Power supply voltage monitoring device for inverter control of motor

摘要

To solve such a problem that when performing inverter control of a motor, a voltage of an external commercial power supply is detected, and when the voltage is fluctuated, it is required to correct inverter control corresponding to the voltage after fluctuation, and although correction of inverter control has been performed, in the past, on a secondary side after stepping-down of the voltage of the external commercial power supply by use of a step-down transformer in order to detect the voltage, the step-down transformer is a relatively expensive, and further, has a larger size compared with other electronic components, whereby down-sizing of a device is inhibited.SOLUTION: A voltage, which is lower than a minimum voltage, which is expected as a fluctuation width of a voltage of a commercial power supply, is set to a threshold, a pulse generating part, which generates a pulse of a time width in which such a state that a voltage of an AC power supplied from the commercial power supply is higher than the threshold is continued, is provided, and this pulse is inputted to a micro computer of a feedback control part.SELECTED DRAWING: Figure 2