Study On Fault Diagnosis Technology Of Switched Reluctance Drive System

The content of this thesis is an important part of the project "Scraper Conveyor Drive System" (Serial Number:110148032), which is the College Students’ Innovation and Entrepreneurship Project sponsored by Taiyuan Science and Technology Bureau. It is proposed in order to further enhance the reliabiliy and stability, at the same time protrude its fault tolerant predominance. According to the requirements that contemporary electrical drive field to the the equipment, a fault diagnosis scheme has been developed based on the Digital Signal Processor (DSP) and then the laboratory debugging is completed. It has been shown by laboratory running that the scheme has been achieved the fault diagnosis. The main content of this paper is as follows:The developmental trend of the fault diagnosis technology for the SRD system is conscientiously analyzed on the basis of domestic and overseas relevant literature reviewing and site investigation. The control strategy and the control mode are synthesized in detail, and the fault diagnosis methods of SRD system are seriously determined.In order to investigate the fault tolerant capabilities of SRM, a simple modeling and simulation technique is used, which is found to be more appropriate compared to other techniques reported in literature. The paper presents a comprehensive analysis of a 2-D finite element analysis carried out on Switched Reluctance Motor (SRM), and the simulation has been implemented to study the winding open circuit fault, the coil open circuit fault, the winding short circuit fault, the coil short circuit fault, the turn-to-turn short circuit fault and the interphase short circuit fault;The effects of inter fault in phase winding on the average torque, ripple torque, and the phase current are studied. The torque and current are used as fault features for winding faults in order to research the fault diagnosis of SRM windings.The power converter fault type is analyzed in an asymmetric half-bridge converter, applied to a 12/8 switched reluctance drive (SRD). The analytical solution of the phase winding current is obtained by formula derivation under normal and fault conditions. Detailed discussions have been presented about the amplitude changes of the DC bus current and its digital analysis results under different work conditions. The short circuit and open circuit fault detect method of transistors is also proposed, which was connected to the voltage pulse width modulation (PWM) signals and the DC bus current. A model is used to build the pattern of the power converter of SRD system and the simulation has been implemented with matlab. As a result, it has been proved that the method is effective.Aiming at the problems of impulse current, the braking torque and the phase-deficient operation state caused by the faulted position signals, this paper makes a study of the fault types and the effects on system in the different states of the position signals are also studied. Regarding to the invalidation of single or double position signals fault types, a detection and diagnostic method has been researched, which detected the the combination sequences of position signals and calculated the angle between the two adjacent combination of position signals. A position signal fault tolerant and fault recovery control scheme is given through reconstructing the lost commutation processes at proper positions by the introduction of the rotor position angle, to make the motor continue run under fault conditions and make the position sensor recover steadily. The effective of the proposed detection and fault tolerant control scheme is verified by simulated fault experiments.Considering the requirements of the applications for SRD system, the communication scheme is developed based on DSP control core and the Human Machine Interface (HMI). The hardware interface circuit has been designed. The HMI is equipped as a platform for interaction between human and system information. The communication protocol for the system is put forward and the application programs of communication are compiled by modular programming method, which realized the display of key parameters and the preliminary diagnosis results for SRD system and achieved human machine interaction. The system debugging has been finished in laboratory, and the debug results show that the software design is reasonable, portability, and can achieve a given function.