Coupled inductors for parallel operation of interleaved three-phase voltage source grid-connected inverters

In this paper, coupled inductors for parallel operation of interleaved three-phase voltage source grid-connected inverters are introduced. When DC-link capacitors of each inverter are shared and interleaving method is employed, more severe circulating currents which are zero-sequence components are emerged than the other cases. In order to suppress carrier frequency zero-sequence components of circulating currents, the filter inductors of each same phase are coupled. Moreover, this technique has additional advantages; 1) Reduction of current ripples of both coupled inductors and outputs of coupled inductors; 2) Reduced size and weight of total filter inductors; 3) Efficiency improvement of conventional topology. The experimental results are shown to verify the advantages of proposed method.