Improvement of operating state by switching two phase-advanced capacitors to an ac ampere type linear magnetic levitation system

Abstract

This paper describes the operating state improved by using phase-advanced capacitors for the ac induction type magnetic levitation(maglev) system. In case many coils are set up in yoke such as this type of maglev, the impedance of electric circuit of the stator has strong inductivity; therefore, a phase-advanced capacitor should be inserted to achieve power-saving operation for the inductive circuit. However, the ferroresonance state occurs as the power-factor of the circuit approaches 1, and then the current steeply increases even if the voltage increases slowly. Thereby, a non-magnetic plate greatly oscillates when it starts to levitate. To improve the starting oscillation, we adopted the method of switching two different capacitors. As a result, both smooth starting of levitation and minimum input power operation functioned successfully.