Patent ID: 9397554
Filing Date: 2016-07-19
CPC Classification: H02M,H02P

Claim Text:
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.