Method and device for diagnosing motor open circuit

Abstract

The invention discloses a motor open circuit diagnosis method and device. The method includes: acquiring DC current values ​​Idc_a, Idc_b and Idc_c corresponding to the three-phase AC power of the motor, wherein Idc_a, Idc_b and Idc_c are respectively DC current values ​​corresponding to phase a, b and c phase AC; The DC current value calculates the average DC current value I of the three-phase alternating current avg Calculate the DC current deviation values ​​Ide_a, Ide_b and Ide_c of the three-phase alternating current according to the average direct current value, wherein, Ide_a, Ide_b and Ide_c are respectively the DC current deviation values ​​of the a, b and c phase alternating currents; The DC current deviation value and the DC current threshold value I of the three-phase alternating current lim making a comparison, and if at least one of the DC current deviation values ​​of the three-phase AC current is greater than the DC current threshold, it is diagnosed that the motor is open circuited. The method overcomes the time delay of motor open circuit diagnosis in the variable speed system, and at the same time improves the missed detection and false detection in circuit open circuit diagnosis.

Description

technical field [0001] Embodiments of the present invention relate to the field of motor control, and in particular, to a method and device for diagnosing an open circuit of a motor. Background technique [0002] In a system with motor control, if there is a single-phase or multi-phase open circuit between the motor controller and the motor wiring, it will cause the motor to rotate abnormally or fail to rotate, and even cause the motor to overheat and cause electrical fires and other accidents. [0003] There are generally two methods for the existing conventional diagnosis of motor open-circuit faults: the first method uses current effective value judgment, and this method takes a long time to judge. In addition, for variable speed systems, the effective value calculation period is difficult to determine; the second method , using Id and Iq to judge, this method is easy to judge for a three-phase symmetrical system, but for an open-circuit phase-deficient system, the calcul...

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Problems solved by technology

[0002] In a system with motor control, if there is a single-phase or multi-phase open circuit between the motor controller and the motor wiring, it will cause the motor to rotate abnormally or fail to rotate, and even cause the motor to overheat and cause electrical fires and other accidents

[0003] There are generally two methods for the existing conventional diagnosis of motor open-circuit faults: the first method uses current effective value judgment, and this method takes a long time to judge. In addition, for variable speed systems, the effective value calculation period is difficult to determine; the second method , using Id and Iq to judge, this method is easy to judge for a three-phase symmetrical system, but for an open-circuit phase-deficient system, the calculated values ​​​​of Id and Iq itself are fluctuating, so it is not easy to judge, and it is prone to misjudgments and missed judgments

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