Patent ID: 8368330

Claim:
Variable speed drive comprising a direct-current power supply bus having a positive line and a negative line, an inverter module supplied by the direct-current bus in order to supply a variable voltage to an electric load, and an energy-recovery device, wherein in that the energy-recovery device comprises: a first direct-current/direct-current converter comprising an input stage and an output stage, the output stage of the first converter being connected in series to the positive line of the direct-current bus, a second direct-current/direct-current converter comprising an input stage and an output stage, the input stage of the second converter being connected between the positive line and the negative line of the direct-current bus, an electric energy storage module which is connected in parallel with the input stage of the first converter and in parallel with the output stage of the second converter, wherein in that the first direct-current/direct-current converter is an uninsulated one-way converter which comprises an active switch and a passive switch; and wherein in that the second direct-current/direct-current converter is an uninsulated two-way converter which comprises a first active switch connected in series to a second active switch or an insulated two-way converter comprising a high-frequency transformer.