This paper discusses the integration of a three-phase Distributed generation (DG) into a grid-tied Photovoltaic (PV) system. A single-stage power conversion system comprising a Current Source Inverter (CSI) capable of dc voltage boost is proposed for this PV MIC system, to control which, a multivariable- proportional- integral (PI) regulator-based power control strategy is designed. It will control the proposed CSI-based MIC system through structural simplicity and fast dynamic response. When contrasted with the conventional PI methods, the proposed control scheme grants a fully decoupled axes in terms of step jumps and falls in the active and reactive power commands. By controlling the modulation index and the angle introduced by the Phasor PWM (PPWM) switching patterns, the active and reactive powers are demonstrated to be obtained and exchanged between the PV MIC and the grid. An experimental verification is provided to justify the performance of the proposed control method through a 300-VA laboratory prototype, and the results are compared with that of the conventional PI regulation approaches.