基于等效传递函数匹配的非侵入电容电流检测电路的设计与应用

Design and Application of the Non-invasive Capacitor Current Sensing Circuit Based on Transfer Function Matching

结合一类简化的非侵入式电容电流检测结构,提出了检测和被测支路二者的等效传递函数近似相匹配的设计思路,给出了参数设计条件并验证了其非侵入检测特性。以Buck变换器的电容电流检测为例,应用所提检测电路构建了电容电流滞环控制电路方案。稳态实验结果表明所提采样电路能够实现电解电容电流的高精度检测,负载的动态实验结果表明所构建滞环控制具有快速负载动态调节能力。

This paper discusses a simplified non-invasive current sensing circuit for an electrolytic capacitor. With a matching of the two transfer functions respectively for the sensing and sensed capacitor branches, the sensing circuit parameters are determined under non-invasive working condition. With an application of the proposed sensing circuit scheme to a capacitor-current based hysteretic controlled Buck converter, accuracy sensing for capacitor currents are achieved, as shown in the steady-state experimental waveforms. Furthermore, load transition experimental results verify the superiority of the proposed hysteretic control scheme.