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

近年来，无轴承传动的发展在世界上许多地方都在进行。无轴承驱动器是具有自磁悬浮的电动机或发电机。因此，人们越来越期望广泛的应用，如真空，低温或高温条件，恶劣环境，长寿命和高可靠性的机器。实际上，在人工心脏血液泵、化工厂的罐装泵、半导体加工、生物工程中的生物反应器、太空卫星中的望远镜定位等领域都可以看到广泛的发展。在当今广泛应用于电机驱动的感应电机中，日本公司和瑞士集团与制造商和大学一起制造了原型无轴承电机。研究者们对感应式无轴承电机进行了大量的研究。以额定负载转矩悬挂旋转轴的控制方法已经变得显而易见。然而，存在可能的触摸问题 关于我们 在本研究中，仅在过载和瞬态条件下观察到磁悬浮的短时间不稳定运行。在加速试验期间，比较了两个通量信号。一种是搜索线圈磁链，它是通过连接到搜索线圈积分器。另一种是感应电机速度反馈回路中滑差频率型矢量控制器产生的磁通参考信号。结果表明，在一段暂态过程中，这两种磁链信号的相位角并不对应。另外，由于两垂直轴上存在径向力干涉，如果相位角不对应，径向定位环的相位裕度会显著减小。在高加速度下，磁悬浮是成功的，最佳磁场方向随转子温度的变化而变化。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