In this paper, a control scheme for a class of electromechanical systems that solves the position/speed tracking control problem is presented. The main characteristics of the proposed control law are that its structure is based on the development of a globally convergent nonlinear observer and that it considers for its design the available information about the system structure, in particular its passivity properties. Regarding the class of electromechanical systems approached, it is considered a generalized model that captures both traslational and rotational systems with an electrical subsystem that considers the existence of magnetic-field and electric-field storing energy elements.