External Controller Cut-Off Line for Electric Motor Error Detection

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Solution Overview

Problem

Existing electrical machine control systems fail to prevent faulty activation, leading to undesirable torque or speed issues that can cause overloading or unsafe behavior in vehicles or units driven by electric machines.

Innovation Solution

A device and method where an external control unit detects errors and sends a switch-off signal to the electrical machine's control system, allowing for quick shutdown via a dedicated switch-off path, ensuring the machine can be safely deactivated even if internal control systems do not recognize the error.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electrical machine control system relies only on internal error detection, then the control system structure remains simple, but the machine may be incorrectly activated due to undetected errors leading to overloading or unsafe behavior

Engineering Contradiction:
Improveerror detection capabilityVSAvoidcontrol system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

An external control device is introduced as an intermediary between the internal control system and the electrical machine. This external device monitors additional error conditions (such as chassis errors, wheel traction errors, engine errors) and can independently trigger shutdown signals, thereby enhancing error detection capability without requiring the internal control system to process all error types

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The error detection and control function is segmented between internal and external control systems. The internal control system handles machine-specific errors, while the external control device handles system-level errors (chassis, wheel, engine). This segmentation allows each subsystem to remain relatively simple while achieving comprehensive error detection through their coordinated operation

Inventive Principle:
Principle #1Segmentation

2Speed

If a dedicated switch-off path is implemented for rapid shutdown, then the shutdown speed increases, but the control system complexity increases due to additional switch-off paths

Engineering Contradiction:
Improveshutdown speedVSAvoidcontrol system structure
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The shutdown function is extracted as a separate, dedicated switch-off path that is independent from the normal control signal path. The external control device can directly activate shutdown without going through the complex data bus communication used for normal control, enabling rapid response to errors while keeping the extraction of this critical function separate from the main control system

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the external control device has direct shutdown authority, then the safety against faulty activation improves, but the ease of operation decreases due to reduced operator control

Engineering Contradiction:
Improvesafety against faulty activationVSAvoidoperator control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The external control device is configured to detect error conditions and initiate shutdown actions before these errors can result in faulty activation, overloading, or unsafe behavior. By implementing preliminary detection and prevention mechanisms, the system automatically counteracts potential hazards before they manifest, prioritizing safety over operator convenience in critical situations

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP2008350B1Device for operating an electric motor
Publication Date: 2016.02.17 MERCEDES BENZ GROUP AG
  • EP2008350B1 patent drawingFigure 1
  • EP2008350B1 patent drawingFigure 2

AI summary

The invention relates to a device for operating an electric motor and corresponding method. The aim of the invention is to prevent an erroneous operation of an electric motor. According to the invention said aim is achieved wherein the electric motor is connected to an external controller by means of a cut-off line and is cut-off off when the external controller recognises an error.