Demagnetization Study of Permanent Magnet Machine Under Three Phase Short Circuit

The influence factors of the demagnetization magnetic field of permanent magnet machine are complicated. This paper investigated the influence of rotor position and current angle on demagnetization by simulation. These two factors were introduced into the three-phase active short-circuit current mode, and then a more comprehensive demagnetization condition analysis method was proposed. The most severe DQ demagnetization combination under the three-phase short-circuit condition and the most severe demagnetization rotor position were calculated, and combined as the most severe demagnetization conditions. Based on the spatial magnetic density vector decomposition of the permanent magnet, the irreversible demagnetization rate of permanent magnet under the most severe demagnetization conditions were calculated more accurately. The rotor thermal test and motor demagnetization test were designed to measure the temperature rise and demagnetization rate of permanent magnet. The similarity between the experimental and simulation results fully shows the validation of this method.