Single Phase DC Brushless Motor Controller Bidirectional Rotation
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Solution Overview
Problem
Single phase DC brushless motors are limited to unidirectional rotation due to the commutating dead angle, restricting their application in devices requiring bidirectional movement.
Innovation Solution
A controller system comprising a micro control unit, Hall sensor, and magnetic field control unit that receives PWM signals to control the rotation speed and direction by generating positive, reverse, or eliminating magnetic fields, allowing the motor to rotate bi-directionally by avoiding the commutating dead angle through proper timing and magnetic field manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If unbalanced wings are designed on laminations to generate repelling forces, then the motor can start and rotate in one direction, but the motor cannot reverse rotation due to commutating dead angle
Solution Approach 1:
The controller detects the Hall sensor signal state before commutation and determines the optimal commutation timing in advance. By performing preliminary detection of the rotor position and predicting the commutation moment, the system avoids the commutating dead angle and enables successful reverse rotation commutation.
Solution Approach 2:
The commutation timing is dynamically adjusted based on the detected Hall sensor signal state and rotation direction. The system continuously adapts the commutation moment to match the actual rotor position, allowing flexible bidirectional rotation control while avoiding the commutating dead angle in both directions.
2Device complexity
If commutation occurs at fixed timing, then the motor structure is simple, but the motor cannot avoid commutating dead angle for reverse rotation
Solution Approach 1:
The system uses Hall sensors to detect the rotor position and provides feedback to the controller. Based on this feedback, the controller dynamically determines the optimal commutation timing, ensuring that commutation occurs at the correct moment to avoid the commutating dead angle while enabling reverse rotation.
Solution Approach 2:
The patent replaces traditional mechanical brush-based commutation with electronic commutation controlled by a microcontroller. This substitution allows precise timing control of the stator magnetic field based on detected rotor position, eliminating the commutating dead angle limitation and enabling bidirectional rotation.
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
Enables the single phase DC brushless motor to rotate in both directions, enhancing its utility in applications like heat dissipating fans, where bidirectional operation is necessary, and improving efficiency by allowing reverse rotation without mechanical brushes.
Implementation Method 1
a Hall sensor 210, coupled to the micro control unit 230, for sensing the magnetic field of a part of the rotator 110 right in front of the Hall sensor 210, and for generating a sensing signal
Implementation Method 2
a magnetic field control unit 220 for generating a magnetic field in a stator 120 of the single phase DC brushless motor 100
Implementation Method 3
when the lamination 121 is excited to be an N pole, which repels the magnetic field of the part of the rotator 110 which is facing the lamination 121, the two unbalanced wings of the lamination 121 will generate two different repelling forces in relation to the rotator 110 and rotate the rotator 110 clockwise
Data Source
AI summary
A single phase DC brushless motor controller, including: a micro control unit including: a Pulse Width Modulation (PWM) pin for receiving a PWM signal from a system; and a commutation logic unit for controlling the speed and rotation of a single phase DC brushless motor according to the PWM signal.