DC/DC功率变换器是一种强非线性系统,传统的PID控制算法简单,设计容易,但依赖于其线性化小信号模型,且当功率变换器的参数发生变化时,其参数不能兼顾动态性能和静态性能,影响最终的控制效果.针对传统PID控制器的不足,结合模糊控制不需要建立被控对象精确数学模型的特点,以Buck变换器为例,提出一种新的模糊控制和PID控制相结合的方法.当输出的偏差范围较大时,采用模糊控制提高其动态响应速度;反之,切换到PID控制以提高其稳态精度.最后利用MATLAB对系统进行仿真验证.仿真结果表明:模糊-PID复合控制器具有响应速度快、超调量小、稳定性好等优点.
DC/DC power converter is a kind of strongly nonlinear system. The design of traditional PID controller is based on precise linearization model, known for its simple algorithm and easy design. When the parameters of the power converter change, they can do well in dynamic performance and static performance, which affect the final control effect. Taking the Buck converter as an example, a fuzzy-PID controller was proposed to address the above disadvantages while the fuzzy control doesn't need the establishment of accurate mathematical model of controlled object. The fuzzy control was used at large error to improve the dynamic response speed. On the other hand, the PID control was switched to improve the steady-state accuracy. The converter was verified in the Matlab software and the simulation results showed that the proposed fuzzy-PID controller has good characteristics including faster response, smaller overshoots and better stability.