Motor Control Circuit Switching for Fan Airflow Optimization
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Solution Overview
Problem
Conventional motor control systems face inefficiencies in controlling motor rotation speed, especially when entering the back-pressure area, where airflow pressure and quantity are affected, and accurate speed control is not maintained.
Innovation Solution
A motor control apparatus with a phase switching unit, sensing unit, judging unit, rotation-speed weighting unit, and rotation-speed control unit that switches between first and second circuit loops based on detected rotation speed, generating different control signals to optimize motor efficiency in both low and high duty cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional open-loop control circuit is used to control motor rotation speed, then the control circuit is simple, but the rotation speed control accuracy deteriorates when the fan enters the back-pressure area
Solution Approach 1:
The patent implements dynamic switching between open-loop and closed-loop control modes based on the operating conditions. The control circuit dynamically adjusts its configuration: using open-loop control when the fan is not in back-pressure area, and switching to closed-loop control when back-pressure conditions are detected, thereby optimizing both circuit simplicity and control accuracy under different operating conditions
Solution Approach 2:
The patent changes the control mode parameter based on the duty cycle and back-pressure detection. When the duty cycle exceeds a threshold indicating back-pressure area, the system transitions from open-loop to closed-loop control, adjusting the control parameter to maintain accuracy while managing circuit complexity
2Measurement precision
If a closed-loop control circuit with rotation-speed detecting circuit is used, then the rotation speed control accuracy is improved at low duty cycle, but the rotation speed is limited when the fan enters the back-pressure area
Solution Approach 1:
The patent dynamically switches control modes based on operating conditions. At low duty cycles, closed-loop control provides accurate speed regulation. When back-pressure conditions are detected (high duty cycle), the system switches to open-loop control, allowing the motor speed to increase without the limitations imposed by closed-loop regulation, thus achieving both accuracy and high speed capability
Solution Approach 2:
The patent segments the control range into two distinct zones: low duty cycle region using closed-loop control for accuracy, and high duty cycle region using open-loop control for high speed performance. This segmentation allows each control mode to operate in its optimal range without compromising the other
3Productivity
If high duty cycle and high rotation speed are used when fan enters back-pressure area, then the airflow quantity and airflow pressure are improved, but the rotation speed control accuracy deteriorates
Solution Approach 1:
The patent segments the operating range by duty cycle threshold. When duty cycle is below the threshold, closed-loop control maintains accuracy. When duty cycle exceeds the threshold indicating back-pressure area, the system switches to open-loop control, allowing high speed operation for improved airflow quantity and pressure without the constraint of maintaining precise speed control
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 allows for accurate rotation speed control at low duty cycles and prevents speed limitations in back-pressure areas, resulting in increased airflow quantity and pressure, thereby optimizing motor efficiency.
Implementation Method 1
controlling a coil set of the motor to generate magnetization so as to drive a rotor of the motor to rotate
Data Source
AI summary
A motor control apparatus and a motor control method determine whether the motor is in a back-pressure area so as to provide different rotation-speed control signals. When the fan is in the low duty cycle, a first circuit loop is switched on, so that the fan has more accurate rotation speed. When the fan is in the high duty cycle, a second circuit loop is switched on, so that the rotation speed of fan does not be limited to a constant rotation-speed as the fan enters the back-pressure area. Thus, the fan has larger airflow quantity and higher airflow pressure.