A Study on Improvement of Operation Efficiency of Magnetic Levitation Train Using Linear Induction Motor

Abstract

In this paper, a study on the efficiency improvement of the magnetic levitation train using the LIM (Linear Induction Motor) was presented. The maglev train has the advantage of being environmentally friendly since much less noise and dust is produced. However, due to structural limitation, compared to a rotating induction motor, linear induction motor, the main propulsion engine of the maglev train has a relatively greater air gap and hence has the lower operation efficiency. In this paper, the relationship between the operating condition of the train and the slip frequency has been investigated to find out the optimum slip frequency that might improve the efficiency of the magnetic levitation train with linear induction motor. The slip frequency is variable during the operation by this relationship only within a range that does not affect the levitation system of the train. After that, the comparison of the efficiency between the conventional control method with the slip frequency fixed at 13.5 [Hz] and the proposed method with the slip frequency variable from 9.5[Hz] to 6.5 [Hz] has been conducted by simulation using Simplorer. Experiments of 19.5[ton] magnetic levitation trains owned by Korea Institute of Machinery and Materials were carried out to verify the simulation results.

Efficiency Improvement by Deriving the Optimal Operating Slip Frequency of a Linear-Induction-Style Maglev Train

“…However, by using the same slip frequency in the operating bands of all trains, a problem occurred in that operating efficiency was lowered by using the same slip frequency, even in sections where high slip frequency was not required (on the basis of train operating conditions). Subsequently, a study of a variable slip-frequency control method was conducted to change the slip Energies 2020, 13, 6544 3 of 13 frequency on the basis of the operating conditions of the train to lower the slip frequency while limiting the normal force of the LIM [10].…”

“…Equation (9) shows the relationship between slip frequency and d-q axis reference currents i d and i q in the induction motor, and Equation (10) shows the relationship between I m and i d , i q derived through the propulsion force. These two equations are used to determine the i d , i q current command in the "reference current generator".…”