Research On High Power Permanent-magnet Intergrated Startor Generator Applied In Hybrid Electric Vehicles

Hybrid vehicle, as the representative of new energy vehicles, provide aneffective way to solve today oil depletion problem and urban environment pollutionproblem.Widely worldwide research on hybrid cars and the core component thatnames starter generator system in hybrid cars has received the widespread attentionin numerous studies.PMSM becomes the best model of starter and generator withthe characteristics of small volume and big power and become the focus object ofstarting generator system study. This paper launches the research on PMSM used asthe starter and generator system based on the background of high power hybrid bus.Firstly, analysis of the starter and generator under each working conditionrunning state has been conducted in view of the vehicle operation condition, anddesign indexes were formulated according to the system matching and runningcondition. Then, transmission mechanism has been researched due to the startinggenerator system.Drive way using planetary gear connecting engine and starteinggenerator has been proposed to improve the power density of the system, and therelationship between the controller loss, system power dissipation density and planetgear transmission ratio is analyzed.Secondly, in order to improve the motor torque density, the factors that affectmotor torque density are analyzed, the mathematical analytic expression is obtainedthrough theoretical analysis. The various factors are thoroughly discussed asfunctions of motor torque density and the motor torque density optimization designhas been carried out according to the targets of motor. Design process of the hightorque density motor has been summarized on this basis, and its feasibility isverified by simulation.Thirdly, the relationship between the placement of Permanent magnets andgeometric structure has been analyzed taken the embedded type permanent magnetmotor on as the object of the research.The relationship between electromagneticparameters and the rotor geometry has been established by setting thevariables.Then geometrical parameters influence on the motor air gap flux density,inductance, magnetic resistance torque and motor voltage regulation rate are studiedto get the corresponding relation curve and the simulation validation has been done.Finally, the motor torque ripple research has been developed taken the motoroutput torque stability on as the object of the research.Causes and influencingfactors on motor torque ripple are analyzed from the perspective of theory and therelationship between various factors and motor torque ripple has been studied. Theeffect of various methods has been validated by computer simulation and the designscheme of low torque ripple motor has been got.