Fault diagnosis of three-level active power filter based on hybrid logic model

Abstract

With the increase of voltage level and capacity of modern power system, three-level converter, as the main circuit of active power filter, meets the requirement of improving compensation capacity. However, the number of power devices of three-level converter is twice as large as that of two-level converter, and the probability of power device failure is greater, which affects the normal operation of the system. Aiming at the fault of three-level active power filter, this paper studies the fault characteristics of different power components of the main circuit T-type three-level converter when open-circuit fault occurs, applies the hybrid theory to the fault diagnosis of the converter, establishes the normal model and the fault model of different power components when open-circuit fault occurs, and realizes the location of the fault components according to the residual generated by the predicted output and the actual output of the model, the effectiveness of this method is verified by simulation.