Method for controlling constant air volume of electric device adapted to exhaust or supply air

Patent metadata

Field	Value
Publication number	US-10539939-B2
Application number	US-201615331904-A
Country	US
Kind code	B2
Filing date	Oct 23, 2016
Priority date	Oct 29, 2014
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A method for controlling air volume of an electric device to be constant, the device being adapted to exhaust or supply air, the method including: A) establishing M constant air volume control functions Qi=F(n) corresponding to M air volume points CFM i in the microprocessor of the system controller; B) allowing the microprocessor to receive or preset a target air volume IN- CFM ; C) starting the motor, when the motor operates in a stable state, comparing M air volume points CFMi with the target air volume IN- CFM , and ensuring that the target air volume IN- CFM falls within two known air volume points CFMi and CFMi−1; D) using the two known air volume points CFMi and CFMi−1 to calculate a constant air volume control function Q0=F(n) corresponding to the target air volume IN- CFM by interpolation method; and E) controlling a motor parameter Q0 and a rotational speed n.

First claim

The invention claimed is:

1. A method for controlling a motor of an electric device, the method comprising:
A) storing M constant air volume control functions Q i =F(n i ) and M air volume points CFM i in a system controller of the electric device, wherein
the motor comprises a rotational shaft, a permanent magnet rotor assembly, a stator assembly, and a housing assembly; the stator assembly comprises a stator core and a coil winding wound on the stator core;
the system controller comprises a main control circuit board; the main control circuit board comprises a microprocessor, an inverter circuit, and an operation parameter detecting circuit;
the motor is a blower motor and is physically connected to the system controller;
the M constant air volume control functions Q i =F(n i ) and the M air volume points CFM i are in one-to-one correspondence;
Q i represents an input power, a DC bus current, or a torque of the motor;
n i represents a rotational speed of the motor; and
i represents an integer ranging from 1 to M;

B) inputting a target air volume IN-CFM into the microprocessor;
C) starting the motor, activating the microprocessor to compare the M air volume points CFM i with the target air volume IN-CFM to determine two air volume points CFM j and CFM j-1 between which the target air volume IN-CFM falls, wherein j represents an integer ranging from 2 to M, and the two air volume points CFM and CFM j-1 correspond to two constant air volume control functions Q j =F(n j ) and Q j-1 =F(n j-1 ), respectively;
D) activating the microprocessor to obtain a constant air volume control function Q 0 =F(n 0 ) corresponding to the target air volume IN-CFM via an interpolation calculation based on the two air volume points CFM j and CFM j-1 and the two constant air volume control functions Q j =F(n j ) and Q j-1 =F(n j-1 ); and
E) activating the system controller to adjust a real-time motor parameter Q 0 and a real-time rotational speed n 0 of the motor in accordance with a definition curve of the constant air volume control function Q 0 =F(n 0 ), whereby controlling a real-time air volume of the electric device at the target air volume IN-CFM, wherein the motor parameter Q 0 is a real-time input power, a real-time DC bus current, or a real-time torque of the motor;

wherein
the electric device further comprises a wind wheel and a power supply;
the motor is connected to the wind wheel;
permanent magnets are mounted in the permanent magnet rotor assembly;
the permanent magnet rotor assembly and the stator assembly form magnetic coupling;
the operation parameter detecting circuit inputs real-time operation parameters into the microprocessor; and
an output terminal of the microprocessor controls the inverter circuit, and an output terminal of the inverter circuit is connected to the coil winding.

2. The method of claim 1 , wherein
the functions Q i =F(n i ) are established as follows: for M target air volumes, allowing the motor to operate at a constant rotational speed, regulating a static pressure from a lower boundary to an upper boundary which covers an actual static pressure range in an air duct device, and then regulating a rotational speed n and a motor parameter Q of the motor to adjust the air volume of the motor to be the target air volumes, and recording the rotational speed n and the corresponding parameter Q at the stable state of the motor, whereby obtaining a group of rotational speeds n i and the motor parameter Q i for each of the M target air volumes, and establishing the function Q i =F(n i ) for each target air volume by curve fitting.

