Analytical Prediction and Multiconstrained Nonlinear Optimization of Slotted Linear PM Motors Taking Into Account Two-Dimensional End Effects

Abstract

This paper presents an analytical prediction and a multiconstrained nonlinear optimization of slotted permanent magnet linear synchronous motors (PMLSMs). Preferentially, an analytical model is developed for the fast and accurate design of slotted PMLSMs. In the process, two key techniques are used for the performance prediction: first, the Schwarz–Christoffel conformal mapping is used to take into account the slotting effects, and as a result, the normal and transverse components of the flux density produced by permanent magnets (PMs) and three-phase current can be calculated; and second, the two-dimensional end effects due to the finite length of moving parts are roughly reflected by the half-side leakage analysis, thereby predicting the second-order harmonic of the force/thrust pulsation. Subsequently, a systematic approach to the design optimization based on an iterative scheme is presented to search for solution set that belongs to the Pareto front. With no need for finite-element analysis or multivariable equation set, the proposed model can save much computational time to reach an optimal solution. The validity of analytical results is confirmed by finite element and experimental results.