A circuit for use with a stator winding of an electrical machine, the stator winding including a number of coils (SC1-SC6) linked by the same number of points of common coupling (PCC1-PCC6), the circuit comprising: an electronic commutator circuit having the same number of switching stages, each switching stage being connected between a respective one of the points of common coupling (PCC1-PCC6) and first and second main dc lines (DC1, DC2) and including: a first reverse blocking semiconductor power device (GTO1, GT03) capable of being turned on and off by gate control having its cathode connected to the first main dc line; and a second reverse blocking semiconductor power device (GT02, GT04) capable of being turned on and off by gate control having its anode connected to the second main dc line; a voltage clamping circuit including: the same number of clamping stages, each clamping stage being connected between a respective one of the points of common coupling (PCC1-PCC6) and first and second auxiliary dc lines (DC3, DC4) and including a first diode (D1, D3) having its cathode connected to the first auxiliary dc line, and a second diode (D2, D4) having its anode connected to the second auxiliary dc line; a first capacitor connected between the first main dc line and the first auxiliary dc line; and a second capacitor connected between the second main dc line and the second auxiliary dc line; and means configured to selectively discharge the first and second capacitors (C1, C2). an electronic commutator circuit having the same number of switching stages, each switching stage being connected between a respective one of the points of common coupling (PCC1-PCC6) and first and second main dc lines (DC1, DC2) and including: a first reverse blocking semiconductor power device (GTO1, GT03) capable of being turned on and off by gate control having its cathode connected to the first main dc line; and a second reverse blocking semiconductor power device (GT02, GT04) capable of being turned on and off by gate control having its anode connected to the second main dc line; a first reverse blocking semiconductor power device (GTO1, GT03) capable of being turned on and off by gate control having its cathode connected to the first main dc line; and a second reverse blocking semiconductor power device (GT02, GT04) capable of being turned on and off by gate control having its anode connected to the second main dc line; a voltage clamping circuit including: the same number of clamping stages, each clamping stage being connected between a respective one of the points of common coupling (PCC1-PCC6) and first and second auxiliary dc lines (DC3, DC4) and including a first diode (D1, D3) having its cathode connected to the first auxiliary dc line, and a second diode (D2, D4) having its anode connected to the second auxiliary dc line; a first capacitor connected between the first main dc line and the first auxiliary dc line; and a second capacitor connected between the second main dc line and the second auxiliary dc line; and the same number of clamping stages, each clamping stage being connected between a respective one of the points of common coupling (PCC1-PCC6) and first and second auxiliary dc lines (DC3, DC4) and including a first diode (D1, D3) having its cathode connected to the first auxiliary dc line, and a second diode (D2, D4) having its anode connected to the second auxiliary dc line; a first capacitor connected between the first main dc line and the first auxiliary dc line; and a second capacitor connected between the second main dc line and the second auxiliary dc line; and means configured to selectively discharge the first and second capacitors (C1, C2).