Ripple-Response Modeling and Design-Oriented Analysis of Output Common Power Flow Regulation in Bipolar SIDO DC-DC Converters

Compared with unipolar single-inductor dual-output (SIDO) dc-dc converters, the output common power flow in the bipolar SIDO dc-dc converters affects lots of system characteristics in high-frequency (HF) region, which poses great challenges for the modeling and design of the bipolar SIDO converters. In this article, a ripple-response model of the bipolar SIDO dc-dc converter is proposed to capture the HF characteristics by analyzing the response nature and the sampling process of the multi-piecewise current ripple. Based on the derived model, the design-oriented analysis with the change of some key parameters is presented to guide the system optimal design and power flow regulation. Then, the compensators are optimized to improve the dynamical performance and the HF stability simultaneously. Furthermore, the cross-regulation of the SIDO converter is explored via the common- and differential-mode transfer functions. Particularly, the effect of the output common power flow on the cross-regulation is revealed by identifying the frequency-domain coupling point. These analysis results help to suppress the cross-regulation significantly. Finally, the effectiveness of the model and analysis is verified by experimental results. These results show that the proposed method is more suitable for the bipolar SIDO converters to improve power flow regulation in comparison with the existing ones.