面向永磁同步电机负载转矩观测的自抗扰改进滑模控制

Improved Sliding Mode Control with Disturbance Rejection for Load Torque Observation of Permanent Magnet Synchronous Motors

针对传统永磁同步电机滑模控制中存在的滑模抖振大及响应速度慢的问题,设计了一种新型趋近律,在传统指数趋近律的基础上加入可变比例系数并引入系统状态变量和滑模面的幂次项,减小抖振的同时提高了趋近速率。随后,为了避免引入转速误差的微分项,减小系统高频抖振,采用积分滑模面,设计了永磁同步电机改进滑模速度控制器。针对控制策略中负载扰动波动会导致系统控制精度降低、抖振增大的问题,设计了一种基于新型饱和函数的扩张状态观测器估计负载扰动,并将扰动估计值前馈至改进滑模控制器中,进一步提高了系统的抗扰性能。数值仿真结果表明:所提出的控制策略可显著提高电机动态性能和抗扰性。在电机受负载转矩波动影响时,比PI控制电机超调量减小约23.1%,响应速度提高62.5%,比传统滑模控制电机超调量减小约15.3%,响应速度提高50%。新型滑模趋近律还可以有效降低滑模抖振,与传统滑模控制器相比,采用改进滑模控制器电机抖振降低约50%。

To address issues like large chattering and slow response in traditional sliding mode control of permanent magnet synchronous motors(PMSMs),a new type of reaching law is designed.This approach incorporates a conventional exponential reaching law with an adaptable proportionality coefficient,system state variables,and the power term of the sliding mode surface to mitigate chattering while enhancing convergence speed.To avoid introducing differential terms of speed error and reduce high-frequency chattering in the system,an integral sliding mode surface is used to design an improved PMSM speed controller.To address the issue of reduced control accuracy and increased chattering in the control system caused by load disturbance fluctuations,a novel saturation function-based extended state observer(ESO)is devised.This ESO is utilized to estimate the load disturbance and the estimated disturbance value is fed forward to the improved sliding mode controller to further enhance the system’s disturbance rejection capability.The numerical simulation results demonstrate that the proposed control strategy substantially improves the dynamic performance and disturbance rejection of the motor.When the motor is affected by load torque fluctuations,compared to PI control,the proposed control strategy reduces overshoot by about 23.1%and increases response speed by 62.5%.Compared to traditional sliding mode control,the proposed control strategy reduces overshoot by about 15.3%and increases response speed by 50%.The new sliding mode reaching law can effectively reduce sliding mode chattering.Compared to traditional sliding mode controllers,the improved sliding mode controller reduces motor chattering by about 50%.