Prototype of SC Inverter

At first a function of physical unit “half pair” including superconducting (SC) elements is described. By combining their plural units, a circuit is constructed, which has essential ability for the inverter action. In practice, the YBCO thin films were used for elements of two half-pairs, which connected with the metallic load Z of R_Z = 50 μΩ. AC magnetic field between 0.1 and 100 Hz was applied in order to transfer mutual elements from SC state to resistive one. The AC current of 50 Hz was observed on the load Z and its amplitude was I_Z,max = 1.0 A when the source DC current of I_o = 32 A was applied. Thus the efficiency became 2.8% in this case. When the frequency was 0.2 Hz, the efficiency became 14%. The main reason of the present low efficiency is owing to the resistance of SC elements. I_z,max increased remarkably when the I_o increased beyond the critical current of SC elements. The inverter action has been reproduced by the computer simulation under the non-linear conditions on the VI characteristics. The conditions giving high inverter efficiency was made clear. Thus the present results gave clear evidence of SC inverter action.