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 the inverter is collected, and then the amplitude and phase of the three-phase current at the sampling time are calculated, and then the three-phase current at the sampling time is calculated based on the method. The per-unit value of the sum of the absolute values ​​of the current, compare this per-unit value with the preset threshold to determine whether an open-circuit fault occurs, and if it occurs, perform fault location based on the three-phase current. The specific method is to perform a per-unit Then perform zero-crossing and “one” processing on the unitized current, calculate the fault location identification at the sampling time, compare the fault location identification with the preset threshold, and realize the location detection of the open circuit fault phase and the fault tube. The invention performs on-line processing on the detected load current to perform open-circuit fault detection, reduces fault detection time, and realizes on-line fault detection.

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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