Boost-flyback converter: Experimental assessment of recent control techniques

The boost-flyback converter is a type of DC-DC power converter that allows for efficient step-up voltage conversion. Despite its potential for achieving high voltage gains, there is a lack of comprehensive analysis and practical implementation of reliable control methods for this converter. To date, only a few control techniques have been thoroughly examined and, more importantly, validated on hardware for this specific converter. In this paper, a comprehensive evaluation of two control techniques is presented, namely, zero average surface (ZAS) and hysteresis band (HB) control, for the boost-flyback converter. Insights into the performance of these techniques and their applicability in real-world scenarios are provided by experimental investigation. Experimental results have shown that the ZAS controller, while promising in theory, requires the inclusion of a secondary feed-forward control loop to achieve accurate regulation of the output and effective disturbance rejection. This finding has highlighted the sensitivity of the ZAS control to measurement noise and the importance of careful consideration when implementing it in hardware. By providing a detailed comparison and insights into the performance of these control techniques, this study contributes to the advancement of control strategies for the boost-flyback converter and guides future research in this field. In this study, we experimentally validate two control techniques for boost-flyback converters: Hysteresis Band and Zero Average Surface (ZAS). The top left panel illustrates the analog circuit scheme of Hysteresis Band control, while bottom left panel showcases the ZAS digital control circuitry. The right panel provides a photograph of the implementation of both controllers. Our results not only demonstrate the effective voltage regulation achieved by both techniques but also underscore the remarkable alignment with the detailed nonlinear theoretical models of these controllers. Hysteresis Band control exhibits superior disturbance rejection and boasts straightforward circuitry. In contrast, ZAS control offers the advantage of fixed-frequency switching but necessitates the incorporation of a secondary control loop to enhance stability. This research sheds light on the unique strengths and trade-offs of these control strategies, offering valuable insights for optimizing boost-flyback converter designs. image