Motor Driver Commutation Correction Using Back-EMF Phase Error
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Solution Overview
Problem
In electronic devices, errors between the actual and ideal positions of sensors in fans lead to incorrect data sensing, resulting in suboptimal motor rotation efficiency due to miscommunication between motor drivers and motors.
Innovation Solution
A motor driver with a correcting mechanism that includes a rotor position detector circuit, back electromotive force detector circuit, actual phase difference calculator circuit, error phase angle calculator circuit, and motor driving circuit, which calculates and corrects the commutation signal based on the phase difference between back electromotive force and commutation signals to align the motor current with the back electromotive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is assembled in the fan to sense motor position data, then the motor can be driven to rotate, but an error exists between the actual sensor position and the ideal position causing incorrect data sensing
Solution Approach 1:
The system performs preliminary calibration by detecting the phase difference between the back electromotive force signal and the commutation signal during an initial calibration phase. This pre-detects the sensor position error, which is then stored and used to correct subsequent position measurements, eliminating the need for precise manual sensor assembly.
Solution Approach 2:
The system continuously monitors the phase difference between the back electromotive force signal and the commutation signal, compares it against a reference phase difference, and automatically adjusts the commutation timing based on the detected error. This closed-loop feedback mechanism compensates for sensor position errors in real-time.
2Productivity
If the motor driver uses incorrect sensor data due to position errors, then the motor can still rotate, but the motor rotation efficiency is suboptimal
Solution Approach 1:
The system changes the commutation timing parameter dynamically by adjusting it based on the detected phase difference error. The motor driving circuit modifies the commutation signal timing to compensate for sensor position errors, thereby optimizing motor rotation efficiency while maintaining reliable operation.
3Productivity
If the motor driver calculates and corrects the commutation signal based on phase difference, then the motor rotates with optimum efficiency, but the device complexity increases
Solution Approach 1:
The motor driving circuit performs multiple functions: it drives the motor, detects the back electromotive force signal, calculates the phase difference, stores the error value, and corrects the commutation signal. By integrating these functions into a single circuit, the patent minimizes additional hardware complexity while achieving optimal motor efficiency.
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
This solution ensures the motor rotates with optimum efficiency by correcting errors in sensed data, aligning the current signal with the back electromotive force signal, thereby improving motor performance.
Implementation Method 1
The back electromotive force detector circuit is connected to the motor. The back electromotive force detector circuit is configured to detect back electromotive force of the motor to output a back electromotive force signal.
Data Source
AI summary
A motor driver using a correcting mechanism on a sensed motor position is provided. A rotor position detector circuit senses a position of a rotor of a motor to output a commutation signal. A back electromotive force detector circuit detects a back electromotive force signal of the motor. An actual phase difference calculator circuit calculates a phase difference between the back electromotive force signal and the commutation signal as an actual phase difference. An error phase angle calculator circuit calculates a difference between the actual phase difference and a reference phase difference as an error phase angle. A motor driving circuit corrects the commutation signal according to the error phase angle. The motor driving circuit determines the position of the rotor of the motor to drive the motor according to the corrected commutation signal.