Patent ID: 8129932

Claim:
A driving apparatus for a three-phase AC synchronous motor, in which a rotor is rotated by a rotating magnetic field produced by a stator coil including three coils star-connected to a neutral point, the driving apparatus comprising: an inverter circuit including pairs of switching elements, each of the pairs of the switching elements being connected in series, the pairs of the switching elements being provided for respective phases and being connected in parallel between a positive-pole bus and a negative-pole bus; a control section configured to turn on, for outputting each of three-phase AC currents from the inverter circuit, one of the switching elements connected to one of the positive-pole bus and the negative-pole bus and two of the switching elements connected to other one of the positive-pole bus and the negative-pole bus; a capacitor; the inverter circuit configured to output the three-phase AC currents to the stator coil for generating the rotating magnetic field based on an output voltage from a DC power source connected between the neutral point and one of the positive-pole bus and the negative-pole bus and an output voltage from the capacitor in association with switching operation of the pairs of the switching elements for the respective phases; an electric current detecting section configured to detect an electric current flowing between one of the positive-pole bus and the negative-pole bus and one of the DC power source and the capacitor; a current acquiring section configured to acquire, for each of the phases, an electric current containing a phase electric current output to one of the three coils as the electric current detected by the electric current detecting section, the current acquiring section further acquiring electric currents detected by the electric current detecting section for all three phases; and the control section configured to set the electric currents for the three-phases detected by the electric current detecting section and acquired by the current acquiring section together into three-phase AC currents, the control section controlling, based on the three-phase AC currents, the pairs of the switching elements for the respective phases such that the switching operation of the pairs of the switching elements for the respective phases is performed.