Boost变换器的输出纹波电压分析与最小电感设计

Output Ripple Voltage of Boost Converter and Design of Its Minimal Inductance

为了便于Boost变换器的小型化、集成化设计以及满足本质安全的要求,根据电感电流最小值的差别,将其分为完全电感供能模式(CISM)、不完全电感供能且连续导电模式(IISM-CCM)和不完全电感供能且不连续导电模式(IISM-DCM).对3种模式的输出纹波电压进行了分析,得出了最大输出纹波电压.指出在给定的工作范围内,最小负载电阻和最低输入电压所对应的CISM和IISM的临界电感,即为使得最大输出纹波电压最低的最小电感,且最大输出纹波电压的极小值与电感无关.实验结果表明:当最小电感接近理论值278μH时,最大输出纹波电压取得极小值;当电感大于该值时,输出纹波电压保持不变;当电感小于该值时,输出纹波电压随电感的减小而增加.实验结果验证了理论分析的正确性.

For the miniaturization and integration of Boost converter and for the requirements of intrinsic safety, the converter is divided into three operating modes according to the minimum inductor-current, i. e. , the complete inductor supply mode （CISM）, the incomplete inductor supply mode with continuous conduction mode （IISM-CCM）, and the incomplete inductor supply mode with discontinuous conduction mode （IISM-DCM）. The output ripple voltage （ORV） in each mode is analyzed respectively, and the maximum value of ORV （MORV） is obtained for the three modes. It is concluded that the minimal inductance to guarantee the MORV to get the minimum is the critical inductance between CISM and IISM in the case of the lowest input voltage and the minimum load resistance, and that the lowest MORV is independent of the inductance. The experiments show that the MORV reaches the minimum when the inductance is approximately the theoretical value of 278 uH. The MORV keeps constant when the inductance is larger, and it increases with the decrement of inductance when the inductance is less than 278 uH. The experimental results verify the feasibility of the proposed methods.