The invention relates to a variable speed drive including a continuous power bus having a positive line (16) and a negative line (17), and an inverter module (14) supplied by the continuous bus to provide a variable voltage to an electric charge (M). The drive includes a power recovery device (10) comprising: a first DC/DC converter (20), the output stage of the first converter (20) being connected in series on the positive line of the continuous bus; a second DC/DC converter (30), the input stage of the second converter (30) being connected between the positive line and the negative line of the continuous bus; and an electric power storage module (Cs), connected in parallel to the input stage of the first converter (20) and to the output stage of the second converter (30).