Fault Diagnosis Of Inverter Based On Observer

With the increasing development of inverter technology,inverter control of its excellent performance and significant energy saving effect has been widely used in many fields.Since working in high frequencies,loss of large state,severe fever state,power tubes' probability of failure become large.Therefore,for the protection of the normal operation of the inverter and the maintenance of the security of the entire frequency control system's production process,the study of inverter's fault diagnosis has important significance.This article starts from several aspects that improving the robustness of fault detection,improving the diagnostic capabilities of fault and achieving fault detection and reconstruction in inverter system.Combining theory of sliding mode observer and unknown input observer,this article systematically and deep study the algorithm of inverter's fault detection and diagnosis based on observers.Firstly,these two fault diagnosis algorithm of sliding mode observer and unknown input observer is analyzed in detail.The design procedures and methods of full state observers,Luenberger state observers and Utkin state observer are introduced.Besides,the design steps and design method of fault detection and reconstruction of the sliding mode observer and the unknown input observer are studied in detail.What's more,these two observers' coordinate transformation step of faulty system and tracking and estimation methods of fault system status and fault signal are studied extensively.Secondly,according to the algorithms' theory of sliding mode observer and the unknown input observer,the construction of the three-phase PWM rectifier and inverter's mathematical model are considered.PWM rectifier and inverter operation principle and the principle of four-quadrant operation are analyzed.Finally,based on the observer fault diagnosis algorithm and mathematical model of three-phase PWM inverter and rectifier and inverter studied in this paper,using MATLAB respectively simulate fault diagnosis of PWM rectifier and inverter based on sliding mode observer and unknown input observer.By way of example simulation,it's showing that the proposed fault diagnosis methods of inverter based on sliding mode observer and unknown input observer can track rectifier system status fast and reconstruct the signal system failure accurately.Thereby,the purpose of fault isolationcan be achieved.And it is robust to external disturbances.After comparative analysis,in the inverter's observer fault diagnosis,unknown input observer's diagnosis effect is better.