Fast and reliable identification of plasma parameters in tokamak reactors is an issue of primary importance for the effectiveness of plasma position control action. A number of different measurement techniques are available, but the magnetic ones play the major role. Anyway, the magnetic field depends also on the currents induced in the confinement structures, which are very difficult to deal with. In this paper a new approach to the identification problem is proposed, based on the electromagnetic dynamical behavior of the system. The currents induced in the passive structures are considered and in addition, advantage is taken by the knowledge of the time derivative of the electrical state variables.