US Patent No. 9,054,620


Patent No. 9,054,620
Issue Date June 09, 2015
Title Motor Driving Device Including Electric Storage Device
Inventorship Masakazu Niwa, Yamanashi (JP)
Koujirou Sakai, Yamanash (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,054,620

1. A motor driving device comprising:
a rectifier that rectifies alternating current power supplied from an alternating current side to output direct current power;
an inverter that is connected to a direct current link on a direct current side of the rectifier and that mutually transforms
electric power between direct current power at the direct current link and alternating current power that is driving electric
power for a motor or electric power regenerated in the motor;

a power failure detecting unit for detecting a power failure on the alternating current side of the rectifier;
an electric storage device that is connected to the direct current link and that includes a capacity for storing direct current

a charging unit that possesses a voltage boosting function of charging the electric storage device to a voltage higher than
a direct current voltage at the direct current link and that has a circuit device having a small current rating smaller than
a rating needed to charging the electric storage device during drive control of the motor when a power failure is not occurring;

a discharging unit for making a short-circuit between the electric storage device and the direct current link to cause direct
current power stored in the electric storage device to be discharged to the direct current link; and

a control unit that outputs a charging command for causing the charging unit to operate before drive of the motor is started,
and outputs a discharging command for causing the discharging unit to operate and a predetermined motor driving command for
causing the inverter to operate when the power failure detecting unit detects a power failure on the alternating side of the