Stability Analysis of a Peak and Deep Current Mode Buck-Boost Converter

In this converter, the problem of interference between buck and boost switches operations are solved by determining four operation modes. The average modeling method is used to obtain a model for the low frequency behavior of the converter. Stability analysis is performed by the root-locus method, which reveals that the current loop causes that the converter acts as single pole system due to the great distance between two poles’. The model also applied for control design. The experimental results on an 110V, 40KW converter show the ability of the proposed control method. The line and load regulation in different situation is below than 0.9%.

Keywords:

Buck , Boost , Current Mode Control , Average model , root locus