| After the first linear induction motor (LIM) driven subway system was established in Toronto, more and more countries like China, Japan, America, Malaysia and etc. have adopted the LIM-driven subway system. Compared to the traditional rotary induction motor (RIM), the LIM has advantages as non-adhesive traction/brake, smaller curve radius, higher climbing capacity, less civil engineering quantities and easier maintain process.Compared with traditional ratoary-induction-motor subway vehicles, the most notable difference is the suspension way of motor, which causes different dynamic performances. Simultaneously different suspension ways of linear induction motor has an effect on the vehicle as well.As so far, there are three main kinds of LIM-suspension bogie:frame-suspension, wheelset-suspension and vice frame-suspension. However, Vehicles adopting different motor suspension ways have different dynamic performance. Bogie early developed by Bombardier is the wheelset-suspension one which has the advantages of less LIM vertical displacement and better passenger comfort index. While bogie adopted by Japanese companies is the wheelset-suspension one which has the advantages of less under-spring mass and smaller wheel\rail force. As lack of related references and parameters, the vice frame-suspension one will not be studied further.There are four kinds of end effects of the LIM compared to the RIM which have an influence on the LIM force. The longitudinal force offers traction or brake, and the lateral force is beneficial for centring motion. As well as the vertical force changes the load of wheelset. No matter what kind of motor suspension has been adopted, different suspension structures will have different interaction forces which differs form the ratoary motor bogie. When the motor is out of work, it has an impact on the vehicle. Plus, when the motor works, an extra influence will be applied to the vehicle. As a result, the suspension way is not only complicated but also has an influence on the dynamic performance of subway vehicle. Based on some reasonable assumptions and simplifications, a new equivalent circuit has been built, and the formula of the LIM three-oriented force has been given. Considering specific parameters of one type of subway LIM, the force curves are indicated.Given the three-dimensional LIM force, a comprehensive comparison of dynamic performance between wheelset-suspension and frame-suspension subway vehicle is carried out. Both the stability and safety of the vehicle and the LIM dynamic character are put into calculation.The simulation result shows that:1)Regards to the LIM, the vibration of the wheelset-suspension LIM is fiercer than the frame-suspension LIM’s, while the former gap is smaller than the later’s which is beneficial for the improvement of traction efficiency;2)Regards to the vehicle, the lateral dynamic performance is almost the same, however, the vertical dynamic performance of the wheelset-suspension one is better than the frame-suspension’s such as rate of wheelload reduction and derailment ratio;3) The displacement of the trail of the Lim is0.3mm to0.5mm larger than the head of it;4) The vertical displacement of the frame-suspension is0.6mm to1.3mm larger than the wheelset-suspension’s;5) The maximum LIM lateral force is1500N on straight track and1700N on curve track;... |
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