In hybrid power system (HPS), there are many inverter-based generators (IBGs) that inject renewable energy into the system as electrical power. Transient stability analysis of HPS in which synchronous generators (SGs) are operated in parallel with IBGs is necessary to operate the network safely under large disturbances. This paper examines the transient behaviour of IBGs with effective strategies, in which constraint on output current of IBGs is strictly considered to bring the results closer to reality. The control strategy is based on reference model tracking and substitution theory for networks, including parallel SG-IBGs to full IBGs. First, for a network with full IBGs, a constant power model reference is proposed as a static model. Then a dynamic reference model called saturated full model of virtual synchronous generator (VSG) or simply SFMVSG is introduced as the final solution for the controller of IBG in HPS. The SFMVSG has all existing VSG features and provides virtual damping torque created by the interaction of virtual damping fluxes. The simulation results confirm that the study is efficient.