Flux field and thrust analysis of permanent-magnet linear machines with isolated movers

A novel permanent-magnet linear machine that consists of several isolated movers and one single stator is proposed in this paper. It is especially suitable for tasks requiring multiple drive machines. Each mover can produce independent thrust and flexible motions by interacting with the stator poles. Compared with conventional multimotor driven system, it helps to achieve more compact size, and thus improve the system working efficiency. The design concept is presented, and the magnetic field distribution in the machine is formulated analytically. The influence of magnetization patterns and back iron is included in the analysis. The research result indicates that the employment of same-magnetization pattern helps to improve the magnetic flux density and thus the thrust output of the system. A research prototype of the linear machine with two isolated movers is developed. Numerical computation and experiment measurement are carried out to verify the analytical models. Comparison shows that the analytical model fits with finite-element analysis and experimental results well, and the influence between the mover motions is negligible. The similar design concept of multimover and single-stator can be implemented into other rotary electromagnetic machines.