1.5MVA grid-connected interleaved inverters using coupled inductors for wind power generation system

Abstract

In this paper, grid-connected interleaved voltage source inverters for PMSG wind power generation system with coupled inductors is introduced. In parallel operation, the undesirable circulating current flows between inverters. There are some differences in circulating currents according to source configuration. It is mathematically analyzed and simulated for the verification of analysis. In case of interleaved inverters, the uncontrollable circulating current in switching frequency level flows between inverter modules regardless of source configuration such as common or separated if filter inductance which is placed between inverters is significantly low. In order to suppress high frequency circulating current, the coupled inductors are employed in each phase. A case of 1.5MVA grid-connected interleaved inverters using coupled inductors prototype for the PMSG wind power generation Back To Back converters in parallel are introduced and experimentally verified the proposed topology.

Circulating Current Control in Interleaved and Parallel Connected Power Converters

“…Another solution, proposed in [6], incorporates a Common Mode (CM) filter at each converter's output to suppress circulating currents, but also comes with added costs. In references [7][8][9][10][11], Coupled Inductors (CIs) are employed for their excellent performance in reducing circulating currents. Nevertheless, these CIs may distort the current sharing between converters during unbalanced load sharing.…”