Photovoltaic power systems (PV systems) are increased. Most of PV systems are controlled with keeping high power factor because the output power ratio to power system capacity is sufficiently small. Recently, single phase PV systems are placed increasingly. They possibly cause an imbalance of three phase voltages and currents. This paper proposes a linkage method for single phase PV systems in order to compensate the imbalance. An estimation of imbalance is introduced based on instantaneous real and imaginary power theory. It is confirmed that the proposed control strategy achieves to minimize the estimation of imbalance theoretically and experimentally.