A robust load-sharing control scheme for parallel-connected multisystems

Parallel connection of inverters or converters is one useful method for solving the high power requirements. However, a load-sharing problem among parallel-connected systems is not an easy task, since crosstalk may take place among the subsystems. We develop a general methodology for solving the load sharing problem using the master-slave concept. In synthesizing the input to the slave system, we utilize system-dynamics-dependent filters. With the proposed method, we can equally distribute the load, or can give a certain offset (in load) to a specific subsystem. To show the usefulness of the proposed control scheme, we perform a simulation study with two practical systems: a current-balancing control in parallel-connected pulsewidth modulation converters and a speed and tension control for a bridle roll system in a steel mill.