On the issues of harmonics, reactive and unbalanced current at point of common coupling, the system use a grid-connection control structure of Three-phase photovoltaic system with power quality regulation function. Then the converter can inject power into the distribution grid and perform as shunt active power filter (APF). So it can improve the power quality and decrease the hardware investment. In addition, it gives an algorithm with no phase-locked loop, and designs a grid-current tracker with current weighted. In the end, this new structure and the control concept was demonstrated with extensive PSCAD simulation studies.