Dual Current Control Loops for Three-Phase Four-Leg Grid-Connected Inverter using Complex-Vector Form

Three-phase four-leg inverter is the widely utilized energy conversion structure for power quality control, voltage/reactive power supporting and power transmission. This paper proposes dual current control loops for three-phase four-leg grid-connected inverter using complex-vector form to optimize the control calculation and realize zero steady-state error and fast regulation in the grid conditions with unbalance and harmonics. The dual current control loops are the control loops for phase abc and phase N respectively. The dual current control loops adopt the unified complex-vector form inputs. The multi complex vector resonant controllers are used to realize fast zero steady-state error control. And the regulation effect of the proposed control method and the correctness of the analysis are verified through current control simulation.