This project is for the development and industrialization of a novel medium-speed wind turbine drivetrain (WTDT) designed to have an intrinsically higher reliability than the current most widely used high-speed WTDT, which employs a 3-stage gearbox and doubly-fed induction generator (DFIG) with partially-rated converter. The reason that this existing WTDT is so widely employed is that it is cost-effective because it makes use of widely available industrial components and adopts a low-cost partially-rated converter. The proposed medium-speed WTDT leverages the advantages of the existing DFIG WTDT, but also improves upon the intrinsic reliability by adopting: a) Medium-speed Brushless DFIG, excluding brush-gear and slip-rings, known to be the highest failure rate components in the generator; b) Partially-rated converter, identical to the high-speed WTDT; c) 2-stage gearbox, excluding the third high-speed stage, known to be the highest failure rate section of the gearbox. The project aims to move the Brushless DFIG technology from being a promising and proven concept, demonstrated in small-scale, to an optimized industrial-scale drivetrain for multi-MW wind turbines. The Brushless DFIG has been demonstrated on a 20 kW wind turbine and most recently, a 250 kW prototype generator on a test bed. However, in order to make the generator commercially attractive, its performance must be optimized to industrial levels and be demonstrated on a real size drivetrain. Further, its mechanical and electrical integration within a wind turbine system must be optimized with respect to cost, weight and size, including converter, generator, gearbox, controller and associated Condition Monitoring System (CMS). The project will study several aspects of the Brushless DFIG including its design, operation, grid connection, control and condition monitoring with an aim to optimize and improve the drivetrain performance for wind generation. Furthermore, its integration into a WTDT and optimization on a system-level will be carried out. A 3 MW medium-speed Brushless DFIG drivetrain will be designed which will be utilized the follow-on exploitation phase to build and test a 3 MW prototype system.