Patent ID: 11169199

Abstract:
A method and device for online insulation monitoring of a motor are applied to an inverter-driven motor system. The method includes: measuring phase-to-ground voltages of three-phase inlet lead ends of a motor; acquiring leakage currents of the three-phase inlet lead ends of the motor; acquiring a voltage common-mode component, a voltage differential-mode component, a current common-mode component and a current differential-mode component from the phase-to-ground voltages and the leakage currents; and acquiring ground-wall insulation equivalent capacitance and phase-to-phase insulation equivalent capacitance according to the components. A ground-wall insulation monitoring result and a phase-to-phase insulation monitoring result are distinguished from each other by the acquired ground-wall insulation equivalent capacitance and phase-to-phase insulation equivalent capacitance, such that two kinds of insulation are monitored respectively. Thus, the accuracy of an online insulation monitoring result of a stator and the monitoring reliability are improved.