平均电流控制型Boost功率因数校正变换器中的中频振荡现象分析

基于输入电压可用其有效值代替以及电感电流与输出电压的波动频率远低于变换器开关频率的假设，建立了用于描述平均电流控制型Boost PFC变换器动力学行为的小信号模型，研究了该变换器中的中频振荡现象问题，揭示了系统发生中频振荡现象的内在物理机理，并给出了系统发生中频振荡现象的参数边界.研究结果表明，该非线性现象不同于已发现的快尺度不稳定性现象和慢尺度不稳定性现象，其主要特征是其振荡频率介于交流输入电压线频率和开关频率之间.最后，电路实验结果证实了理论分析的正确性. 关键词： 中频振荡 平均电流控制 Boost功率因数校正变换器 小信号模型

Analysis of medium-frequency oscillation in the Boost power factor correction converter with average current mode control

On the assumption that the input voltage can be replaced by its RMS value and the frequencies of the inductor current and the output voltage are much lower than the switching frequency of the converter, the small-signal model of Boost PFC converter is constructed and the medium-frequency oscillation in Boost PFC converter is studied. The underlying mechanism of this nonlinear phenomenon is analyzed and the stability conditions are also given. These obtained results indicate that this type of nonlinear phenomenon is different from the fast- and slow-scale instabilities, and the main characteristic of this type of nonlinear phenomena is that its oscillation frequency lies between the line frequency and the switching frequency. Finally, an experimental circuit is designed, and its experimental results agree very well with the simulation results.