Coil Design for a Moving-Magnet Planar Motor Using the Stream-Function Method

This article concerns the synthesis of a coil for a moving-magnet planar motor that reduces the inherent force ripple, which is present in the traditional racetrack coil. The synthesis is performed by the stream-function method (SFM), which gives extra degrees of freedom in the design and allows the coil shape to be defined based on constraints on the force production. The shape of the optimized coil is analyzed, and the harmonic content in the force production is compared with a racetrack coil. The coil synthesized by the SFM reduces the peak and root-mean-square value of the parasitic force in the y-direction by 73%, and the harmonic content in the force production in the x-, y-, and z-directions is reduced by over 71.4%.