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| Diagnosis of process oscillation based on closed-loop testing |
| CHEN Shao-mian1, ZHAO Jun1, ZHU Yu-cai2, QIAN Ji-xin1 |
1. Institute of Industrial Control, Zhejiang University, Hangzhou 310027, China;
2. Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB, Netherlands |
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Abstract A method based on closed-loop testing principle was presented to diagnose the root cause of the oscillation so as to remove the disturbances aiming at the phenomena of plant-wide oscillation caused by a loop with valve friction, which propagates disturbances throughout many loops due to coupling relationships. Extra testing signal was injected to calculate the excited signal which had the same waveform as original oscillating signal but with inverse phase, and the excited signal was added to the closed-loop to detect whether the oscillation was effectively restrained or not. Then the method can distinguish the self-oscillation generated by interior non-linear modules from the oscillatory loops caused by outer disturbances. The root cause of the plant-wide oscillation can be detected by removing all the oscillatory loops caused by external source. Experimental results show that the method can exactly isolate the source of oscillation.
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Published: 03 March 2011
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基于闭环测试的过程振荡诊断方法
针对一个回路由于自身阀门黏滞产生的振荡会传播到多个与之相关联的回路,从而引起工厂级的振荡这一现象,提出一种基于闭环测试原理来诊断过程系统振荡的起源以消除振荡的方法.通过叠加额外的测试信号计算与该回路原振荡信号波形相同、相位反相的激励信号,将该激励信号加入到闭环回路中以检测该回路的振荡是否被有效地抑制,从而能够辨别出由外部扰动造成的回路振荡和由内部非线性环节造成的自激振荡.通过排除所有由外部源造成的振荡回路,可以确定造成大范围回路振荡的源头.实验仿真结果表明,该方法能够准确地诊断出振荡源.
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