Control of Non-conventional Synchronous Motors

Chapter 7

Advanced Control of the Linear Synchronous Motor ¹

7.1. Introduction

This chapter presents some advanced controls of the permanent magnet linear synchronous motor (PMLSM). In section 7.1.1 we present a short historical and general introduction of this type of motor. We take a short look at state-of-the-art PMLSM technology in industry at present.

In section 7.2.1, we propose a brief overview of state-of-the-art of industrial controls available for linear synchronous motors. Then, advanced controls specific for linear motors are presented.

In particular in this chapter, control design is elaborated using the causal ordering graph (COG) principle that is applied to advanced analytical models of PMLSM, including cogging forces and end-effect forces. The COG principle facilitates the analysis of the physical model for controller tuning. Some advanced controls are presented, including estimator and feed-forward control, resonant controller and the nth derivative of the control variables in open-loop control.

7.1.1. Historical review and applications in the field of linear motors

One of the first transportation designs using linear motors was patented more than a century ago. It was designed by Alfred Zehden and patented in Switzerland in 1902 [ZEH 02] and in the US in 1905. The patents focus on the use of linear induction motors (LIMs) to move passenger trains. In such an application, the primary was fixed by sections on top of a rail, along the railway. Each section successively ...