US Patent No. 9,397,554


Patent No. 9,397,554
Issue Date July 19, 2016
Title Motor Drive Device Having Function Of Estimating Dead Time In Output Stage
Inventorship Kunio Tsuchida, Yamanashi (JP)
Taku Sasaki, Yamanashi (JP)
Assignee Fanuc Corporation, Yamanashi (JP)

Claim of US Patent No. 9,397,554

1. A motor drive device of a motor for driving a feed shaft and a main shaft of a machine tool, or arms of an industrial machine
or an industrial robot, comprising:
an inverter having a plurality of power elements, configured to generate an alternating current voltage for driving the motor
from a direct current voltage by switching of the plurality of power elements;

a current detection unit configured to detect a current to be inputted from said inverter to the motor;
a current controller configured to generate a voltage command from a current command and a current detection value detected
by said current detection unit;

a gate drive command generator configured to generate drive commands for the plurality of power elements upon receiving the
voltage command from said current controller, such that a dead time in an output stage, that is a period of time in which
both of the power elements for an upper arm and a lower arm that compose the output stage of said inverter are turned off,
becomes a predetermined value;

a gate drive circuit unit configured to output signals to drive gates of the plurality of power elements upon receiving the
drive commands from said gate drive command generator; and

a dead time estimator configured to estimate the dead time in the output stage that is produced by the signals to drive the
gates of the plurality of power elements, from a difference between the current command and the current detection value.