Development of a levitated motor for liquid hydrogen car pumps

将自感知技术应用于主动磁悬浮轴承(AMBS)是非常有前途的。我们小组一直在研究在液氮中工作的主动磁轴承。当在液氮中使用普通AMB时，它们不能很好地工作。由于液氮温度较低，磁悬浮轴承的位移传感器无法工作。为了使用在液氮中工作的位移传感器，必须购买特别开发的非常昂贵的传感器。我们研制了一种用于液氮温度下磁悬浮轴承的位移传感器。在这项研究中，不仅在液氮中对位移传感器进行了评估，而且在空气中也进行了评估。自感知磁悬浮轴承由一个转子(轴)、一对带有四个电磁铁的磁悬浮轴承和一个驱动电机组成。转子由磁悬浮轴承的一对铁件组成，直径24毫米，长160毫米，重量0.37公斤。驱动电机是一台PM型摩托车…More r由一个带有永磁体(PM)的转子、四个用于驱动的电磁铁和用于检测旋转角度的霍尔传感器组成。电机在没有任何机械接触的情况下旋转，自感知传感器的原理是基于差动变压器。磁悬浮轴承有四个线圈的上部和下部电磁铁。上端电磁铁的两个初级线圈由脉宽调制放大器激励。感应电压被引导到两个次级线圈，用于传感位移。结果表明，在液氮温度范围内，输出电压与转子垂直位移呈线性关系，位移范围为-0.3~0.3 mm。研究了电磁轴承的冲激响应。结果表明，在冲击响应中观察到了衰减的自由振动曲线。振动曲线似乎呈指数递减。从这些结果来看，自感知磁悬浮轴承对抑制转子振动是有用的--即使在低温环境中也是如此。较少

Applying self-sensing technique to active magnetic bearings (AMBs) is very promising. Our group has been studying active magnetic bearings working in liquid nitrogen. When normal AMBs are used in liquid nitrogen, they do not work well. The displacement sensors for the AMBs do not work due to the low temperature of liquid nitrogen. In order to use displacement sensors working in liquid nitrogen, very expensive sensors which are especially developed would have to be bought. We have developed a displacement sensor for the AMBs used at the temperature of liquid nitrogen. In this study, the displacement sensors are evaluated not only in liquid nitrogen, but also in air. Dynamics of the self-sensing AMBs are also discussed.The self-sensing AMBs consist of a rotor (shaft), a pair of AMBs with four electromagnets, and a driving motor. The rotor consisted of a pair of iron parts for the AMBs, and measures 24 mm in diameter, 160 mm long and 0.37 kg in weight. The driving motor was a PM-type moto … More r which consisted of a rotor with permanent magnet (PM), Four electromagnets for driving, and Hall sensors for detecting the rotation angle. The motor spun without any mechanical contacts.The principle of the self-sensing sensors is based on a differential transformer. The AMB has upper and lower electromagnets with four coils. Two primary coils of the upper electromagnet are excited by the PWM amplifiers. The induced voltage is led to the two secondary coils for sensing displacements. From the results, the relationship between output voltage and vertical rotor displacement at liquid nitrogen temperature is linear in the displacement range from -0.3 to 0.3 mm.The dynamics of the self-sensing AMBs were studied. Impulse responses for the AMBs were investigated. As a result, damped free-vibration curves are observed in impulse responses. The vibration curves seem to decrease exponentially. From these results, the self-sensing AMBs are useful for suppressing the rotor vibrations - even in the low temperature environment. Less