Research On Fault Diagnosis Of PWM Rectifier

With the rapid development of power electronic technologies and the continuouslyupgrading of control chip, dual PWM converters have been widely used in the field of variablefrequency speed regulation. They use IGBT as switching devices, which are full controllableand could work at high frequency on-off condition. Due to the vulnerability of power electronicdevices and the complexity of control strategies, rectifiers and inverters are the frequentlytroubled places in variable frequency speed regulation system. Real-time monitoring andefficient diagnosis of faults are helpful to improve the reliability of the whole system, which hasgreat significance.Failures of rectifiers mainly refer to open circuit and short circuit faults of IGBT and so on.Nowadays, fault diagnosis researches of IGBT are mostly based on inverters. Few of them arebased on rectifiers, especially large-capacity dual closed-loop SVPWM rectifiers which useIGBT as switching devices. At the same time, conventional fault diagnosis methods have theirown advantages and disadvantages. Based on the description above, faults are diagnosed byHilbert’s Vector Method in this paper.In this paper, the simulation model of three-phase dual closed-loop SVPWM rectifiers isconstructed. On this basis, fault information of IGBT and bridge leg is analyzed in time domainand frequency domain respectively, fault information is extracted, the characteristics of faultsare investigated and the fault tube is located preliminarily. Then, faults and the deteriorationprocess of IGBT and bridge leg are diagnosed respectively by Hilbert’s Vector Method.Theoretical analysis and simulation results demonstrate that Hilbert’s Vector Method couldlocate faults effectively and is more simple and direct than Park’s Vector Method.