Interleaved power converters are now used in many different conversion systems involving various topologies (series or parallel) and related to different fields or loads. This paper deals with interleaved parallel commutation cells using coupling transformers with a possibly high number of cells. The first part of the paper is a reminder of the basics of magnetic couplers addressing monolithic as well as distributed implementations. The limits associated with the conventional supply of such couplers (supply voltages forming a direct polyphase system) are described. In the second part of the paper, an optimized voltage supply improving the performances of the system is introduced. Experimental results obtained on a seven-cells test bench validate the approach