Ripple-based matrix modeling and cross-coupling effect analysis of double-input DC-DC Boost converters

This paper deals with the modeling and cross-coupling effect analysis in double-input Boost converters with multiplex current control. A ripple-based multiplex current controlled matrix model is proposed to restore the system’s high-frequency domain dynamics information and resolve the coexistence problem of the sample-and-hold effect in multiplex current controllers, which significantly improves the resolution of the conventional average model. Based on the proposed model, both sub-harmonic and low-frequency oscillations are identified in terms of stability analysis, and the inherent mechanism of these complicated nonlinear dynamic behavior is revealed, which not only illustrates the origin of the oscillations but also points out the dominant factors in diverse types of instability situation. Besides, cross-coupling effect analysis is performed to study the interaction between the input ports with the help of the Gershgorin band, and the mechanism of the special unbalanced oscillation phenomenon is revealed. Furthermore, the sensitivity analysis approach is used to identify the key parameters with respect to the cross-coupling effect, which provides more design-oriented knowledge for practical engineering. In addition, the benefits of the proposed model are further illustrated through a comparative analysis. Finally, these theoretical results are verified by experimental ones. These results are beneficial to the improvement of performance as well as the understanding of the cross-coupling effect of multi-input converters.