Electric Vehicle Controller Abnormality Detection

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Solution Overview

Problem

Existing electric vehicle control systems require additional arithmetic circuits to detect motor control ECU abnormalities, increasing costs and complexity.

Innovation Solution

A controller that calculates a final indication torque confirmation value based on the target driving torque with a preset delay, allowing for abnormality determination by comparing it with the actual final indication torque, without the need for additional arithmetic units, thereby reducing costs and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an auxiliary CPU is built into the motor control ECU to detect arithmetic abnormality separately, then the reliability of abnormality detection is improved, but the device complexity and cost increase

Engineering Contradiction:
Improveabnormality detection reliabilityVSAvoidcontroller structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the abnormality detection function into the existing travel control ECU by adding a confirmation value calculator and abnormality determinor. Instead of using a separate auxiliary CPU in the motor control ECU, the detection functionality is combined with the travel control ECU's existing CPU, thereby reducing device complexity while maintaining detection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a confirmation value calculator as an intermediary component that calculates a confirmation value based on the target driving torque. This confirmation value serves as a reference for the abnormality determinor to compare against the final indication torque, enabling indirect detection of arithmetic abnormalities without requiring direct access to the motor control ECU's internal CPU operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If communication delay is not considered in abnormality detection, then the detection response speed is improved, but the measurement precision deteriorates due to timing errors

Engineering Contradiction:
Improvedetection response speedVSAvoidabnormality detection accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by calculating the confirmation value in advance using the target driving torque before it is processed by the motor control ECU. By performing this calculation beforehand and storing the confirmation value, the system eliminates the need for real-time communication during the detection process, thereby avoiding communication delays while maintaining detection accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a copy of the torque calculation process by having the travel control ECU's confirmation value calculator compute a confirmation value that mirrors what the motor control ECU would calculate. This copying approach allows the system to have a reference value ready for comparison without requiring simultaneous access to the same data, thus eliminating timing errors caused by communication delays.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2161831B1Controller of electric vehicle
Publication Date: 2020.02.19 MITSUBISHI MOTORS CORP
  • EP2161831B1 patent drawingFigure 1
  • EP2161831B1 patent drawingFigure 2
  • EP2161831B1 patent drawingFigure 3~4

AI summary

A controller for electric vehicles is provided for reliably detecting the abnormality of a motor control ECU and also reducing costs. The controller has travel control means 1 for calculating a target driving torque for an electric motor 3 which drives a vehicle 50, and motor control means 2 for calculating a final indication torque which has corrected the target driving torque input from the travel control means 1, and supplying electric power according to the final indication torque to the electric motor 3. The travel control means 1 includes target driving torque calculating means 21 for calculating the target driving torque, final indication torque confirmation value calculating means 23 for calculating a final indication torque confirmation value based on the calculated target driving torque, and abnormality determining means 24 for determining the abnormality of the motor control means 2 based on a result of comparison between the final indication torque and the final indication torque confirmation value.