BLDC Motor Driver Circuit With Abnormal Rotation Diagnosis
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Solution Overview
Problem
Conventional BLDC motor driver circuits cannot detect mechanical malfunctions such as aging or malfunctioning components, which can lead to undesirable situations like over-current, over-voltage, or over-temperature, and do not provide real-time monitoring for abnormal rotation conditions.
Innovation Solution
A BLDC motor driver circuit with an integrated abnormality diagnosis circuit that monitors parameters like rotation speed, temperature, input current, input voltage, and duty ratio of the PWM signal to detect and report any abnormal conditions, enabling early detection of mechanical malfunctions and issuing alarms or error reports to an external host.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no abnormality diagnosis circuit is used, then the device complexity is low, but long-term operation leads to undetected mechanical degradation and malfunction
Solution Approach 1:
The abnormality diagnosis circuit utilizes existing motor parameters (rotation speed, temperature, current, voltage, duty ratio) that are already measured for normal motor control. By analyzing these existing parameters for abnormality detection, the circuit achieves multiple functions (motor control + fault diagnosis) without requiring entirely separate sensing systems, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the abnormality diagnosis circuit continuously monitors motor parameters and compares them against expected ranges. When abnormalities are detected (such as unexpected rotation speed variations or temperature patterns indicating bearing failure), the system provides feedback to trigger alarm signals or error reports to the external host, enabling timely intervention.
2Reliability
If real-time monitoring of multiple parameters is implemented, then mechanical malfunctions can be detected early, but the device complexity and monitoring requirements increase
Solution Approach 1:
The abnormality diagnosis circuit leverages existing parameter measurement infrastructure already present in BLDC motor control systems. By reusing these measurements for dual purposes (normal control and abnormality detection), the system achieves comprehensive monitoring without proportionally increasing device complexity.
Solution Approach 2:
The motor's own operational parameters serve as the diagnostic indicators. The system uses the motor's self-generated data (rotation speed, temperature, current, voltage, duty ratio) to diagnose its own health status, eliminating the need for external diagnostic equipment or additional complex sensing systems.
Data Source
AI summary
A brushless DC electric (BLDC) motor driver circuit includes: a power stage circuit configured to operably drive a brushless DC electric (BLDC) motor according to a pulse width modulation (PWM) signal; and an abnormality diagnosis circuit, wherein when a first parameter is under control, the abnormality diagnosis circuit is configured to operably determine a rotation abnormality condition of the BLDC motor according to a second parameter; wherein the first parameter and the second parameter are correlated with the rotation of the BLDC motor.