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The virtual equivalent line method for the axial-flux permanent magnet eddy current coupler is proposed in this paper to solve the problem of the difference in the length of the magnetic flux path between the inner radius and outer radius of the axial section of the radial centerline of the magnetic pole. Different from the average radius equivalent method, the virtual equivalent line method adopts the function of variable pole radius instead of the fixed average radius, which establishes a uniform analytical expression of the air gap flux density and can accurately calculate the magnetic flux density at any magnetic pole radius. Furthermore, the end-effect compensation function is obtained. In order to investigate the effectiveness of the proposed method, the results calculated by the analytical method are compared with the finite element method. It is shown that the novel method proposed in this paper is highly consistent with the air gap flux density calculated by the finite element method.

This paper proposes an input-output feedback linearization techniques for linear induction motors, taking into consideration the dynamic end-effects. As a main original content, this work proposes a new control law based on the on-line estimation of the induced-part time constant. The estimation law is obtained thanks to a Lyapunov based analysis and thus the stability of the entire control system, including the estimation algorithm, is intrinsically guaranteed. Moreover, with such an approach even the on-lihe variation of the induced-part time constant with the speed is retrieved, thus improving the behavior of previously developed approaches where such a variation vs. speed is considered a priori known. The proposed control technique, integrating the on-line induced-part time constant estimation, is tested by means of simulations and experiments carried out on a suitably developed test set-up. (C) 2016 Elsevier Ltd. All rights reserved.