Electric Motor Eccentricity Detection via Vibration and Inductance
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Solution Overview
Problem
Existing technologies face challenges in accurately detecting air gap and eccentricity errors in electric motors, which can lead to vibration, noise, and premature wear, affecting the motor's efficiency and lifespan.
Innovation Solution
The proposed solution involves an eccentricity detection system that includes a vibration eccentricity module, an inductance eccentricity module, and a fault module. These modules determine vibration and inductance eccentricities based on measured vibrations and incremental inductance curves, respectively, and indicate the presence of an eccentricity fault by comparing these values with predetermined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration-based detection is used, then detection capability is improved, but false detections increase due to operational vibrations
Solution Approach 1:
The patent introduces incremental inductance as an intermediary measurement method that is not affected by operational vibrations. By measuring inductance changes during motor operation, the system obtains eccentricity information without being influenced by mechanical vibrations, thus resolving the contradiction between detection capability and false detection rate
Solution Approach 2:
The patent replaces the mechanical vibration-based detection system with an electrical inductance-based detection system. By substituting mechanical measurement with electrical measurement, the system eliminates the interference from operational vibrations while maintaining eccentricity detection capability
2Reliability
If inductance-based detection is used, then reliability is improved, but detection precision decreases due to waveform complexity
Solution Approach 1:
The patent segments the complex inductance waveform analysis into specific characteristic points (peaks and valleys) and corresponding current intervals. By focusing on these segmented features rather than the entire complex waveform, the system maintains high detection precision while improving reliability
Solution Approach 2:
The patent uses the analogy of waveform shape changes (similar to color changes) to detect eccentricity. By monitoring changes in the incremental inductance waveform characteristics (peaks, valleys, intervals), the system can precisely detect eccentricity conditions while maintaining reliability
3Measurement precision
If multiple detection methods are combined, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing motor controller perform multiple functions: it controls motor operation and simultaneously measures incremental inductance during normal operation. By making the controller universal, the system combines multiple detection capabilities without adding separate dedicated detection devices, thus improving accuracy while limiting complexity increase
4Productivity
If detection is performed during motor operation, then productivity is improved, but measurement precision decreases due to dynamic conditions
Solution Approach 1:
The patent performs preliminary characterization of the motor's incremental inductance waveform during normal operation, storing reference data for later comparison. By preparing reference data in advance during operation, the system can detect eccentricity conditions without stopping the motor, maintaining both productivity and measurement precision
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
This solution effectively detects eccentricity faults in electric motors, reducing the likelihood of vibration, noise, and premature wear, thereby enhancing motor efficiency and extending its lifespan.
Implementation Method 1
a vibration eccentricity module configured to determine a vibration eccentricity of the electric motor based on vibration of the electric motor measured during operation of the motor
Implementation Method 2
an inductance eccentricity module configured to determine an inductance eccentricity of the electric motor based on an incremental inductance curve of the electric motor
Implementation Method 3
A direct current (DC) bus capacitor may be connected between the inverter module and the battery. Pulse width modulated (PWM) signals are used to control switching of the legs
Data Source
AI summary
An eccentricity detection system includes: a vibration eccentricity module configured to determine a vibration eccentricity of the electric motor based on vibration of the electric motor measured during operation of the motor; an inductance eccentricity module configured to determine an inductance eccentricity of the electric motor based on an incremental inductance curve of the electric motor; and a fault module configured to indicate whether the electric motor includes an eccentricity fault based on both (a) the vibration eccentricity of the electric motor and (b) the inductance eccentricity of the electric motor.