Research On Fault Diagnosis Of High Voltage Frequency Inverter

Various faults of high voltage frequency inverters inevitably occur in practice, resulting in equipment destruction and economic cost. The faults are usually complex and thus difficult to diagnose. Experts are often needed to diagnose the faults. However, there are not so many experts available in general. Instead of experts, fault diagnosis expert systems can work effectively with human-machine cooperation, integrating the experience of many experts. So it's very necessary to develop an expert system for fault diagnosis of high voltage frequency inverter.According to the research of fault tree analysis and expert system technology, we first analyze the common faults of the high-voltage frequency inverter, and then propose a fault diagnosis method by combining the expert system with fault trees. This dissertation clarifies the main content and the frame of the expert system, and research the constructing way of the knowledge base and the reasoning machine of fault diagnosis mainly. Based on comparing these ways, we put forward the method of frame and rule to construct the knowledge base, and combine with qualitative analysis. In order to improve the deficiencies of traditional fault diagnosis expert systems, this dissertation proposes a reasoning measure of forward and reverse based on quantitative analysis. Then, based on the calculated results of importance degrees, we do a priority sorting as a way of conflict resolution. We can reduce the number of blind search and improve the probability of first hit by this method.The expert system is developed by using the Visual C++ and the SQL Sever language. The main part of the system including knowledge base, reasoning machine, and explanation program are created by using Visual C++, while the knowledge base is stored by using the SQL Server. Simulations are conducted to test the developed fault diagnosis expert system. The results show that the system can analyze the faults fast, and handle them properly.