Improvement of ATO efficiency by varying slip frequency for a magnetic lévitation propulsion system using a linear induction motor

In this paper, the possibility of energy efficiency improvement of the maglev train with variable slip operation other than constant one for the linear induction motor drive is discussed. Such novel operation pattern is considered to be plausible by applying proper operating süp to the linear induction motor when a certain acceleration/deceleration operation pattern is determined. Investigation of the relationship between normal force and tracking force has been conducted. The relationship between Süp frequency and normal force and tracking force has been studied by comparing constant süp current control and variable slip current vector control. It has provided the most efficient süp curve along with varying operation pattern after testing a band of possible süp/pattern combination. An algorithm is used to implement the variable süp control scheme. During simulation and field test, the algorithm of automatic train operation which applies the best slip curve to different operation pattern has been proved to be efficient and feasible. However, the best efficiency süp curve has to consider the influence of the change of the lévitation force since the lévitation force tend to increase along with the decreasing slip frequency. Then the ATO system select the süp curve that provide best efficicncy under constraints due to safety to conduct the field test.