System and method for look ahead detection of electrical problems at a motor of a vehicle

• US 20080084229A1
• Filed: 09/19/2006
• Published: 04/10/2008
• Est. Priority Date: 09/19/2006
• Status: Active Grant

• Current Assignee: Flextronics Automotive Inc
• Original Assignee: Flextronics Automotive Inc
• Inventors: Singh, Shashank Kumar, Tahir, Wasim, Dominik, Tomasz T., Chinsen, Jason, Frommer, Thomas
• Granted Patent: US 7,489,483 B2
• Time in Patent Office: Days
• US Class Current: 324/772
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58

Abstract

A system for sensing short circuits and open circuits prior to operation of a motor (i.e., while the motor is in a static state), thereby sparing the electrical system from destructive effects of these electrical problems. In addition, the system may detect a short circuit during operation of the motor (i.e., while the motor is in a dynamic state). Still yet, the system may detect an open circuit at the motor. The motor may be any electromechanical motor, such as a direct current (DC) motor, used in a vehicle or otherwise for controlling motion of a mechanical device.

Claims

1. A circuit for determining an electrical problem at a motor, said circuit comprising:

a first voltage divider circuit connected to a first terminal of the motor via a first conductor;

a first test point disposed on the first conductor; and

an input line connected to said first voltage divider circuit to enable a first supply voltage to be applied to said first voltage divider circuit and cause a first test voltage to be applied to the first conductor, the first test voltage being available at said first test point for measurement if a short circuit does not exist along the first conductor.

2. The circuit according to claim 1, further comprising:

a second voltage divider circuit connected to a second terminal of the motor via a second conductor;

a second test point disposed on the second conductor; and

an input line connected to said second divider circuit to enable a second supply voltage to be applied to said second voltage divider circuit and cause a second test voltage to be applied to the second conductor, the second test voltage being available at said second test point for measurement if a short circuit does not exist along the conductor.

3. The circuit according to claim 2, further comprising:

a pair of switches connected at a common terminal to the first and second conductors, respectively, said pair of switches each having a first and second selectable terminal, a first voltage source conductor connected to the first selectable terminals of said pair of switches;

a third switch connected to the second selectable terminals; and

a second voltage source conductor connected to one side of said third switch, said third switch selectability being switched to apply a voltage on said second voltage source conductor to the second selectable terminals.

4. The circuit according to claim 3, wherein the first and second terminals of the motor are electrically coupled when said third switch is in an open state and said pair of switches are in an off state.

5. The circuit according to claim 3, further comprising a processor in communication with said pair of switches, said third switch, and executing a software program to cause said pair of switches and third switch to be in states to enable said processor to measure voltages at at least one of said first and second test points to determine if an electrical problem exists at the terminals of the motor.

6. The circuit according to claim 5, wherein the states of said pair of switches and third switch cause the motor to be in a static state and said processor determines if a short circuit exists at either of the terminals by measuring at least one test voltage at said first and second test points.

7. The circuit according to claim 5, wherein said processor is further configured to configure said pair of switches and third switch to determine if an open circuit exists at the motor.

8. The circuit according to claim 5, wherein the states of said pair of switches and third switch cause the motor to be in a dynamic state and said processor determines if a short circuit exists at either of the terminals by measuring voltages at said first and second test points.

9. The circuit according to claim 5, wherein the software is configured to receive a motor activation signal and measure at least one of the test points before activating the motor.

10. The circuit according to claim 2, wherein said first and second voltage dividers each include a pair of resistors having the same values and the first and second supply voltages are the same.

11. The circuit according to claim 10, wherein the pair of resistors include resistors having different values.

12. A system for determining whether an electrical problem exists at a motor of a vehicle, said system comprising:

a motor having a first terminal and a second terminal;

a test circuit connected to the first and second terminals of said motor and configured to test whether an electrical problem exists at said motor; and

a processor in communication with said test circuit and be configured to determine whether an electrical problem exists at said motor prior to activation of the motor.

13. The system according to claim 12, wherein said motor is a DC motor.

14. The system according to claim 12, wherein said test circuit includes first and second switches, respectively, electrically connected to the first and second terminals of said motor.

15. The system according to claim 14, wherein said first and second can be solid state or electro-mechanical switches.

16. The system according to claim 15, further comprising a third switch electrically connected selectable to said first and second switches.

17. The system according to claim 16, wherein said third switch is an electrical switch.

18. The system according to claim 12, wherein said test circuit further includes at least one voltage divider connected to at least one of the first and second terminals of said motor, respectively.

19. The system according to claim 18, wherein said at least one voltage divider includes two resistors.

20. The system according to claim 19, wherein each of the resistors has the same resistance value.

21. The system according to claim 19, wherein each of the resistors has a different resistance value.

22. The system according to claim 12, wherein said test circuit is configured to test whether an open circuit exists at the first and second terminals of said motor.

23. The system according to claim 12, wherein said test circuit and processor are further configured to test whether the short circuit exists when the motor is in both a static and dynamic state.

24. The system according to claim 12, wherein said test circuit is configured to apply a bias voltage to the first and second terminals of the motor prior to activation thereof in determining whether an electrical problem exists at the motor.

25. A method for determining if an electrical problem exists at a motor of a vehicle, said method comprising:

prior to activation of a motor, applying a bias voltage to terminals of the motor to maintain a static state of the motor;

measuring at least one voltage being applied to the terminals of the motor; and

determining if a short circuit exists at the motor based on said at least one measured voltage.

26. The method according to claim 25, further comprising:

after determining if a short circuit exists while the motor is in the static state, applying a first voltage on a first terminal of the motor and a second voltage to a second terminal of the motor, the first and second voltages being different to cause the motor to be in a dynamic state; and

repeating said measuring and determining if a short circuit exists at the motor while in the dynamic state.

27. The system according to claim 25, wherein said determining if a short circuit exists includes determining if at least one measured voltage is below or above a threshold voltage.

28. The system according to claim 25, further comprising:

after determining if a short circuit exists while the motor is in the static state, applying a first voltage on a first terminal of the motor and a second voltage to a second terminal of the motor, the first and second voltages being different;

measuring voltages at the terminals of the motor; and

determining if an open circuit exists at the motor based on the measured voltages.

29. A method for determining if an electrical problem exists at a motor of a vehicle, said method comprising:

applying a first voltage to a conductor connected to a first terminal of the motor;

applying a second voltage to a conductor connected to a second terminal of the motor, said first and second voltages being applied to the terminal of the motor causing the motor to be in a dynamic state;

measuring a voltage on at least one of the conductors connected to the first and second terminals of the motor; and

determining if a short circuit exists based on the measurement of the voltage on the at least one conductor.

30. The method according to claim 29, wherein applying the first and second voltages includes applying the voltages prior to activating the motor in response to a driver or passenger attempting to activate the motor.

31. The method according to claim 29, further comprising:

prior to applying the first and second voltages to the terminals of the motor, applying a bias voltage to the terminals to cause the motor to be in a static state;

measuring at least one second voltage at the terminals; and

based on said measurement of one second voltage, determining whether a short circuit exists while the motor is in the static state.

32. The method according to claim 31, further comprising:

after applying the bias voltage to the terminals, applying a reference voltage to one of the terminals, wherein the reference voltage is different from the bias voltage;

measuring the voltages on the terminals; and

determining if an open circuit exists at the motor based on the measured voltages.

33. The method according to claim 31, wherein applying the bias voltage is performed prior to activating the motor.