Demagnetization study of an interior permanent magnet synchronous machine considering transient peak 3 phase short circuit current

A sudden short circuit fault could potentially be a serious problem of interior permanent magnet synchronous machine (IPMSM) when the entire or partial demagnetization has occurred inside the permanent magnet. This paper investigates the maximum current limit of an IPMSM considering a large transient current at a symmetrical 3 phase short circuit fault. Finite Element Analysis (FEA) is used for the computation of 3 phase short circuit peak current while varying operating conditions including; input current vector and rotating speed. This computed 3 phase short circuit current is converted into dq-frame and then applied to check the irreversible demagnetization possibility of the IPMSM. During this process, the worst current angle is also investigated for considering partial demagnetization of permanent magnet.