Brushless Motor Current Control for AC Power Stability
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Solution Overview
Problem
Existing power tools powered by AC supply face instability due to commercial power fluctuations, limiting their high-power applications, and DC power tools are insufficient for meeting high power requirements.
Innovation Solution
A power tool with a brushless motor, drive circuit, detection device, and controller that adjusts the motor current based on load parameters to maintain stability, using an AC power module, rectifier, EMI module, and capacitor configuration to ensure consistent output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If AC power supply is used to meet high power requirements, then power output is improved, but output stability deteriorates due to commercial power fluctuations
Solution Approach 1:
The controller receives feedback from the detection device about the actual current and load parameters, then adjusts the drive circuit's output accordingly to maintain stable motor operation despite AC power fluctuations
Solution Approach 2:
The system dynamically changes operating parameters (current, voltage, drive waveform) based on detected load conditions and power supply variations to maintain optimal and stable motor performance
2Ease of operation
If DC power supply is used to provide limited power, then power tool portability is improved, but power output deteriorates due to limited power capacity
Solution Approach 1:
The power tool is designed with a universal power adapter that can accept both AC and DC inputs, allowing the same tool to function in both high-power AC mode and portable DC mode, thus achieving both high power output and portability
3Productivity
If load parameter exceeds preset range, then motor current increases to meet demand, but system stability deteriorates and overheating risk increases
Solution Approach 1:
The detection device continuously monitors load parameters and provides feedback to the controller, which adjusts the drive circuit to reduce current when load exceeds preset ranges, preventing overheating and maintaining system stability
Solution Approach 2:
The system dynamically adjusts motor current based on real-time load detection, reducing current when load parameters exceed preset ranges to prevent overheating while maintaining optimal performance within safe operating limits
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 provides a stable output for power tools, enhancing their performance and efficiency by managing load parameters and electromagnetic interference, allowing for reliable operation with AC power.
Implementation Method 1
a brushless motor including several windings
Implementation Method 2
using an AC power module, rectifier, EMI module, and capacitor configuration
Implementation Method 3
using an AC power module, rectifier, EMI module, and capacitor configuration to ensure consistent output
Implementation Method 4
using an AC power module, rectifier, EMI module, and capacitor configuration
Data Source
AI summary
A power tool includes a brushless motor including several windings, a drive circuit for driving the brushless motor, a detection device for detecting the brushless motor so as to obtain a load parameter corresponding to a load of the brushless motor, and a controller for outputting a first control signal to reduce current of the brushless motor in a first slope when the load parameter exceeds a first preset range.