Study of Photovoltaic Three-Phase Grid-Connected Inverter Based on the Grid Voltage-Oriented Control

In this paper, the topology and the control scheme of the photovoltaic three-phase grid connected inverter based on voltage-oriented control ( VOC) is analyzed. In VOC, a current control loop is used. The currents are controlled in a synchronous rotating dq-frame using a decoupled feedback control. The reference current of d-axis controller is extracted from instruction which comes from the former system. Furthermore, in order to achieve a unity power factor, the q-axis reference is set to zero. And the modeling and the simulation of the system based on Matlab/Simulink environment are presented too. The experimental prototype has also been constructed. The simulation and experiment verifies that the scheme can work well, the current controller can improve the dynamic quality of the system and can help to realize the non steady-state error for tracking the instruction.