Motor controller for electric blower motors

• US 10,294,950 B2
• Filed: 05/15/2017
• Issued: 05/21/2019
• Est. Priority Date: 05/15/2017
• Status: Active Grant

• Current Assignee: Regal Beloit America, Inc. (Regal Rexnord Corp.)
• Original Assignee: Regal Beloit America, Inc. (Regal Rexnord Corp.)
• Inventors: Beifus, Brian Lee, Bloomfield, Kathryn, Barry, Andrew C.
• Primary Examiner(s): Duda, Rina I
• Application Number:
  US15/595,420
• Publication Number:
  US 20180328370A1
• Time in Patent Office: 736 Days
• Field of Search: 318461, 318432, 318434
• CPC Class Codes: F04D 27/001 Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring
• CPC Class Codes: F04D 27/004 by varying driving speed
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: H02P 6/08 Arrangements for controlling the speed or torque of a single motor H02P6/10, H02P6/28 take precedence
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A motor controller for an electric motor is provided. The electric motor is configured to drive a blower to generate an airflow. The motor controller includes a memory and a processor coupled thereto. The memory is configured to store a speed-to-airflow ratio associated with an airflow restriction on the blower. The processor is configured to receive a command for a calibrating airflow and operate the electric motor in a constant airflow mode to generate the calibrating airflow at a calibrating speed. The processor is further configured to write the calibrating speed and the calibrating airflow to the memory as the speed-to-airflow ratio.

Claims

1. A motor controller for an electric motor configured to drive a blower to generate an airflow, said motor controller comprising:

a memory configured to store a single speed-to-airflow ratio associated with an airflow restriction on the blower; and

a processor coupled to said memory and configured to;

receive a command for a calibrating airflow;

operate the electric motor in a constant airflow mode to generate the calibrating airflow at a calibrating speed;

write the calibrating speed and the calibrating airflow to said memory as the single speed-to-airflow ratio;

receive a first command for a first objective airflow;

compute a first objective speed based on the single speed-to-airflow ratio and the first objective airflow;

operate the electric motor at the first objective speed to generate a first output airflow;

receive a second command for a second objective airflow;

compute a second objective speed based on the single speed-to-airflow ratio and the second objective airflow; and

operate the electric motor at the second objective speed to generate a second output airflow.

2. The motor controller of claim 1, wherein said processor is further configured, in computing the objective speed, to linearly extrapolate the single speed-to-airflow ratio for the objective airflow.

3. The motor controller of claim 2, wherein said processor is further configured, in computing the objective speed, to apply a correction function to the linear extrapolation for the objective airflow.

4. The motor controller of claim 1, wherein said processor is further configured to monitor torque output at the objective speed to detect a change in the airflow restriction on the blower.

5. The motor controller of claim 1, wherein said processor is further configured, before operating the electric motor in a constant airflow mode to generate the calibrating airflow, to determine the single speed-to-airflow ratio has not been stored.

6. The motor controller of claim 1, wherein said processor is further configured to stabilize the calibrating speed before writing the calibrating speed and the calibrating airflow to said memory as the single speed-to-airflow ratio.

7. The motor controller of claim 1, wherein said processor is further configured, before operating the electric motor in a constant airflow mode to generate the calibrating airflow, confirm a calibrating torque, at which the calibrating airflow is achieved, is within a calibrating range defined as 40% to 80% maximum torque output, inclusively.

8. A method of operating an electric motor configured to drive a blower to generate an airflow, said method comprising:

operating the electric motor at a calibrating speed to drive the blower to generate a calibrating airflow;

storing the calibrating speed and the calibrating airflow in a memory as a single speed-to-airflow ratio;

receiving a first command for a first objective airflow that is less than the calibrating airflow;

computing first objective speed based on the single speed-to-airflow ratio and the first objective airflow;

operating the electric motor at the first objective speed to drive the blower to generate a first output airflow;

receiving a second command for a second objective airflow;

computing a second objective speed based on the single speed-to-airflow ratio and the second objective airflow; and

operating the electric motor at the second objective speed to generate a second output airflow.

9. The method of claim 8 further comprising, before storing the calibrating speed and the calibrating airflow:

determining a calibrating torque, at which the calibrating airflow is achieved, is within a calibrating range; and

determining a valid speed-to-airflow ratio is not stored.

10. The method of claim 9 further comprising:

monitoring a torque output when operating the electric motor at the objective speed;

detecting a change in the torque output when operating the electric motor at the objective speed;

marking the single speed-to-airflow ratio as invalid in response to detecting the change in the torque output; and

initiating a recalibration and storing of a single new speed-to-airflow ratio.

11. The method of claim 8, wherein computing the objective speed comprises:

linearly extrapolating the single speed-to-airflow ratio for the objective airflow; and

applying a correction function to the linear extrapolation for the objective airflow.

12. The method of claim 11, wherein applying the correction function comprises raising the ratio of the objective airflow to the calibrating airflow, to the power of a correction factor.

13. The method of claim 8, wherein operating the electric motor at the calibrating speed comprises operating the electric motor in a speed-control mode.

14. A blower system, comprising:

a blower configured to generate an airflow;

an electric motor coupled to said blower and configured to drive said blower; and

a motor controller coupled to said electric motor and configured to;

receive a command for a calibrating airflow;

determine a calibrating speed at which said electric motor turns to drive said blower to generate a calibrating airflow;

operate the electric motor to drive said blower to generate the calibrating airflow at the calibrating speed; and

store the calibrating speed and the calibrating airflow in a memory as a single speed-to-airflow ratio;

compute a first objective speed based on the single speed-to-airflow ratio and a first commanded objective airflow; and

operate said electric motor at the first objective speed to generate a first output airflow;

compute a second objective speed based on the single speed-to-airflow ratio and a second commanded objective airflow; and

operating the electric motor at the second objective speed to generate a second output airflow.

15. The blower system of claim 14, wherein said motor controller is further configured, in determining the calibrating speed, to:

determine a calibrating torque, at which the calibrating airflow is achieved, is within a calibrating range; and

determine a valid speed-to-airflow ratio is not stored.

16. The blower system of claim 14, wherein said motor controller is further configured, in computing the objective speed, to:

linearly extrapolate the single speed-to-airflow ratio for the objective airflow; and

apply a correction function to the linear extrapolation for the objective airflow.

17. The blower system of claim 16, wherein said motor controller is further configured, in computing the objective speed, to raise the ratio of the objective airflow to the calibrating airflow, to the power of a correction factor.

18. The blower system of claim 14, wherein said motor controller is further configured to determine a new calibrating speed at which said electric motor turns to drive said blower to generate the calibrating airflow after detecting an airflow restriction of the blower system has changed.