Motor control device including electric storage device and resistance discharge device

A motor control device comprising:

• a rectifier that rectifies AC power supplied from an AC side to output DC power;
• an inverter that is connected to a DC link at a DC side of the rectifier, and performs interconversion of electric power between DC power at the DC link and drive power for a motor or regenerative electric power, which are AC power;
• a power failure detecting unit that detects power failure at the AC side of the rectifier;
• a voltage detecting unit that detects a DC voltage value at the DC link;
• an electric storage device that is connected to the DC link, and stores DC power;
• a charging unit that has a boosting function of charging the electric storage device at a voltage higher than a DC voltage at the DC link;
• a discharging unit that makes short-circuiting between the electric storage device and the DC link to discharge DC power stored in the electric storage device to the DC link;
• a resistance discharge device that is connected to the DC link wherein after the power failure detecting unit detects power failure, the resistance discharge device starts resistance discharging operation of consuming DC power of the DC link by resistance discharging when a DC voltage value detected by the voltage detecting unit is equal to or higher than a resistance discharging start level, and the resistance discharge device stops the resistance discharging operation when a DC voltage value detected by the voltage detecting unit is equal to or lower than a resistance discharging stop level lower than the resistance discharging start level;
• and
• a discharging operation determining unit that does not output a discharging start command during a period from the time after the power failure detecting unit detects power failure to the time that a motor driving command commanding power running operation of the motor or motor output information that is information on the output of the motor performing power running operation based on the motor driving command, becomes equal to or higher than a third threshold, and that outputs the discharging start command for operation of the discharging unit when the motor driving command or the motor output information becomes equal to or higher than the third threshold.