Field failure on-line diagnostic method and system for permanent magnet synchronous motor

Abstract

The invention discloses a field failure on-line diagnostic method and system for a permanent magnet synchronous motor. The field failure on-line diagnostic method comprises the steps of (1) sampling a stator three-phase current signal of the motor to be detected, (2) determining a field failure characteristic frequency according to the number of poles of the permanent magnet synchronous motor to be detected, using the field failure characteristic frequency as a field failure characteristic quantity, (3) estimating the frequencies of frequency components in the stator three-phase current signal to be detected, judging whether a field failure happens or not according to whether the field failure characteristic quantity appears or not, and (4) after estimating the amplitudes of the frequency components in the stator three-phase current signal to be detected, calculating the ratios of the amplitudes of the frequency components to the amplitudes of same-frequency components within a same-current range of a motor in the normal state so as to judge the degree of severity of a field failure. The field failure on-line diagnostic system comprises the permanent magnet synchronous motor, a Hall current sensor, a signal conditioning circuit, a data acquisition circuit, a diagnosis control circuit and a display circuit. The field failure on-line diagnostic system is short in sampling time and high in anti-jamming capability, can judge field failures at different rotating speeds and under different load conditions, and is applicable to dynamic on-line monitoring.

Description

technical field [0001] The invention relates to an on-line diagnosis method and system for a loss-of-excitation fault of a permanent-magnet synchronous motor in electrical control engineering, in particular to a diagnosis of a loss-of-excitation fault for an electric vehicle, and belongs to the field of motor fault diagnosis. Background technique [0002] The driving motor is the core equipment of electric vehicles and the source of power for vehicles. Its reliability directly affects the driving safety of electric vehicles. Due to its compact structure, small size, light weight, high efficiency, reliable operation and low noise, permanent magnet synchronous motor has the best comprehensive index of electric vehicle drive motor, and is the best choice for electric vehicle drive motor. If any fault in the drive motor cannot be diagnosed and corrected in time, the fault may be further expanded, resulting in functional failure and affecting the normal operation of the vehicle. ...

AI Technical Summary

Problems solved by technology

In the literature on the research of permanent magnet synchronous motor loss-of-excitation fault diagnosis methods, it mainly focuses on two aspects: one is to use numerical analysis methods, that is, to use electromagnetic field software to establish a permanent magnet synchronous motor model in an ideal state, and to apply excitation conditions and boundary conditions. Carry out simulation and analyze the harmonic components of the stator current to determine the occurrence of the demagnetization fault. Because it is a permanent magnet synchronous motor model in an ideal state, there is a certain gap with the actual running motor. Therefore, the reliability of the results is more convincing. Low

The second is to adopt a joint diagnosis method that combines multiple methods. For example, different analysis methods have different sensitivities to rotational speeds, and different fault diagnosis methods are used for different rotational speed ranges. The diagnostic range of the system is limited; The sensitivity to the load size is different, forming different fault diagnosis methods according to the load size, and the engineering applicability is relatively poor

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