Inverter online open circuit fault detection method

Abstract

The invention discloses an inverter online open circuit fault detection method. Firstly, the two-phase current of an inverter is collected; calculating is performed to obtain the amplitude and the phase of the three-phase current at the sampling moment; calculating is performed to obtain a per-unit value of the sum of absolute values of the three-phase current at the sampling moment; the per-unitvalue is compared with a preset threshold value; whether an open circuit fault occurs is judged, if yes, fault positioning is performed according to the three-phase current. The method comprises the following specific steps: carrying out per unit processing on the three-phase current, carrying out zero-crossing one-resetting processing on the per unit current, calculating a fault positioning identifier at the sampling moment, and comparing the fault positioning identifier with a preset threshold value to realize the positioning detection of the open-circuit fault phase and the fault tube. According to the method, the detected load current is subjected to online processing for open-circuit fault detection, so that the fault detection time is shortened, and online fault detection is realized.

Description

technical field [0001] The invention belongs to the technical field of inverter fault detection, and more specifically relates to an inverter online open-circuit fault detection method. Background technique [0002] Inverters are widely used in power grids, motor systems, and power supplies. However, the hidden dangers caused by the failure of semiconductor power devices in the system cannot be ignored, especially for the undetectable open circuit faults of inverters. At present, fast and accurate inverter fault detection is realized by detecting the inverter output current, and the key methods and technologies of inverter fault detection and fault-tolerant control can be extended to grid inverters, motor inverters and power inverters. In the fault tolerance of transformer fault detection, it has been paid attention by experts and scholars at home and abroad. [0003] The current-based inverter fault detection method detects and locates faults through technologies such as c...

AI Technical Summary

Problems solved by technology

The fault detection method based on the load current can use the sensors in the current closed-loop system without additional current sensors, but the current is a state quantity, and it is easily affected by the system operation, so it cannot directly reflect the fault information in a timely manner. It is extremely vulnerable to external changes, resulting in false positives and missed faults, poor anti-interference performance, and low detection reliability

In addition, many existing technologies based on current are often limited by the current fundamental wave period in terms of fault detection time. The detection time is usually based on the current fundamental wave cycle as a reference, and the detection time is relatively long.

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