Modelling and current control of parallel-connected multiple inverter systems

A mathematical model which governs a parallel-connected multiple inverter system is described The multiple inverter system is controlled to feed required amounts of active and reactive currents to a utility grid, while suppressing the cross currents flowing among the parallel-connected unit inverters. An optimal regulator is applied to create a robust feedback control system having multiinput and multioutput signals. Validity of the proposed modelling and control method is confirmed by simulation studies.