Numerical modelling of the engines governors of a CODLAG propulsion plant

In recent times the Department of Marine Engineering of Genoa University has been involved in two important projects related to the development of the propulsion controllers of the Italian aircraft carrier “Cavour” and the FREMM Class Frigates. In both cases, the authors have cooperated with the automation provider of the vessels by developing two simulators representing the dynamic behaviour of the two different propulsion systems. Obviously, in order to achieve reliable simulation results, it is important to rely on a detailed modelling of the engines dynamics, mainly depending on the behaviour of their relevant governors. Although in literature there are many theories regarding the engines thermodynamics, unfortunately their governor logics are not always well known, since they belong to the particular “know-how” of the several engines manufacturers. This paper is focused on the simulation approach followed by the authors to represent the governors behaviour of the marine gas turbine and the electric motors employed by the CODLAG system of the FREMM frigates. In particular, a brief description of the adopted models and of the pertinent validation procedures is reported in the paper, in order to provide useful information, not directly available by the engines manufacturers but deduced by the authors on the basis of their experience gained in the marine simulation field.