Component position determination circuit using a brushless DC motor commutation sensor

• US 20080018282A1
• Filed: 07/05/2006
• Published: 01/24/2008
• Est. Priority Date: 07/05/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Potter, Calvin, Hanlon, Casey, Wingett, Paul
• Granted Patent: US 7,486,042 B2
• Time in Patent Office: Days
• US Class Current: 318/466
• CPC Class Codes: G05B 2219/37171 Commutation brushes, sensors deliver increment
• CPC Class Codes: G05B 2219/41321 Brushless dc motor
• CPC Class Codes: H02P 6/14 Electronic commutators
• CPC Class Codes: Y10S 388/901 Sample and hold

Abstract

A position determination circuit uses the commutation sensor of a brushless DC motor to determine the position of an actuator and/or actuated component 125. The commutation sensor supplies a rotational position signal representative of the rotational position of the motor to a pulse generator. The pulse generator generates a pulse each time the rotational position signal represents a complete revolution of the brushless DC motor. The generated pulses are supplied to an integrator circuit, which selectively supplies a position signal having a voltage magnitude representative of the position of the actuator and/or component.

Claims

1. A position determination circuit for determining a position of a component driven by a brushless DC motor, the circuit comprising:

a commutation sensor configured to sense a rotational position of the brushless DC motor and operable to supply a rotational position signal representative thereof;

a pulse generator coupled to receive the rotational position signal and operable to generate a pulse each time the rotational position signal represents a complete revolution of the brushless DC motor; and

an integrator circuit coupled to receive (i) an enable signal and (ii) each pulse generated by the pulse generator, the integrator circuit operable, upon receipt of both the enable signal and each pulse, to selectively supply a position signal having a voltage magnitude representative of the position of the component.

2. The circuit of claim 1, wherein the component is driven between at least a first end-of-travel position and a second end-of-travel position, and wherein the circuit further comprises:

an integrator enable circuit coupled to receive (i) one or more command signals representative of a command to move the component to the first or second position and (ii) an end-of-travel signal indicating that the component is not in either the first or second end-of-travel positions, the integrator enable circuit coupled to the integrator and configured to supply the enable signal thereto, upon receipt of the one or more command signals and the end-of-travel signal.

3. The circuit of claim 1, further comprising:

a sample-and-hold circuit coupled to receive the position signal from the integrator and configured, upon receipt thereof, to (i) selectively supply the position signal and (ii) selectively store the voltage magnitude representative of the position of the component.

4. The circuit of claim 3, wherein the sample-and-hold circuit stores the voltage magnitude when the position signal is not being supplied thereto.

5. The circuit of claim 3, further comprising:

a switch electrically coupled between the integrator and the sample-and-hold circuit, the switch movable between a closed position, in which the integrator is electrically coupled to the sample-and-hold circuit, and an open position, in which the integrator is electrically isolated from the sample-and-hold circuit.

6. The circuit of claim 5, wherein the switch is in the closed position when the circuit is energized, and in the open position when the circuit is deenergized.

7. The circuit of claim 6, wherein:

the switch is a solenoid operated switch;

the switch is moved to the closed position when the solenoid is energized; and

the switch is moved to the open position when the solenoid is deenergized.

8. The circuit of claim 1, further comprising:

signal conditioning circuitry electrically coupled between the commutation sensor and the pulse generator.

9. An actuation control system, comprising:

a motor control circuit configured to receive position command signals and operable, upon receipt thereof, to supply DC excitation signals;

a brushless DC motor coupled to receive the DC excitation signals and operable, upon receipt thereof, to rotate and supply a drive force;

an actuator coupled to receive the drive force and operable, upon receipt thereof, to move to an actuator position;

a commutation sensor configured to sense rotational position of the brushless DC motor and operable to supply a rotational position signal representative thereof;

a pulse generator coupled to receive the rotational position signal and operable to generate a pulse each time the rotational position signal represents a complete revolution of the brushless DC motor; and

an integrator circuit coupled to receive (i) an enable signal and (ii) each pulse generated by the pulse generator, the integrator circuit operable, upon receipt of both the enable signal and each pulse, to selectively supply a position signal having a voltage magnitude representative of the actuator position.

10. The system of claim 9, wherein the actuator is driven between at least a first end-of-travel position and a second end-of-travel position, and wherein the system further comprises:

an integrator enable circuit coupled to receive (i) one or more signals at least indicating that position command signals are being supplied to the motor control circuit and (ii) an end-of-travel signal indicating that the component is not in either the first or second end-of-travel positions, the integrator enable circuit coupled to the integrator and configured to supply the enable signal thereto, upon receipt of the one or more command signals and the end-of-travel signal.

11. The system of claim 10, further comprising:

a first end-of-travel switch movable between a first position and a second position, the first end-of-travel switch configured to be in the first position when the actuator is in the first end-of-travel position, and in the second position when the actuator is not in the first end-of-travel position; and

a second end-of-travel switch movable between a first position and a second position, the second end-of-travel switch configured to be in the first position when the actuator is in the second end-of-travel position, and in the second position when the actuator is not in the second end-of-travel position,

wherein the end-of-travel signal is supplied to the integrator enable circuit when the first and second end-of-travel switches are both in the second position.

12. The system of claim 9, further comprising:

a sample-and-hold circuit coupled to receive the position signal from the integrator and configured, upon receipt thereof, to (i) selectively supply the position signal and (ii) selectively store the voltage magnitude representative of the position of the component.

13. The system of claim 12, wherein the sample-and-hold circuit stores the voltage magnitude when the position signal is not being supplied thereto.

14. The system of claim 12, further comprising:

a switch electrically coupled between the integrator and the sample-and-hold circuit, the switch movable between a closed position, in which the integrator is electrically coupled to the sample-and-hold circuit, and an open position, in which the integrator is electrically isolated from the sample-and-hold circuit.

15. The system of claim 14, wherein the switch is in the closed position when the circuit is energized, and in the open position when the circuit is deenergized.

16. The system of claim 15, wherein:

the switch is a solenoid operated switch;

the switch is moved to the closed position when the solenoid is energized; and

the switch is moved to the open position when the solenoid is deenergized.

17. A position determination circuit for determining a position of a component driven by a brushless DC motor, the circuit comprising:

a commutation sensor configured to sense a rotational position of the brushless DC motor and operable to supply a rotational position signal representative thereof;

a processor including a counter and a pulse generator, the processor coupled to receive the rotational position signal and operable, upon receipt thereof, to (i) command the counter to count a number of complete revolutions of the brushless DC motor and (ii) command the pulse generator to generate a pulse each time the brushless DC motor makes a complete revolution; and

an integrator circuit coupled to receive each pulse generated by the pulse generator and operable, upon receipt thereof, to supply an analog position signal having a voltage magnitude representative of the position of the component.

18. The circuit of claim 17, wherein the processor is further operable to determine the position of the component based at least in part on the number of complete revolutions counted by the counter.

19. The circuit of claims 17, further comprising:

an analog-to-digital converter coupled to receive the analog position signal and operable, upon receipt thereof, to convert the analog position signal to a digital position signal representative of the position of the component,

wherein the processor is further coupled to receive the digital position signal from the ADC and is further operable to determine the position of the component based on the digital position signal.

20. The system of claim 17, further comprising:

a sample-and-hold circuit coupled to receive the analog position signal from the integrator and configured, upon receipt thereof, to (i) selectively supply the analog position signal and (ii) selectively store the voltage magnitude representative of the position of the component.