Linear electric motor controller and system for providing linear control

• US 7,622,885 B2
• Filed: 08/01/2007
• Issued: 11/24/2009
• Est. Priority Date: 12/13/2001
• Status: Expired due to Fees

• Current Assignee: 2112376 Ontario Limited (Carter Group, Inc.)
• Original Assignee: 2112376 Ontario Limited (Carter Group, Inc.)
• Inventors: LaCroix, Michael Charles
• Primary Examiner(s): Ro; Bentsu
• Assistant Examiner(s): GLASS, ERICK DAVID
• Application Number:
  US11/832,024
• Publication Number:
  US 20080024084A1
• Time in Patent Office: 846 Days
• Field of Search: 318/806, 388/801, 326/46
• US Class Current: 318/806
• CPC Class Codes: H02H 7/0822 Integrated protection, motor control centres
• CPC Class Codes: H02P 29/02 Providing protection against overload without automatic interruption of supply protection against faults of stepper motors H02P8/36

Abstract

The invention relates to a method of, and system for, linear speed control for an electric motor, in which a digital to analog converter means is used for converting an 8-bit digital signal to an analog voltage for setting voltage across a motor, a digital state machine means is used for converting the duty cycle of an input signal for output to the digital to analog converter means, and a closed loop feedback loop means is used for monitoring and setting the voltage across the motor. An over-current sense circuit can be used for monitoring the current across the electric motor. An over/under voltage sense circuit can be used for monitoring voltage of the electric motor. The resulting 8-bit digital control signal is converted to an analog voltage for the electric motor. Such methods and systems find particular use in automotive applications.

Claims

1. An electric motor linear speed controller, comprising:

a digital to analog converter means for converting an 8-bit digital signal to an analog voltage for setting voltage across a motor;

a digital state machine means comprising a digital logic means and a state machine, which digital state machine is adapted and configured to convert the duty cycle of an input signal for output to the digital to analog converter means;

a closed loop feedback means for monitoring and setting the voltage across the motor; and

an over-current sense circuit for monitoring a current across the motor.

2. The controller according to claim 1, wherein the closed loop feedback means is adapted to set the voltage to a constant voltage across the motor.

3. The controller according to claim 1, further comprising an over/under voltage sense circuit for monitoring a supply voltage to the electric controller.

4. A system for controlling an electric automotive component comprising a component and the electric motor linear speed controller of claim 1.

5. The system according to claim 4, wherein the component is an electric motor.

6. The system according to claim 4, wherein the component is an electric light.

7. The system according to claim 4, further comprising an over/under voltage sense circuit for monitoring a supply voltage to the electric controller.

8. A circuit arrangement in a variable speed electric motor controller, comprising:

a controller logic circuit for operating a controller logic finite state machine to convert an analog signal to a digital signal, wherein the state machine sets the voltage supplied to an electric motor, wherein the controller logic circuit comprises a microprocessor and a memory, each configured for collectively controlling the state machine; and

a closed loop feedback circuit for generating a signal indicating the voltage across the electric motor, the signal being for comparison to the voltage set by the state machine.

9. The circuit arrangement of claim 8, wherein the state machine comprises at least a running state.

10. The circuit arrangement of claim 9, further comprising one or more of the following set of states:

a sleep state, a lockout state, an overcurrent state, a timeout state, or a battery check state.

11. The circuit arrangement of claim 8, additionally comprising a digital to analog converter for converting an 8-bit digital signal to an analog voltage for setting the voltage supplied to the electric motor.

12. The circuit arrangement of claim 8, wherein the circuit arrangement is directly coupled with the electric motor.

13. A system for controlling an electric automotive component, comprising:

an electric light; and

an electric motor linear speed controller which comprises;

a digital to analog converter means for converting an 8-bit bit digital signal to an analog voltage for setting voltage across a motor;

a digital state machine means comprising a digital logic means and a state machine, which digital state machine is adapted and configured to convert the duty cycle of an input signal for output to the digital to analog converter means; and

a closed loop feedback means for monitoring and setting the voltage across the motor.

14. A system for controlling the speed of an electric motor-comprising:

a digital to analog converter means, for converting a digital signal to analog voltage for setting a voltage across the electric motor;

a microprocessor and associated digital memory for generating the digital signal, the microprocessor configured to instantiate and operate a digital state machine for converting the duty cycle of an input signal to the microprocessor and associated digital memory, wherein the state machine sets the voltage supplied to the electric motor based on the input signal; and

a closed loop feedback loop means adapted and configured to monitor the voltage across the motor and generate a signal for input to the microprocessor.

15. An automobile comprising the system of claim 14.

16. The automobile of claim 15, wherein the system comprises a temperature-control system.

17. A linear speed controller for an automotive electric motor, comprising:

a digital state machine for converting a duty cycle of an input signal for setting the voltage to be supplied to the motor;

an over-current sense circuit, for monitoring the current across the electric motor;

an over/under voltage sense circuit, for monitoring a supply voltage to the electric controller;

a digital to analog converter, for converting an 8-bit digital signal to analog voltage for setting voltage across the electric motor; and

a closed loop feedback loop and configured to monitor the voltage across the motor and generate a feedback signal for adjusting the voltage supplied to the motor.

18. The linear speed controller of claim 17 wherein the duty cycle is provided to the digital state machine by digital circuitry.

19. The linear speed controller of claim 17 wherein the closed loop feedback circuit comprises a differential amplifier.