Speed controller including a device for protection against overcurrents and overvoltages

Speed controller (1) comprising:

• at the input, a rectifier module (12) in order to generate, on a power bus (10, 11), a direct voltage from an alternating voltage available on an electrical 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) supplied by the power bus and controlled to deliver an alternating voltage to an electric load (2), characterized in that:
• the controller (1) comprises a device (14) for protecting the controller against overcurrents associated with voltage variations on the electrical supply network (A),
• and in that this device comprises:
• a first electronic switch of the JFET transistor type (T1) made in a wide forbidden band material and placed on the power bus in series between the rectifier module (12) and the bus capacitor,
• a second electronic switch (T2) mounted on the power bus, in parallel with the JFET transistor,
• means (140) for controlling both the JFET transistor and the second electronic switch.