In this paper, the experimental results for the design and operation of a special linear electromagnetic motor as a variable engine valve actuator are presented. A detailed description is given on the design procedure aimed at meeting the requirements of a high dynamic range and low power consumption, including determinations of the actuator’s topology and parameters, the force and the dynamic and power loss calculations. Moreover, based on a nonlinear model, an adaptive two-stage observer is presented to tackle unobservable points and achieve sensorless control. Further, this paper presents feasible real-time self-tuning of an approximated velocity estimator based on measurements of current and input voltage. The robustness of the velocity tracking is addressed using a
minimum variance approach. The effect of the noise is minimised, and the position can be achieved through a two-stage structure between this particular velocity estimator and an observer based on the electromechanical system. This approach avoids a more complex structure for the observer and yields an acceptable performance and the elimination of bulky position-sensor systems. A control strategy is presented and discussed as well. Computer simulations of the sensorless control structure are presented in which the positive effects of
the observer with optimised velocity are visible in the closed-loop control.