Research on Motor Rotor Fault Diagnosis Method Based on Speed Sensorless Closed Loop Control System

Asynchronous motors are important energy conversion devices in industrial systems, but in production and operation, rotor bar breakage faults often occur in asynchronous motors. Rotor bar breakage faults have the characteristics of hidden occurrence locations and being affected by operating conditions. In order to provide an alarm and severity warning for the occurrence of faults in the early stage of the monitoring system, this paper proposes a fault diagnosis method for motor rotor bar breakage under closed-loop control structure. By establishing mathematical models for rotor bar breakage and vector control, the influence of controller parameters and setpoint changes on the fault characteristics of rotor bar breakage in asynchronous motors under closed-loop control conditions is studied. Compare the stator current excitation component id and torque component iq in the d-q coordinate system, the stator current, and the transformed fault characteristics of the i<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</inf> and i<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</inf> current components in the αβ coordinate system, and select i α and i β as the fault diagnosis features. This paper proposed the diagnosis of current physical quantities and reactive power faults under decoupling control, compared and analyzed the two methods, and verified them through simulation.