Electrical Actuators: Applications and Performance

Chapter 8

Observation of the Rotor Position to Control the Synchronous Machine without Mechanical Sensor ¹

8.1. State of the art

Intense industrialization has resulted in a large proliferation of electromechanical actuators in an increasing number of industries (home automation, transportation, heavy industry, etc.). More recently, this phenomenon has greatly affected embedded systems in which the electrical solution is preferred over the traditional hydraulic solution. This is due to the specificities of the electrical actuator, characterized by gains in power and mass volume, as well as to the many diagnosis and monitoring possibilities that this type of actuator facilitates. The embedded devices reveal a large number of actuators necessary for the movement control of different objects (servo-cylinders, electric pumps, windages, etc.). Specifications involve speed systems to follow and positioning trajectories to satisfy, paving the way for different and varied actuators obtaining different power and quality in the function finally obtained. We often find trapezoid electromotive force magnetic machines for speed control as well as sinusoidal electromotive force machines to ensure position control. Other combinations are clearly possible and thus a machine, developing trapezoid electromotive forces, can be fed by sinusoidal currents and vice versa.

Because of the increase in speed, often dictated by the goal of volume reduction, controlling these actuators creates new challenges ...