Motor driving apparatus
AssigneeFanuc Corporation
InventorsYasusuke IWASHITA, Masakazu Niwa, Takashi Harada, Koujirou Sakai, Shinichi Horikoshi
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Abstract
When the output of motor reaches or exceeds a predetermined value during acceleration of the motor, the control target value of the DC link voltage which is the voltage of a power storage device is gradually lowered in corresponding relationship to the motor output. When the motor enters a constant speed control mode, the DC link control target value is maintained at a constant level. When the motor enters a deceleration control mode, the DC link control target value is gradually raised in corresponding relationship to the motor output, and regenerative power is recovered by the power storage device and reused in the next control cycle.
Claims10
A motor driving apparatus 1 comprising:
- a PWM converter which, under PWM control, converts AC power supplied from a power source into DC power and vice versa;
- a PWM inverter which converts the DC power output from said PWM converter into variable-frequency AC power and vice versa, and which drives a motor with said variable-frequency AC power;
- a power storage device, provided between said PWM converter and said PWM inverter, that can store electric power in an amount capable of driving said motor;
- and
- a PWM converter control circuit which operates said PWM converter under PWM control, and wherein:
- said PWM converter control circuit operates said PWM converter under PWM control such that power less than the power required by said motor during an acceleration control period of said motor is supplied from said PWM converter and any deficit in power required to drive said motor is supplied from said power storage device, so that the voltage of said power storage device at the start of a deceleration control period of said motor is decreased and thus at least a portion of regenerative power occurring in said motor during the deceleration control period of said motor is recovered by said power storage device.
Dependencies are inferred from the claim text.