Brushless DC External Rotor Motor for Ceiling Fans
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Solution Overview
Problem
Conventional ceiling fan motors using single-phase AC induction motors suffer from high energy consumption, noise, instability at low speeds, complex configuration, difficult assembly, and high costs.
Innovation Solution
A brushless DC external rotor motor with a simple structure comprising a shaft, stator, and rotator, where the rotator is engaged with the shaft via bearings, and includes magnets and a circular box for the electrical control member, allowing for efficient operation and easy assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If single-phase AC induction motors are used in ceiling fans, then the motor can operate continuously, but energy consumption is high and efficiency is low
Solution Approach 1:
The patent replaces the single-phase AC induction motor with a brushless DC motor, substituting the electromagnetic induction principle with a permanent magnet synchronous motor principle controlled by electronic commutation. This substitution achieves significantly lower energy consumption while maintaining continuous operation capability through electronic control and feedback mechanisms.
Solution Approach 2:
The patent changes the fundamental operating parameters of the motor system by switching from AC induction to DC permanent magnet technology. This parameter change includes using permanent magnets instead of induction fields, electronic commutation instead of mechanical brushes, and PWM control for speed regulation, all of which contribute to reduced energy consumption while preserving reliability.
2Object-affected harmful factors
If single-phase AC induction motors are used in ceiling fans, then the motor can provide sufficient power, but noise level is high
Solution Approach 1:
The patent eliminates the mechanical brush-commutator system inherent in traditional motors by adopting a brushless DC motor design. This substitution removes the primary source of mechanical noise and electromagnetic interference, significantly reducing noise levels while maintaining adequate motor power through optimized permanent magnet configuration and electronic control.
3Reliability
If single-phase AC induction motors are used in ceiling fans, then the motor can operate at various speeds, but operation stability at low speeds is poor
Solution Approach 1:
The patent incorporates feedback control mechanisms in the brushless DC motor system, using Hall sensors or other position sensors to detect rotor position and speed, and adjusting the commutation timing and current magnitude accordingly. This feedback enables stable low-speed operation by maintaining precise control over the electromagnetic fields even at reduced speeds, overcoming the instability inherent in single-phase AC induction motors.
Solution Approach 2:
The patent employs dynamic electronic control of the motor parameters, adjusting commutation timing, current magnitude, and PWM duty cycle in real-time based on load conditions and desired speed. This dynamic control enables the motor to maintain stability across the entire speed range, particularly at low speeds where traditional AC induction motors struggle.
4Ease of manufacture
If conventional rotator configuration is used in ceiling fan motors, then the motor structure is established, but the configuration is complicated and assembly is difficult
Solution Approach 1:
The patent divides the motor into distinct modular segments: the stator assembly, the rotor assembly with permanent magnets, the bearing support structure, and the housing. This segmentation allows each component to be manufactured and assembled separately, simplifying the overall assembly process and reducing complexity compared to conventional integrated designs.
Solution Approach 2:
The patent inverts the traditional design approach by making the rotor a separate, pre-assembled unit with permanent magnets attached to a simplified core, rather than constructing the rotor as part of a complex integrated assembly. This inversion of the assembly sequence simplifies manufacturing and assembly operations significantly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The brushless DC motor achieves low energy consumption, reduced noise, stable operation at low speeds, and simplified assembly, resulting in a cost-effective and efficient ceiling fan motor solution.
Implementation Method 1
The rotator comprises a top end cover, a bottom end cover, an outer shell cover ring, and a plurality of magnets, wherein the magnets are positioned along the circumferential direction of the inner wall of the outer shell cover ring
Implementation Method 2
The rotator is engaged with the shaft via a pair of bearings
Data Source
AI summary
The invention teaches a ceiling fan motor, and specifically, a brushless DC external rotor motor, comprising an electrical control member and a motor structural member, wherein the motor structural member comprises a shaft 1, a stator 2, and a rotator 3, the stator is fit over the shaft 1, the rotator is fit over the stator 2, and the stator 3 is engaged with the shaft 1 via a pair of bearings 4. The rotator 3 comprises a top end cover 5, a bottom end cover 6, an outer shell cover ring 7, and a plurality of magnets 8, wherein the magnets 8 are positioned along the circumferential direction of the inner wall of the outer shell cover ring 7. The top end cover 5 and the bottom end cover 6 are installed on the top and bottom of the cover ring 7, respectively, and are connected to each other by means of a plurality of bolts and nuts. The ceiling fan motor of the invention provides the advantages of efficient energy consumption, low noise, and high operational stability at low speeds.