一种采用高频电流前馈补偿的Boost变换器系统稳定方法

A Stability Method Using High-frequency Current Feed-forward Compensation for Boost Converter Systems

在开关电源变换器设计中,经常会在功率输入端加入滤波器。输入滤波器可以减小或消除电磁干扰,消除变换器输入电流波形的开关谐波,还可用于在给定电压瞬间,保护变换器及其负载免受冲击而损坏,从而提高系统的可靠性。但是输入滤波器改变了系统的动态性能,与具有负阻抗特性的恒功率负载级联时,会造成系统的不稳定甚至可能产生谐振。该文提出了一种基于输入滤波器谐振频率处的高频电流前馈补偿技术,能够在不改变系统体积重量和原有控制结构的前提下,抑制系统的振荡和波形畸变。为了在振荡发生时能够保证电路正常工作,提出了一种具有冗余结构的Boost变换器拓扑。首先对系统的数学模型进行分析,然后给出仿真及实验结果,证明了所提控制策略与拓扑结构的正确性和可行性。

In the design of switching power converters, the filter is often added to the power input terminal. The input filt can not only reduce or eliminate electromagnetic interference and eliminate the switching harmonics of the input current of the converter, but also protect the converter and the load from being impacted when the voltage steps instantaneously. So it can improve the reliability of the system. But the input filter changes the dynamic performance of the. system. When it is cascaded with a constant power load, it will cause the instability of the system and may even produce resonance. In this paper, a high-frequency current feed-forward compensation technique based on the resonant frequeficy of the input filter is proposed. It can suppress the oscillation and the waveform distortion of the system without changing the volume weight of the system and the original control structure. In order to guarantee the normal operation of the circuit, a Boost converter with a redundancy structure is presented in this paper. Firstly, the mathematical model of the system was analyzed. Furthermore, the simulation and experimental results were given to prove the correctness and feasibility of the proposed control strategy and topology structure.