Magnetic guidance of the mover in a long-primary linear motor

Modern in-plant transport and handling systems benefits from using long-primary linear motors. To improve these systems, the lateral guidance of the vehicle is performed by magnetic forces instead of a mechanical guiding assembly. In this paper, an active guiding system is presented for PM-synchronous linear motors with long and double-sided primary. The air-gap and the yaw angle are controlled while a simple wheel-rail system fixes the vertical displacement. Each side of the primary is supplied by its own inverter allowing the necessary degree of freedom to control the air-gap and yaw angle in addition to the thrust. With this arrangement, the mover can be kept passive avoiding any energy transmission system to it. Experimental tests were performed on a laboratory prototype. The experimental results show good dynamic performance that in turn provides stiffness in the guidance.