Brushless three phase direct current motor control circuit
First Claim
1. A control circuit for providing switching drive signals to establish synchronous phase current drive through the stator windings of a brushless direct current motor which is coupled to the control circuit, comprising:
- increment drive circuit means responsive to trigger signals supplied thereto when the motor is in a run mode for producing clock pulses as well as cyclical, sequential output signals at a plurality of outputs therefrom;
switching circuit means having a plurality of inputs and outputs, each output being coupled to a respective stator winding at an output of the control circuit, said inputs being coupled with respective ones of said plurality of outputs of said increment drive circuit means, said switching circuit means being responsive to said cyclical and sequential output signals for producing the switching drive signals such that phase current is establish in a cyclical and sequential manner through the stator windings in timed relationship with the operation of the motor;
trigger circuit means which is responsive to enabling signals supplied thereto at an input thereof for producing said triggering signals, said triggering signals being supplied to an input of said increment drive circuit means; and
feedback circuit means coupled between said plurality of outputs of said increment drive circuit means and each stator winding which is responsive to said sequential output signals and the EMF voltage established across the stator windings for producing said enabling signals in synchronism with the operation of the motor such that the phase current drive is established in the next succeeding stator winding in correct timed relationship.
1 Assignment
0 Petitions
Accused Products
Abstract
A driver circuit is coupled to the stator windings of a brushless three phase DC motor which is responsive to the open circuit back EMF voltage induced in the next stator winding to be energized as a permanent magnet rotor of the motor is caused to be rotated for producing phase current drive to the stator winding in synchronous with the operation of the motor. The driver circuit includes an increment drive circuit for supplying periodic switching command signals in succession to a switching circuit to produce phase current drive in each stator. The increment drive circuit increments a switch command signal to cause phase current through the next phase stator winding in reference to the magnitude of the EMF voltage induced across said phase stator winding falling below a reference level. A feature of the invention is that the frequency of the periodic switch command signals is varied during starting of the motor dependent on the magnitude of starting potential supplied to the driver circuit to prevent the motor from "locking" which would otherwise inhibit start thereof.
51 Citations
9 Claims
-
1. A control circuit for providing switching drive signals to establish synchronous phase current drive through the stator windings of a brushless direct current motor which is coupled to the control circuit, comprising:
-
increment drive circuit means responsive to trigger signals supplied thereto when the motor is in a run mode for producing clock pulses as well as cyclical, sequential output signals at a plurality of outputs therefrom; switching circuit means having a plurality of inputs and outputs, each output being coupled to a respective stator winding at an output of the control circuit, said inputs being coupled with respective ones of said plurality of outputs of said increment drive circuit means, said switching circuit means being responsive to said cyclical and sequential output signals for producing the switching drive signals such that phase current is establish in a cyclical and sequential manner through the stator windings in timed relationship with the operation of the motor; trigger circuit means which is responsive to enabling signals supplied thereto at an input thereof for producing said triggering signals, said triggering signals being supplied to an input of said increment drive circuit means; and feedback circuit means coupled between said plurality of outputs of said increment drive circuit means and each stator winding which is responsive to said sequential output signals and the EMF voltage established across the stator windings for producing said enabling signals in synchronism with the operation of the motor such that the phase current drive is established in the next succeeding stator winding in correct timed relationship. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification