A Study on Applying Interleaved Switching Pattern on a Double-Input/Single-Output Zeta Converter

This paper presents behavior of a double-input/single-output (DISO) zeta converter by applying interleaved switching pattern in continuous conduction mode (CCM). This converter is implemented by combining two H-bridge cells and a conventional zeta converter, based on DISO buck-boost topologies. The converter can be utilized in either step-down or step-up modes. By adopting the interleaved switching pattern, a delay time is generated between gate pulses of H-bridge cells transistors. As a result, the converter output voltage can be varied by changing the delay time while the pulse duty cycles are kept constant. Moreover, the output voltage ripple, which is depended on the duty cycles is also kept constant. According to the chosen duty cycles and delay time, the converter can operate either in step-up or step-down modes. The output voltage ripple value of the proposed converter is less than that of both buck-boost converters, and the output voltage polarity is positive as opposed to DISO buck-boost converter. As the input filter inductor is placed in a parallel branch, adding several numbers of H-bridge cells in series as the input stage of zeta converter is very easy and does not need any changes in the formation of the converter components, which is a great advantage of utilizing zeta converter in comparison to cuk and SEPIC. Steady state analyses and calculations are done, and the proposed converter is simulated in both step-up and step-down modes.