Design and Simulation of a Continuously Variable Hydraulic Power-Split Drivetrain for Wind Turbines

Abstract. This paper focuses on the development of a continuously variable, hydromechanical power-split transmission concept for modern large-scale wind turbines. Current wind turbine designs rely primarily on direct-drive or gearbox-based solutions with frequency converters for variable speed operation, each presenting trade-offs in terms of cost, efficiency and failure rates. The proposed drivetrain design aims to reduce cost and weight, increase reliability, and maintain turbine efficiency. This paper examines various conceptual arrangements and designs with regard to efficiency and feasibility. It shows that structural changes to the drivetrain transmission ratio have a major impact on the efficiency and general behavior of the drivetrain and that, depending on the design and site conditions, the powers-split drivetrain is able to reach similar efficiencies as standard geared drivetrains.