Fanuc Corporation

Hirokazu Nagai

Naoki Masuda

Hironao Tanouchi

Masato Watanabe

Yasuyuki Matsumoto

Masaya Tateda

A motor control apparatus includes: a converter configured to convert alternating current power of an AC source into direct current power; an inverter configured to convert the direct current power in a DC link into alternating current power for motor driving by the switching device being subjected to ON/OFF control, a DC link voltage detection unit configured to detect a DC link voltage, a DC link voltage determination unit configured to determine whether the DC link voltage exceeds a voltage threshold value, an alarm signal output unit configured to output an alarm signal in an abnormal condition; and a switching control unit configured to perform ON/OFF control on the switching device, and, when the alarm signal is output and the DC link voltage exceeds the voltage threshold value, the switching control unit performs control in such a way as to turn on all the switching device of a lower arm.

Motor control apparatus including protection mechanism

A motor control apparatus includes: a main power conversion circuit that converts power that is supplied from a power supply into alternating current power for driving a motor, and outputs the alternating current power; a counter electromotive force protection circuit including a rectifier unit that rectifies alternating current power based on counter electromotive force of the motor and outputs direct current power, a short-circuit unit that short-circuits terminals on a direct current output side of the rectifier unit, and an alarm signal output unit that outputs an alarm signal at occurrence of an abnormality; a monitoring unit that monitors whether the alarm signal is output from the alarm signal output unit; and a protection operation unit that performs a protection operation for preventing damage to the main power conversion circuit when the monitoring unit determines that the alarm signal is output from the alarm signal output unit.

There are provided a driving control portion configured to output a closing command for bringing a contact to a closed state to a first driving portion, and also to output to the first driving portion an opening command for bringing the contact to an open state and the closing command in an alternate and repeated manner until the current runs through the contact; a number-of-retries obtaining portion configured to obtain, as a number of retries, the number of times that the driving control portion repeated the opening command and the closing command until the current runs through the contact after the driving control portion outputted the closing command to the first driving portion; and a usable period estimating portion configured to estimate a usable period from the present time of a first relay in accordance with the number of retries.

Growing community of inventors

Yamanashi, Japan

Hirokazu Nagai