| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor control device which can stably drive a motor without stopping the motor by overcurrent protection or the like even when direct voltage of an inverter is changed during driving, and a refrigeration machine using the motor control device.SOLUTION: The motor control device has: a power conversion circuit which converts DC power into AC power; a controller which outputs a drive signal which drives the power conversion circuit; an automatic voltage regulator which adjusts an output voltage instruction value according to DC voltage of the power conversion circuit; an electric motor driven by the power conversion circuit; and a load connected to the electric motor. In the motor control device, two phases which are energized are selected out of three-phase coils of the electric motor to apply pulsed-voltage, and phase and speed estimation is performed on the basis of non-energization phase electromotive voltage. When the product of a pulse width and a voltage value of a voltage pulse reaches a predetermined value, the pulse width is fixed to a predetermined maximum value. |
