A constant DC-capacitor voltage control based strategy for current balancer in single-phase three-wire distribution systems

This paper proposes a constant dc-capacitor voltage control based strategy for a current balancer in single-phase three-wire distribution systems. The proposed control strategy only uses the constant dc-capacitor voltage control block commonly used in active power conditioners to calculate the compensation current. No calculation blocks to obtain the reactive and unbalanced-active components are necessary. Thus, we provide the simplest possible control strategy for the current balancer. The basic principle of the proposed control method is discussed in detail then its validity is confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that balanced source currents with a power factor of unity are obtained on the secondary side of a pole-mounted distribution transformer while retaining unbalanced load current conditions with a lagging power factor.