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In this article, the magnetic analysis of a rail eddy current brake (ECB) with ring structure winding and ac excitation is presented. Differing from the ECBs with dc excitation, the proposed ECB can generate electricity and reduce rail heating. First, the structure and working principle are described. Second, the three-dimensional (3-D) analytical model (AM) is established considering the nonlinear permeability of the secondary rail and the transverse end effect. Third, the accuracy of AM is verified by the finite-element method and experimental results. Furthermore, the ECB's braking force and power characteristics are analyzed based on the finite-element analysis. Finally, four different winding schemes possibly suitable for ECBs are compared to determine the superiority of the ring structure winding.

The Maglev launch assist system (MLAS) has been adopted as part of a reusable launch vehicle system to lower launch costs. In this article, a dual-conductor plate parallel electric suspension and guiding mechanism (DPESGM) serving the suspension and guidance function of the MLAS is proposed. First, the MLAS and the structure of the DPESGM are introduced. Then, a DPESGM magnetic drag analysis model is established based on the multilayer theory for the fast calculation of the magnetic drag. However, its accuracy is poor at high speed. To solve this problem, an improved analytical model suitable for the full speed range is developed, which takes the equivalent conductivity replacement approach to consider the skin effect. Finally, the improved analysis model is verified by the finite element method (FEM) and prototype experiments. The results show that the improved analytical model is highly accurate in the evaluation of the DPESGM magnetic drag from low speed to high speed. As the improved analytical model takes less computational time than 3D FEM, it is an efficient tool for the DPESGM magnetic drag calculations to complete the preliminary design of the propulsion and braking systems.

Permanent magnet synchronous motors (PMSMs) provide many attractive electromagnetic performances such as high torque density, high efficiency and simple structure, which make them more competitive in electric vehicles (EVs). However, designing a PMSM with a wide constant-power speed range and high power factor at high speeds is still full of challenges and requires further effort. In this paper, the performance of vehicle motors considering their operating conditions is analyzed. The design rules of the reverse-salient permanent magnet synchronous motor (RSPMSM) are summarized, and an RSPMSM is proposed. The principle of the RSPMSM with high torque especially in the flux-weakening states is studied by analyzing the variable flux leakage and variable saliency ratio in detail. The electromagnetic performance of the proposed RSPMSM is investigated using the finite element method (FEM), and its prototype is manufactured and tested. The experimental results show that the constant-power speed range is 5.5:1, and the power factor is close to 1 at high speed. Thus, the RSPMSM proposed in this paper is a favorable candidate for EVs.