基于离散指数趋近律的开关电源模糊滑模控制

对于Buck/Boost变换器,传统的控制器如PID控制器、Ⅲ型误差放大器等存在超调量过大、响应时间过长、鲁棒性不强等问题,为克服这些缺点,提出基于离散指数趋近律的开关电源模糊滑模控制方案.首先,针对工作在电感电流连续模式(CCM)的Buck/Boost变换器采用状态空间平均法建立平均线性模型;然后设计离散指数趋近律的滑模控制器,并分析了切换参数对系统的影响;最后,为改善控制效果,设计了模糊控制器.仿真结果表明,相对于传统的控制器,指数趋近律的模糊滑模控制器有效地降低了超调量,提高了系统的响应时间,并且对外部干扰的鲁棒性较好.利用所设计的控制算法实现了对50 W高频开关电源样机的良好控制,进一步证明了所提方法的有效性.

Fuzzy Sliding Mode Control of Switching Power Supply Based on Discrete Exponential Reaching Law

In order to solve the problems of bigger overshoot,longer response time and weaker robustness in traditional controllers such as PID controller and type III error amplifier for Buck/Boost converter,a fuzzy sliding mode control strategy based on discrete exponential reaching law(DERL) is proposed for switching power supply.Firstly,the averaged linear model based on state-space averaging method is built for the Buck/Boost converter in continuous inductive current mode.Then the sliding mode controller based on DERL is designed and the influence of switching function parameters on the system is analyzed.Finally,a fuzzy controller is added to improve the control effect.The simulation result shows that compared to traditional controller,the proposed controller is better in overshoot,response time and robustness to external disturbance.The good control to 50 W high-frequency switching power supply is realized by the proposed control algorithm,which further proves the effectiveness of the proposed method.