An advanced-time-sharing switching strategy for multiple-input buck converters

Multiple-input converter (MIC), which has higher efficiency, less component count, lower cost and simpler control method, is a promising candidate for energy harvesting in hybrid systems, and for power distribution in micro and nano grids. The principle of the proposed advanced-timesharing switching (ATSS) strategy is that the effective duty ratio of each switch is an integer multiple of a common duty ratio (CDR). CDR is the duty ratio of a common-switching-function (CSF) generated at a higher frequency by frequency division. ATSS transforms the original MIC into an equivalent single-input single-output system, simplifying system analysis, control design and implementation, where CDR is the only control variable for output voltage regulation. Additionally, multiplied by a regulation coefficient a, the fixed CDRs can become the control variables for current limitation, which releases the degree of freedom. By using this technique, smooth and accurate limitation to sources´ current is able to be implemented without loss of output-voltage-regulation convenience. Its corresponding circuit modeling, small-signal analysis, controller design, and performance tests have been put forward.