Design of a Linear PCB Winding Resolver With Longitudinal End Effect Suppression

The linear variable reluctance (VR) resolver as a contactless measurement component is essentially a small electric machine and presents a better reliability than other linear position sensors. For the high-density automated store shelves scenarios, the desired position sensor should have features of low-cost, small-size, high-precision, and easy-to-install on a several tens or even one hundred meters rail. The previously proposed linear resolvers for the long-distance application cannot well satisfy the above requirements. To address the issues, this article proposes a linear resolver system, which replaces the mover teeth and wire-wound winding with the printed circuit board (PCB) winding. This slotless structure is good for saving the manufacturing cost but induces a high flux leakage, which then causes a significant signal asymmetry. To suppress this longitudinal end asymmetry and its induced precision issue, this article investigates the PCB winding design. The additional auxiliary coils are added, and the complementary scheme is applied on the PCB. Experiments validate this extremely low-cost solution, which provides a less than 0.2 mm precision in a long rail.