Comparison of permanent magnet synchronous and induction generator for a tidal current conversion system with onshore converters

Tidal current conversion systems are moving towards commercialisation. Tidal energy developers are looking to optimise their systems by testing all the available options and taking advantage of the experience from the wind energy industry. The key focus of this paper is to compare an induction generator with a permanent magnet synchronous generator in a tidal current conversion system with onshore converters. The architecture of a tidal system with onshore converters is an option for tidal sites with small distances to shore as previous research has shown. In order to investigate the two generator technologies full resource-to-grid models in MATLAB/Simulink are developed. The analysis of these models compares generator efficiency, energy capture, losses at each stage, the cost and the maintenance for each system. Results show that the tidal system with PMSG is more efficient and generates fewer losses to transmit power onshore. In addition, since both systems tested are using a gearbox, the size, cost and maintenance of the PMSG are comparable to the reliable and cost-effective option of SCIG.