A Study on the Moving of an AC Attraction-type Magnetic Levitation Transport System Using a Two-phase Linear Motor

Magnetic Levitation Transport system is suspended by magnetic levitation, and it is therefore basically free of contact parts that produce dust particles by friction. In order to take advantage of this no-dust characteristic, a number of magnetic levitation systems are currently being developed as transport systems for use in semiconductor manufacturing processes.The authors proposed the development of a new magnetic levitation system using a linear induction motor. Although the magnetic levitation characteristic was stabilized successfully, the moving control was complicated because the moving speed is dependent on the frequency of the commercial-frequency power supply. The present paper proposes the moving control of an AC attraction-type magnetic levitation transport system using a two-phase linear motor. The present system uses a low-frequency two-phase sinusoidal power supply amplitude-modulated from the commercial-frequency power supply. The levitation force is generated and controlled by a commercial-frequency AC magnetic field. In order to control the moving of the system, a low-modulation frequency control method is adopted.