Self-sensing electromagnetic levitation system taking account of ripple currents excited by PWM amplifier

This paper presents a linear model for self-sensing electromagnetic levitation system. We consider one degree of freedom magnetic levitation system composed of a suspended object and an electromagnet driven by a pulse-width-modulation amplifier. The proposed model makes use of the airgap information contained in the derivative of the coil current. We design a controller based on the proposed model, and show that the system performs well by using computer simulation.