脉冲跨周期调制连续导电模式Buck变换器低频波动现象研究  

Low-frequency oscillation of continuous conduction mode buck converter with pulse skipped modulation

作　　者：钟曙[1] 沙金[1] 许建平[1] 许丽君 周国华[1] 

机构地区：[1]磁浮技术与磁浮列车教育部重点实验室,西南交通大学电气工程学院,成都610031

出　　处：《物理学报》2014年第19期364-372,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51177140;61371033);四川省青年科技基金(2013JQ0033);中央高校基本科研业务费专项资金(批准号:2682013ZT20)资助的课题~~

摘　　要：揭示了脉冲跨周期调制(pulse skipped modulation,PSM)电感电流连续导电模式(continuous conduction mode,CCM)Buck变换器中存在的低频波动现象,分析了PSM调制CCM Buck变换器的能量转换过程,阐述了低频波动的产生机理,给出了低频波动的判断条件.建立了PSM调制CCM Buck变换器的同步开关映射模型,基于该模型给出了电感电流与输出电压随输出电容等效串联电阻(equivalent series resistance,ESR)变化的分岔图,分析了ESR对低频波动的影响.为消除PSM调制CCM Buck中存在的低频波动,提出了电容电流脉冲跨周期调制(capacitor current pulse skipped modulation,CC-PSM)方法.研究结果表明:在ESR较小时,CC-PSM调制CCM Buck变换器消除了PSM调制CCM Buck变换器存在的低频波动.仿真与实验结果验证了理论分析的正确性.Low-frequency oscillation phenomenon in pulse skipped modulation（PSM） buck converter operating in continuous conduction mode（CCM） is reported in this paper. Energy transfer difference between the PSM-controlled buck converter operating in discontinuous conduction mode（DCM） and that in CCM is studied. The mechanism of low-frequency phenomenon in PSM-controlled CCM buck converter is revealed, and a discrete-time model of PSM-controlled buck converter operating in CCM is established. Based on this model, the border collision bifurcation with variations of the ESR is studied; meanwhile, the inhibition effect of output capacitor equivalent series resistance（ESR） on low-frequency oscillation is presented. Based on the above analysis, a capacitor current pulse skipped modulation（CC-PSM） technology is proposed; the energy transfer principle of CC-PSM controlled buck converter is analyzed. The control pulse of CCPSM is generated by the comparison between the sampled capacitor current and preset peak reference current, and thus the range of inductor current ripple is limited. Results show that CC-PSM effectively eliminates the low-frequency oscillation in CCM buck converter under classical PSM when the ESR is low. Finally, the experimental results validate the correctness of theory and simulation analysis

关 键 词：开关变换器 脉冲跨周期调制 低频波动 边界碰撞分岔 

分 类 号：TM46[电气工程—电器]