Application of coupled inductors in parallel inverter system

The difference of amplitude and phase between each module´s output voltage can cause large loop-current among modules in parallel inverter system. Individual inductor connected between the inverter´s output terminal and the load can restrain loop-current well with the disadvantage of reducing steady-state voltage accuracy of parallel system. Aiming at this problem, a new loop-current restraining method based on coupled inductors is proposed in this paper. Design principle of coupled inductors in parallel inverter system with two or more modules is also discussed. Simulation and experimental results in a 6 kVA two-module parallel inverter system prove that coupled inductors are better than individual one on the performance of restraining loop-current and have no impact on the steady-state voltage accuracy of parallel inverter system.