Method to control an electric power system of an electric vehicle

1) A method to control an electric power system (18) of an electric vehicle (1) and provided with at least two electric machines (4);

• the electric power system (18) comprises two electronic DC-AC power converters (9), each having a DC side connected to a battery (6) and an AC side connected to a respective electric machine (4);
• the control method comprises the steps of:
• controlling a first electronic power converter (9) with a master switching period (Tmaster);
• controlling a second electronic power converter (9) with a slave switching period (Tslave);
• establishing a desired time difference (Δt*) between a switching of the first electronic power converter (9) and a switching of the second electronic power converter (9);
• determining an actual time difference (Δt) between the switching of the first electronic power converter (9) and the switching of the second electronic power converter (9);
• comparing the desired time difference (Δt*) with the actual time difference (Δt);
• and
• changing, if necessary, the sole slave switching period (Tslave) based on the comparison between the desired time difference (Δt*) with the actual time difference (Δt).