A Real-Time Multiple Open-Circuit Fault Diagnosis Method in Voltage-Source-Inverter Fed Vector Controlled Drives

Abstract

This paper proposed a fast, real-time and fair robustness scheme for single switch and double switches open-circuit fault diagnosis in pulse-width-modulated voltage source inverter (VSI) for vector-controlled induction motor drives based on three phase output currents, which is also easy to insert into the controlled algorithm as a subroutine without major modification. The concept of allelic points is proposed and corresponding functions are defined to describe the symmetry of the VSI physical topology under healthy and faulty conditions. The residuals between any two phase functions are applied as criterion for allelic points. Under healthy condition, three legs are symmetrical and the residuals are all closed to zero, when open-circuit fault occurs, the residuals will be larger than a predefined threshold, so it is used to detect fault occurrence. When fault occurs, the near-zero current samples per fundamental period will get large, its proportions in a period will be different when different fault classes occur. The fault can be located combined the functions and residuals based on the analysis of VSI topology. The simulations and experiments are carried out and the results show the effectiveness and the merits of the proposed method.