Switch Fault Diagnosis For DC-DC Converters

Switching power devices are indispensable in modern electrical.As a core component of the devices,DC-DC converter are widely used in many industrial applications such as electrical vehicles,large computer system,communications,ships,aerospace and renewable energy power systems.DC-DC converter plays an important role in maintaining the reliability of the equipment. The function of the whole system can be destroyed because of the switch fault in theDC-DC converter and even endanger peoples live.So It is demanded that multiple faults can be accurately detected and diagnosed in a DC-DC converter.DC-DC converter is selected as the study object of this paper and the switch fault diagnosis is implemented based on the inductance current and diode current. This method is simple and has higher correct recognition rate. Besides,itprovides an effective solution for the DC-DC converter switch fault diagnosis.Firstly the history of the DC-DC converter and the basic principle,including the classification of the DC-DC converter and common fault diagnosis methods are introduced. Boost converter and Buck converter are selected as the study object of this paper. The main circuit topology structure and working principle of the two converters are introduced in details. According to the analysis of the circuit principle under normal working condition and fault condition, the fault performance of the inductor current and the diode current are expounded.Besides,circuit theoretical model for Boost converter under switch open fault condition and Buck converter underswitch short fault condition is established.Based on the analysis on all kinds of possible fault types of Boost converter and Buck converter,the paper investigated current trends under different fault types and proposed corresponding fault detection method,which can detect the fault type of the two converters effectively.By using the simulink toolbox in MATLAB,the diagnosis for open fault and short fault of Boost converter and Buck converter is implemented and the simulation results confirm the correctness and effectiveness of the fault diagnosis method.