Design and construction of the cryogenic cooling system for the rotating magnetic validator of the 10 MW SUPRAPOWER Offshore superconducting wind turbine

The SUPRAPOWER, an EU FP7 funded research project, is developing an innovative 10 MW class superconducting generator to provide an important breakthrough in the offshore wind industry. The 10 MW generators adopts modular concept to the superconducting coil and associated cryogenic systems. And the modular superconducting coil and cryostat of this novel generator will be validated through a scale-down rotating magnetic validator (RMV). The cryogenic cooling system for the RMV consists of two modular cryostats: a distributing cryostat and the corresponding rotating cryocooler system with a self-developed rotary joint. In order to achieve the SC coils’ working temperature of 20 K, a two-stage G–M cryocooler will be applied and linked to the two modular cryostats by way of a conductive copper connection. The distributing cryostat was developed to envelop the cold head of the cryocooler, thermal link, and three binary current leads to electrically feed the coils. A rotary joint with Ferrofluid sealing was developed to transfer the helium gas between the rotating cold head and stationary oil-lubricated compressor. In this paper, the design, manufacture, and assembly of this cryogenic system for RMV will be presented in detail.