后缘调制Buck变换器的周期借用数字电流控制

Digital cycle-borrowing current mode control for buck converters with trailing-edge modulation

为了解决数字电流控制环路的硬件处理速度与带宽之间的矛盾,提出了基于后缘调制Buck变换器的周期借用数字电流控制方法,实现了传统延迟电流控制的硬件速度要求和无拍差电流控制的环路带宽。针对谷值、平均值和峰值电流控制目标,建立了电流控制律,研究了次谐振荡现象及其消除方法,分析了周期借用数字电流控制的Buck变换器鲁棒性。仿真结果表明,周期借用数字电流控制和无拍差电流控制的Buck变换器具有相同的瞬态性能,并且优于延迟电流控制。

To solve the contradiction between processing speed of hardware in the feedback and loop bandwidth for the digital current mode control, digital cycle-borrowing current mode control is proposed for buck converters with trailing-edge modulation. The proposed control is the same as delayed current control for the requirement of hardware processing speed and the same as deadbeat current control for loop bandwidth, so the above contradiction is solved. Current mode control laws were derived for valley, aver- age and peak current control, sub-harmonic oscillation and its eliminated method was researched, and ro- bustness of buck converters was discussed under the proposed current mode control. Simulation results show that the transient performance of buck converters under cycle-borrowing current mode control is the same as that of deadbeat control and better than that of delay current mode control.