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

A method for controlling a motor of an electric device, the method comprising:

• A) storing M constant air volume control functions Qi=F(ni) and M air volume points CFMi 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 Qi=F(ni) and the M air volume points CFMi are in one-to-one correspondence;
• Qi represents an input power, a DC bus current, or a torque of the motor;
• ni 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 CFMi with the target air volume IN-CFM to determine two air volume points CFMj and CFMj-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 CFMj-1 correspond to two constant air volume control functions Qj=F(nj) and Qj-1=F(nj-1), respectively;
• D) activating the microprocessor to obtain a constant air volume control function Q0=F(n0) corresponding to the target air volume IN-CFM via an interpolation calculation based on the two air volume points CFMj and CFMj-1 and the two constant air volume control functions Qj=F(nj) and Qj-1=F(nj-1);
• and
• E) activating the system controller to adjust a real-time motor parameter Q0 and a real-time rotational speed n0 of the motor in accordance with a definition curve of the constant air volume control function Q0=F(n0), whereby controlling a real-time air volume of the electric device at the target air volume IN-CFM, wherein the motor parameter Q0 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.