Protection method and apparatus for electric motor

The invention discloses a protection method and apparatus for an electric motor. The protection method comprises the steps of obtaining first current information of the electric motor in a last period when it is detected that the bus voltage of the electric motor disappears, and recording time-delay duration, wherein the last period refers to a last detection period based on a detection period at the first moment when the bus voltage disappears; when the recorded time-delay duration achieves predetermined duration, sampling second current information at a second moment when the time-delay duration achieves the predetermined duration; comparing the first current information with the second current information; and if the comparison result indicates that the electric motor has a feedback current at the second moment, starting low-voltage protection of the electric motor. By adoption of the protection method and apparatus, the technical problem of misoperation of the low-voltage protection caused by direct imple