Modeling and controlling of zero sequence current in directly paralleled 3-phase 4-wire inverter

For high power grid connected devices with power quality compensation function, directly paralleled 3-phase 4-wire inverter is the most simple configuration to chose, but the zero sequence current is always a big problem that have to deal. This paper established the phase-leg averaging model of this type system, developed the dynamic model of zero sequence current, then indroduced a simple method under carrier-based SPWM, which can fully control the zero sequence current in the system, and verified by simulaiton and experimental results.