ROBUST BLOWER MOTOR STARTUP TECHNIQUE

• US 20090096398A1
• Filed: 10/10/2007
• Published: 04/16/2009
• Est. Priority Date: 10/10/2007
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Kyrtsos, Christos, Brown, Kenneth Gerard, Issa, Ibrahim Mohammed
• Granted Patent: US 7,834,572 B2
• Time in Patent Office: Days
• US Class Current: 318/432
• CPC Class Codes: B60H 1/00828 Ventilators, e.g. speed control B60H1/00864 takes precedence
• CPC Class Codes: B60H 1/00978 Control systems or circuits characterised by failure of detection or safety means; Diagnostic methods
• CPC Class Codes: H02P 1/04 Means for controlling progress of starting sequence in dependence upon time or upon current, speed, or other motor parameter
• CPC Class Codes: H02P 1/18 for starting an individual dc motor
• CPC Class Codes: H02P 29/0241 the fault being an overvoltage
• CPC Class Codes: H02P 29/032 Preventing damage to the motor, e.g. setting individual current limits for different drive conditions

Abstract

A method for starting a blower motor with a locked rotor condition, the motor having one or more speed settings, each speed setting having a reference voltage and reference current value associated therewith, the method comprising, from a motor off condition, applying the reference voltage to the motor, the reference voltage associated with a desired speed setting; measuring current flowing through the motor to define a measured current value; comparing the measured current value to the reference current value associated with the desired speed setting to determine if a locked rotor condition exists; if a locked rotor condition exists, increasing the motor speed from the desired speed setting until either the output speed is at a maximum speed or the locked rotor condition ceases to exist; and adjusting the motor output speed value to the desired speed setting.

Claims

1. A method for starting a blower motor with a locked rotor condition, the motor having one or more speed settings, each speed setting having a reference voltage and reference current value associated therewith, the method comprising:

from a motor off condition, applying the reference voltage to the motor, the reference voltage associated with a desired speed setting;

measuring current flowing through the motor to define a measured current value;

comparing the measured current value to the reference current value associated with the desired speed setting to determine if a locked rotor condition exists;

if a locked rotor condition exists, increasing the motor speed setting from the desired speed setting until either the output speed is at a maximum speed or the locked rotor condition ceases to exist; and

upon the motor start, adjusting the motor output speed value to the desired speed setting.

2. The method of claim 1 further comprising:

if a locked rotor condition exists, generating a diagnostic fault code having information associated with the locked rotor condition;

3. The method of claim 2, wherein the step of generating a diagnostic fault code further comprises logging the fault code in a computer readable memory location.

4. The method of claim 1, wherein the step of comparing the measured current value to the reference current value is defined by the expression

I_error=I_measured−

I_reference

where;

I_error is an error value,

I_measured is the measured current value, and

I_reference is the reference current value;

wherein the locked rotor condition exists if the error value exceeds a predetermined threshold value.

5. The method of claim 1, wherein the step of comparing the measured current value to the reference current value is defined by the expression

I_error=I_measured/I_reference

where:

I_error is an error current value,

I_measured is the measured current value, and

I_reference is the reference current value;

wherein the locked rotor condition exists if the error value exceeds a predetermined threshold value.

6. A controller for controlling a blower motor, the controller comprising a computer readable storage medium having a lookup table encoded therein, the lookup table having a plurality of speed settings associated with the motor, each speed setting having an associated reference voltage and reference current value, the controller adaptable to:

apply the reference voltage to the motor, the reference voltage associated with a desired speed setting;

measure current flowing through the motor to define a measured current value;

compare the measured current value to the reference current value associated with the desired speed setting to determine if a locked rotor condition exists;

if a locked rotor condition exists, increase the motor speed from the desired speed value until either the speed setting is maximized or the locked rotor condition ceases to exist; and

adjust the motor speed setting to the desired speed setting.

7. The controller of claim 6, wherein the measured current value and the reference current value are compared by the expression

I_error=I_measured−

I_reference

where;

I_error is the error current value,

I_measured is the measured current value, and

I_reference is the reference current value.

8. The controller of claim 6, wherein the measured current value and the reference current value are compared by the expression

I_error=I_measured/I_reference

where:

I_error is the error current value,

I_measured is the measured current value, and

I_reference is the reference current value.

9. The controller of claim 6, wherein the lookup table further comprises one or more additional parameters associated with each speed value.

10. The controller of claim 6, wherein the controller is adaptable to store diagnostic codes to the storage medium.

11. The controller of claim 10, wherein the controller is adaptable to send the diagnostic codes to an engine control unit.

12. A system for protecting against a locked rotor condition in a blower motor, the system comprising:

a blower motor adaptable to produce an output speed setting as a function of a voltage value;

a controller adaptable to produce the voltage value, the controller having a computer readable storage medium, the storage medium including a lookup table encoded therein, the lookup table having a plurality of speed settings associated with the motor, each speed setting having an associated reference voltage value and reference current value defined in the lookup table, the controller adaptable to receive a desired speed setting, the storage medium including;

an instruction for applying the reference voltage to the motor, the reference voltage associated with the desired speed setting;

an instruction for measuring current flowing through the motor to define a measured current value;

an instruction for comparing the measured current value to the reference current value associated with the desired speed setting to determine if a locked rotor condition exists;

an instruction for, if a locked rotor condition exists, increasing the motor output speed from the desired speed value until either the speed setting is maximized or the locked rotor condition ceases to exist; and

an instruction for adjusting the motor output speed to the desired speed setting.

13. The system of claim 12, wherein the instruction for comparing the measured current value to the reference current value is further defined by the expression

I_error=I_measured−

I_reference

where;

I_error is the error current value,

I_measured is the measured current value, and

I_reference is the reference current value.

14. The system of claim 12, wherein the instruction for comparing the measured current value to the reference current value is further defined by the expression

I_error=I_measured/I_reference

where:

I_error is the error current value,

I_measured is the measured current value, and

I_reference is the reference current value.

15. The system of claim 12, wherein the controller lookup table further comprises one or more additional parameters associated with each speed value.

16. The system of claim 12, wherein the storage medium further includes an instruction for storing diagnostic codes to the storage medium.

17. The system of claim 16 further comprising an engine control unit in electrical communication with the controller, the storage medium further including an instruction for sending the diagnostic codes to the engine control unit.

18. The system of claim 16, wherein the controller instruction for storing diagnostic codes to the storage medium further includes logging the diagnostic code in a computer readable memory location.