电网不平衡下基于MMC的分数阶积分滑模控制策略研究

为增强模块化多电平换流器(modular multilevel converter,MMC)在电网不平衡条件下的系统性能,该文提出一种分数阶积分滑模控制(fractional order integral sliding mode control,FO‐I‐SMC)策略。首先,分析MMC的拓扑结构,并推导出正、负序电压与输出电流的基频外特性方程和正负零序环流的二倍频内特性方程。其次,结合控制目标和MMC的数学模型,设计出应用于电网电压不平衡的分数阶滑模控制器。该控制器旨在降低交流侧输出电流与直流侧环流谐波含量。最后,在MATLAB/Simulink仿真平台建立相应模型,验证该算法的有效性。研究结果证明:采用FO‐I‐SMC控制策略的MMC的系统性能要明显优于采用比例积分(proportional integral,PI)控制策略和积分滑模控制(integral sliding mode control,ISMC)策略的。

水下机械手分数阶积分滑模轨迹跟踪控制方法研究

针对未知有界外部干扰下水下机械手的轨迹跟踪问题,提出了一种分数阶积分滑模控制方法。该方法采用了基于分数阶积分滑模面的指数趋近律,考虑外部扰动,在模型中添加了外部扰动的近似估计项,使得系统可以实现快速收敛,且具有较强的抗干扰能力。利用李雅普诺夫理论证明了该方法的稳定性。对六自由度水下机械手的跟踪问题进行了仿真,结果表明,该控制方法具有良好的轨迹跟踪能力,且对外部干扰表现出良好的鲁棒性。

基于非线性扰动观测器的PMLSM自适应反推分数阶积分滑模控制

为提高永磁直线同步电机(PMLSM)伺服系统的位置跟踪精度,克服其易受外部扰动、参数变化、摩擦力等不确定因素影响的问题,本文提出了一种基于非线性扰动观测器(NDO)的自适应反推分数阶积分滑模(ABFOSMC)控制方法.首先,对PMLSM建立动态数学模型.其次,针对PMLSM的非线性特性,采用反推控制设计虚拟控制函数,实现系统位置的精准跟踪,并结合分数阶积分滑模控制方法增强系统的鲁棒性.最后,引入NDO估计系统不确定性,将观测结果动态补偿到ABFOSMC中,有效降低不确定性因素对系统伺服性能的影响,提高位置跟踪精度.实验结果显示,所提出的方法切实可行,有效提高了系统鲁棒性能和跟踪性能.

不确定分数阶PMSM混沌系统自适应滑模控制

针对参数不确定分数阶永磁同步电机混沌系统,研究在含非线性不确定项和外部扰动情况下的控制问题。结合自适应控制理论和滑模控制理论,通过选取一种具有较强鲁棒性的分数阶积分滑模面,设计自适应滑模控制器。该控制器可在参数不确定项、非线性不确定项和外部扰动的上界未知的情况下,实现局部渐进稳定。数值仿真结果验证了该控制器的有效性。

基于FOISMC+ESO的PMSM调速系统控制策略研究

针对永磁同步电机炮控系统存在时变、非线性、强耦合等特征,结合分数阶微积分及滑模变结构理论,提出了一种新型分数阶积分滑模控制策略。为解决传统趋近律收敛时间过长和滑模控制的抖振等问题,提出了一种具有快速收敛的新型双幂次趋近律,并给出了收敛时间证明。鉴于炮控系统负载变化大且扰动无法正确测量的问题,结合扩张状态观测器理论,设计了一种基于扩张观测器的扰动补偿方法,将扰动观测量以前馈的形式引入控制器以提高控制系统的鲁棒性。数值仿真实验结果表明了该控制策略的有效性。

Fractional order integral sliding mode control for PMSM based onfractional order sliding mode observer

In view of the variation of system parameters and external load disturbance affecting the high-performance control of permanent magnet synchronous motor(PMSM),a fractional order integral sliding mode control(FOISMC)strategy is developed for PMSM drive system by means of fractional order sliding mode observer(FOSMO).Based on FOISMC technology,a fractional order integral sliding mode regulator(FOISM-based regulator)is designed,and a global integral sliding mode surface design method is presented,which can guarantee the global robustness of the system.Combining fractional order theory and sliding mode control theory,the FOSMO is constructed to achieve better identification accuracy of the speed and rotor position.Meanwhile the sliding mode load observer is used to observe the load torque in real time,and the observed value is transmitted to speed regulator to improve the capability of accommodating the challenge of load disturbance.Simulation results validate the feasibility and effectiveness of the proposed scheme.

Iterative sliding mode control strategy of robotic arm based on fractional calculus

In order to improve the control performance of industrial robotic arms,an efficient fractional-order iterative sliding mode control method is proposed by combining fractional calculus theory with iterative learning control and sliding mode control.In the design process of the controller,fractional approaching law and fractional sliding mode control theories are used to introduce fractional calculus into iterative sliding mode control,and Lyapunov theory is used to analyze the system stability.Then taking a two-joint robotic arm as an example,the proposed control strategy is verified by MATLAB simulation.The simulation experiments show that the fractional-order iterative sliding mode control strategy can effectively improve the tracking speed and tracking accuracy of the joint,reduce the tracking error,have strong robustness and effectively suppress the chattering phenomenon of sliding mode control.