Electric Motor Fault Detection With Independent Shutdown Pathways

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Solution Overview

Problem

Existing electric motor systems rely on hardware-based protection schemes that may fail if hardware malfunctions, leading to continued operation under abnormal current conditions, highlighting the need for redundant fault detection and response mechanisms.

Innovation Solution

Implementing both hardware-based and software-based pathways for detecting and responding to fault conditions in electric motors, where the hardware pathway uses a power module and resistor block to generate a voltage signal for immediate shutdown, and the software pathway employs a microprocessor and resistor block to process digital signals for fault detection and response.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If hardware-based protection scheme is used, then response speed is improved, but reliability deteriorates due to potential hardware failure

Engineering Contradiction:

Improveresponse speedVSAvoidprotection reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The protection system is segmented into two independent pathways: a hardware-based pathway for fast response and a software-based pathway for redundant verification. The hardware pathway processes fault detection independently through dedicated circuitry, while the software pathway provides backup through microprocessor-based monitoring, ensuring that failure in one pathway does not compromise overall system reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements beforehand cushioning by preparing a software-based backup pathway that can take over if the hardware pathway fails. This redundant software monitoring pathway is pre-configured to detect the same fault conditions, providing a safety cushion that prevents protection failure even when hardware components malfunction.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If software-based protection scheme is used, then redundancy is improved, but response speed deteriorates

Engineering Contradiction:

Improveprotection redundancyVSAvoidresponse speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Device complexity

If single pathway protection is used, then device complexity is reduced, but reliability deteriorates due to lack of redundancy

Engineering Contradiction:

Improveprotection system complexityVSAvoidprotection redundancy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system merges hardware-based and software-based protection pathways into a unified dual-path protection architecture. Both pathways monitor the same motor system and can independently initiate shutdown commands, combining the advantages of hardware speed with software redundancy to achieve high reliability without excessive complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 dual-pathway approach provides faster and more reliable fault detection and response, combining the speed of hardware-based protection with the redundancy of software-based protection, effectively preventing motor operation under abnormal conditions such as over-current, under-current, voltage, or temperature faults.

Implementation Method 1

by Ohm's law, the voltage is representative of the current

Methodology Applied

Scientific EffectOhm's law: Ohm's Law

Implementation Method 2

by Ohm's law, the voltage is representative of the current

Methodology Applied

Scientific EffectOhm's law: Ohm's Law

Data Source

PatentUS9214885B1Independent pathways for detecting fault condition in electric motor

Publication Date: 2015.12.15 NIDEC MOTOR CORP

AI summary

An electric motor system having substantially independent hardware-based and software-based pathways for detecting and initiating responses to fault conditions, such as over-current conditions, in an electric motor which is powered by a power inverter which is controlled by a power module and a microprocessor. Each pathway involves comparing a voltage, which is representative of an electric current flowing to the motor, to a predetermined maximum voltage, and if the former exceeds the latter using hardware or software to initiate shutting off the motor, such as by shutting off the power inverter. When one pathway detects a fault condition it may notify the other pathway, and the notified pathway may also initiate shutting off the motor.