Brushless Exciter Based on Nanomaterials for 1 MVA HTSC Wind Power Alternator

The paper is devoted to testing of a brushless exciter intended for a 1 MVA high-temperature superconductive (HTSC) synchronous generator. It was decided to make a ambient-temperature version on the 1-st stage with a latter transaction to a cryogenically-cooled version. The exciter incorporates a number of nanomaterials: rare-earth Nd-Fe-B magnets and magnetic cores, manufactured of amorphous alloy tape.

Effects of Cu/Ba Ratio in Precursor on MOCVD-Deposited YBa2Cu3O7-x Films on YYC Buffered Ni-W Alloy Tape

To study the effects of Cu/Ba ratio of precursor on YBa2Cu3O7-x (YBCO) film, we have employed the technique of metal-organic chemical vapor deposition to prepare 500 nm thick YBCO films on CeO2/YSZ/Y2O3 (YYC) buffered Ni-W alloy tapes at series of Cu/Ba ratios of precursor. The analysis obtained from X-ray diffraction and scanning electron microscope revealed that the YBCO films crystallized better and became more continuous and denser as Cu/Ba ratio increased from 0.81 to 1.00, yielding that the critical current density (Jc) of YBCO films at 77K and 0T rose from 1.0 MA/cm2 to 1.4 MA/cm2. Moreover, the energy dispersive spectroscopy indicated that the increase in Cu/Ba ratio of precursor made the Cu/Ba ratio of the YBCO film matrix closer to the theoretical value of 1.5. However, for the Cu/Ba ratio of precursor in the range of 1.00~1.21, the crystallization and texture deteriorated severely and many unexpected precipitates of Ba-Cu-O and Cu-O arose, resulting in the dramatic drop of Jc from 1.4 MA/cm2 to 0.1 MA/cm2.