A Current Balancer in Single-Phase Three-Wire Distribution System

The single-phase three-wire distribution system is employed extensively in Japan and the several countries. It has two voltage sources, which are in phase and have the same effective values. Numerous loads are connected to this distribution system. System line currents from two sources tend to be out of balance, because consumers make use of these loads at random. If many working loads lean to a one-sided source, the power interruption will occur by the operation of circuit breakers. For preventing the above trouble, we propose a novel Current Balancer. It consists of two half-bridge converters composed of an ac reactor and two bidirectional switching devices in common with a neutral line and two dc capacitors. In this paper, it is made clear that the proposed system can equalize both source currents even if the load currents are unbalanced. Moreover, we discuss the several characteristics in steady state and transient state by simulations and experiments.