A circuit for combining direct current (DC) power including multiple direct current (DC) voltage inputs; multiple inductive elements connected in a series circuit having first and second end terminals and intermediate terminals. The inductive elements are adapted for operatively connecting respectively to the DC voltage inputs at the first and second end terminals and intermediate terminals. Multiple switches connect respectively with the inductive elements. A controller is configured to switch the switches periodically so that direct currents flowing through the inductive elements are substantially zero. A direct current voltage output is connected across one of the DC voltage inputs and a common reference to both the inputs and the output.