Brushless Motor Torque Protection via Speed Monitoring
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Solution Overview
Problem
Existing torque protection systems for brushless motors rely on current measurement, which is complex, inaccurate, and prone to fluctuations, leading to ineffective protection against over-torque.
Innovation Solution
A torque protection mechanism for brushless motors that uses rotation speed measurement instead of current measurement, leveraging existing electronic speed control systems to establish torque levels and implement shutdowns when over-torque is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current measurement is used for torque protection, then torque protection can be provided, but the system becomes complex and inaccurate
Solution Approach 1:
The patent replaces the electrical measurement system (current measurement) with a mechanical parameter measurement system (rotation speed measurement). The electronic speed control unit that already exists in brushless motors is utilized to measure rotation speed, which serves as an indicator of torque conditions. This substitution eliminates the need for separate current measurement devices and simplifies the overall system while maintaining protection functionality.
Solution Approach 2:
The patent leverages the existing electronic speed control system in brushless motors to serve a dual purpose: both speed control and torque protection. The rotation direction setter and electronic speed control unit, which are already part of the motor system, are configured to also monitor rotation speed for torque detection. This self-service approach eliminates the need for additional dedicated torque measurement components.
2Measurement precision
If current measurement is used for torque protection, then torque monitoring is possible, but the measurement is inaccurate and prone to fluctuations
Solution Approach 1:
The patent replaces electrical current measurement with mechanical rotation speed measurement to achieve more accurate and stable torque monitoring. Rotation speed provides a direct mechanical indicator of torque conditions without the electrical noise and fluctuations that affect current-based measurements.
Solution Approach 2:
The electronic speed control unit continuously monitors rotation speed and provides feedback to the control system. When the rotation speed deviates from expected values indicating excessive torque, the system receives feedback signals and can respond by adjusting operation or triggering protection mechanisms. This closed-loop feedback ensures accurate and reliable torque monitoring.
Data Source
Figure 1
AI summary
The mechanism enables torque protection in a brushless motor without the need to use measurement of the current drawn, establishing the torque level based on measurement of the brushless motor rotation speed. The rotation speed corresponding to the nominal torque has therefore been previously established so that when there is over-torque, the rotation speed is decreased. This makes it possible to infer that there is over-torque, thus achieving torque protection for brushless motors which is effective, simple and highly economical. The mechanism is comprised of the following: A power supply (1), a rotation direction setter (2), a control unit (3) which is connected to the rotation direction setter (2); a brushless motor (5) which has a connection for sending a BREAK instruction from the control unit (3) to the motor (5), a signal which is sent when a shutdown occurs due to over-torque.