Motor driving device

• US 9,787,084 B2
• Filed: 06/16/2016
• Issued: 10/10/2017
• Est. Priority Date: 06/29/2015
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Yoshida, Tomokazu
• Primary Examiner(s): DUDA, RINA I
• Application Number:
  US15/183,881
• Publication Number:
  US 20160380571A1
• Time in Patent Office: 481 Days
• Field of Search: 318727, 318798, 318800, 318801
• CPC Class Codes: H02H 7/1216 for AC-AC converters
• CPC Class Codes: H02M 7/062 Avoiding or suppressing excessive transient voltages or currents
• CPC Class Codes: H02P 2201/03 AC-DC converter stage controlled to provide a defined DC link voltage general aspects of plural converters in cascade H02M

Abstract

A motor driving device includes: a converter that converts AC power into DC power; a DC link capacitor provided for the DC link; an inverter that converts DC power into AC power for a motor; an initial charging circuit that charges the DC link capacitor; a potential difference determination unit that determines a potential difference between both ends of the initial charging circuit; a direct current detecting unit that detects direct current supplied to the initial charging circuit; an alternating current detecting unit that detects alternating current supplied to a motor; and an abnormality determination unit that determines that abnormal heat generation occurs in the initial charging circuit when the alternating current detecting unit detects alternating current and the direct current detecting unit detects direct current, in a case in which a potential difference occurs between both of the ends of the initial charging circuit.

Claims

1. A motor driving device, comprising:

a converter that converts alternating current power supplied from an alternating current power source side to output direct current power;

a DC link capacitor provided for a DC link which is in a direct current output side of the converter;

an inverter that converts direct current power in the DC link to output alternating current power for driving a motor;

an initial charging circuit that is provided for the DC link and charges the DC link capacitor with direct current power output by the converter;

a potential difference occurrence determination unit that determines whether or not a potential difference occurs between both ends of the initial charging circuit;

a direct current detecting unit that detects direct current supplied from the converter to the initial charging circuit;

an alternating current detecting unit that detects alternating current supplied from the inverter to a motor; and

an abnormality determination unit that determines that abnormal heat generation occurs in the initial charging circuit when the direct current detecting unit detects generation of direct current and the alternating current detecting unit detects generation of alternating current, in a case in which the potential difference occurrence determination unit determines that a potential difference occurs between both of the ends of the initial charging circuit.

2. The motor driving device according to claim 1, wherein

the initial charging circuit comprises:

a charging resistance; and

a switch that is connected in parallel to the charging resistance to short-circuit both ends of the charging resistance when being closed, and

the initial charging circuit charges the DC link capacitor with direct current that is allowed to flow from the converter through the charging resistance by opening the switch.