Study On The Dynamic Performance Of Linear Induction Motor Metro Vehicle Based On Electromechanical Coupling

As a new type of urban rail transit,the linear induction motor(LIM)metro vehicle has the advantages of not relying on the wheel/rail adhesion,the high climbing ability and the good performance of the curve passing.It has brought many conveniences to the city line selection.Different from the traditional rotary motor vehicle,LIM metro vehicle will not only produce longitudinal traction,but also produce large vertical electromagnetic force which have a certain influence on the dynamic performance of the vehicle.In the actual service of LIM metro vehicle,there are some problems such as poor dynamic performance and intensified vibration of vehicle parts in some sections.Therefore,it is necessary to study the dynamic performance of LIM metro vehicle.In this paper,considering the special side effect of the linear motor,the mathematical model of the electromagnetic force of LIM is established by means of the centralized parameters and the equivalent circuit based on the principle of equal power of the field path complex.Then the structural characteristics of the bogie of LIM metro vehicle with large and medium volume are analyzed.The dynamic model of the two kinds of LIM metro vehicle with bolster,axle box built-in and no bolster,axle box outside are set up.In order to consider electromagnetic force of LIM,the electromechanical coupling dynamic model of LIM metro vehicle is established by co-simulation.Based on this model,the dynamic performance of two bogie structure of LIM metro vehicles is analyzed.The research shows that the stability and the curving performance of the bolster and axle box built-in are better than the structure of the non-bolster and outer axle box,and the sperling of which is different at different speed.Based on the better comprehensive performance of LIM vehicle with bolster and axle box built-in,the key suspension parameters and the positioning stiffness of LIM are optimized.Through the optimization,the influence of suspension parameters on stability,sperling and curving performance of LIM metro vehicle is obtained,and the suitable range of the suspension parameters is selected.With a comparison of dynamic performance before and after optimization,the optimized LIM metro vehicle is significantly improved,especially sperling and curving performance.Through the prediction of the optimized LIM vehicle performance,the research shows that: 1)The lateral concave wear of the wheel tread will increase equivalent conicity,reduce the stability of the vehicle,change the bifurcation form of hunting motion,the lateral sperling and the derailment coefficient increase,but the vertical force of the wheel/rail and the load reduction rate of wheel weight have been reduced.2)The polygonal wear will reduce the stability of the vehicle,the lower polygonal wear has a certain influence on the vertical sperling when the speed is low,and greater polygonal wave depth is,more obvious influence is.The polygonal wear has a great influence on the vertical vibration of the wheelsets,the frame and the LIM,especially when the excitation frequency of the polygonal wear is close to the vibration modal frequency of the LIM,it will also cause serious deterioration of the curve passing performance.3)Rail corrugation of short wavelength has no effect on sperling.The excitation produced by the rail corrugation will cause a larger vertical vibration of wheelsets.Due to the attenuation of primary suspension and secondary suspension,it has little influence on the vertical vibration of the frame,and has no effect on the vertical vibration of the car body.4)The irregularity of rail welded joints has an impact on the vertical sperling,and causes greater impact on the wheel/rail system,the larger wave depth and the shorter wavelength,the greater the impact on the wheel rail system.