Linear electric actuators and generators

Abstract

Linear electric actuators and generators (LEAGs) are electromagnetic devices which develop directly short-travel progressive (or oscillatory) linear motion. Machine tool sliding tables, pen recorders, and free piston power machines are typical industrial applications for LEAGs. Their recent revival in applications in compressors, pumps, electromagnetic valve actuators, active shock absorbers, vibrators, etc. prompts this review, which presents main LEAGs configurations. their principles of operations. comparative performance evaluation, motion control and existing as well as potential applications.

Thrust ripple optimization and experiment for a permanent magnet linear synchronous motor

“…Figure 7 demonstrates that experimental force ripple was quite in line with that calculated by the fitting Eq. (14). So the optimal theory and analysis method is effective.…”

A review of free-piston linear engines

“…Many researchers have used three-phase linear alternators for highpower FPLEs [30,40,52], whereas they've found single-phase linear alternators suitable for small power FPLEs [53][54][55]. The various arrangements of magnets also differentiate various types of linear alternators, including moving-magnet, moving-iron, and moving-coil linear alternators [56], as shown in Fig. 12.…”

“…The moving-coil linear alternator requires flexible leads, which tend to wear out, especially in high-power machines. Moreover, moving-coil linear alternators are unsuitable for any significant power generation [56]. The moving-magnet linear alternator has the lowest moving mass [57]; however, it contains the following drawbacks: large magnet leakage fields; exposure of permanent magnets to continuous vibration that could demagnetize them; constraints on power conversion capabilities by the stroke length and the magnet length; thickness of the magnets as dictated by the air gap; and size of the magnets as limited by the mass of the moving member of the linear alternator [56].…”

Development of flux reversal linear synchronous motor for precision position control

“…2 Most of previous research works related to FRM concentrated mainly on rotary machine except flux reversal linear oscillomachine for short stroke application. [3][4][5] Recent research works on FRLSM successfully showed feasibility for long stroke linear motion systems. 6,7 The proposed model in this paper introduces auxiliary salient poles between adjacent PMs.…”