中文摘要：

对于单输出电容应用情形，已有文献报道了恒定导通时间（COT）控制Buck变换器的稳定性分析方法，且给出了输出电容时间常数或者等效串联电阻（ESR）的稳定性判据。然而对于复合输出电容应用情形，COT控制Buck变换器的时域分析相当复杂，动力学建模过于繁琐，难以给出相应的稳定性判据来有效指导工程实践。针对工程实践中两种常见的复合输出电容并联使用情况，在此提出一种新颖的COT控制Buck变换器复阻抗等效分析法，其核心思想是将复合输出电容电路经过简化计算，等效变换成单输出电容电路。基于该等效分析法．导出单输出电容的等效电路参数．并通过具体例子进行PSIM电路仿真和实验电路测量。仿真和实验结果验证了复阻抗等效分析法的有效性。

英文摘要：

For the single type output capacitor application case of constant on-time （COT） controlled Buck converter, the stability analysis method has reported in literatures and the stability criterion for the time constant or the equivalent series resistance （ESR） of the output capacitor has given.However, for the combined output capacitor application case of COT controlled Buck converter, the time-domain analysis is quite complex and the dynamical modeling is unduly tedious, which is difficult to provide corresponding stability criterion for effectively guiding engineering practices. Aiming for two common parallel usages of the combined output capacitors in engineering practices, a novel complex impedance equivalent analysis approach to COT controlled buck converter is proposed, whose core idea is that the combined output capacitors circuit is equivalently transformed into the single type output capacitor circuit via simplified calculation.Based on this equivalent analysis approach,the equivalent circuit parameters of the single type output capacitor are derived, and PSIM circuit simulations and experimental circuit measurements are performed by a specific example.The simulation and experimental results of verify the validity of the complex impedance equivalent analysis approach.