Vehicle Speaker Temperature Compensation via Inductance

Solution Overview

Problem

Vehicle speakers experience variations in sound output due to temperature changes, leading to distortion in sound quality as the magnetic flux density changes, affecting the electromagnetic force acting on the voice coil and consequently the speaker's inductance.

Innovation Solution

A control unit measures the current or voltage of the speaker, determines the temperature based on inductance variations, and adjusts the current supplied to compensate for these changes, ensuring consistent sound output by calculating compensation current to match the magnetic flux at a reference temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the speaker operates without temperature compensation, then the device complexity is reduced, but the sound quality varies with temperature changes

Engineering Contradiction:

Improvespeaker control systemVSAvoidsound quality consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control unit continuously monitors the speaker's inductance to detect temperature changes and dynamically adjusts the current supplied to the voice coil. This closed-loop feedback mechanism compensates for temperature-induced variations in magnetic flux density, maintaining consistent sound output quality across different operating temperatures.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the electrical parameter (current) supplied to the speaker based on detected temperature conditions. By measuring inductance variations that correlate with temperature and adjusting the current accordingly, the system compensates for changes in magnetic flux density and maintains optimal speaker performance across temperature ranges.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the current to the speaker is increased to compensate for high temperature, then the sound output is maintained, but the energy consumption increases

Engineering Contradiction:

Improvesound output consistencyVSAvoidspeaker energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies current compensation only to the extent necessary to counteract temperature-induced performance degradation. Rather than continuously over-compensating, the control unit adjusts the current by the precise amount needed to maintain reference sound output levels, avoiding unnecessary energy consumption while ensuring adequate compensation during temperature variations.

Inventive Principle:

Principle #16Partial or excessive action

3Use of energy by moving object

If the speaker operates at high temperature without compensation, then the energy consumption is reduced, but the magnetic flux density changes causing sound quality distortion

Engineering Contradiction:

Improvespeaker energy consumptionVSAvoidsound quality

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The control unit continuously monitors the speaker's inductance to detect temperature changes and dynamically adjusts the current supplied to the voice coil. This closed-loop feedback mechanism compensates for temperature-induced variations in magnetic flux density, maintaining consistent sound output quality across different operating temperatures.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the electrical parameter (current) supplied to the speaker based on detected temperature conditions. By measuring inductance variations that correlate with temperature and adjusting the current accordingly, the system compensates for changes in magnetic flux density and maintains optimal speaker performance across temperature ranges.

Inventive Principle:

Principle #35Parameter changes

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 approach stabilizes sound quality by adjusting the current to maintain consistent electromagnetic force on the voice coil, preventing sound quality loss and ensuring the speaker operates effectively across temperature ranges.

Implementation Method 1

A sensing unit may measure at least one of current or a voltage of the speaker

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

A control unit may measure inductance of the speaker on the basis of the at least one of the current or the voltage of the speaker

Methodology Applied

Scientific EffectInductance: Inductor

Implementation Method 3

a mechanical force acts on a voice coil in a magnetic field of a permanent magnet according to the intensity of power applied to the voice coil thus causes the voice coil to move

Methodology Applied

Scientific EffectElectromagnetic Force: Lorentz Force

Implementation Method 4

determine compensation current that compensates for a change in magnetic flux of the speaker with respect to a temperature

Methodology Applied

Scientific EffectMagnetic Flux: Magnetic Field

Data Source

PatentUS10841708B2Vehicle speaker and method of controlling the same

Publication Date: 2020.11.17 HYUNDAI MOTOR CO LTD

AI summary

A speaker system includes a speaker configured to output sound from an electric signal, a sensing unit configured to measure at least one of current or a voltage of the speaker, an amplifier configured to supply current to the speaker, and a control unit configured to measure inductance of the speaker on the basis of the at least one of the current or the voltage of the speaker, to determine a current temperature on the basis of the inductance, and to adjust current to be applied to the speaker by the amplifier on the basis of the current temperature such that a variation in output of the speaker with respect to a temperature is compensated for.