation and measurement result

to to be comparable with measuremen, the simulation is evaluated the normal component of magnetic field strength density B on the surface with 1mm distance (red circle in the picture above) from the magnet. It shows that the simulation is 35% stronger than the measurement.

左侧为仿真结果,右侧为实验测得结果