BOOST变换器恒功率负载时动态性能分析

Stability and Dynamics of BOOST Converter with Constant Power Load

以恒功率负载时双闭环控制的 BOOST变换器为例 ,基于相平面法 ,分析了变换器开环运行模式下的稳定性问题 ;基于平均大信号模型 ,分析了变换器过载运行模式下的动态响应过程。分析表明 ,恒功率负载时 ,变换器开环运行可能自激振荡 ,并给出判别是否产生自激振荡的方法 ,说明小滤波电感和大滤波电容有利于避免自激振荡 ,从而为变换器主电路参数的优化设计提供依据。过载运行时 ,变换器最终进入开环运行模式 ,稳定性能与开环运行模式下相同。实验结果验证了理论分析的正确性。

The stability and dynamic properties of a multiloop-c on trolled BOOST converter with constant power load are studied. Based on the phase portrait theory, the stability of the converter in open loop operate mode is an alyzed. Results show that self-oscillation may be existed in the system. The de sign oriented method is presented to distinguish self-oscillation or not. The m ethod places design constraints on converter parameters and indicates that small inductor and large capacitor are propitious to avoid self-oscillation. Based o n the averaged large signal model, dynamic response process of the converter in over-loaded operated mode is also analyzed. When the converter is over-loaded, the current loop cannot limit inductor current like the converter with a resist ive load and the converter goes into an open loop operated mode. Finally, the th eoretical analysis is confirmed with experimental results.