基于离散指数趋近律的开关电源模糊滑模控制

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

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。

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 con- verter 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 con- troller 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.