3. The method of claim 1 , wherein the M air volume points CFM i comprises a maximum output air volume and a minimum output air volume.

4. The method of claim 2 , wherein the M air volume points CFM i comprises a maximum output air volume and a minimum output air volume.

5. The method of claim 1 , wherein Q i =F(n i ) is a second-order function, and each target air volume point corresponds to a function Q=C 1 +C 2 ×n+C 3 ×n 2 , where C 1 , C 2 , and C 3 represent coefficients, and n represents the rotational speed of the motor.

6. The method of claim 2 , wherein Q i =F(n i ) is a second-order function, and each target air volume point corresponds to a function Q=C 1 +C 2 ×n+C 3 ×n 2 , where C 1 , C 2 , and C 3 represent coefficients, and n represents the rotational speed of the motor.

7. The method of claim 5 , wherein the constant air volume control function Q 0 =F(n 0 ) corresponding to the target air volume IN-CFM is acquired as follows:
1) selecting three rotational speeds of the motor represented by n 1 , n 2 , and n 3 , inputting the rotational speed n 1 into the two constant air volume control functions Q j =F(n j-1 ) and Q j-1 =F(n j-1 ) to obtain two values Q 11 and Q 21 ; inputting the rotational speed n 2 into the two constant air volume control functions Q j =F(n j-1 ) and Q j-1 =F(n j-1 ) to obtain two values Q 12 and Q 22 ; inputting the rotational speed n 3 into the two constant air volume control functions Q j =F(n j-1 ) and Q j-1 =F(n j-1 ) to obtain two values Q 13 and Q 23 ;
2) calculating a weighted value according to

w
=

CFM
-

CFM
⁢

⁢
2

CFM
⁢

⁢
2

-

CFM
⁢

⁢
1

,

 and using the weighted value to calculate Q 01 , Q 02 , and Q 03 of Q 0 in the constant air volume control function of the target air volume IN-CFM corresponding to the three rotational speeds n 1 , n 2 , and n 3 , where Q 01 =Q 21 +W×(Q 11 −Q 21 ), Q 02 =Q 22 +W×(Q 12 −Q 22 ), and Q 03 =Q 23 +W×(Q 13 −Q 23 ); and
3) inputting the three rotational speeds n 1 , n 2 , and n 3 and the corresponding Q 01 , Q 02 , and Q 03 into the function Q=C 1 +C 2 ×n+C 3 ×n 2 to acquire coefficients C 1 , C 2 , and C 3 .

8. The method of claim 6 , wherein the constant air volume control function Q 0 =F(n 0 ) corresponding to the target air volume IN-CFM is acquired as follows:
1) selecting three rotational speeds of the motor represented by n 1 , n 2 , and n 3 , inputting the rotational speed ni into the two constant air volume control functions Q j =F(n j-1 ) and Q j-1 =F(n j-1 ) to obtain two values Q 11 and Q 21 ; inputting the rotational speed n 2 into the two constant air volume control functions Q j =F(n j-1 ) and Q j-1 =F(n j-1 ) to obtain two values Q 12 and Q 22 ; inputting the rotational speed n 3 into the two constant air volume control functions Q j =F(n j-1 ) and Q j-1 =F(n j-1 ) to obtain two values Q 13 and Q 23 ;
2) calculating a weighted value according to

w
=

CFM
-

Assignees

• Zhongshan Broad Ocean Motor Co

Inventors

• Wang Jizhong
• Zhou Yiqiao
• Zhang Zheng
• Hu Ge
• Zhang Xiansheng
• Zhao Yong

Classifications

• G05B17/02 Primary

  electric · CPC title

• F24F11/75 Primary

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

• F24F11/63

  Electronic processing · CPC title

• Y02B30/70

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