Halbach PM ironless linear motors mostly adopt film windings. In this paper, a novel Halbach PM ironless linear motor with trapezoid windings is proposed and analyzed. The trapezoid windings can achieve a primarily single-sided and well sinusoidal magnetic field. After current density formula is derived, the magnetic flux density equations of the trapezoid windings are formulated using the vector potential method. Based on analytical field, the force ripples of the Halbach PM ironless linear motor with trapezoid windings are analyzed using Maxwell stress tensor method. The simulations with FE method and numerical Lorentz force method are presented to show the validity of the analysis method.@en

Power frequency electromagnetic field (PFEMF) is an important part of the ultra high voltage alternating current (UHVAC) transmission line's electromagnetic environment. In this paper, the distribution of PFEMF was obtained by finite element method, and the influence of lines' configuration, vertical height and the distance between phases was discussed. Furthermore, the electrostatic induction was calculated and analyzed, which includes distorted electric field around human body, induced current density within human body and the special characteristics of electric field in rainy weather. The results and conclusions in this paper can be treated as reference for the evaluation of UHVAC transmission lines' electromagnetic environment.@en