Sensorless BLDC Fan Commutation via Back EMF
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Solution Overview
Problem
Conventional three phase brushless direct current (BLDC) fan motor systems are inefficient due to variations in supply voltage affecting PWM signals, requiring additional sensors for proper operation, which increases complexity and power consumption.
Innovation Solution
A system and method for remote three phase fan commutation integration control that uses a fan control module and drive circuit with pulse width modulation (PWM) signals based on back EMF signals, eliminating the need for sensors and stabilizing supply voltage, thereby optimizing motor efficiency and reducing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional three phase BLDC fan motor systems are used, then the motor can operate with standard components, but supply voltage variations affect PWM signals requiring additional sensors which increases complexity and power consumption
Solution Approach 1:
The system uses the motor's own back EMF signals to generate PWM control signals through the bridge driver circuit, eliminating the need for external sensors. The controller detects back EMF zero-crossing points and generates complementary PWM signals autonomously, making the system self-sufficient and sensorless.
Solution Approach 2:
The bridge driver circuit acts as an intermediary between the controller and motor windings, converting control signals into three-phase PWM signals. It uses the back EMF signals as an intermediate reference to generate the required commutation signals without external sensors.
2Measurement precision
If additional sensors are added for proper operation, then motor control precision is improved, but power consumption and complexity increase
Solution Approach 1:
The motor system uses its own back EMF signals for commutation control without requiring external sensors. The controller extracts position information from the back EMF waveforms generated during normal motor operation, eliminating additional power-consuming sensing components.
Solution Approach 2:
The patent replaces physical sensor-based detection systems with an electronic signal processing approach. Instead of using Hall effect sensors or other physical sensors to detect rotor position, the system uses electronic detection and processing of back EMF signals to achieve the same control function.
3Stability of the object's composition
If supply voltage is stabilized, then PWM signal reliability is improved, but additional voltage regulation components increase complexity
Solution Approach 1:
The system dynamically adapts to supply voltage variations by using the back EMF signals as a reference. The PWM generation is synchronized with the back EMF zero-crossing points, allowing the system to maintain proper commutation timing even when supply voltage fluctuates, without requiring active voltage regulation.
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 solution results in a more power-efficient BLDC fan motor system that uses less current at every rotation per minute, enhancing overall efficiency and compatibility with older generation BLDC fan motors without the need for additional sensors.
Implementation Method 1
uses a fan control module and drive circuit with pulse width modulation (PWM) signals based on back EMF signals
Data Source
AI summary
An information handling system includes a three phase brushless direct current motor and a motherboard which in turn includes a drive circuit. The three phase brushless direct current motor is configured to rotate a cooling fan in the information handling system based on a control signal. The drive circuit is connected to the three phase brushless direct current motor, and the drive circuit is configured to adjust the control signal sent to the three phase brushless direct current motor based on a back electromagnetic flux signal.