Control strategies of the multiple-input dc-dc converter

Recently, the clean electric power generation systems have been developed aggressively to exploit the clean energy resources such as solar array, fuel cell and so forth. In this case, the multiple-input dc-dc converter is useful to combine the multiple input power sources and to take the appropriate amount of power from these multiple input power sources, in which their voltage levels and/or their power capacities are different. We have proposed a novel multiple-input dc-dc converter, in which the distinctive feature is its simpler circuit configuration in comparison with that in parallel with the multiple converters. This paper presents two control methods for the two-input dc-dc converter. In the first control method, the on-time of one switch is determined only by the input current and that of another one is controlled by both of the input current and the output voltage. On the other hand, in the second control method, though the on-time of one switch is determined only by the input current as well as in the first control method, the on-time of the another switch is controlled only by the output voltage. The comparative analysis of the steady-state and dynamic characteristics of the two-input dc-dc converter using two control methods are performed theoretically and experimentally. As a result, it is revealed that the first control method is superior to the second one in the steady-state and dynamic performances.