Discontinuous Conduction Mode Analysis of Two-Phase Interleaved Buck Converter With Inversely Coupled Inductor

Abstract

This study comprehensively analyzes the discontinuous conduction mode (DCM) of a two-phase interleaved buck converter (IBC) with an inversely coupled inductor (ICL). With ICL, nine circuit configurations are possible when the IBC operates in the DCM. Depending on the duty ratio and load condition, DCM can also be classified into seven types. Each type of DCM has a corresponding combination of circuit configurations. Consequently, the application of the combinations for distinguishing DCM types is proposed to analyze the DCM operation of two-phase IBCs with ICL. Different DCM types have different DCM characteristics, such as state space averaged models and time interval calculations, which are needed to be analyzed for small-signal modeling. Therefore, the state space averaged models and time intervals equations are derived for each DCM type, and boundary conditions between adjacent DCM types are analyzed. Experimental tests on the hardware prototype of the IBC are conducted to verify the practical effectiveness of the proposed analysis.

Keywords

• Buck converter
• coupled inductor
• discontinuous conduction mode
• interleaved
• time interval
• voltage gain