A feedforward control based power decoupling scheme for voltage-controlled grid-tied inverters

Voltage-controlled inverters have been widely used in distributed generation due to their flexibility and smooth transition between grid-connected and islanded modes. However, in the grid-tied mode, the inherent coupling between active and reactive power will challenge the independent control of active power and reactive power, and therefore deteriorate system performance. To deal with this issue, this paper proposes a feedforward control based power decoupling scheme for voltage-controlled grid-tied inverters. A phase angle feedforward and a magnitude feedforward are introduced separately to the active power control loop and reactive power control loop, adjusting the output phase angle and magnitude to address the coupling problem. The feedforward phase angle and magnitude are regulated in every control cycle according to the power equation to cancel the coupling precisely. The effectiveness of the proposed decoupling scheme has been validated by simulation and experimental results.