Research On Doubly Salient Electro-magnetic Generator System In Vehicle Application

Doubly Salient Electro-Magnetic(DSEM) is relatively a new type of brushless machine, which offers an excellent balance between cost, reliability, power density and high-speed capability as like as Switched Reluctance Motor (SRM). The excitation winding simplifies the control system, and makes it flexible to control output voltage. Recently, the brushless DC generator consisting of DSEM has important practical value in the fields of aeronautics and automotive power-supply system.Firstly, this dissertation introduces the components of automobile power system, operation principle and operation characteristics. It also introduces the basic structure, electromagnetic characteristic and the regulator operation performance of doubly salient electro-magnetic generator system. Based on electrical formulas, the simulation model is established with MATLAB software.In order to upgrade the power density of DSEM generaror, this dissertation proposes the eight-diodes rectifying mode which introduces two neutral-point diodes into normal three-phase rectifier circuit. The operation principle and performances of the presented mode are analyzed at the aspect harmonic component.The researches on fault diagnosis and fault-tolerant running are rather important for the reliable generator system. A fault diagnosis algorithm for rectifier circuit in DSEM generator is proposed in this dissertation. Through the wavelet packet analysis of various fault voltage signals, the fault pattern vectors are built up based on energy eigenvalue in each frequency band which are defined as the criterion of fault category. The experimental results indicate that the analysis technique is accurate and effective.Finally, the design of software and hardware of doubly salient electro-magnetic generator system based on DSP is introduced in detail, and the prototype has been set up. A series of experiments have been made, and the results show that the system has excellent static and dynamic characteristic and high reliability which validate the feasibility of DEEG application scheme in vehicle low-voltage power system.