Imported: 23 Feb '17 | Published: 22 Oct '02
USPTO - Utility Patents
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.
The present invention will be understood more fully from the detailed description given hereinbelow and from the accompanying drawings of the preferred embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments but are for the purpose of explanation and understanding only.
In the drawings:
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:
where A is a constant of proportion which is given by a relation of A =k·/2 where k is a constant of electromotive force and is magnetic flux over one of the armature windings
where VB is a voltage supplied to the motor driver to operate the motor.
2. An apparatus as set forth in
3. An apparatus as set forth in