基于改进型降阶观测器的永磁直驱伺服电动机转矩扰动抑制策略

Torque Disturbance Suppression Strategy of Permanent Magnet Direct Drive Servo Motor Based on Improved Reduced Order Observer

由于永磁直驱电机的直驱特性,电机转速平稳性受转矩扰动影响大,低速运行时受齿槽转矩影响,电机转速波动剧烈。该文分析传统比例积分速度控制方法无法兼顾跟踪性能和抗扰性能的缺点。为此引入传统降阶状态观测器,对转矩扰动进行估计和前馈补偿;分析系统扰动转矩到真实转矩之间传递函数的伯德图及锯齿波响应,根据零极点对消原则对传递函数进行期望设计,引入微分环节对传统降阶观测器进行改进,给出改进观测器的锯齿波响应并证明其补偿响应速度的提升,提出基于引入微分模块的降阶观测器前馈补偿方法。搭建永磁直驱伺服电动机扰动抑制实验平台,通过仿真和实验验证改进的降阶观测器对补偿谐振的抑制具有良好性能,且抗扰动能力更强,实现较大扰动低速下的稳定运行。

Due to the direct drive characteristics of the permanent magnet direct drive motor, the stability of the motor speed is greatly affected by torque disturbance, and the motor speed fluctuates violently affected by the cogging torque when running at low speed. This paper analyzes the disadvantage that the traditional proportional-integral speed control method cannot take into account both the tracking performance and the anti-disturbance performance. To this end, a traditional reduced-order state observer is introduced to estimate and feedforward the torque disturbance. The Bode plot and sawtooth wave response of the transfer function between the system disturbance torque and the real torque are analyzed, and the zero-pole cancellation is performed. Based on the principle,the transfer function is expected to be designed, and the differential unit is introduced to improve the traditional reduced-order observer. The sawtooth wave response of the improved observer is given and the improvement of the compensation response speed is demonstrated. A feedforward compensation method is proposed. An experimental platform for perturbation suppression of permanent magnet direct drive servo motor is built. Simulation and experiments verify that the improved reduced-order observer has good performance in suppressing compensation resonance, and has strong anti-disturbance ability,which can achieve stable operation under large disturbance and low speed.