Modeling of magnetization patterns for 2-DoF rotary-linear actuators

Purpose – The purpose of this paper is to present a semi-analytical modeling technique to describe magnetic fields due to PMs in 3D cylindrical structures. The model is based on 2D Fourier series and is applied to model the magnetic field of checkerboard magnetization patterns for rotary-linear actuators. Design/methodology/approach – The modeling technique based on Fourier series provides a direct solution of the Poisson and Laplace equation by means of separation of variables and is widely used to describe magnetic fields in electromagnetic devices in 2D coordinate systems. In this paper the magnetic scalar potential is used in the Poisson and Laplace equations. Findings – The magnetic field calculated by the semi-analytical model is compared with that obtained by Finite Element Modeling and shows excellent agreement. The calculation time of the semi-analytical model is approximately 60 times shorter than that of finite element analysis. Research limitations/implications – The method as presented in the paper assumes linear material properties, e.g. the non-linear B-H characteristics of iron cannot be taken into account. Furthermore, the structure is assumed to be slotless, that is, stator slots or end-effects cannot be taken into account. Practical implications – The semi-analytical modeling technique is applied to checkerboard magnetization patterns for 2-DoF actuators in this paper. However, it can be applied to a wide range of slotless cylindrical electromagnetic devices. Originality/value – As an addition to the common 2D modeling by means of Fourier series, this paper extends the applicability to 3D cylindrical structures. Furthermore, a new checkerboard magnetization is presented which can be used in 2-DoF rotary linear actuators.