前馈型电压模式控制Buck变换器

摘要

A control scheme applied to Buck converter is proposed based on voltage-mode proportional control, which takes the integral of input voltage and capacitor current samples as the dynamic carrier signal of PWM( Pulse Width Modulation), adopts the input voltage feed-forward to ensure zero steady error of system under proportional control and the excellent capability against input voltage disturbance, and applies the capacitor current feedback to improve the capability against load fluctuation. The control performances of system are analyzed based on the small signal model and the control parameters are optimized. The overall control structure is simple and the parameter design is convenient. The correctness of theoretical analysis is verified by both the simulative and experimental results.%在比例控制电压模式结构基础上,结合Buck变换器给出了一种新的控制方式,将输入电压与电容电流采样之和的积分作为PWM环节的动态载波信号,输入电压的前馈确保了比例控制下系统的稳态无差以及良好的抗输入电压扰动能力,电容电流反馈则改善了系统抗负载跳变能力.然后基于系统小信号模型,理论分析了系统的控制性能,并给出了控制参数的选取.整个控制结构简单,参数设计简便,最后仿真和实验结果验证了理论分析的正确性.