An Integrated Rotary Transformer and 3-Phase Dual-Active-Bridge Converter for High Power Transfer in Novel X-Rotor Wind Turbines

The slip ring solution for power transfer between rotating structures has adverse impacts on the maintenance of offshore wind turbines. Rotary transformer systems transfer electric energy based on the electromagnetic induction through the air-gap without mechanical contact. The rotary transformer can be integrated into dual active bridge converters (DAB) to utilize leakage inductance instead of the cumbersome inductor used typically in the system. The X-rotor wind turbine concept uses this idea to eliminate the need for slip rings and transfer bulk power to the AC network from generators mounted in a rotating structure. In this paper the design, performance, efficiency, and manufacturing details of a 1 MW wireless power transfer system for the novel X-rotor offshore wind turbine concept is presented. The results show that this design methodology that includes rotary transformers and dual active bridge converters is suitable for high-efficiency high-power wireless transfer systems.