Force density improvements from increasing the number of airgap surfaces in synchronous linear actuators

Abstract

This paper presents a realistic comparison of several electromagnetic architectures for high force density actuators. Four equivalent architectures are chosen and computed with a two-dimensional finite element model. For each architecture, size is optimised in order to maximise the force-volume ratio. This optimisation step is performed with a fixed mechanical airgap. A thermal model is then used to calculate the current density in the coils. Results show that globalcoil architecture performance increases more sharply than other architectures; a scaling effect is thereby introduced for global-coil architectures. A global-coil multi-airgap actuator is presented to illustrate the theoretical results.

Actionneur linéaire synchrone à aimants permanents multi-tiges

“…Des solutions innovantes de type polyentrefer ont été imaginées en particulier au laboratoire d'électrotechnique d'Orsay [1]. Ces solutions, combinant la multiplication des surfaces d'entrefers et l'emplois d'un bobinage global, permettent l'obtention de performances volumiques très élevées [2] pourvus que la complexité mécanique soit accompagnée de solutions satisfaisantes sur les plans économique et de faisabilité. Les différentes architectures polyentrefers à bobinages globaux (la distinction est importante avec les autres) développées à ce jour essentiellement au laboratoire d'Orsay, au SATIE (depuis les années 90) et au LEM ont mis en évidence le fort potentiel de ce principe mais également les nombreuses difficultés de sa mise en oeuvre.…”

Design of a High-Force-Density Tubular Motor

“…From the various, linear machine topologies that exist today [5,[7][8][9][10], in general it is the TLPM motor topology with inset permanent magnets (IPM), that offers the best force density performances [11,12]. Considering this, then it was decided to focus the design on such an arrangement, which also has the advantage of facilitating manufacturing (in terms of the moving part, henceforth called the mover) and also reduced the amount of mover, magnetic material required.…”

New multi-rod linear actuator for direct-drive, wide mechanical bandpass applications

“…The optimal value (acceleration maximization) of is (5) (5) With this value, the maximum acceleration becomes (6) (6) The first part of this equation relates to the actuator: this value is directly linked to the size of the actuator. The scaling effect gives the evolution of torque and inertial load as a function of dimension [13].…”

“…The same methodology as in Section II [6], [7], [8] has, thus, been applied, with only an elementary pattern being modeled by the FEM. First, the magnetic salience of the pattern was calculated.…”

“…In order to demonstrate the benefit of multi-air-gap structures, we have compared [5] two basic permanent-magnet actuator architectures [i.e., distributed coil ( Fig. 7), multi-air-gap and global-coil, multi-air-gap ( Fig.…”