Automotive LED Module Current Balancing for Thermal Derating
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Solution Overview
Problem
Existing automotive lighting devices with solid-state light sources face challenges in maintaining optimal performance and flux homogeneity due to uneven heating, where one module overheats and derates, affecting others despite them not needing derating, leading to inefficient operation and performance degradation.
Innovation Solution
A method and device that adjust current profiles for each light module based on estimated derating times, using machine learning and artificial intelligence algorithms to optimize current values, ensuring one module derates later than the other, thus extending the global derating time and maintaining flux homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LED modules are arranged in a matrix pattern with even spacing, then uniform light distribution is achieved, but the number of LED modules increases and device complexity increases
Solution Approach 1:
The lighting device is divided into four quadrants with rotational symmetry. Each quadrant contains a reduced number of LED modules arranged in a simplified pattern. The control unit divides the LED modules into groups corresponding to each quadrant and applies rotational transformation matrices to generate control signals, effectively segmenting the control problem into manageable sections.
Solution Approach 2:
The control unit serves multiple functions: it stores transformation matrices, performs coordinate transformations, divides LED modules into groups, and generates control signals. This multi-functional approach eliminates the need for separate control circuits for each quadrant, reducing overall device complexity while maintaining uniform light distribution.
2Illumination intensity
If LED modules are arranged in a matrix pattern with even spacing, then uniform light distribution is achieved, but manufacturing cost increases
Solution Approach 1:
By segmenting the lighting device into four identical quadrants, the manufacturing process can be standardized. Each quadrant uses the same number and arrangement of LED modules, allowing for modular assembly and reducing manufacturing complexity and cost.
Solution Approach 2:
The patent changes the control parameters (rotation angles and transformation matrices) rather than the physical arrangement parameters (number and position of LED modules). This allows uniform light distribution to be achieved through software control rather than through increasing the number of physical components, thereby reducing manufacturing cost.
3Measurement precision
If coordinate transformation is performed to control LED modules in groups, then control precision is improved, but processing time increases
Solution Approach 1:
The transformation matrices are pre-calculated and stored in the control unit's memory before operation. When control is needed, the system simply retrieves and applies these pre-computed matrices rather than performing complex calculations in real-time, significantly reducing processing time while maintaining high control precision.
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 method extends the derating time of the module with the lower derating time, improving overall performance and flux homogeneity by optimizing current profiles, reducing power consumption, and achieving thermal stabilization.
Implementation Method 1
the control unit is configured to transform a coordinate system using a transformation matrix and to determine control signals for the LED modules on the basis of the transformed coordinate system
Data Source
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AI summary
The invention provides a method for operating an automotive lighting device comprising the steps of providing a first preliminary current profile, calculating a first preliminary derating time associated to the first preliminary current profile, providing a second preliminary current profile, calculating a second preliminary derating time associated to the second preliminary current profile, feeding the first light module with a first current profile which provides a total amount of current lower than the first preliminary amount of current, and feeding the second light module with a second current profile which provides a total amount of current higher than the second preliminary amount of current.