Motor drive device with function of switching to power regenerative operation mode

Abstract

A motor drive device comprising a converter for carrying out a power running operation for supplying power from a three-phase AC power supply to a three-phase AC motor and a power regenerative operation for returning energy generated by the three-phase AC motor to the three-phase AC power supply. The converter has power switching elements, a first power regenerative control unit for controlling an on/off action of the power switching elements at the time of carrying out the power regenerative operation by using pulse width modulation signal whose pulse width changes in accordance with a value indicated by a command signal; a second power regenerative control unit for controlling the on/off action of the power switching elements at the time of carrying out the power regenerative operation in order to generate respective power regenerative currents in a phase representing the maximum electric potential among three phases of the three-phase AC power supply and a phase representing the minimum electric potential among the three phases, and a power regenerative operation switching unit for switching control of the on/off action of the power switching elements at the time of carrying out the power regenerative operation between a control carried out by the first power regenerative a control unit and that carried out by the second power regenerative control unit.

Dependencies are inferred from the claim text.