US Patent No. 9,166,514

MOTOR CONTROL APPARATUS INCLUDING AT LEAST TWO RESISTANCE DISCHARGE UNITS


Patent No. 9,166,514
Issue Date October 20, 2015
Title Motor Control Apparatus Including At Least Two Resistance Discharge Units
Inventorship Masakazu Niwa, Yamanashi (JP)
Kenta Yamamoto, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,166,514

4. A motor control apparatus comprising:
a rectifier for rectifying AC power supplied from an AC input side to output DC power;
an inverter for performing power interconversion of DC power of the DC link and AC power that is driving power or regenerative
power of a motor, the inverter being connected to the DC link that is a DC output side of the rectifier; and

at least two resistance discharge units each for performing resistance discharge of DC power of the DC link, the resistance
discharge units each being connected to the DC link, in which each resistance discharge unit executes a resistance discharge
operation for performing resistance discharge of DC power of the DC link when predetermined conditions are satisfied,

the resistance discharge units respectively including:
resistance discharge parts for starting or stopping the resistance discharge operation for performing resistance discharge
of DC power of the DC link based on a received command;

voltage detection parts for detecting a DC voltage value in the DC link;
temperature information production parts for producing temperature information indicating a temperature in the resistance
discharge parts each;

discharge operation condition setting parts for setting a first threshold value that is a resistance discharge operation start
level based on the temperature information; and

discharge operation determination parts for commanding the resistance discharge parts to start the resistance discharge operation
when having determined a DC voltage value detected by the voltage detection parts each to be larger than the first threshold
value and for commanding the resistance discharge parts to stop the resistance discharge operation when having determined
the DC voltage value detected by the voltage detection parts each to be smaller than a second threshold value that is smaller
than the first threshold value.