| 摘要 |
PROBLEM TO BE SOLVED: To drive a motor with a higher efficiency even when having a step-up circuit.SOLUTION: An inverter device 10 comprises: a step-up circuit 18 for stepping up a voltage of a DC power; and an inverter circuit 20 converting a DC power obtained by being stepped up by the step-up circuit 18, into an AC power, and supplying the AC power to a compressor motor 12. In an A region from the minimum rotation number of the compressor motor 12 and equal to or less than an intermediate rotation number, the step-up circuit 18 does not perform the stepping-up. In a B region of more than the intermediate rotation number and less than a rating rotation number, the step-up circuit 18 performs the stepping-up in proportion to a rotation number of the compressor motor 12. In a C region of more than the rating rotation number and equal to or less than the maximum rotation number, the step-up circuit 18 performs the stepping-up by a constant value. At a rotation number exceeding the A region, overmodulation control of the compressor motor 12 is performed by the inverter circuit 20. In addition, an induction voltage constant of the compressor motor 12 is a value that overmodulation control becomes possible at a rotation number where the rotation number is shifted from the A region to the B region. |
