【摘要】 悬浮金属转子是机电陀螺仪、力矩球等仪器的核心敏感部件,其温度变化对仪器性能有影响。仪器由冷启动进入热平衡工作状态需要较长时间。研究了一种非接触式主动加热悬浮于真空腔体内的旋转金属转子而不干扰其旋转运动的方法,为缩短这类仪器的启动时间提供了技术途径。金属球形转子可在变化磁场中会产生涡流感应热,但此过程在加热球体的过程中会产生额外力矩。为了对非接触球体加热而不施矩,提出了一种椭圆形旋转磁场,可以在加热过程中不引入力矩。首先通过理论计算证明了这种零施矩感应加热椭圆形旋转磁场的存在;然后,通过3-D有限元模型(FEA)模型验证了理论计算的结果;并设计了一种结构紧凑的两相两极线圈,仿真模型预测了零施矩的可行性;最后制作了实验样机,用半分法调整相位实现零施矩感应加热。零施矩相位角与有限元仿真结果相差1.4?,测试结果进一步验证了理论正确性。更多还原

【Abstract】 A suspending metal rotor is the core component of electromechanical gyroscope, reaction sphere and other instruments, and the temperature of the rotor has an impact on the performance of the instrument. It takes a long time for the instrument to enter thermal equilibrium state from a cold start. A method to contactless heat a spinning metal sphere that suspended inside a vacuum housing without disturbing its motion is studied. When a spinning metal sphere is placed in an alternating magnetic field, eddy current and induction heat is generated on metal sphere as expected, but simultaneously additional disturbing torque is also produced. To inductively heat the metal sphere without applying disturbing torque to change its momentum, an elliptical rotating magnetic field is proposed to heat the sphere with no torque applied during the heating process. Firstly, the existence of the elliptical rotating magnetic field with zero moment applied induction heating is proved by theoretical calculation. Then, a FEA model with Helmholtz coils is modeled and the simulation result perfectly verified the theory. To coincide with the engineering prototype, a compact two-phase two-pole winding with high magnetic permeability is modeled and the simulation results show that the compact design also has null-torque potential by adjusting phase difference between the two alternating magnetic field. Finally, a prototype is designed and built. Null-torque heating is achieved by using dichotomy method to fine-tune the phase angle. The phase angle differs from the finite element simulation result by 1.4 °, and thus verified the theory.更多还原