Current and voltage control of paralleled multi-module inverter systems

Power inverters are used to acquire an ac output voltage from a dc power supply. The parallel connection of inverters results in several advantages, like improvement of the system reliability and increasing of the power capacity. The control problem for parallel-connected inverters is proper voltage regulation and equal current distribution. In this paper, a characteristic loci based compensator (Approximate commutative compensator) is used to obtain design objectives. In order to compare results, Hæ and LQG/LTR controllers, are also implemented on parallel inverters. Simulation results of the single-module, two-module and three-module inverter systems with different kinds of loads and parametric uncertainties, have demonstrated the feasibility of the proposed control scheme in proper voltage regulation and equal current distribution.