Traction Machine Coupling Control for Torque Transient Stability

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Solution Overview

Problem

Existing methods for controlling the coupling of traction machines to wheel sets in hybrid, electric, or internal combustion engine vehicles face instability and energy inefficiency due to frequent changes in coupling states, leading to mechanical damage and increased energy consumption.

Innovation Solution

A method that detects the current coupling state and authorizes control requests only when the state matches the target state, or calculates a validation parameter to ensure stability, reducing unnecessary oscillations and energy consumption by confirming requests based on predetermined criteria.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If coupling state requests are validated using multiple torque thresholds to avoid unstable control signals, then coupling stability is improved, but during high torque gradient phases, repeated threshold crossings cause transient oscillations that damage the coupling device

Engineering Contradiction:
Improvecoupling control signal stabilityVSAvoidmechanical damage to coupling device
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by checking whether the traction machine is already in the target coupling state before authorizing the control request. This pre-check prevents unnecessary state transitions and validates requests in advance, avoiding transient oscillations during high torque gradient phases while maintaining coupling stability through threshold-based validation

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If coupling state requests are validated using multiple torque thresholds, then control signal stability is improved, but the complexity of the control system increases due to multiple validation parameters

Engineering Contradiction:
Improvecoupling control signal stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control system performs preliminary validation by checking the current coupling state against the target state before processing the request. This pre-validation step simplifies the overall control logic by eliminating the need for complex post-validation mechanisms, while still maintaining signal stability through threshold-based criteria

Inventive Principle:
Principle #10Preliminary action

3Loss of time

If coupling requests are authorized immediately upon detection, then response time is improved, but unnecessary oscillations occur when the current state already matches the target state

Engineering Contradiction:
Improvecoupling control response timeVSAvoidcoupling control signal stability
Core Design Contradiction:
Loss of timeVSStability of the object's composition

Solution Approach 1:

The system performs a preliminary check to determine if the traction machine is already in the target coupling state before authorizing the control request. This pre-check enables immediate authorization when needed while preventing unnecessary oscillations by blocking redundant requests, thus achieving both fast response and signal stability

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3844415B1Method for controlling the status of the coupling of a traction machine to a wheelset of a motor vehicle
Publication Date: 2023.01.18 STELLANTIS AUTO SAS
  • EP3844415B1 patent drawingFigure 1
  • EP3844415B1 patent drawingFigure 2~3
  • EP3844415B1 patent drawingFigure 4

AI summary

The invention relates to a method for controlling a coupling means of a motor vehicle. The control signal of such a device is liable to be disturbed by short-lived demands because of the detection of successive demands for a coupling status during a steep-gradient transient of setpoint torque at the wheels. In order to avoid oscillations in the control signal, when a target coupling status demand is detected, the control method according to the invention comprises the successive steps of determining (403) the coupling status of the coupling means which is instructed at the moment of detection of said demand, and the command (407) for a demand for coupling status is authorised as soon as said demand is detected when the coupling status instructed at the time of the detection is identical to the target coupling status.