Fault Diagnosis Method of Matrix Converter Motor Drive System

Abstract

The invention provides a fault diagnosis method of a matrix converter motor driving system. The method is based on model prediction control and comprises the following steps: a matrix converter drivesa permanent magnet synchronous motor system, and an expected relation model of output voltage and output current under a normal working condition and a fault condition is established; according to the model after the fault, identification conditions of two different faults are obtained by obtaining a difference value between an output current prediction value of a next sampling period after the fault and a previous period; if the fault is identified as a switch open-circuit fault of the driving system, a motor model is used for obtaining an estimated value of an output line voltage, then a residual error and a threshold value are defined, and according to the characteristic that the switching state of the matrix converter predicted and controlled by a finite set model in one sampling period is known and fixed, the open-circuit fault position of a switch can be rapidly diagnosed and positioned in one sampling period after a fault occurs; if the current sensor fault is identified, the current sensor fault is compared with the actual value of the output phase current sensor, and then the fault is diagnosed.

Description

technical field [0001] The invention relates to the field of switch open circuit fault diagnosis, in particular to a fault diagnosis method for a matrix converter motor drive system. Background technique [0002] Matrix converter (MC) has excellent characteristics such as low harmonic distortion rate, high efficiency and high power density, and has broad application prospects in the field of motor drive. However, the electrical failure of the matrix converter seriously threatens the safe operation of the motor drive system. Therefore, fast and reliable fault diagnosis is of great significance for improving system reliability and avoiding electrical operation accidents. [0003] According to different measurements, open circuit diagnosis methods can be divided into two categories: current method and voltage method. Commonly used in current measurement methods are the average current method, the slope method and the method based on the current observer. In addition, a metho...

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Problems solved by technology

Both methods are highly dependent on model parameters, affecting the robustness of the diagnostic system

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