Research on an Axial Maglev Device With Primary Superconductive Coils for a 1000 MW Hydraulic Generator Set

Abstract

Hydraulic turbogenerators are widely used in hydroelectric power systems. Because of the heavy axial gravitation load of the rotor and main shaft, problems with heat and friction are unavoidable, and will cause mechanical abrasion. To solve these problems, this paper presents a superconducting induction magnetic levitation device for hydraulic generator systems. The induction maglev device has advantages including a simple structure, inherent dynamic stability, large air-gap, and high controllability. Based on the performance of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> superconducting wires, ac superconducting windings are implemented to increase the levitation force. A coreless structure is used to avoid the core saturation. The basic structure and principles are introduced. The ac losses of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> winding are deprived. According to the calculated magnetic field distribution, the ac loss power of the MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> winding is estimated under different currents. In addition, the levitation force and rotation torque are calculated and analyzed under different conditions. All the results show the proposed device is well suited for the deload application of thrust bearings in hydraulic turbogenerators.