Wide Air-gap Control for Multi-module Permanent Magnet Linear Synchronous Motors without Magnetic Levitation Windings

Abstract

This paper proposes a wide air-gap control method for the multi-module permanent magnet linear synchronous motor (MM-PMLSM) based on independent vector control. In particular, the MM-PMLSM consists of symmetrical multi-module and multi-phase structures, which are basically three-phase configurations without a neutral point, unlike conventional three-phase machines. In addition, there are no additional magnetic levitation windings to control the normal force of the air-gap between each stator and mover. Hence, in this paper, a dq-axis current control applying a d-q transformation and an independent vector control are proposed for the air-gap control between the two symmetric stators and mover of the MM-PMLSM. The characteristics and control performance of the MM-PMLSM are analyzed under the concept of vector control. As a result, the proposed method is easily implemented without additional windings to control the air-gap and the mover position. The effectiveness of the proposed independent vector control algorithm is verified through experimental results.

Design and Analysis of Novel Synchronous Motion Technique for a Multi-Module Permanent Magnet Linear Synchronous Motor

“…Based on Kirchhoff's voltage law and Faraday's induction law [23], the three-phase voltage of each module can be expressed as…”

“…Furthermore, the synchronous motions of the multi-module adopt independent vector control strategies and inverters. In [23], each module of the multimodule PMLSM is driven and controlled independently, forming an independent drive unit. However, the above research only focuses on independent control of the multi-module and how to reduce thrust ripple.…”

Levitation Control for a Double-Sided Bearingless Linear Motor Based on Feedback Linearization

“…To evaluate the accuracy of the simplified feedback linearization, Fig. 6 compares the numerical values obtained from (17) and (18) to the corresponding FEM results. As an example, Fig.…”

“…However, the levitation control design in [15] is based on applying a linear motor model. Instead of systematically synthesizing the levitation control system, proportional-derivative (PD) or PID controllers, with trial-and-error tuning, are used [13], [16]- [18].…”