Patent ID: 9698717
Date: 2017-07-04
CPC Classifications: G01R,H02P

Claim:
1. A motor drive device driving any of a feed shaft or spindle of a machine tool or arm of an industrial machine or industrial robot etc., comprising a current detecting part detecting a current flowing through a motor, a current control part using an output from said current detecting part as the basis to output a command for running a desired current to said motor, and a power converting part using a command from said current control part as the basis to supply power to said motor, said current detecting part comprising a current slope detecting part detecting a slope of an increase or decrease of current at a certain point of time and a switching part using an output of said current slope detecting part as the basis to switch a mode of current detection, wherein said switching part switches among a plurality of two or more filters differing in filter characteristics to thereby switch the mode of current detection, and, wherein said switching part switches to a narrow bandwidth filter when a slope of current is small and switches to a broad bandwidth filter when a slope of current is large.