Battery Fan Motor Control Circuit for Stable Speed
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Solution Overview
Problem
Fans powered by storage batteries experience a significant drop in rotating speed as the battery voltage decreases, leading to a poor user experience due to unstable wind speed.
Innovation Solution
A control circuit that includes a motor drive unit and a processing control unit, which adjusts the drive current based on the difference between the actual and target motor speeds, maintaining stable motor speed by modulating the drive current and adjusting the target speed according to battery level, thereby prolonging battery endurance and service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fan is powered by a storage battery, then the fan can operate portably and be used without power outlet, but the motor speed decreases significantly as the battery voltage drops during discharging
Solution Approach 1:
The control circuit continuously detects the actual motor speed and compares it with the target speed, then adjusts the drive current accordingly. This closed-loop feedback mechanism ensures that the motor speed is maintained at the target level even as battery voltage drops during discharging, resolving the contradiction between portable operation and speed stability.
Solution Approach 2:
The system dynamically adjusts the drive current to the motor based on real-time speed detection and battery status. By making the drive current adaptive rather than fixed, the system maintains optimal motor performance throughout the battery discharge cycle, preventing significant speed degradation.
2Speed
If the control circuit maintains motor speed by increasing drive current, then the motor speed remains stable, but the battery consumption increases and endurance decreases
Solution Approach 1:
The control circuit applies partial action by adjusting the drive current only to the extent necessary to maintain target speed, not exceeding what is needed. This prevents excessive battery consumption while still achieving stable motor operation, optimizing the balance between speed maintenance and battery endurance.
Solution Approach 2:
The system changes the drive current parameter dynamically based on battery voltage levels and actual motor speed. By adapting the current parameter to actual operating conditions rather than using a fixed high current, the system maintains motor speed stability while minimizing unnecessary battery consumption and extending endurance.
3Speed
If the fan operates at high speed initially, then the user experience is good, but the battery voltage drops quickly causing rapid speed decline
Solution Approach 1:
The feedback control mechanism detects when the motor speed begins to drop and responds by adjusting the drive current to maintain the target speed. This prevents the rapid speed decline that would occur with simple high-initial-speed operation, extending the period during which the fan provides good user experience while managing battery consumption more effectively.
Data Source
AI summary
A control circuit including a motor drive unit and a processing control unit is provided. The motor drive unit includes a drive current for a motor according to a modulation signal, and the motor is powered by a storage battery. The processing control unit obtains an actual speed of the motor, calculate the modulation signal by comparing the actual speed and a target speed, and transmit the modulation signal to the motor drive unit. Also, the modulation signal is used to control rotation of the motor by modulating the drive current, so that the actual speed tends to be equal to the target speed.