Improved control strategy based on splitting-capacitor for grid-connected inverter

As a single current feedback method, the WAC (Weighted-Average Control) strategy achieves low distortion of the current with less steady-state error, and it also avoids the capacitance design problems that exist in traditional method based on splitting-capacitor. But the WAC strategy is limited to the interference from grid and an neglected resonant frequency. In this paper, an active damping method is used to improve the grid-connected current quality and restrain the resonance of system while degrading the control system. In addition, a grid voltage feed-forward control strategy is proposed to resist the grid disturbance which can not only change the control transfer function, but also have a negative effect on active damping method. Effectiveness and feasibility of the proposed strategy are verified by the simulation results.