On-line monitoring method for end insulation state of inverter driving motor

Abstract

The invention relates to an on-line monitoring method for the end insulation state of an inverter driving motor, and the method comprises the steps: 1) collecting current signals on three-phase phase lines of the motor, and intercepting a switch high-frequency oscillation current segment; 2) decomposing the intercepted switch high-frequency oscillation current segment into three sub-modes by using a variational mode decomposition algorithm, obtaining a high-frequency common-mode current and a center frequency thereof, and taking the center frequency of the high-frequency common-mode current as an extracted frequency feature; 3) calculating the total variation of the three-phase insulation capacitance by using the center frequency of the high-frequency common-mode current; and 4) obtaining the amplitude variation of the three-phase high-frequency common-mode current at the resonance point as an extracted amplitude feature, and carrying out fault phase positioning by using the amplitude feature. Compared with the prior art, the method has the advantages of high sensitivity, high robustness, high safety and the like.

Description

technical field [0001] The invention relates to the field of on-line monitoring of motor insulation, in particular to an on-line monitoring method for the end insulation state of an inverter-driven motor. Background technique [0002] The inverter-driven motor using pulse width modulation technology has the advantages of easy start, high efficiency and good speed regulation, and is widely used in new energy vehicles, wind power generation, ship propulsion and other industrial fields, and its reliability is the basis for the economical and safe operation of the system. The essential. Motor failures can lead to unplanned downtime, financial loss, and even catastrophic failure. Industry investigations have shown that main insulation failures are an important cause of motor failures. Main insulation faults account for more than 30% of all motor faults. For variable frequency speed regulating motors, the high dv / dt generated by the inverter output will exert excessive electric...

AI Technical Summary

Problems solved by technology

The overvoltage is distributed non-linearly and non-uniformly throughout the winding, and the first turn of the winding near the end of the phase bears greater voltage stress than other parts, which makes the insulation at the end of the motor more prone to deterioration

Existing methods usually monitor the overall insulation deterioration of the motor, and cannot monitor the insulation state at the end of the motor winding

Sometimes the end insulation has been damaged, but the overall insulation state has little change, so it is necessary to monitor the end insulation state

Images