The invention discloses a
permanent magnet synchronous motor demagnetization fault detection method and device, and an automobile. The method comprises the steps of acquiring the state of a motor; when the motor state is a
steady state, obtaining a first torque
estimation value output under the
steady state condition of the motor, and calculating
steady state deviation
delta E according to the first torque
estimation value; when the motor state is a
transient state, obtaining a second torque
estimation value output under the motor
transient state condition, and calculating a transient characteristic evaluation parameter Es according to the second torque estimation value; and judging whether the motor has a demagnetization fault according to the steady-state deviation
delta E and the transient characteristic evaluation parameter Es. The
permanent magnet synchronous motor demagnetization fault detection method realizes fault detection when a motor permanent
magnet demagnetization fault,especially when the motor permanent
magnet demagnetization fault does not reach a severe demagnetization state, is clear in thought, clear in detection mechanism, small in required calculation amountand easy for
engineering realization, does not involve change of
system hardware, does not increase
system cost. Therefore, the method has good popularization value.