Insulation state online monitoring method for inverter driving motor and monitoring system thereof

Abstract

The invention discloses an insulation state online monitoring method for an inverter driving motor and a monitoring system thereof. The method comprises the following steps: measuring current responsecomponents I<a_deltaf>, I<b_deltaf> and I<c_deltaf> of the inverter driving motor under a high-frequency characteristic frequency band f<c> in real time during running of the inverter driving motor;sampling and representing the current response components I<a_deltaf>, I<b_deltaf> and I<c_deltaf> to obtain motor current real-time characteristic values I<ar_deltaf>, I<br_deltaf> and I<cr_deltaf>;comparing the motor current real-time characteristic values I<ar_deltaf>, I<br_deltaf> and I<cr_deltaf> with pre-measured motor current initial characteristic values I<a0_deltaf>, I<b0_deltaf> and I<c0_deltaf>; and assessing the current insulating running state of the inverter driving motor according to a comparison difference value, wherein the motor current initial characteristic values I<a0_deltaf>, I<b0_deltaf> and I<c0_deltaf> are motor current characteristic values of the inverter driving motor under the high-frequency characteristic frequency band f<c> pre-measured in an insulating normal running state. The insulation state online monitoring method and system have the advantages of high sensitivity, continuous online monitoring, easiness and convenience in operation, high security,low monitoring cost and easiness in implementation and popularization.

Description

technical field [0001] The invention belongs to the field of inverter-driven motors, and in particular relates to an on-line monitoring method for the insulation state of an inverter-driven motor, and also relates to a monitoring system used in the on-line monitoring method for the insulation state of an inverter-driven motor. Background technique [0002] Inverter-driven motors using pulse width modulation technology have the advantages of energy saving, easy start-up, high efficiency and good speed regulation, and are widely used in new energy vehicles, rail transit, wind power generation, frequency conversion speed regulation, ship propulsion and other fields . Due to the high dv / dt repetitive voltage shock electrical stress and the heat loss caused by high-frequency voltage and current harmonics during inverter operation, the insulation state of inverter-driven motors is more likely to deteriorate than conventional power-frequency motors. The deterioration of the insula...

AI Technical Summary

Problems solved by technology

[0006] The Chinese invention patent with the publication number CN105158659A discloses an automatic detection system for the insulation of variable frequency motors. This system can only perform offline detection of the insulation of the motor during shutdown intervals, and cannot accurately evaluate the insulation state of the motor during real operation.

[0007] To sum up, the existing motor insulation condition monitoring technology generally has the problems of insufficient detection sensitivity of early deterioration state, high cost of monitoring system and unfavorable for sustainable on-line monitoring.

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