Synchronverters can imitate the characteristics of the synchronous generators including the rotor inertia

frequency and voltage regulation

which is helpful in improving the operational performance of the distribution network or microgrid. This paper focuses on the control scheme for synchronverters under non-ideal grid condition. The control model of the synchronverters in time domain is introduced briefly. Then

the impacts of the unbalanced and harmonic grid voltages to the grid current are analyzed. An improved method is proposed to calculate the current reference value based on the double second order generalized integrator

in which the improved grid voltage feed-forward control scheme is adopted to suppress the harmonic and unbalanced components of current affected by non-ideal grid. The basic relationship and the design method between the main parameters of the improved grid voltage feed-forward control strategy for the LC synchronous inverter are derived and analyzed

and a reasonable theoretical explanation is given based on the output impedance characteristics of the synchronous inverters. Finally

both simulation and experimental platform are established

and simulation and experimental results verify the correctness and feasibility of the proposed control scheme.