MOTOR DRIVING APPARATUS

• US 20090091281A1
• Filed: 10/03/2008
• Published: 04/09/2009
• Est. Priority Date: 10/05/2007
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: HANYU, Shigeki, SAKAI, Koujirou, YAMADA, Yuuichi, MATSUBARA, Shunsuke, IWASHITA, Yasusuke, SHIROUZU, Masatomo
• Granted Patent: US 8,054,012 B2
• Time in Patent Office: Days
• US Class Current: 318/440
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02P 27/08 with pulse width modulation

Abstract

A motor driving apparatus having a converter, which receives AC voltage and converts it to DC power, and an inverter, which receives the DC power and converts it to AC power, includes a charge/discharge control circuit and a capacitor connected in parallel to a link section between the converter and the inverter, and energy stored in the capacitor C8 is charged and discharged at arbitrary timing by the charge/discharge control circuit. The invention thus provides a motor driving apparatus that supplies energy to a motor so that the peak of the input current from a power supply to the motor can also be suppressed when particularly large energy is needed during the second half period of motor acceleration.

Claims

1. A motor driving apparatus having a converter, which receives AC voltage and converts said AC voltage to DC power, and an inverter, which receives said DC power and converts said DC power to AC power, wherein

said motor driving apparatus includes a charge/discharge control circuit and a capacitor connected in parallel to a link section between said converter and said inverter, and energy stored in said capacitor is charged and discharged at arbitrary timing by said charge/discharge control circuit.

2. A motor driving apparatus as claimed in claim 1, wherein said arbitrary timing includes timing specified by an external input signal.

3. A motor driving apparatus as claimed in claim 1, wherein said external input signal is a signal that is output from a limit switch for detecting a position of a moving object in a machine driven by a motor, or a signal that is output when a motor position specified by a program or the detected position of said moving object exceeds a predetermined position.

4. A motor driving apparatus as claimed in claim 1, wherein when an AC current input from a power supply to said converter or a converter output current obtained by rectifying said AC current to DC current becomes equal to or exceeds a predetermined current value, a discharge circuit provided in said charge/discharge control circuit is turned on so that the energy stored in said capacitor is supplied to said inverter.

5. A motor driving apparatus as claimed in claim 1, wherein when DC voltage in said link section becomes equal to or drops below a predetermined voltage value, a discharge circuit provided in said charge/discharge control circuit is turned on so that the energy stored in said capacitor is supplied to said inverter.