Motor controller for electric blower motors

Patent metadata

Field	Value
Publication number	US-10774838-B2
Application number	US-201815963738-A
Country	US
Kind code	B2
Filing date	Apr 26, 2018
Priority date	Apr 26, 2018
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A motor controller for an electric motor is provided, including a drive circuit and a processor. The drive circuit regulates power supplied to a stator of the electric motor to turn a rotor and blower to generate an airflow. The processor receives an air density, an airflow rate demand, and at least one of a measured torque and a measured speed of the electric motor. The processor computes one of a torque set point and a speed set point for the electric motor using an airflow algorithm and based on the air density, the airflow rate demand, and the at least one of the measured torque and the measured speed. The processor controls the drive circuit based on the one of the torque set point and the speed set point to supply electrical power to the electric motor and to operate the blower to generate the airflow.

First claim

What is claimed is:

1. A motor controller for an electric motor configured to drive a blower to generate an airflow, said motor controller comprising:
a drive circuit configured to regulate electrical power supplied to a stator of the electric motor to turn a rotor of the electric motor and generate the airflow; and
a processor coupled to said drive circuit and configured to:
receive an air density value;
receive an airflow rate demand value;
compute at least one of a measured torque and a measured speed of the electric motor;
compute one of a torque set point and a speed set point for the electric motor using an airflow algorithm and based on the air density value, the airflow rate demand value, and the at least one of the measured torque and the measured speed; and
control said drive circuit based on the one of the torque set point and the speed set point to supply electrical power to the electric motor and to operate the blower to generate the airflow.

2. The motor controller of claim 1 further comprising a memory configured to store a plurality of air density values, and wherein said processor is further configured to retrieve the air density value from said memory based on a user selection.

3. The motor controller of claim 2 , wherein said processor is further configured to receive the user selection from a system controller.

4. The motor controller of claim 2 , wherein said processor is further configured to receive the user selection from at least one of a jumper configuration and a DIP switch configuration.

5. The motor controller of claim 1 , wherein said processor is further configured to receive the air density value from a system controller.

6. The motor controller of claim 1 , wherein said drive circuit is further configured to regulate a current and a frequency of the electrical power supplied to the stator based on the torque set point, and wherein said processor is further configured to:
compute the torque set point using the airflow algorithm and based at least on the measured speed; and
control said drive circuit based on the torque set point.

7. The motor controller of claim 1 , wherein said drive circuit is further configured to regulate a current and a frequency of the electrical power supplied to the stator based on the speed set point, and wherein said processor is further configured to:
compute the speed set point using the airflow algorithm and based at least on the measured torque; and
control said drive circuit based on the speed set point.

8. A method of operating an electric motor configured to drive a blower to generate an airflow, said method comprising:
receiving an airflow rate demand value from a system controller;
receiving an air density value;
computing at least one of a measured torque and a measured speed of the electric motor;
computing one of a torque set point and a speed set point for the electric motor using an airflow algorithm and based on the air density value, the airflow rate demand value, and the at least one of the measured torque and the measured speed; and
controlling a drive circuit for the electric motor based on the one of the torque set point and the speed set point to supply electrical power to the electric motor and to operate the blower to generate the airflow.

9. The method of claim 8 , wherein receiving the air density value comprises:
receiving a location of a space in a memory; and
retrieving the air density value, from among a plurality of air density values, from the space in the memory.

10. The method of claim 8 , wherein computing the torque set point comprises applying the air density value as a scalar to a polynomial defined as a function of the airflow rate demand value and the measured speed.

11. The method of claim 10 , wherein the polynomial includes at least one term based on a product of the measured speed and the airflow rate demand value.

12. The method of claim 10 , wherein the polynomial includes at least first term based on the airflow rate demand value raised to a power and a second term based on a square of the measured speed.

13. The method of claim 8 , wherein computing the speed set point comprises applying the air density value as a scalar to a polynomial defined as a function of the airflow rate demand value and the measured torque.

14. The method of claim 8 , wherein receiving the measured speed comprises:
detecting a frequency at which the electric motor is energized; and
translating the frequency to a speed of the electric motor.

15. A constant airflow system, comprising:
a blower;
an electric motor coupled to and configured to drive said blower to generate an airflow, said electric motor comprising a stator and a rotor coupled to said blower;
a current sensor coupled to said electric motor and configured to measure a stator current from which at least one of a torque and a speed of said electric motor are derived; and
a motor controller coupled to said sensor, said motor controller comprising a drive circuit configured to regulate electrical power supplied to said stator to turn said rotor and said blower to generate the airflow, and a processor configured to:
receive an airflow rate demand value and an air density value,
compute one of a torque set point and a speed set point for said electric motor using a constant airflow algorithm and based on the air density value, the airflow rate demand value, and the at least one of the torque and the speed,
control said drive circuit based on the one of the torque set point and the speed set point to supply electrical power to said stator to operate said blower to generate the airflow.

16. The constant airflow system of claim 15 , wherein said blower comprises a forward curved blower.

17. The constant airflow system of claim 15 further comprising a system controller configured to transmit the airflow rate demand value to said motor controller.

18. The constant airflow system of claim 17 , wherein said motor controller further comprises a communication interface configured to establish a communication channel with said system controller over which the airflow rate demand value is received.

19. The constant airflow system of claim 15 , wherein said motor controller further comprises a memory within which a plurality of airflow rate demand values are stored, and wherein said processor is further configured to retrieve the airflow rate demand value from said memory based on a memory location corresponding to a selection by at least one of a user and a system controller.

20. The constant airflow system of claim 19 , wherein said processor is further configured to receive the selection from at least one of a jumper configuration and a DIP switch configuration on said motor controller.

Assignees

• Regal Beloit America Inc

Inventors

• Yang Bin
• Beifus Brian L
• Becerra Roger C

Classifications

• F04D27/004 Primary

  by varying driving speed · CPC title

• F24F11/75

  for maintaining constant air flow rate or air velocity · CPC title

• F05D2270/335

  Output power or torque · CPC title

• F24F11/77

  by controlling the speed of ventilators · CPC title

• Y02B30/70

  Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating · CPC title