Design of a Tubular Linear Oscillating Motor With a Novel Compound Halbach Magnet Array

A linear oscillating motor provides shortstroke reciprocating motion directly and is widely used in linear actuation systems. However, with the increase of actuation frequency to achieve high power density, the large mover mass becomes the main obstacle. Existing solutions either sacrifice force density or increase fabrication difficulties for high dynamic performance. In this paper, a novel compound Halbach magnet array is proposed for moving-magnet tubular linear oscillating motor in high-frequency applications. In this structure, dual-layer magnets are utilized for better self-shielding effects. Thus, the conventional back-iron in the mover is no longer needed, which contributes to both high force density and low mover mass simultaneously. The analytical model is first set up based on harmonic function method. Then, finite-element-method results are used for validation and comparison with conventional designs. Based on the verified model, electromagnetic structure optimization is conducted, which leads to the prototype structure. Finally, experimental results on electromagnetic performance are provided for validation of the proposed motor with a novel magnet array.