Motor drive system

• US 20040239271A1
• Filed: 05/24/2004
• Published: 12/02/2004
• Est. Priority Date: 05/27/2003
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Yaeshima, Mamoru, Matsubara, Shunsuke
• Granted Patent: US 7,126,300 B2
• Time in Patent Office: Days
• US Class Current: 318/434
• CPC Class Codes: H02H 7/0833 for electric motors with control arrangements
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02P 5/74 controlling two or more ac dynamo-electric motors H02P5/46, H02P5/60 take precedence

Abstract

A first and a second motor drive amplifiers connected to a motor drive power supply include a first and a second memories which store specifications of the amplifiers, respectively. A memory provided in a power supply unit stores an overcurrent detection value for detecting an overcurrent according to the specifications of the respective motor drive amplifiers. A microcontroller reads the specifications from the first and second memories, and integrates overcurrent detection values corresponding to the respective specifications. If a current sensor detects that a current exceeding a reference value calculated based on a set integrated value, the current sensor outputs an overcurrent detection signal.

Claims

1. A motor drive system, comprising a motor drive power supply and a plurality of motor drive amplifiers connected to the motor drive power supply, and driving motors by the respective motor drive amplifiers, the motor drive system comprising:

overcurrent detection means for detecting a current flowing in said motor drive power supply, wherein

an overcurrent detection value to be detected as an overcurrent by said overcurrent detection means can be changed.

2. The motor drive system according to claim 1, wherein

said motor drive amplifiers comprise memories that store specifications of the respective motor drive amplifiers,

said motor drive system further comprises:

means for reading storage contents of said memories;

overcurrent detection value storage means for storing overcurrent detection values corresponding to the specifications of the respective motor drive amplifiers; and

means for reading the overcurrent detection values from the overcurrent detection value storage means based on the specifications read from said respective memories, and for integrating the overcurrent detection values, and wherein

an integrated value of the overcurrent detection values of the plurality of motor drive amplifiers connected to said motor drive power supply is set as a reference value for detection made by said overcurrent detection means.

3. A motor control device comprising:

a plurality of motor drive amplifiers connected to a motor drive power supply;

allowable current storage means for storing information on maximum currents allowed by the respective motor drive amplifiers;

allowable current reading means for reading the information on the maximum currents allowed by the respective motor drive amplifiers from said allowable current storage means;

reference value setting means for integrating the allowed maximum currents of the respective motor drive amplifiers, read by said allowable current reading means, and for setting a reference value for overcurrent detection based on an integrated value;

supply current detection means for detecting a sum of currents supplied from said motor drive power supply to said plurality of motor drive amplifiers, respectively; and

overcurrent detection means for comparing the sum of current detected by said supply current detection means with the reference value set by said reference value setting means, and for detecting an overcurrent based on a comparison result.