基于自适应全阶观测器的感应电机低速发电运行稳定性

Regenerating-Mode Stabilization of Induction Motors Based on Adaptive Full-Order Observer

速度自适应全阶观测器已经被成功和广泛地应用于感应电机无速度传感器驱动系统,然而许多研究和实践工作都表明,基于自适应全阶观测器的感应电机驱动系统在低速发电运行状态会出现不稳定现象。本文利用自适应控制理论,推导出基于开环全阶磁链观测器的使转速估计值及估计磁链稳定的充分必要条件,并进而给出了在给定转速条件下驱动系统发生不稳定现象的发电性质负载转矩边界值,从理论上阐明了何时会出现不稳定现象的问题。同时基于转矩-转速平面下的驱动系统相关特性分析,提出通过增大磁链幅值,增强驱动系统在低速发电模式下的带载能力,扩大稳定运行范围。仿真和实验结果验证了文中理论分析和提出方法的有效性。

Full-order adaptive observers are successfully and widely applied for the speed- sensorelss induction-motor drives. However, it is well recognized that the rotor speed estimation based on the adaptive full-order observer of induction motor can be unstable in the regenerative region. Based on the open loop full-order adaptive observer, the necessary and sufficient conditions for the stability of the speed estimation and the flux estimation are analytically derived by the adaptive control theory. So it can be indicated that the unstable region will occur in the regenerative mode with large enough regenerative load, and then the question of when and how this instability phenomenon occurs is solved. At the same time, to see the resultant drive performance including the stability on the torque-speed plan, the stability boundary is derived. The instability region in the low speed regenerating mode can be remedied by increasing the flux amplitude within a reasonable range. Simulation and experiment are given to demonstrate the effectives of the proposed method for the adaptive full-order observer to enlarge the operation region of the regenerating mode.