Online Passive Filter Parameter Identification and Filter Fault Diagnosis for LCL Grid-Tied Inverters

LCL grid-connected inverters are widely used in new energy power generation field, which is an important part of new energy grid connection. With the frequent operation of the grid and the harsh operating environment, the filters are subject to aging, damage, and other faults, while the traditional manual operation and maintenance workload is large and the detection time is long. In this paper, an online parameter identification strategy based on state observer is proposed for the difficulty of traditional filter fault detection, which enhances the accuracy of identification parameters. Based on the characteristics of the identified parameters and the rated parameters, the filter fault diagnosis process is designed to realize the fault online diagnosis. Simulation verifies the correctness and effectiveness of the parameter identification.