Boost变换器的能量传输模式及输出纹波电压分析

分析了Boost变换器在开关关断期间的能量传输模式，根据流经电感的最小电流与输出电流的比较，将其分为完全电感供能模式（CISM）和不完全电感供能模式（IISM），得出了CISM和IISM的临界电感和临界条件。指出工作在连续导电模式（CCM）的Boost变换器，既可能工作在CISM也可能工作在IISM；而在不连续导电模式（DCM）的Boost变换器，必定工作在IISM。指出对于给定负载、电容和开关频率的Boost DC-DC变换器，CCM-CISM模式的输出纹波电压最小且与电感无关；CCM-IISM模式的输出纹波电压较大且随电感减小而增大；DCM模式的输出纹波电压最大且亦随电感减小而增大；CISM和IISM的临界电感即为使得变换器的输出纹波电压最低的最小电感。文中给出了实例，并用实验结果验证了理论分析的正确性。

Energy Transmission Modes and Output Ripple Voltage of Boost Converters

Energy Transmission Modes(ETM)during the period of switch turned off of Boost converters are analyzed. Comparing the minimum current through the inductor with the output current, ETM can be divided into two types, i.e., the Complete Inductor Supply Mode(CISM)and the Incomplete Inductor Supply Mod(eIISM). The critical inductor and critical condition are deduced. It is pointed out that a Boost converter in Continuous Conduction Mode(CCM)may work in CISM or IISM while that in Discontinuous Conduction Mode (DCM)must be in IISM. As for Boost converters with certain load, output capacitor and switching frequency, some important conclusions are drawn. The converter in CCM-CISM has the smallest output ripple voltage independent of the inductance. The converter in CCM-IISM has rather larger output ripple voltage that is decreasing with the inductance. The one in DCM has the largest output ripple voltage that is also decreasing with the inductance. The minimum inductance to guarantee the lowest output ripple voltage is the critical inductance of CISM and IISM. The experiment results are in positive to the analysis results showing the feasibility of the proposed methods.