Electromagnetic actuators - Topological classification

Although new solutions are emerging (piezoelectric, magnetostrictive, even electrostatic in very small dimensions), electromagnetic actuators still occupy, and will probably continue to occupy for a long time, a predominant place in reversible –– electromechanical energy conversion.

In addition to the so-called conventional actuators, which benefit from a high level of technological maturity and scientific dissemination (DC machines with commutators, synchronous machines with wound rotors, asynchronous machines with squirrel cages, etc.), a wide variety of so-called non-conventional actuators coexist and are still being developed. They generally meet specific requirements and are not standardized. Their operation is often poorly understood, and their potential even more mysterious. They can be found in mass-market applications (often low-power, sub-kilowatt) such as household appliances, home automation, automobiles and toys, as well as in high-performance applications. Their evolution has been accelerated by the formidable developments in power electronics (particularly its "high frequency" capabilities) and in microprogrammable electronics.

At first sight, a classification of these different actuators seems risky, if not impossible, especially as their topologies are so numerous and varied. However, after an in-depth analysis of a number of existing actuators, or actuators currently the subject of research, it has proved possible to highlight fundamental topological criteria, notably relating to the type of power winding (supply), the supply mode and the motion generated.

The article follows on from the and dealing, on the one hand, with the principles of electromechanical energy conversion and, on the other, with the constitution of rotating machines, by which we mean conventional machines. Of course, all motions, linear or otherwise, will be considered here.

Following the actuator classification presented here, another article compares their respective performances.