Design of a PM direct drive synchronous generator used in a tidal stream turbine

The design of a direct drive PM synchronous generator for a tidal stream subsea turbine is presented in this paper. The generator design must comply with a set of very narrow restrictions concerning the available volume, the required output, the maximum current of the three-phase marine cable and the inverter maximum voltage. For these reasons the obtained design is not able to completely fulfill the requirements, especially for the case of short time overload. The results show however the feasibility of the concept. With a relatively small correction of the requirements it will be possible to obtain the required results.