Motor Driver Seamless Transition Back-EMF to Phase Control
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Solution Overview
Problem
Existing motor driver devices face challenges in smoothly transitioning from the window driving method to the windowless driving method, which can disrupt the quietness and vibration characteristics of 180-degree conducting methods used in brushless DC motors.
Innovation Solution
A motor driver device that includes a first driving method based on zero cross timing of back electromotive force and a second driving method where the differential phase between the zero cross timing of the driving current and voltage is adjusted to a target phase, allowing for seamless transition and automatic advance adjustments to maintain optimal rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the window driving method is used to detect back electromotive force zero cross point, then the detection accuracy is improved, but the quietness and vibration characteristics deteriorate due to forced high impedance state
Solution Approach 1:
The system performs preliminary detection of the differential phase between driving voltage and driving current zero cross points during the window driving method operation. This preliminary action stores the detected differential phase value to be used as the target phase during the transition to windowless driving method, enabling smooth transition without abrupt changes that would cause noise and vibration.
2Object-affected harmful factors
If the transition from window driving method to windowless driving method is performed, then the quietness and vibration characteristics are improved, but the rotational speed stability deteriorates
Solution Approach 1:
The system changes the control parameter from using back electromotive force zero cross timing (window driving) to using driving voltage and driving current differential phase (windowless driving). By setting the detected differential phase as the target phase during transition, the parameter change is performed smoothly without abrupt shifts, thereby maintaining rotational speed stability while achieving improved quietness and vibration characteristics.
3Ease of operation
If the differential phase is not adjusted during transition, then the transition simplicity is improved, but the driving performance deteriorates due to phase mismatch
Solution Approach 1:
The system uses feedback by detecting the actual differential phase between driving voltage and driving current zero cross points during window driving operation. This detected phase information is fed back to set the target phase for windowless driving operation, ensuring that the transition maintains proper phase alignment and driving performance while keeping the transition process relatively simple.
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
Enables smooth transition from window driving to windowless driving, maintaining stable rotational speed and reducing noise and vibration, while ensuring the advantages of both driving methods are retained.
Implementation Method 1
a zero cross timing of a back electromotive force generated in a coil of a predetermined phase
Data Source
AI summary
A motor driver device includes: a driver driving a motor by a driving method, wherein the driving method includes: a first driving method performing driving control of the motor based on zero cross timing of back electromotive force generated in a coil of a predetermined phase; and a second driving method performing driving control of the motor such that a first differential phase between zero cross timing of driving current flowing through the coil of the predetermined phase and zero cross timing of driving voltage applied to the coil of the predetermined phase coincides with predetermined first target phase, and wherein, even when the motor is being driven by the first driving method, the first differential phase is sequentially detected and, when transition from the first driving method to the second driving method occurs, the first differential phase detected immediately before the transition is set to the first target phase.