According to the diversity of control structure and complexity of modeling methods of power electronics devices in distributed generation system， a universal structure of control system for power electronics devices is proposed. The control system is composed of outer and inner loop controller modules. Both controller modules contain mode switches. By changing the state of mode switches， power control， voltage control， droop control and constant voltage/frequency control can be realized with outer-loop controller， while current control can be achieved with inner-loop controller. The universal model can represent a specific kind of control system structure and control strategy for various power electronic power devices， which are suitable for simulation software development of distributed generation system based on object-oriented modeling.