Demagnetization Effect on Permanent Magnets Due to Short Circuit in SimLab/Flux

Charishma_Modem

Introduction:

A permanent magnet can lose it properties under certain circumstances including high temperature and magnetic loading . This phenomenon is called Demagnetization. In the event of short-circuit the demagnetization effect is more rapid and significant.

Demagnetization Effect on Permanent Magnet due to short-circuits:

Short circuits in PMSMs (e.g., stator winding or inverter faults) can cause severe current surges.•These high currents generate strong magnetic fields that directly oppose the magnetization of the permanent magnets.

How It Happens:

• High Current = Strong Opposing Magnetic Field, A short circuit causes a large magnetic field that acts against the magnetic field of the rotor magnets.
• Thermal Stress: The short circuit current also generates excessive heat, which may raise the rotor temperature beyond the magnet’s thermal limit (e.g., knee or Curie temperature).

Workflow in SimLab/Flux:

The workflow to evaluate the demagnetization effect using SimLab is demonstrated in the video below. The workflow remains same in the Flux tool as well.

https://www.youtube.com/embed/lkrX7g2wARw?si=64khJxXyaKs_PaDc