DC bus voltage stability improvement using disturbance observer feedforward control

The constant power load (CPL) property of a load converter with tight control results in DC bus voltage oscillations in interconnected power converter systems. In this paper, a disturbance observer (DOB) feedforward compensation scheme is proposed to stabilize the DC bus voltage of a cascaded power converter. An equivalent DC link voltage control model and a disturbance observer are used to reconstruct the dynamic changes of the DC bus current to correct the inner current loop reference of the load converter. Simulation and experimental results show that the proposed method is effective in stabilizing the DC bus voltage.