Dynamic optimization design of hanging parameters for traction transformer of high-speed train

A vehicle-equipment rigid-flexible coupling system model with 21 degrees of freedom was proposed in order to optimize the hanging parameters of traction transformer.The new and rapid explicit numerical integration method was used to compute the vibration response of the vehicle and traction transformer.The vehicle comfort degree indexes and equipment vibration severities of vehicle system under different speeds were calculated, and the optimal hanging frequency of the transformer was obtained.A mathematical model of the transformer and a rigidflexible coupling model of vehicle-equipment were set up, the multi-object dynamic optimization was performed on the vibration isolator parameters under considering the optimal hanging frequency, vibration severity, comfort degree index, dynamic force of vibration isolator, and matching index of transformer suspension mode and vehicle floor local mode, and the optimalparameters of vibration isolator in the transformer were computed.Research result indicates that when the suspension frequency ratio of the traction transformer is 0.82-0.92, the vehicle comfort degree index is less than 2, and the vibration severity of the equipment is less than 4.5 mm·s-1, which can satisfy the requirements of related standards.After optimization, the vertical stiffness of the first group isolator, the stiffness ratio of three groups of isolators and the three directions' s stiffness ratio of each group of isolators are 2 142 N·mm-1, 1∶1.3∶2.5 and 1.7∶0.5∶1, respectively.Compared with the original suspension scheme of the transformer, the vibration severity of equipment decreases by up to 42%at the speed more than 200 km·h-1, the comfort degree indexes of front, middle and rear vehicle respectively increase by 3.53%, 3.45% and2.01% on average, the vertical forces of the isolators 1 and 4 decrease by 13.3%on average, the vertical forces of the isolators 2 and 5 decrease by 3.8%, and the vertical forces of the isolators 3 and 6 decrease by 20.9%.Thus it can be seen the comfort degree index of vehicle, vibration severity of equipment and vertical dynamic force of vibration isolator improve after optimization.