Converter apparatus, inverter apparatus, and DC link voltage control method

• US 7,135,835 B2
• Filed: 08/10/2005
• Issued: 11/14/2006
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Yoshida, Tomokazu, Yamada, Yuuichi, Hanyu, Shigeki
• Primary Examiner(s): Leykin, Rita
• Application Number:
  US11/200,201
• Publication Number:
  US 20060033466A1
• Time in Patent Office: 461 Days
• Field of Search: 318/801, 318/800, 320/137, 320/138, 320/166, 324/239, 363/34, 363/37, 363/116, 702/193, 939/07
• US Class Current: 318/800
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements
• CPC Class Codes: H02P 23/06 Controlling the motor in four quadrants

Abstract

The invention is directed to the provision of a converter apparatus, an inverter apparatus, and a DC link voltage control method, wherein the upper limit value of the DC link voltage that rises due to regenerative energy occurring from a motor is set high, thereby increasing the regenerative energy to be stored in a DC link. The converter apparatus (10) comprises: a voltage detection part (11) for monitoring the DC link voltage occurring across the DC link (30); and a charge stopping part (12) for stopping charging a power storage part (C) when the detected value of the DC link voltage exceeds a predetermined upper limit voltage as the motor (3) is decelerated.

Claims

1. A converter apparatus which is connected via a DC link to an inverter circuit for driving a motor, said DC link having a power storage part capable of storing regenerative power from said motor, and which converts AC power supplied from a power source into DC power and supplies said DC power to said inverter circuit through said DC link, said converter apparatus comprising:

a voltage detection part detecting a DC link voltage appearing across said DC link; and

a charge stopping part stopping charging said power storage part when the DC link voltage detected by the voltage detection part exceeds a predetermined upper limit voltage.

2. A converter apparatus as claimed in claim 1, wherein said predetermined upper limit voltage is determined based on the breakdown voltage of any one of component devices in said converter apparatus, said DC link, and said inverter circuit or on the breakdown voltage of said power storage part.

3. A converter apparatus as claimed in claim 1, further comprising a voltage value storing part for storing the value of the DC link voltage detected when said power storage part begins to store said regenerative power, wherein

said charge stopping part stops charging said power storage part when the DC link voltage currently detected by said voltage detection part exceeds the upper limit voltage whose value is set by adding a predetermined potential difference to the value of the DC link voltage stored in said voltage value storing part.

4. A converter apparatus as claimed in claims 1, wherein when said detected DC link voltage exceeds said upper limit voltage, said charge stopping part causes said converter apparatus to feed the power stored in said power storage part back into said power source.

5. A converter apparatus as claimed in claims 1, wherein when said detected DC link voltage exceeds said upper limit voltage, said charge stopping part causes said converter apparatus to start feeding the power stored in said power storage part back into said power source and, when the DC link voltage detected after starting feeding the power back into said power source is lower than said upper limit voltage by a predetermined level, said charge stopping part causes said converter apparatus to stop feeding back said power.

6. An inverter apparatus wherein said DC power supplied through said DC link after conversion by a converter apparatus as claimed in 1 is converted by said inverter circuit into AC power to drive said motor.

7. A method for controlling a DC link voltage appearing across a DC link connected between an inverter for driving a motor and a converter for converting AC power supplied from a power source into DC power and for supplying said DC power to said inverter, said DC link having a power storage part capable of storing regenerative power from said motor, wherein said control method comprises:

detecting said DC link voltage; and

stopping charging said power storage part with said regenerative power when the DC link voltage detected by a voltage detection part exceeds a predetermined upper limit voltage due to the regenerative power occurring from said motor.

8. A control method as claimed in claim 7, further comprising:

storing the value of the DC link voltage detected when said power storage part begins to store said regenerative power; and

stopping charging said power storage part when the DC link voltage currently detected exceeds the upper limit voltage whose value is set by adding a predetermined potential difference to said stored value of said DC link voltage.

9. A control method as claimed in claim 7, wherein when said detected DC link voltage exceeds said upper limit voltage, said converter is caused to feed the power stored in said power storage part back into said power source.

10. A converter apparatus connected via a DC link to an inverter circuit and connected to a power source, comprising:

a power storage part storing regenerative power from a motor; and

a charge stopping part causing regenerative current to be fed back into the power source and thereby reducing DC link voltage across the DC link to stop storing the regenerative power when the DC link voltage exceeds an upper limit voltage.

11. A method of controlling a DC link voltage across a DC link connecting an inverter circuit and a converter apparatus, comprising:

storing regenerative power from a motor; and

causing regenerative current to be fed back into a power source connected to the converter apparatus and thereby reducing the DC link voltage across the DC link to stop storing the regenerative power when the DC link voltage exceeds an upper limit voltage.