Analysis and evaluation of current-sharing control for parallel-connected DC-DC converters taking into account cable resistance

Paralleling of power converters has become increasingly important due to increased utilization of multiple power converters in high-power and distributed system applications. The paper presents a better current-sharing control technique for parallel-connected converters, known as central-limit control, as an improvement over the master-slave control. The limitations of the master-slave control technique are discussed and a few central-limit control topology variations are analyzed. It is shown in the paper that stable operation of current-sharing control depends not only on the method of current-sharing control, but also on converter output cable resistance. By selecting suitable converter output cable resistance, adequate phase margin for stable operation of paralleled converters can be achieved under all load conditions