The invention discloses a surface-mounted
permanent magnet synchronous motor short-circuit fault diagnosis method under a
servo working condition, belongs to the field of
servo motor fault diagnosis, and aims to solve the problems that
harmonic-wave-based surface-mounted
permanent magnet synchronous motor short-circuit fault characteristics under the
servo working condition are influenced by working conditions, the diagnosis speed is low, and the accuracy is not high. The method comprises the following steps: 1, constructing a motor
mathematical model of a servo working condition, deducing a q-axis current
analytic expression, and calculating and generating a decoupled theoretical current characteristic
signal based on a theoretical coordinate transformation relation; 2, collecting the three-phase current and the rotor position of the motor in real time, and extracting an actual current characteristic
signal through a coordinate transformation chain including Clarke transformation, Park transformation, coordinate stretching transformation and
Servo-Park transformation; and 3, calibrating the average value and the standard deviation of the actual characteristic signals in the
normal state of the motor as a health reference. And 4, during online diagnosis, comparing an actual characteristic
signal extracted in real time with a health reference, and carrying out fault judgment according to a preset statistical threshold value.