A high-speed shaft supported by magnetic bearings applied to energy systems

Abstract

This paper presents the construction of a mechanical shaft supported by active magnetic bearings (AMB), reproducing a prototype of a turbogenerator. In turbogenerators, the shaft is supported by two radial and one axial magnetic bearings. At the center of the shaft was inserted a rotor of an induction machine, which will operate as motor as well as generator, and at the shaft extremity is coupled a small turbine. The mechanical modeling and assembly are presented in detail. After that the control system of the AMB is introduced. The high-speed AMB-supported shaft reduces the length of the system as well as losses and increases the system efficiency. The validation of the high-speed shaft supported by AMB allows the energy generation, in the future, provided by the asynchronous generator mounted upon the shaft. Prime mover, such as gas, will be considered to provide the mechanical power. Finally, for injecting the energy into the grid, an indirect field-oriented control (IFOC) was used for high performance of the generator side. On the grid side, the voltage-oriented control (VOC) is applied to guarantee the high quality of the current injected into the grid.