Brushless Motor Control Unit for Power Tool Drive Consistency
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Solution Overview
Problem
Power tools driven by brushless motors experience variations in drive characteristics due to manufacturing differences and errors in rotational position detection, leading to suboptimal performance and discomfort for users.
Innovation Solution
A control unit dynamically adjusts the current conduction angle and advance angle of the brushless motor to achieve target rotational speed and current values, optimizing drive characteristics by referencing battery voltage and adjusting angles based on real-time conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If preset fixed values for current conduction angle and advance angle are used, then the brushless motor can be simplified and manufactured easily, but variations in drive characteristics occur due to manufacturing differences and sensor placement errors
Solution Approach 1:
The patent applies dynamics by transitioning from fixed preset values to dynamically adjustable current conduction angle and advance angle. The control unit automatically adjusts these parameters based on actual motor operation conditions, allowing the system to adapt to manufacturing variations and sensor placement errors while maintaining consistent drive characteristics across different power tools.
2Reliability
If the current conduction angle and advance angle are dynamically adjusted, then drive characteristic consistency is improved, but the control system complexity increases
Solution Approach 1:
The patent implements self-service through automatic adjustment mechanisms where the control unit autonomously optimizes current conduction angle and advance angle based on real-time motor conditions. This eliminates the need for manual calibration and compensates for manufacturing variations automatically, achieving consistent drive characteristics without requiring complex external adjustment systems.
3Ease of manufacture
If fixed preset values are used for all power tools, then manufacturing cost is reduced, but performance optimization for individual tools is compromised
Solution Approach 1:
The patent applies parameter changes by enabling dynamic modification of current conduction angle and advance angle based on actual motor performance and operating conditions. This allows each power tool to optimize its drive parameters independently, achieving tool-specific performance optimization while maintaining a standardized manufacturing process through automatic parameter adjustment.
Data Source
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AI summary
A power tool (1) according to one aspect of one embodiment described in the disclosure includes a brushless motor (2), a battery voltage detection unit (16) configured to detect a voltage of a battery (4) that provides energy for driving the brushless motor (2), a rotational position detection unit (20) configured to detect a rotational position of the brushless motor (2), and a control unit (12, 30) configured to control a drive output supplied to the brushless motor (2) based at least in part on a signal from the rotational position detection unit (20). The control unit (12, 30) controls a current conduction angle and/or an advance angle supplied to the brushless motor (2) so that, during control of the drive output to the brushless motor (2), a rotational speed or a conducting current of the brushless motor (2) approaches or reaches a target value, the target value being based at least in part on a battery voltage detected by the battery voltage detection unit (16).