A method and device for diagnosing a phase loss fault of a three-phase power line of an electric vehicle motor

Abstract

The invention discloses a method and device for diagnosing a phase loss fault of a three-phase power line of an electric vehicle motor. The method includes the following steps: S1. Diagnosing abnormal torque fluctuations and zero-sequence current faults. When a torque fluctuation fault occurs or does not occur In case of zero-sequence current fault, skip to step S2, otherwise, skip to step S3; S2. When the maximum value of the current value of each phase is greater than the preset phase current threshold, it is judged as a phase loss fault, and the The phase corresponding to the minimum value of the current value is the fault phase, otherwise jump to step S3; S3. End this fault diagnosis. The invention has the advantages of high fault diagnosis accuracy, small error, small calculation amount, high diagnosis efficiency and accurate determination of faults under special working conditions such as high speed, low current, torque ripple, and current sampling faults of the motor.

Description

technical field [0001] The invention relates to the field of three-phase power fault diagnosis, in particular to a method and a device for diagnosing a phase-loss fault of a three-phase power line of an electric vehicle motor. Background technique [0002] The motor drive controller and its driving motor are the core components of the electric vehicle, and together they provide power for the normal driving of the electric vehicle. The motor drive controller receives the command signal from the vehicle controller, converts the battery voltage on the high-voltage DC side of the electric vehicle into an AC voltage of a specific frequency and amplitude through pulse width modulation technology, and outputs it to the drive motor to generate the required torque , speed, the motor drive controller and the drive motor are connected with a three-phase power line. [0003] After long-term use of the three-phase power line, the joints may become loose and broken due to vibration, corr...

AI Technical Summary

Problems solved by technology

[0003] After the three-phase power line is used for a long time, the joints may become loose or broken due to vibration, corrosion and other reasons, which will lead to the failure of the connection between the motor drive controller and the drive motor. This phenomenon is usually called phase loss

[0004] In the prior art, there is some research on the phase loss fault of the three-phase power line of the motor, but there are still some deficiencies, including: 1. Misdiagnosing the three-phase current imbalance as a phase loss; 2. The attenuation of the faulty phase current The process is long, the phase loss detection time is long, and the timeliness is not high; 3. For the phase loss detection of each phase current, three sets of data need to be stored, and the calculation amount is large; 4. In special working conditions, there are misjudgments, Missed detection and inability to diagnose specific fault phases; 5. Faulty phase location errors, etc.

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