Apparatus for transferring electric power between an AC network and a multiphase electric machine

Apparatus for transferring power between an electricity network (U P ) operating on alternating-current electricity and a multiphase electric machine (M2, M3), which apparatus comprises low-voltage power cells (C S , C 11 ...C N6 ) operating on a cascade principle, which power cells comprise a single-phase output connector (OUT), and at least one transformer (T A , T 1 ...T N ), comprising for each power cell connected to it a single-phase or multiphase winding dedicated to the specific power cell, which transformer comprises at least one additional winding (W A , W B1 ...W BN ) connected to the same magnetic circuit as the other windings for the purpose of at least one auxiliary circuit, which can be connected to the aforementioned additional winding.