Motor drive system including power storage device

A motor drive system comprising:

• a converter configured to convert power between AC power in a power source and DC power in a DC link;
• an inverter for drive configured to convert power between the DC power in the DC link and AC power serving as one of drive power and regenerative power for a servomotor for drive;
• a motor control unit for drive configured to control the servomotor for drive connected to the inverter for drive to operate the servomotor for drive in accordance with a predetermined operation pattern;
• a power storage device configured to store the DC power from the DC link or supplies the DC power to the DC link;
• and
• a determination unit configured to determine whether a holding energy of the power storage device is lower than a threshold for energy shortage determination defined in advance,
• wherein when the determination unit determines that the holding energy is lower than the threshold for energy shortage determination, the motor control unit for drive controls the servomotor for drive by setting an additional standby period in which the servomotor for drive is inactive at a certain point of time in the predetermined operation pattern.