Motor Electrical Signature Analysis for Mechanical Failure Prediction

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Solution Overview

Problem

Existing systems for predicting mechanical failures in electric motors of vehicles are costly and prone to false positives due to external noise interference, making it difficult to accurately identify impending failures without significant maintenance or sensor additions.

Innovation Solution

A method that generates motor electrical signatures from the characteristics of electrical energy supplied to the motors, compares fault measures across motors, and predicts mechanical failures based on these comparisons, using a system comprising an I/O module, signature generation module, and analysis module to identify impending failures without additional costly sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional sensors are added to detect motor failures, then detection capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedetection capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical vibration sensors with electrical signature analysis. By monitoring electrical parameters (current, voltage, frequency) already present in the motor system and analyzing their spectral characteristics, the system detects bearing faults without adding mechanical sensors. This substitution maintains detection capability while reducing device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an electrical signature (a type of copy or representation) of the motor's operational state through spectral analysis of electrical signals. This electrical signature serves as a proxy for mechanical conditions, allowing fault detection through electrical measurements rather than direct mechanical sensing, thereby avoiding additional hardware complexity.

Inventive Principle:
Principle #26Copying

2Reliability

If sensors are added to predict motor failure, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:
Improvefailure prediction accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The motor system uses its own electrical signals for self-diagnosis. The electrical parameters generated during normal motor operation are analyzed to detect bearing faults, eliminating the need for separate sensing systems. This self-service approach improves reliability through failure prediction without increasing manufacturing costs, as it utilizes existing electrical infrastructure.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent substitutes expensive mechanical vibration sensing systems with electrical signature analysis using readily available electrical measurements. This replacement maintains or improves failure prediction accuracy while significantly reducing manufacturing costs by avoiding additional sensor hardware and associated installation complexities.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If vibration-based sensors are used to detect bearing faults, then detection capability is improved, but false positive rate increases due to external noise

Engineering Contradiction:
Improvefault detection accuracyVSAvoidexternal noise interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces vibration-based detection (which is susceptible to external mechanical noise from tracks and uneven surfaces) with electrical signature analysis. Electrical signals generated by the motor itself are used to detect bearing faults, making the system immune to external mechanical disturbances. This substitution maintains fault detection accuracy while eliminating false positives caused by environmental noise.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electrical spectral analysis as an intermediary between the motor's operational state and fault detection. By analyzing the spectral characteristics of electrical signals (particularly sideband frequencies around the supply frequency), the system indirectly detects bearing conditions without being directly exposed to external mechanical noise that would interfere with vibration-based sensing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2729323B1System and method for predicting mechanical failure of a motor
Publication Date: 2021.05.12 TRANSPORTATION IP HOLDINGS LLC
  • EP2729323B1 patent drawingFigure 1
  • EP2729323B1 patent drawingFigure 2
  • EP2729323B1 patent drawingFigure 3

AI summary

A method for predicting mechanical failure of a traction motor in a vehicle includes monitoring first characteristics of an electrical signal supplied to a traction motor of a vehicle during a first detection window. The First characteristics represent a First motor electrical signature for the traction motor. The method also includes deriving one or more signature values from a first mathematical model of the first motor electrical signature and predicting a mechanical failure of the traction motor based on the one or more signature values.