Research On The Basic Characteristic Of Doubly Salient Brushless DC Generator In Vehicle Application

Doubly Salient Electro-magnetic Machine is a new brushless motor proposed on the basis ofDoubly Salient Permanent-magnet Machine. It has simple structure with no winding or permanentmagnet on the rotor, high reliability and low cost. In generating mode, excitation current could beregulated to keep the output voltage constant when the load or the speed changes, so it is easy tocontrol and has a wide application prospect in the field of aeronautics and wind power generation.This paper introduces the basic structure, operation principle and mathematical model first. Thestatic characteristics, no-load characteristics and external characteristics of doubly salient brushless DCgenerators with different excitation schemes are analyzed by two-dimensional finite element method.This paper gives a detailed analysis of the magnetic circuit of the DSEG. Setting the stator-pole’swidth as the base, it compares and analses the features of the motor’s magnetic circuit in differentheight of stator-yoke, stator-pole, rotor-pole and rotor-yoke. The external characteristics, powercharacteristics of the generators with different structure parameters are compared by simulation.Optimize the generator’s structure and draw some rules of the DSEG in using in the high-speed,high-power automotive power-supply system.To reduce the power of excitation, this thesis puts forward the novel double salient motor, doublesalient machine with dual excitation windings. Due to the self-excitated effect of series excitationwinding, the voltage regulation is low and the power of excitation is also low. It is particularly suitablefor automotive power-supply system. Compared with the traditional DSEG, the characteristics of thenovel machine are obtained. Comparative analysis of double salient machine with dual excitationwindings under no-load characteristics and external characteristics under DSG2are investigated. Thecalculation method of iron loss by simulation is described.A prototype machine of double salient machine with dual excitation windings is developed. Themeasurements of the no-load characteristics and load characteristics of the prototype machine arefinishied. The experimental results verify the theoretical analysis and the finite element method, whichconfirms that the novel machine has great application and research value in the automotivepower-supply system.