A system (1703; 1300; 1600) for converting mechanical power into electrical power, the system comprising: - a switched reluctance machine having a rotor and a stator, the stator having a number (Npw) of phase windings (A,B; A,B,C; A,B,C,D), the phase windings being partitioned in one or more groups, each group comprising at least two phase windings (A,B; A,B,C; A,B and C,D), all phase windings of each group being connected in series to form a ring structure (R1; R1; R1,R2); - a power electronic circuit comprising: * for each ring structure (R1; R1; R1,R2), a means (V2; V2; V2a,V2b) for causing a circulating current (I2, I2; 12a,12b) to flow in said ring structure (R1; R1; R1,R2),; * a number (Npw) of legs (Leg1, Leg2; Leg1,Leg2,Leg3; Leg1,Leg2,Leg3,Leg4) equal to the number of phase windings (A,B; A,B,C; A,B,C,D), each of the legs comprising only passive components including at least two diodes (D1,D2) connected in series between a first voltage rail and a second voltage rail, each leg having an intermediate node (m1, m2; m1,m2,m3; m1,m2,m3,m4) located between the two diodes (D1, D2), each intermediate node (m1, m2; m1,m2,m3; m1,m2,m3,m4) of the legs being connected to a corresponding intermediate node (k1, k2; k1,k2,k3; k1,k2,k3,k4) of the ring structure, the intermediate nodes (k1, k2; k1,k2,k3; k1,k2,k3,k4) of the ring structure being located between two phase windings (A, B; A,B,C; A,B,C,D), characterised in that the means for causing a circulating current (12, 12; 12a,12b) is controllable independent of the driving of the phase windings. - a switched reluctance machine having a rotor and a stator, the stator having a number (Npw) of phase windings (A,B; A,B,C; A,B,C,D), the phase windings being partitioned in one or more groups, each group comprising at least two phase windings (A,B; A,B,C; A,B and C,D), all phase windings of each group being connected in series to form a ring structure (R1; R1; R1,R2); - a power electronic circuit comprising: * for each ring structure (R1; R1; R1,R2), a means (V2; V2; V2a,V2b) for causing a circulating current (I2, I2; 12a,12b) to flow in said ring structure (R1; R1; R1,R2),; * a number (Npw) of legs (Leg1, Leg2; Leg1,Leg2,Leg3; Leg1,Leg2,Leg3,Leg4) equal to the number of phase windings (A,B; A,B,C; A,B,C,D), each of the legs comprising only passive components including at least two diodes (D1,D2) connected in series between a first voltage rail and a second voltage rail, each leg having an intermediate node (m1, m2; m1,m2,m3; m1,m2,m3,m4) located between the two diodes (D1, D2), each intermediate node (m1, m2; m1,m2,m3; m1,m2,m3,m4) of the legs being connected to a corresponding intermediate node (k1, k2; k1,k2,k3; k1,k2,k3,k4) of the ring structure, the intermediate nodes (k1, k2; k1,k2,k3; k1,k2,k3,k4) of the ring structure being located between two phase windings (A, B; A,B,C; A,B,C,D), characterised in that the means for causing a circulating current (12, 12; 12a,12b) is controllable independent of the driving of the phase windings. * for each ring structure (R1; R1; R1,R2), a means (V2; V2; V2a,V2b) for causing a circulating current (I2, I2; 12a,12b) to flow in said ring structure (R1; R1; R1,R2),; * a number (Npw) of legs (Leg1, Leg2; Leg1,Leg2,Leg3; Leg1,Leg2,Leg3,Leg4) equal to the number of phase windings (A,B; A,B,C; A,B,C,D), each of the legs comprising only passive components including at least two diodes (D1,D2) connected in series between a first voltage rail and a second voltage rail, each leg having an intermediate node (m1, m2; m1,m2,m3; m1,m2,m3,m4) located between the two diodes (D1, D2), each intermediate node (m1, m2; m1,m2,m3; m1,m2,m3,m4) of the legs being connected to a corresponding intermediate node (k1, k2; k1,k2,k3; k1,k2,k3,k4) of the ring structure, the intermediate nodes (k1, k2; k1,k2,k3; k1,k2,k3,k4) of the ring structure being located between two phase windings (A, B; A,B,C; A,B,C,D), characterised in that the means for causing a circulating current (12, 12; 12a,12b) is controllable independent of the driving of the phase windings.