电流型双脉冲跨周期调制Buck变换器研究

摘要

提出一种断续导电模式(Discontinuous Conduction Mode,DCM)Buck变换器的电流型双脉冲跨周期调制(Dual Pulse Skipping Modulation,DPSM)技术.与电压型DPSM技术比较,电流型DPSM技术采用双环控制技术,检测电感电流以产生具有不同占空比的控制脉冲,克服电压型DPSM开关DC-DC变换器无法检测电感电流的问题,有效防止启动过程中电感电流过冲现象发生.以DCM Buck变换器为例说明电流型DPSM技术的原理和输出电压纹波与脉冲组合之间的关系.运用动力学分析方法建立电流型DPSM DCM Buck变换器的离散时间模型,得出高功率脉冲、低功率脉冲以及跨周期脉冲的组合规律.最后,给出仿真和实验结果,表明有着良好瞬态性能的电流型DPSM Buck变换器低输出电压纹波与较宽的负载可调范围等优点.%Current-mode dual pulse skipping modulation(DPSM) technique for buck converter operating in discontinuous conduction mode(DCM) is proposed.Comparing with the voltage-mode DPSM technique,the current-mode DPSM technique adopts double closed-loops control technique and the inductor current is detected to generate control pulses with different duty ratios,which overcomes the question that the inductor current in voltage-mode DPSM switching dc-dc converter can not be detected,effectively preventing the overshoot phenomenon of the inductor current to happen in the process of start-up.Buck converter operating in DCM is taken as an example to explain the principle of the current-mode DPSM technique and the relationships between the pulse combination and the output voltage ripple.By using the dynamical analysis method,the discrete time model of current-mode DPSM DCM buck converter is established,and the combination laws of high power control pulse,low power control pulse and skipped control pulse are concluded.Finally,the results by simulations and experiments are presented to indicate that current-mode DPSM buck converter,with favorable transient performance,has much lower output voltage ripple,much wider load adjustable range and so on.