永磁直线同步电机(PMLSM)预测电流控制(PCC)时存在易受参数变化和延迟以及负载扰动影响,为此提出基于二阶超螺旋滑模观测器(STSMO)的改进型PCC.首先,建立包含不确定性的PMLSM动态数学模型.然后,为了补偿参数变化以及延迟的影响,采用二阶STSMO估计下一周期的电流和参数变化造成的扰动电压,估计值用以计算下一周期的给定电压,以提高电流跟踪精确度,通过李雅普诺夫函数证明观测器的稳定性.同时,采用基于改进指数趋近律的自适应滑模控制器(ASMC)对速度进行跟踪,将状态变量和滑模面加入到指数趋近律中,不仅削弱了电流抖振,且进一步提升了系统的鲁棒性.半实物仿真实验结果表明,与传统PCC相比,提出方法能有效地抑制不确定性对系统影响,使系统具有更好的跟踪性能和鲁棒性.
Aiming at the problem that predictive current control(PCC)of permanent magnet linear syn-chronous motor(PMLSM)is susceptible to parameter change,delay and load disturbance,an improved PCC based on second-order super twisting sliding mode observer(STSMO)was proposed.Firstly,a dy-namic mathematical model of PMLSM with uncertainty was established.Then,in order to compensate for the influence of parameter change and delay,STSMO was used to estimate the current in the next cycle and the disturbance voltage caused by parameter changes.The estimated value was used to calculate the reference voltage in the next cycle to improve the current tracking accuracy,the stability of the observer was proved by Lyapunov function.At the same time,the adaptive sliding mode controller(ASMC)based on the improved exponential reaching law was used to track the speed.By adding the state variables and sliding mode surface to the exponential reaching law,the current chattering is not only weakened,but al-so the robustness of the system is further improved.The results of hardware in the loop simulation experi-ment show that,compared with traditional PCC,the proposed method can effectively suppress the influ-ence of uncertainty on the system,and make the system have better tracking performance and robustness.