摘要
多数自动控制理论教科书在叙述正频率情况下的 Nyquist 稳定判据时没有讲清使用条件,容易造成混乱。本文中讨论了正频率下 Nyquist 图或 Bode 图中 Nyquist 稳定判据的使用条件,指出只有最小相位系统才能使用这种形式的稳定判据,并作了相应证明。给出了一个非最小相位系统的反例。
The applicable condition of Nyquist stability criterion described in the Nyquist diagram or Bode diagram under positive frequency is discussed,because the fact that the applicable condition using Nyquist stability criterion in some textbook of automatic control theory is not clear.It is presented that Nyquist criterion of this form can only be used in minimum phase system.A counter example of non-mini- mum phase system is provided.
关键词
频率特性函数
最小相位系统
frequency characteristic function
Nyquist stability criterion
minimum phase system
