Fault Method Strategy for Inter-Turn Short Circuit Based on Linear Extended State Observer

In response to the problem of misdiagnosis caused by changes in surface-mounted permanent magnet synchronous motor (SPMSM) load torque and speed, a fault diagnosis method for inter-turn short circuit (ITSC) fault based on linear extended state observer (LESO) is proposed in this paper. First, a linear extended state observer is built to estimate the variation of the motor's back electromotive force (EMF) of the
$d-q$
axis. Second, second order generalized integrator (SOGI) is built to extract the negative sequence component of the back EMF, and the normalized amplitude is used as the fault index. Then to build fault location index, the sum of back EMF of the
$d-q$
axis is calculated, and its second order harmonic phase angle and current phase angle are extracted. Finally, the simulation results indicate that the proposed diagnostic method simultaneously improves the robustness of the variation of load torque and speed based on the guaranteed accuracy.