Motor drive system including power storage device

Abstract

The invention provides a motor drive system including a power storage device. The motor drive system includes a converter configured to convert power between AC power in a power source and DC power ina DC link, an inverter for drive configured to convert power between the DC power and AC power in a servomotor for drive, a motor control unit for drive configured to control the servomotor for drive, 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 the holding energy of the power storage device is lower than a threshold for energy shortage determination, wherein when 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 in a predetermined operation pattern.

Description

technical field [0001] The invention relates to a motor drive system with an electrical storage device. Background technique [0002] In a motor drive system for driving a servo motor (hereinafter referred to as a driving servo motor) installed in machines including machine tools and robots, AC power supplied from an AC power source is converted into DC power by an inverter (rectifier) After that, it is output to the DC link, and the DC power of the DC link is converted into AC power by the inverter, and the AC power is used as power for driving the driving servo motor provided for each drive shaft. Generally, for the purpose of reducing the cost and space occupied by the motor drive system, one converter is often provided for a plurality of inverters. That is, an inverter that converts AC power supplied from an AC power source into DC power serves as a common power supply unit for a plurality of driving inverters (servo amplifiers for driving) using the output from the pow...

AI Technical Summary

Problems solved by technology

[0008] In a motor drive system that limits the power supply from an AC power source in order to reduce power peaks, if the DC power stored in the power storage device is insufficient for some reason, it may not be possible to generate power for driving the servo motor. The AC power required, the motor control system, and the machine tool containing the motor control system stop inadvertently with a warning

For example, when an unexpected high load is applied to the driving servo motor, the driving servo motor consumes more power than usual

In such a case, the DC power stored in the power storage device will be consumed more than originally planned, so there is a high possibility that the driving servo motor cannot continue to be driven due to insufficient power.

Images