Influence of Fixed-Pitch Tidal Turbine Hydrodynamic Characteristic on the Generator Design

Abstract

This paper deals with the global design of direct driven permanent magnet (PM) generator associated with fixedpitch turbine for tidal energy generation. A global design approach of the generator design is proposed which takes into account the tidal site energy potential, the turbine hydrodynamic characteristic, the converter characteristics and an original power levelling control strategy. Because the considered turbine is without variable pitch control, the power levelling strategy is only based on torque/speed electrical control of the generator. Applying this global design process, it can be shown that the hydrodynamic characteristic (shape of the power coefficient curve (Cp)) have strong effects on the final design of the generator. The aim of the presented work is to evaluate this influence. Two Cp curves are considered for the same resource, turbine diameter and rated power. The obtained designs are compared in terms of cost and mass of the active parts and power factor of the generator. In the last part of the paper, the qualitative influence of the shape of the different parts of the Cp curve on the generator design is discussed.