System for controlling a voltage converter

A system for controlling a voltage converter, the voltage converter being configured to connect a rotary electric machine to a DC voltage source, notably to an on-board network, the voltage converter comprising a plurality of switching arms connected in parallel, each arm comprising a high-side switch and at least one low-side switch connected to one another at a midpoint configured to be connected to said rotary electric machine, the high-side switches forming a high group and the low-side switches forming a low group, the control system comprising:

• a first module for measuring a voltage of the DC voltage source;
• a module for comparing the measured voltage with a first safety threshold;
• a second measurement module configured to measure a speed of rotation of the rotary electric machine;
• a control module generating a first short-circuit command if the comparison module indicates that the measured voltage is greater than a first safety threshold, the first short-circuit command being made up of a command to close a first group of switches selected between the high group and the low group and a command to open a second group of switches comprising the switches of the high group or of the low group that do not form the first group;
• wherein the control module then generates an open-circuit command, the open-circuit command being made up of a command to open the first group of switches and a command to open the second group of switches:
• if a variation over time of the measured voltage of the DC voltage source is less than a first safety variation;
• and
• if the speed of rotation measured by the second measurement module is less than a first safety speed.