Fault Diagnosis Of Z-source Inverter Based On Fault Tolerant Operation

Due to the massive exploitation and use of fossil energy,the traditional energy crisis has not only appeared,but also caused great damage to the environment.Countries begin to pay attention to this problem gradually.Among them,the development and utilization of electric energy,wind energy,solar energy and other new energy has become the focus of research.In the part of new energy vehicles,it is necessary to add an inverter to invert and lift the output energy,so as to achieve the purpose of controlling the motor.The traditional inverter,due to its own topology structure,will cause low energy conversion efficiency,resulting in the stability and practicability of the system.Moreover,the topology of the traditional inverter due to its own need to join a dead zone to prevent loss of electrical components of the problems of arm straight up and down phenomenon,and the addition of dead band time can make the output current waveform distortion,thus affecting system stability,the present stage in order to reduce the effects of dead zone time,need to access complex compensation circuit to compensate dead band time,This reduces the reliability of the system.This paper consider the Z source inverter is used to overcome this problem,but the Z source inverter in the running process will inevitably produce the problem such as short circuit,open circuit,in order to solve this problem is proposed in this paper two methods to respectively of the two faults are testing,so as to improve the reliability and stability of the system,and finally to the fault of inverter fault-tolerant operation.The research content of this thesis mainly includes the following aspects.Firstly,the advantages and disadvantages of traditional inverter and Z-source inverter are analyzed according to the topology diagram,and the operation characteristics and change rules of Z-source inverter are analyzed through modeling.Then,according to the operation law of the Z-source inverter,the SVPWM technology is used to control the Z-source inverter.Compared with the traditional inverter,the Z-source inverter has higher stability and reliability.Secondly,the open-circuit and short-circuit faults of the Z-source inverter are analyzed,and the operation characteristics of the Z-source inverter under different faults are pointed out respectively in combination with the topology structure of the Z-source inverter.A simple,reliable,economical and fast fault diagnosis method is proposed according to the operation characteristics of different faults.After the fault diagnosis,the fault location is carried out according to the different diagnosis methods and fault characteristics.Finally,two kinds of faults and fault detection methods are simulated in MATLAB to verify the correctness and practicability of the proposed fault detection method.Finally,the fault tolerant operation of the Z-source inverter is carried out.In the process of selecting the fault tolerant operation method,the evaluation index of fault tolerant operation is briefly introduced,and different fault isolation technologies are compared.Then,according to different fault types and positioning accuracy,the fault tolerant method is determined.Through MATLAB simulation,the feasibility of the selected fault-tolerant operation method is verified.