Optimization of mover acceleration in DC tubular linear direct-drive machine using response surface method

This paper presents a new analytical model for both magnetic flux density and thrust force in a linear direct-drive machine. The model is then used to design a tubular linear direct drive machine (TLDDM) by optimizing its effective parameters. Although the machine has many applications when it works as a motor, but the same design can be used when it works as a generator, where it has applications in renewable energy and sustainable systems. Twodimensional finite element method (FEM) is used for numerical analysis. Magnetic flux density and thrust force computed numerically shows a good agreement with the values resulted from proposed analytical model. This research, investigates the effect of some geometrical dimensions of Tubular Linear Direct-Drive Machine (TLDDM). The sensitivity analysis of parameters by response surface method (RSM) highlights the influence of effective parameters and their interactions. Permanent magnet (PM) radius, PM length, air gap, coil thickness, and current density of phases are effective factors on Mover’s acceleration. It is found that lower air gap, higher coil thickness and longer PM cause higher ratio of maximum thrust force to mover’s mass. It is shown that RSM can predict the optimum acceleration with error of 6%. The general shape of thrust force in different current densities is also confirmed by experimental results.