Design of yaw system
This report is the product of a bachelor project, and is written as a proof of concept for the company Danish Wind Design (DWD). Its scope is to design an alternative and improved yaw system for DWD ́s existing 2 MW wind turbine. The system is based on a concept which involves a yaw ring sliding on friction pads preloaded with springs. The produced friction in the system is necessary to reduce the dynamics when yawing and to reduce the loads acting on the yaw drives. The main purpose of the project is to increase the friction produced in the system, without radically increasing the cost of the system.
A full load report of the existing DWD turbine is examined, to discover extreme load cases acting on the turbine. The yaw system is designed to withstand these extreme load cases.
Through a brainstorm several yaw system concepts are developed, but only one passes on to the final dimensioning stage. This concept introduces the yaw drives as an integrated part of the system, by enabling the use of spring packs on the motor axles, and thereby prevents interruption of the friction surfaces. The system is fitted with eight yaw drives, as opposed to the three used in the current solution designed by DWD. Doing so reduces the load on each tooth on the yaw ring and pinion, which despite the extra motors and gearbox reduces the overall weight of the construction while increasing its performance. The gearboxes chosen are smaller due to the quantity, which has proven to be an economically valid solution.
The performance of the designed system has increased the friction produced by approximately 41.5 %. An economical estimation has evaluated the system to approximately 4 % cheaper than the DWD yaw system. As a conclusion the concept is considered eligible to proceed to the next step in the design phase.