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| 摘要: |
| 通过对趋近律形式的离散变结构控制律的研究,提出了一种具有准滑动模态切换带宽衰减的离散变结构趋近律,并指出准滑动模态切换带宽衰减的条件是切换函数进入准滑动模态.通过设计时变的到达速度指数,使其按约束条件取值,再利用离散趋近律方法求出切换带衰减的指数趋近律离散变结构控制律,当切换函数一旦进入准滑动模态,其穿越切换面的幅度将递减地趋近于零,从而消除抖振,且衰减系数越小,到达切换面的速度越快.该控制律的数学形式简单,易于实现,克服了离散变结构控制的稳态抖振现象.将切换带宽衰减的趋近律应用到离散变结构控制的设计中,并针对电力系统的频率控制问题,设计了离散变结构控制器.计算机仿真结果显示该控制器能显著改善系统的动态性能,提高控制精度,并使系统具有很强的鲁棒性. |
| 关键词: 离散系统 变结构控制 电力系统 准滑动模态 |
| DOI： |
| 分类号:TP273 |
| 基金项目: |
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| Load-frequency controller based on discrete variable structure control theory |
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MENG Guangwei YAO Qionghui LI Huaishu
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| Abstract: |
| Based on theoretical analysis,a discrete-time variable structure reaching law with attenuating quasi-sliding mode band is proposed,and its condition is given:the switching function reaches quasi-sliding mode band. Variable exponential rate fitting the restriction conditions is designed,based on it,a discrete-time variable structure control law with exponential reaching rate is obtained using discrete-time reaching law. Once the switching function reaches quasi-sliding mode band,the width of quasi-sliding mode band will approach zero to eliminate system chattering. The less the attenuated coefficient is,the quicker the speed is. The control law is simple in math structure and easy in implementation. A load - frequency controller is designed by applying the discrete reaching law with attenuating quasi-sliding mode band to power system. Simulation results show that it improves system dynamic performance and control precision effectively,and enhances system robustness. |
| Key words: discrete-time system,variable structure control,power system,quasi-sliding mode |
