Topology for current balancer with half‐bridge inverters in single‐phase three‐wire distribution systems with DC‐capacitor‐voltage balancer

Abstract

This paper proposes a new topology for a current balancer with half-bridge inverters in single-phase threewire distribution systems. Two half-bridge inverters are connected to the sources. The midpoint of the two capacitors on the DC-side is connected to a neutral line. The two half-bridge inverters function as a current balancer for single-phase three-wire distribution systems by exchanging the active and reactive power on each feeder through the two DC capacitors. The third leg functions as a DC-capacitor-voltage balancer for two DC capacitors connected to the half-bridge inverters. Thus, balanced source voltages and currents are obtained on the secondary side on the polemounted distribution transformer with balanced DC-capacitor voltages. The basic principle of the proposed current balancer is discussed in detail, and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results show that balanced source voltages and currents are obtained on the secondary side on the polemounted distribution transformer with balanced DC-capacitor voltages.