This paper proposes a new configuration to improve stability of an integrated wind/PV power generation system connected to a synchronous generator (SG)-based power system. Different renewable-energy power sources can be connected to the proposed common DC bus to constitute a flexible power-system configuration. The proposed control scheme uses a DC-to-AC inverter joined with a proportional-integral-derivative (PID) damping controller to contribute adequate damping characteristics to the dominant modes of the studied system under various operating conditions. A frequency-domain approach based on a linearized system model and a time-domain scheme based on a nonlinear system model subject to disturbances are systematically performed to examine the effectiveness of the proposed control scheme.