Brushless DC Motor Speed Control via AC Power Line Signal Modulation
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Solution Overview
Problem
Existing brushless DC motor speed control systems for fans are costly due to the use of analog-to-digital conversion chips, time-consuming manufacturing processes, and suffer from signal attenuation issues during long-distance transmission.
Innovation Solution
A long-distance speed control system for brushless DC motors in fans, comprising a mains power supply, switch, switch circuit, voltage detection module, and drive unit, which eliminates the need for analog-to-digital conversion chips and uses a switch circuit with capacitor banks for multi-stage speed control, enabling long-distance transmission with reduced signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If analog-to-digital conversion chips are used for speed control switching, then speed control functionality is achieved, but manufacturing cost increases by more than 50%
Solution Approach 1:
The patent removes the analog-to-digital conversion chip from the system entirely. Instead of using a chip to convert AC power signals for speed control, the invention uses the existing AC power signal directly through a switching device with capacitor banks that can be selectively connected to control motor speed without any analog-to-digital conversion
Solution Approach 2:
The patent replaces the expensive analog-to-digital conversion chip with inexpensive passive components (capacitor banks and switching devices). These simple components achieve the same speed control function at a fraction of the cost, eliminating the need for expensive electronic conversion chips
2Productivity
If analog-to-digital conversion chips are installed in fans, then speed control is enabled, but earth resources are wasted and manufacturing process becomes time-consuming
Solution Approach 1:
The patent extracts and removes the time-consuming analog-to-digital conversion chip from the manufacturing process. By using simple capacitor banks and switching devices instead, the manufacturing process becomes significantly faster and more efficient, as these passive components require no complex assembly or calibration
Solution Approach 2:
The invention uses simple, inexpensive passive components that are quick to manufacture and assemble. The capacitor banks and switching devices can be rapidly produced and installed, eliminating the time-consuming chip assembly and calibration processes
3Length of stationary object
If low-voltage digital transmission wire is used to connect speed control switching device and processor, then control signals are transmitted, but signal attenuation is severe and long-distance transmission is impossible
Solution Approach 1:
The patent uses the AC power signal itself as an intermediary carrier for speed control information. Instead of using separate low-voltage digital transmission wires that suffer from attenuation, the invention modulates speed control information onto the high-voltage AC power lines, which can transmit signals over much longer distances without significant loss
Solution Approach 2:
The invention changes the transmission medium from low-voltage digital wires to high-voltage AC power lines. By utilizing the existing AC power infrastructure and varying the capacitance connections to encode speed information, the system achieves long-distance transmission capability using the high-voltage power lines that naturally resist signal attenuation
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 system achieves low-cost, environmentally friendly multi-stage speed control with reduced resource waste and enhanced signal integrity over long distances, eliminating the need for expensive analog-to-digital conversion chips and minimizing signal loss.
Implementation Method 1
The components are defined as a first wire and a plurality of capacitor banks, respectively. The highest speed position of the switch corresponds to the first wire. The speed control positions of the switch correspond to the capacitor banks, respectively.
Implementation Method 2
The voltage detection module is electrically connected to the first node of the switch circuit for the voltage detection module to receive the switching signal. The voltage detection module is configured to detect, judge and process the switching signal and to detect and judge a voltage of the switching signal
Data Source
AI summary
A long-distance speed control system for a brushless DC motor of a fan is provided. The long-distance speed control system includes a switch connected with a mains power supply, a switch circuit, a voltage detection module, a power cord, a processing unit, and a drive unit, which can control the multi-stage rotational speed of the motor. In the field of brushless DC motors for fans, there is no need to use analog-to-digital conversion chips between the mains power supply and the processor, having the advantages of low cost, environmental protection, and reduction of waste of earth resources. Besides, the switch, the switch circuit and the power cord can withstand the mains power supply, having the advantages of less signal attenuation and long-distance transmission.