Developments of stable controller in induction type bearingless drives under transient conditions.

近年来，无轴承传动的发展正在世界上几个地区发生。无轴承传动装置是带有自磁悬浮的电机或发电机。因此，人们对真空、低温或高温条件、恶劣环境、长寿命和高可靠性机器等广泛应用的期望越来越高。事实上，在人造心脏血泵、化工厂的屏蔽泵、半导体工艺、生物工程中的生物反应堆、太空卫星中的望远镜定位等方面都可以看到广泛的发展。在今天广泛使用的电机驱动应用中，感应电机由一家日本公司和瑞士的制造商和大学集团制造的无轴承电机原型。研究人员在感应型无轴承电机方面做了值得注意的研究。提出了一种以额定负载扭矩悬挂转轴的控制方法。然而，可能存在触摸…的问题在扭矩载荷快速变化、加减速较大的情况下，轴向下较多。在本研究中，磁悬浮的短期不稳定运行仅在过载和暂态条件下出现。在加速试验中，对两种磁通信号进行了比较。一种是搜索线圈磁链，它通过连接到搜索线圈的积分器来获得。另一种是由转差频率型矢量控制器在感应电机速度反馈回路中产生的磁链参考信号。研究发现，这两种磁通信号的相角在一个暂态周期内并不对应。另外，由于在两个垂直轴上存在径向力干扰，如果相位角不对应，径向定位回路的相位裕度会显著减小。在高加速时成功悬架。研究还表明，最佳磁场取向随转子温度的变化而变化。较少

In recent years, developments of bearingless drives are undergoing several parts of the world. The bearingless drives are the electric motors or generators with self-magnetic suspensions. Thus, there is increasing expectation of wide range of applications such as vacuum, low or high temperature conditions, harsh environments, long life and highly reliable machines. In fact, extensive developments can be seen in artificial heart blood pumps, canned pumps in chemical plants, semiconductor processes, bio reactors in bio engineering, telescope positioning in space satellites.In induction motors, used in wide ranges of today's motor drive applications, prototype bearingless motors are built by a Japanese company and Switzerland groups with manufactures and university. The investigators have been done notable research in induction type bearingless motors. A control method to suspend a rotation shaft at rated load torque has been made obvious. However, there exist a possible problem of touch … More down of the shaft during fast change in torque load, high acceleration and decelerations.In this research, a short time unstable operation of magnetic suspension is seen only at overloaded and transient conditions. During the acceleration tests, two flux signals have been compared. One is search coil flux linkage, which is obtained through integrators connected to search coils. The other is flux reference signal generated by slip-frequency type vector controllers in an induction motor speed feedback loop. It is found that phase angle of these two flux signals are not corresponding in a period of transient conditions. In addition, phase margin of the radial positioning loops is significantly decreased if the phase angle is not corresponding because there exist radial force interference in two-perpendicular axesTo solve the problem, a new orientation method to the air-gap flux is proposed. Successful suspension during high acceleration is found. It is also shown that the optimal field orientation varies in accordance with rotor temperature. Less