REAL-TIME DETECTION METHOD FOR T-TYPE THREE-PHASE FOUR-WIRE RECTIFIER OPEN CIRCUIT FAULT

摘要

A real-time detection method for a T-type three-phase four-wire rectifier open circuit fault, which belongs to the online detection field. The method comprises: calculating the number of sampling points L in a sliding window according to the frequency f of the three-phase power supply and sampling frequency v; calculating the centroid distance Δ in the diagnosis period of two capacitor voltages according to the sampling voltages of the two capacitors; calculating the operating domain size D of the centroid distance Δ according to the diameter of the operating track in the diagnosis period of two capacitor sampling voltages; judging whether the centroid distance Δ exceeds the operating domain size D, if so, the T-type three-phase four-wire rectifier has an open circuit fau otherwise, no open circuit fault occurs. Compared with the certain characteristic fault manifestations in the whole period of the power supply voltage, the method detects the capacitor voltage fault manifestations of a bus in a 1/3 of the power supply voltage period, and has better real-time performance, thereby achieving rapid detection of system faults. In the method, fault detection is designed by balancing the two capacitor voltages of the bus, and improves the robustness of fault detection.