在三级式交流发电系统中一般使用传统PID控制器进行调压控制，但是在某些工况下该控制策略难以满足复杂系统的高精度、快响应要求。通过在传统PID控制器的基础上，分析了其不足之处，引入了模糊PID控制策略。同时,针对模糊PID在系统的动态调节过程中论域过小的问题，提出了一种基于变论域模糊控制理论的PID控制器，并与传统双环PID控制和普通的模糊PID控制在MATLAB/Simulink软件中进行对比仿真，验证了该控制策略具有更好的稳态调节精度和动态调节性能，与传统双环PID控制器相比，稳态误差从0.5%优化到0.3%，动态调节时间从0.4 s缩短至0.2 s。

Although traditional PID controller is generally used for voltage regulation control in the three-stage AC power generation system, this control strategy cannot meet the requirements of high precision and fast response of complex system in some cases. Based on the analysis on the shortcomings of traditional PID controller, the fuzzy PID control strategy is introduced. There is a problem that the domain of fuzzy PID is too small in the process of dynamic regulation of the system. In order to solve this problem, a PID controller based on the theory of variable universe fuzzy control is proposed. It is compared with the traditional double-loop PID controller and the common fuzzy PID controller on MATLAB/Simulink platform. Simulation results show that the proposed control strategy has better steady-state regulation accuracy and dynamic regulation performance. Compared with the traditional double-loop PID controller, the steady-state error is improved from 0.5% to 0.3%, and the dynamic regulation time is shortened from 0.4 s to 0.2 s.