不同负载条件下DICM Cuk PFC变换器稳定性分析

Stability Analysis of DICM Cuk PFC Converter under Different Load Condition

重点分析了系统负载变化时,不连续电感电流模式Cuk功率因数校正PFC(power factor correction)变换器稳定性的变化情况。在变换器工作特性的基础上,根据谐波平衡法和Floquet理论分析,研究结果表明:当负载电阻变小时,即系统由轻载到重载变化时,系统发生了工频频率上的倍周期分岔。给出了系统发生倍周期分岔时的电阻,以及在输出电感、输入电压产生改变时和负载电阻共同构成的系统不稳定与稳定的边界区域图,基于输入电感电流-输出电压的相轨图和输出电压的谐波分析谱,更好地观察到系统的动力学行为。最后通过实验验证了理论分析的正确性。

The stability of a Cuk power factor correction(PFC)converter in discontinuous inductive current mode is analyzed in detail when the system load changes.Based on the working characteristics of the PFC converter and according to the harmonic balance method and Floquet theoretical analysis,results show that when the load resistance becomes smaller(i.e.,the light load is changed to heavy load),a period-doubling bifurcation of power frequency will occur in the sys-tem.The resistance value is given when the system undergoes the period-doubling bifurcation.At the same time,the system’s unstable and stable boundary regions which are composed of load resistance,output inductance and input voltage are also given when the output inductance and input voltage change.In addition,based on the phase orbit diagram of input inductor current-output voltage and the harmonic analysis spectrum of output voltage,the dynamic behavior of the system can be better observed.Finally,the theoretical analysis was verified by experimental results.