Résumé : This paper investigates a variable speed direct drive optimization and control for marine current energy application based on a Double Stator Permanent Magnet Generator (DSPMG). At first, turbine concepts, relative projects and usual conversion chains for tidal energy conversion are briefly presented. An original generator multi-objective optimal design method taking into account the tidal speed occurrence, control strategy and converter size to minimize the investment and maximize the annual energy output is developed. The conceptual advantages of the DSPMG are also used to show the possibility of uninterruptible operation under converter open phase faults. Simulation results are given and demonstrate the effectiveness of the optimization design and the proposed fault tolerant control.