Control Scheme of Grid-Connected Inverter Based on Virtual Circuit

Main control objectives of grid-connected inverters include making the current injected into the grid keep accordance to its setting value without deviation, minimizing the harmonic current injected into the grid, and providing the system with good stability. To take all these indicators into account, this paper proposes a virtual circuit structure control scheme for grid-connected inverters. Aiming at designing the structure of circuit directly, we combine the variation of parameters into the design of circuit structure, which enables we achieve the control objectives in an indirect way. Simulation and experiment verified that the designed grid-connected inverter can enable the steady-state error to be zero, restrain harmonic current, and maintain good stability.