Variable speed drive provided with a supercapacitor module
A variable-speed drive including: a DC power supply bus including a positive line and a negative line; a bus capacitor connected between the positive line and the negative line of the DC power supply bus; an inverter module supplied with power by the DC power supply bus and controlled to provide a variable voltage to an electrical load; a first switching branch connected between the positive line and the negative line of the bus and including at least one first electronic switch; and a first module including a braking resistor, or a second module including a mechanism for storing and regenerating electrical energy generated during braking of the electrical load, wherein the first module and the second module are removable and interchangeable.
1. A variable-speed drive comprising:
a DC power supply bus including a positive line and a negative line;
a bus capacitor connected between the positive line and the negative line of the DC power supply bus;
an inverter module powered by the DC power supply bus and controlled to deliver a variable voltage to an electrical load;
a first switching leg connected between the positive line and the negative line of the bus and comprising at least one first electronic switch;
a first module comprising a braking resistor or a second module comprising means for storing and regenerating electrical energy generated during braking of the electrical load;
wherein the first module and the second module are removable and interchangeable;
wherein the first module and the second module take a form of a cassette that connects to the DC power supply bus and to the first switching leg.
2. The variable-speed drive as claimed in claim 1 , wherein the first switching leg comprises a diode mounted in series with the first electronic switch and defining between them a connection mid-point.
3. The variable-speed drive as claimed in claim 2 , wherein the second module comprises a second switching leg and one or more supercapacitors.
4. The variable-speed drive as claimed in claim 3 , wherein the second switching leg is connected in parallel with the first switching leg.
5. The variable-speed drive as claimed in claim 4 , wherein the second switching leg comprises a second electronic switch and a diode connected in series and defining a connection mid-point connected to the connection mid-point of the first switching leg,
the diode of the second switching leg being connected in antiparallel with the first electronic switch and the diode of the first switching leg being connected in antiparallel with the second electronic switch.
6. The variable-speed drive as claimed in claim 4 , wherein the second module comprises an inductor connected in series with the supercapacitor.
7. The variable-speed drive as claimed in claim 2 , wherein the braking resistor of the first module is connected in parallel with the diode of the first switching leg.
8. The variable-speed drive as claimed in claim 1 , further comprising control means configured to operate differently depending on whether the first module or the second module is connected.