This paper presented an expandable grid-connected power quality compensator with distribution generation interface for three-phase three-wire system. The proposed system not only can control the active power flow, but also mitigate load unbalance, harmonics, and manage reactive power. The power quality compensator can simultaneously perform the two functions of power control station and active power filter or either one. To make the system more flexible, the grid current, instead of output current of the converter, is shaped to be a sinusoidal current in phase with the grid voltage. The refere...