Vehicle Head Lamp Lighting System with Dynamic Boost Converter Frequency Control

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Solution Overview

Problem

The head lamp lighting system of vehicles faces challenges in providing stable power to high power LEDs due to varying battery voltages, and existing step-up converters generate heat and are not suitable for diverse LED functions.

Innovation Solution

A head lamp lighting system utilizing a DC/DC boost converter and multiple DC/DC buck converters, where the boost converter's switching frequency is adjusted based on battery voltage to provide a stabilized output voltage for LEDs, minimizing heat generation and optimizing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a step-up converter is used to provide power supply to head lamp lighting device, then voltage can be increased to suit high power LEDs, but heat is generated and it is not suitable for wide diversity of LED functions

Engineering Contradiction:
Improvevoltage outputVSAvoidheat generation
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The power conversion system is segmented into two distinct stages: a boost converter for voltage elevation and multiple buck converters for voltage reduction. This segmentation allows each converter to operate in its optimal efficiency range, reducing overall heat generation while providing diverse voltage outputs for different LED functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects and configures buck converters based on the specific LED function requirements. Different buck converters can be activated or deactivated depending on whether high beam, low beam, turn indicators, or other functions are needed, optimizing efficiency and reducing heat generation for each specific application.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If battery voltage is used directly for head lamp lighting system, then system simplicity is maintained, but voltage instability and unsuitability for high power LEDs occur

Engineering Contradiction:
Improvesystem structureVSAvoidvoltage stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The boost converter acts as an intermediary between the unstable battery voltage source and the LED lighting system. It stabilizes the voltage by converting it to a consistent elevated level, ensuring reliable operation of high power LEDs while maintaining relative system simplicity through a standardized conversion approach.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If boost converter switching frequency is fixed, then control simplicity is maintained, but efficiency is not optimized across varying battery voltages

Engineering Contradiction:
Improvecontrol simplicityVSAvoidconversion efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The boost converter switching frequency is made dynamic rather than fixed. The control system automatically adjusts the switching frequency based on the detected battery voltage level, ensuring optimal conversion efficiency across the entire operating range while maintaining simple automated control without manual intervention.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms that monitor battery voltage and automatically adjust the boost converter switching frequency in response. This closed-loop control optimizes energy conversion efficiency across varying battery conditions while keeping the control process automated and simple for the user.

Inventive Principle:
Principle #23Feedback

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 system ensures stable power supply to various LED functions by adjusting the boost switching frequency according to battery voltage, improving efficiency and reducing heat generation, thus providing a flexible and adaptable lighting solution.

Implementation Method 1

a step-up voltage converter named a direct current-to-direct current (DC/DC) boost converter (22)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

three step-down voltage converters named three direct DC/DC buck converters (36, 38, 40)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3503684B1Head lamp lighting system of a vehicle and its control method
Publication Date: 2022.08.10 APTIV TECHNOLOGIES LTD
  • EP3503684B1 patent drawingFigure 1
  • EP3503684B1 patent drawingFigure 2
  • EP3503684B1 patent drawingFigure 3

AI summary

A head lamp lighting system (10) of a vehicle (12) comprises a DC/DC boost converter (22) configured to provide a common boosted output voltage (24) from a battery voltage (20), a plurality of DC/DC buck converters (36, 38, 40), each DC/DC buck converter (36, 38, 40) being configured to provide an adjusted buck output current (42, 44, 46) from the common boosted output voltage (24), a plurality of strings (26, 28, 30) of Light-Emitting Diodes (32, 34), each string (26, 28, 30) of Light-Emitting Diodes (32, 34) being electrically connected to only one adjusted buck output current (42, 44, 46) and vice versa, a main controller (16) electrically connected to the DC/DC boost converter (22) and configured to provide a boost switching frequency value to the DC/DC boost converter (22), a battery voltage supervisor (56) electrically connected to the main controller (16) and electrically connected to the battery voltage (20), said battery voltage supervisor (56) being configured to provide the battery voltage value to the main controller (16); the main controller (16) being configured to determine the boost switching frequency value according to the battery voltage value.