Device for protecting a speed controller against overcurrent

Speed controller comprising:

• as input, a rectifier module (12) for generating a direct voltage on a power bus (10, 11) from an alternating voltage available on an electrical power-supply network (A);
• a bus capacitor (Cb) connected between a positive line and a negative line of the power bus;
• and
• an inverter module (13) powered by the power bus and controlled to deliver an alternating voltage to an electrical load (2);
• characterized in that:
• the controller (1) comprises a protection device (14) for protecting the controller against overcurrents linked with voltage variations on the electrical power-supply network (A);
• and in that the device comprises:
• a first electronic switch located on the power bus in series between the rectifier module (12) and the bus capacitor (Cb);
• a first resistor (R1) mounted in parallel with the first electronic switch;
• an assembly comprising a second electronic switch (T2) and a second resistor (R2) mounted in series, said assembly being mounted in parallel with the first electronic switch and the first resistor (R1);
• control means (140) for controlling the first electronic switch (T1) and the second electronic switch (T2).