Motor control device having protective unit of charging resistor

摘要

A motor control device includes a rectifier, a smoothing capacitor provided to a DC link, an inverter that power-converts DC power of the DC link and AC power of a motor side, an initial charging unit that charges the smoothing capacitor before motor driving start, a current detection unit that detects an AC current detection value of an input side of the rectifier, a current conversion unit that converts the detection value into a value corresponding to a DC link current, a current integration unit that outputs an integration value obtained by integrating the conversion value, an alarm output unit that outputs an alarm when the integration value is equal to or more than a first threshold value, a disconnecting unit that disconnects the AC power to the rectifier in response, and a protective unit that commands the disconnecting unit to disconnect the AC power when the alarm is output.

主权项

1. A motor control device comprising:
a rectifier that rectifies AC power supplied from an three-phase AC input side and outputs DC power; a smoothing capacitor provided to a DC link which is a DC output side of the rectifier; an inverter that mutually power-converts DC power in the DC link and AC power which is driving power or regenerative power of a motor; an initial charging unit having a switch unit and a charging resistor connected in parallel to the switch unit, opening the switch unit before motor driving is started, and charging the smoothing capacitor with a DC current output from the rectifier via the charging resistor; a current detection unit that detects an AC current value of the three-phase AC input side of the rectifier, and outputs an AC current detection value; a current conversion unit that outputs a conversion value obtained by converting the AC current detection value into a value corresponding to a DC current in the DC link; a current integration unit that outputs an integration value obtained by integrating the conversion value output from the current conversion unit during a charging period of the smoothing capacitor by the initial charging unit; an alarm output unit that outputs an alarm when the integration value is equal to or more than a first threshold value; a disconnecting unit that is able to disconnect supply of the AC power to the rectifier in response to a received command; and a protective unit that commands the disconnecting unit to disconnect the supply of the AC power when the alarm is output.