Current distribution control for parallel connected converters. I

For pt.II, see ibid., vol.28, no.3, p.841-851 (1992). A master-slave control scheme for a uniform current distribution among converter modules in a parallel connected system is presented. In this technique, inner current loops are introduced to the system to achieve output current equalization. The current distribution error is used as a criterion for judging system performance. Using this control scheme, the current distribution error can be reduced greatly even with nonidentical converters in the system. To optimize system efficiency and facilitate the fault-tolerant algorithm realization, this technique is refined so that only the necessary number of converters are activated for different load conditions