Motor Control Device for Vehicle Drive Shaft Vibration Suppression

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Solution Overview

Problem

Existing motor control methods for induction motors result in high battery power consumption and inability to effectively suppress vibration caused by drive shaft torsion, especially when starting from a steep slope or similar conditions.

Innovation Solution

A motor control device and method that adjusts the excitation current and magnetic flux in response to drive shaft torsion, channeling excitation current only when necessary to suppress vibration and optimize battery power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If excitation current is constantly channeled to improve torque responsiveness and suppress drive shaft torsion vibration, then vibration suppression is improved, but battery power consumption increases

Engineering Contradiction:
Improvevibration suppressionVSAvoidbattery power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by controlling the inverter to output excitation current only during specific periods when vibration is detected, rather than continuously. The control unit monitors vibration levels and activates excitation current supply only when vibration exceeds a threshold, thereby reducing overall power consumption while maintaining effective vibration suppression when needed.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the parameter of excitation current supply from constant to variable based on vibration conditions. The control unit dynamically adjusts the excitation current magnitude and timing according to detected vibration levels, optimizing the balance between vibration suppression effectiveness and power consumption by supplying current only at appropriate moments and intensities.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If magnetic flux is raised in conformity with lock release to suppress vibration, then vibration suppression is improved, but battery power consumption increases

Engineering Contradiction:
Improvevibration suppressionVSAvoidbattery power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by raising the magnetic flux in advance in conformity with lock release detection. When the control unit detects lock release, it proactively increases the magnetic flux before vibration occurs, preparing the system to suppress vibration effectively while minimizing the duration of high power consumption by timing the flux increase with the lock release event.

Inventive Principle:
Principle #10Preliminary action

3Speed

If excitation current is channeled to improve torque command responsiveness, then torque responsiveness is improved, but battery power consumption increases

Engineering Contradiction:
Improvetorque command responsivenessVSAvoidbattery power consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by supplying excitation current intermittently based on vibration detection rather than continuously. The control unit monitors vibration conditions and activates current supply only when vibration is detected, achieving torque responsiveness improvement during vibration events while reducing overall power consumption through periodic rather than continuous operation.

Inventive Principle:
Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively reduces battery power consumption while efficiently suppressing drive shaft torsion-induced vibrations, improving torque responsiveness and vehicle safety.

Implementation Method 1

an inverter 2, which converts a voltage from the battery 1 into AC voltage and outputs the AC voltage

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a drive motor 3, which is an induction motor that rotates by use of the AC voltage to thereby transfer a torque

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2939866B1Motor control device and motor control method
Publication Date: 2021.01.06 NISSAN MOTOR CO LTD
  • EP2939866B1 patent drawingFigure 1
  • EP2939866B1 patent drawingFigure 2
  • EP2939866B1 patent drawingFigure 3

AI summary

A motor control device of a vehicle provided with a motor and a lock mechanism (11) for locking the rotation of vehicle wheels; wherein the motor control device comprises detection means for detecting that the lock mechanism (11) will be released, damping control means for suppressing torsional vibration of a drive shaft, and current control means for controlling current flowing to the motor on the basis of a motor torque command value set by the damping control means; and the current control means channels an excitation current for generating a magnetic flux in the motor on the basis of the detection result of the detection means.