I^2控制Buck变换器稳定性的研究

Study on the Stability of I^2 Controlled Buck Converter

研究了电感电流检测电阻对电流模式控制开关变换器稳定性的改善作用。以I2控制Buck变换器为例,建立了含有输出电容等效串联电阻ESR(equivalent series resistance)的二阶离散迭代映射模型。在此基础上,通过分析输出电容时间常数和电感电流检测电阻变化时的分岔图、特征根轨迹、最大Lyapunov指数、稳定边界,深入研究了电感电流检测电阻对变换器动力学特征的影响。研究结果表明,增大电感电流检测电阻,可以使变换器在较小输出电容时间常数时稳定工作,拓宽稳定工作范围。最后,通过仿真和实验,验证了理论分析的正确性。研究结果可以推广到其他开关变换器,对开关变换器的设计和优化具有指导意义。

In this paper, the improvement effect of the sensing resistance of inductance current in a current-mode controlled switching converter is investigated. An I^2 controlled Buck converter is taken as an example, and the second-order discrete iterative map model including the output capacitance equivalent series resistance(ESR) is established. On this basis, by analyzing the bifurcation diagrams, trajectories of eigenvalues, maximum Lyapunov exponent, and stable boundary with the variation of output capacitance time constant and the sensing resistance of inductance current, the effect of the sensing resistance of inductance current on the dynamic characteristics of the converter is studied. Research indicates that increasing the sensing resistance of inductance current can make the converter with a smaller output capacitance time constant operate in a stable state and broaden the range of stable operation. Finally, the theoretical analysis was verified by simulation and experimental results. The results of this paper can be generalized to other switching converters, providing guidance for their design and optimization.