Design and analysis of a linear permanent magnet machine with three phase multi-layered structure

Linear permanent magnet machines (LPMMs) are widely used in the industrial field for its high-performance of position accuracy, acceleration, deceleration, and tracking characteristics. In addition, LPMMs have no transmission error and backlash owing to the direct drive system. However, the direct drive system is easily affected by disturbance. If the system contains several LPMMs, the movement of LPMM is affected by other LPMM. Therefore, using several LPMMs makes control and structure complicated. In this paper, a new LPMM with three phase multi-layered structure is proposed. This proposed motor has magnet layers (stators) and coil layers (movers) stacked up in layers alternately. Accordingly, the thrust characteristics can be changed by varying the number of layers. This could adjust the thrust without controlling the current value and simplify the structure of the system. Therefore, this proposed motor can be applied to various conditions with different demands of thrust characteristics. Moreover, it can be expected to attain the high-thrust density. This paper firstly introduce the structure of this proposed motor. Next, the magnetic field analysis is performed by changing the number of layers to see how the thrust characteristics is changed by layer changes. Then, the result of magnetic field analysis at relationship between thrust and number of layers is shown. Additionally, the experiment of the proposed motor is shown. The utility of the proposed motor is confirmed from the result.