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In this paper, a novel radial hybrid magnetic bearing is proposed, which is driven by an AC 3-phase power converter, and biased magnetic fluxes are provided by an axial magnetized permanent magnet ring. Based on the introduction of the configuration and principle of the radial AC hybrid magnetic bearing (AC HMB), the methods in parameter design and design results for the prototype are presented. The parameter design results for the prototype of the radial AC HMB are simulated by 3D electromagnetic finite element method and the simulation results show that the obtained parameter is reasonable. The manufactured prototype applying to the parameter is operated and the test results also show that the design result for the prototype is available, and the AC HMB has good dynamic and static performance.

We investigate the influence of grain size on mechanical properties in a Fe-9Ni-12Mn-2.5Si-1.0C TWIP steel by unidirectional tensile. Meanwhile the microstructures of the TWIP steel were observed and analyzed by optical microscope (OM) and transmission electron microscope (TEM). The experimental results show that the TWIP steel’s yield strength and tensile strength decrease with the increasing of grain size, whereas the plasticity increases with it. When the average grain size reaches to 27μm, the tensile strength is 1080MPa, the elongation percentage is 77%, and the strength-plasticity product achieves the 83160MPa•%. Steel’s strain hardening rate can be changed from three-stage to four-stage with the increasing of grain sizes, the areas of strain hardening by twin deformation mechanism are expanded. Through the microstructure observation we found that, coarse-grained TWIP steel conducts to twinning formation, the high density twins can increase the alloy’s ductility by splitting the grain.

A dynamic decoupling control method based on neural network inverse system theory is developed for the 5 degrees of freedom (5-DOF) rotor system. The rotor system suspended by AC hybrid magnetic bearings (HMBs) is a multivariable, nonlinear and strong coupled system. Firstly, the configuration of 5-DOF HMBs and the mathematical equations of suspension forces are set up. Secondly, it is demonstrated the system is reversible by analyzing mathematical model. On the basis, the neural network inverse system which is composed of the static neural networks and integrators, and original system are in series to constitute pseudo linear systems. Finally, linear system theory is applied to these linearization subsystems for designing close-loop controllers. The simulation results show that this kind of control strategy can realize dynamic decoupling control, and control system obtains good dynamic and static performances.