Motor control apparatus

• US 6,469,461 B1
• Filed: 10/04/2000
• Issued: 10/22/2002
• Est. Priority Date: 10/05/1999
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Konda, Shinichi, Ueda, Susumu
• Primary Examiner(s): Fletcher, Marlon T.
• Application Number:
  US09/678,848
• Time in Patent Office: 748 Days
• Field of Search: 318/131-134, 318/138, 318/254, 318/439
• US Class Current: 318/400.21
• CPC Class Codes: H02H 7/0838 with H-bridge circuit
• CPC Class Codes: H02P 6/34 Modelling or simulation for control purposes

Abstract

A motor control system designed to monitor a failure in a multi-phase dc motor is provided. The motor control system includes an inverter which controls an operation of the motor, a failure detecting circuit which monitors the voltage appearing at one of terminals of armature windings of the motor every active time when a PWM signal is at an active level to turn on switching elements of the inverter and determines occurrence of the failure based on the monitored voltage, and a switching operation prohibiting circuit which prohibits one of the switching elements connected to the one of the terminals of the windings of the motor from being turned on, thereby avoiding additional damages of the motor control system.

Claims

1. An apparatus for detecting a motor current flowing through delta-connected armature windings of a three-phase brushless dc motor when the motor is operated through a motor driver, comprising:

a neutral voltage detecting circuit including three resistors which are connected at one end to the armature windings of the motor, respectively, and at the other end to a common junction, said neutral voltage detecting circuit measuring a voltage developed at the common junction as a neutral voltage V1 of the motor;

a speed proportional voltage generator generating a voltage V2 proportional to a speed N of the motor according to an equation (1) below; and

2. An apparatus as set forth in claim 1, further comprising an operation suspending circuit which suspends the operation of the motor for a preselected period of time when the voltage Vo exceeds a given threshold value.

3. An apparatus as set forth in claim 2, wherein said operation suspending circuit stops the operation of the motor completely when the number of times the operation of the motor is suspended reaches a preselected number.