In this paper, Z-Source (ZS) four-leg inverter equipped with a Model Predictive Control (MPC) strategy for standalone Photovoltaic (PV) system under various load conditions is presented. The inverter is aimed to supply simultaneously three-phase and single-phase AC loads with balanced voltage and constant frequency. In this topology, a simple LC (Z) network is used instead of the boost converter to obtain single stage power conversion system. The MPC scheme is developed to control output currents of the inverter and ZS network current and voltage. Hardware-In-The-Loop (HIL) tests have been performed to verify steady-state and transient performances of the proposed system under balance/unbalanced load and/or reference current conditions.