Electric Vehicle Motor Torque Control for Power Train Vibration Reduction

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Solution Overview

Problem

Existing methods for reducing vibrations in power trains of electric vehicles, such as using rubber or hydro mounts, are ineffective in quickly addressing vibrations caused by road protrusions due to increased inertia forces, leading to passenger discomfort and manufacturing cost concerns.

Innovation Solution

A vibration reduction apparatus that utilizes a processor to detect vibrations through an acceleration sensor, applies a compensation torque to the motor torque in a reverse direction using a negative feedback control mechanism, effectively reducing vibrations by calculating and applying a compensation torque based on the change in acceleration signal components within specific frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If passive vibration reduction methods using rubber or hydro mounts are used, then vibration isolation is provided, but they are ineffective in quickly addressing vibrations caused by road protrusions due to increased inertia forces

Engineering Contradiction:

Improvevibration reduction effectivenessVSAvoidresponse speed to vibration

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent employs a feedback control mechanism where vibration sensors detect power train vibrations in real-time, and the controller adjusts motor torque accordingly to counteract the vibrations. This closed-loop system enables rapid response to vibration events caused by road protrusions, overcoming the slow response of passive isolation methods.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces passive mechanical vibration isolation systems (rubber mounts, hydro mounts) with an active control system using motor torque adjustment. Instead of relying on mechanical cushioning materials that cannot respond quickly to sudden vibrations, the system uses electronic control to generate counter-torques that actively cancel vibrations in real-time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If passive vibration reduction methods are used, then vibration isolation is provided, but manufacturing costs increase due to high-cost materials and installation space requirements

Engineering Contradiction:

Improvevibration isolation capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The motor serving the propulsion function also provides vibration reduction functionality through torque control. The existing motor and its control system are utilized to generate counter-torques for vibration cancellation, eliminating the need for separate passive isolation components and their associated costs.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The motor is designed to perform multiple functions: primary propulsion and secondary vibration reduction. By controlling the motor torque to counteract vibrations, the same component serves dual purposes, reducing the need for additional specialized vibration isolation parts and lowering overall system cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This solution effectively eliminates power train vibrations when an electric vehicle passes over road protrusions, providing stable driving conditions and reducing manufacturing costs by using motor torque control.

Implementation Method 1

detect vibrations through an acceleration sensor, applies a compensation torque to the motor torque in a reverse direction using a negative feedback control mechanism

Methodology Applied

Scientific EffectAcceleration sensing: Accelerometer

Implementation Method 2

applies a compensation torque to the motor torque in a reverse direction using a negative feedback control mechanism, effectively reducing vibrations

Methodology Applied

Scientific EffectNegative feedback control: Feedback

Data Source

PatentUS8909442B2Vibration reduction control method and apparatus of power train by controlling motor torque of electric vehicle

Publication Date: 2014.12.09 HYUNDAI MOTOR CO LTD

AI summary

The present invention relates to a vibration control method and apparatus of a power train in a vehicle for reducing the vibrations in a power train when driving on a protruded portion of a road surface using a motor torque control. The apparatus comprises a processor configured to determine the generation of vibrations in a power train as the vehicle passes on the protruded portions of the road surface; and calculate a compensation torque for a vibration reduction of the power train when vibrations occur in the power train as the vehicle passes on the protruded portions of the road surface.