A HTS synchronous machine with rotating armature for wind power applications

This paper deals with a new topology for high-temperature Superconducting (HTS) machines. In order to achieve high torque and optimum flux density, an innovative approach is proposed to the invert the entire concept of the rotating parts of a Synchronous machine. Here, it is proposed to rotate the stator of the Synchronous machine and allow the Superconducting coils to remain static. The result will altogether nullify the necessity of the complicated cryo-coolers that normally need to be rotated along with the superconducting windings. Thus, one obtains a simpler machine in terms of construction which still maintains high efficiency because of the use of Superconducting coils. It is proposed that this type of machine may be suitable for offshore wind turbine applications with a geared drive. This, in turn, will reduce the high COE (Cost of Energy)associated with Superconducting machines. A prototype of the proposed concept with 4 Hz frequency has been analyzed through 2D-FEA and provides satisfactory results to go forward with this idea. We intend to optimize the current prototype to obtain a better torque output than the PM machines available at present in the market. The finished system will include a DC to DC converter, slip rings on the line and diode bridge rectifier to produce a power adequate to be fed to the grid. Furthermore, one may be able to integrate a battery storage system and a feedback loop for the power supply to the converters and make this a standalone system for offshore applications. Keeping this in our mind, in this paper, we have emphasized on the analysis and challenges faced in this particular machine prototype.