Electric Drive Torque Characterization for Energy Efficiency

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Solution Overview

Problem

Existing electric drive systems often default to either dynamic or economic performance modes without selecting the most appropriate approach for the specific torque/speed ratio application, leading to suboptimal energy efficiency.

Innovation Solution

A method that automatically determines the torque characteristics of an electric drive system by analyzing data points to distinguish between linear and quadratic torque/speed ratios, allowing for automatic selection of the appropriate operating mode to maximize energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nominal flux is used to maintain full torque output at various motor speeds, then dynamic performance is improved, but energy efficiency deteriorates

Engineering Contradiction:
Improvedynamic performanceVSAvoidenergy efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the flux level based on real-time detection of torque characteristics. The control method transitions from static flux selection (either always nominal or always limited) to dynamic flux adjustment, where the flux is adapted according to the detected load behavior, thereby optimizing both dynamic performance and energy efficiency for the actual operating conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the flux parameter based on detected torque characteristics. By detecting whether the load exhibits linear or quadratic torque/speed behavior and adjusting the flux level accordingly, the system optimizes energy consumption while maintaining appropriate dynamic performance for the specific application type

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If limited flux is used to achieve economic performance and energy savings, then energy efficiency is improved, but dynamic performance deteriorates

Engineering Contradiction:
Improveenergy efficiencyVSAvoiddynamic performance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts the flux level based on real-time detection of torque characteristics. The control method transitions from static flux selection (either always nominal or always limited) to dynamic flux adjustment, where the flux is adapted according to the detected load behavior, thereby optimizing both dynamic performance and energy efficiency for the actual operating conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the flux parameter based on detected torque characteristics. By detecting whether the load exhibits linear or quadratic torque/speed behavior and adjusting the flux level accordingly, the system optimizes energy consumption while maintaining appropriate dynamic performance for the specific application type

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If default operating mode is selected without user input, then ease of operation is improved, but adaptability to specific applications deteriorates

Engineering Contradiction:
Improveautomatic mode selectionVSAvoidapplication-specific optimization
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system performs self-characterization by automatically detecting the torque characteristics of the connected load through measurement and analysis of torque/speed data points. The drive system itself determines whether the application is linear or quadratic type without requiring external user input or manual configuration, thereby achieving both ease of operation and application-specific optimization

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention implements a feedback mechanism where the drive system measures actual torque and speed, compares the data against linear and quadratic models, and uses this feedback to automatically determine the appropriate operating mode. This closed-loop approach ensures the system adapts to the specific application while maintaining ease of operation

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2736162B1Method and apparatus for maximising energy efficiency of an electric drive system
Publication Date: 2019.11.13 ABB (SCHWEIZ) AG
  • EP2736162B1 patent drawingFigure 1~2
  • EP2736162B1 patent drawingFigure 3
  • EP2736162B1 patent drawing

AI summary

The present disclosure discloses a method and an apparatus implementing the method for maximising energy efficiency of an electric drive system comprising an electric motor and a load. In the method, the torque characteristics of the system can be selected from two types of behaviour: linear and quadratic behaviour of a torque of the motor in respect to a rotational speed of the motor. The method gathers a plurality of data points and with which behaviour the data points correlate best. The torque characteristics to be used are determined on the basis of the correlation, and the motor is controlled on the basis of the determined torque characteristics.