Electric Vehicle Motor Torque Control via Lookup Table

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Solution Overview

Problem

Existing control apparatuses for electric vehicles require repetitive calculations to determine the final torque instruction value, making the process cumbersome.

Innovation Solution

Calculating power limit values for each motor based on a power source limit value and torque limit values, allowing for direct calculation of torque instruction values without repetition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the torque instruction value is determined by gradually reducing it and repeating calculations, then the final torque instruction value can be obtained, but the calculation processing becomes cumbersome

Engineering Contradiction:
Improveaccuracy of torque instruction valueVSAvoidcalculation processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing the relationship between battery output power and torque instruction values in a lookup table before actual operation. During runtime, the control device simply queries this pre-prepared table to obtain torque instruction values, eliminating the need for repetitive gradual reduction calculations while ensuring accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a simplified copy of the complex calculation relationship by representing the correspondence between battery power and torque values in a tabular format. This table serves as a simplified model that captures the essential relationships without requiring the full computational complexity of the original gradual reduction method.

Inventive Principle:
Principle #26Copying

2Reliability

If the torque instruction value is determined by repetitive calculation, then the battery power limit is respected, but the calculation time increases

Engineering Contradiction:
Improvecompliance with battery power limitVSAvoidcalculation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs the power limit compliance checks and calculations in advance, storing the results in a lookup table that maps battery output power levels to appropriate torque instruction values. This eliminates real-time calculation delays while ensuring continuous compliance with battery power limits.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring the battery's actual output power and using this information to query the appropriate torque instruction value from the lookup table. This ensures that the torque instructions always comply with the current battery power capacity while avoiding repetitive calculations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3514003B1Control device of electrically driven vehicle, control system of electrically driven vehicle, and method for controlling electrically driven vehicle
Publication Date: 2023.06.14 ASTEMO LTD
  • EP3514003B1 patent drawingFigure 1
  • EP3514003B1 patent drawingFigure 2
  • EP3514003B1 patent drawingFigure 3

AI summary

Provided is a control apparatus for an electric vehicle that can set a final torque instruction value without necessitating a repetition of a calculation. A control apparatus calculates a power limit value of each motor that is used when power is supplied to a plurality of motors, based on a power limit value of a power source, and calculates a torque instruction value of each motor based on the power limit value of each motor.