System stability refers to a certain stable state exhibited by the system elements under external influences. Its meaning roughly falls into the following three categories: (1) Various changes such as external temperature, mechanical changes, and others will not significantly affect the state of the system. (2) If a system deviates from its normal state due to some interference, and when the interference is eliminated, it can return to its normal state, then the system is stable; conversely, if the system once deviates from its normal state and cannot return to the normal state anymore, and the deviation becomes larger and larger, then the system is unstable. (3) There is an overall trend that the system automatically occurs or is prone to occur. If a system can automatically tend towards a certain state, it can be said that this state is more stable than the original state.