Motor Vehicle LED Lighting Control Frequency Variation
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Solution Overview
Problem
Existing methods for operating motor vehicle LED lighting devices using pulse-width modulation require high modulation frequencies to avoid the stroboscopic effect, leading to increased stress on expensive semiconductor components and potential electromagnetic compatibility issues.
Innovation Solution
The method involves varying the modulation frequency continuously while maintaining a constant mark-to-space ratio, allowing for a reduction in modulation frequency without causing a stroboscopic effect, thereby reducing the stress on LED components and improving electromagnetic compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a constant high modulation frequency is used to avoid the stroboscopic effect, then the stroboscopic effect is avoided, but the stress on LED semiconductor components increases and expensive high-quality modules are required
Solution Approach 1:
The patent applies dynamics by making the modulation frequency variable rather than constant. The control device continuously varies the modulation frequency within a defined frequency band, preventing the viewer's eye from detecting a constant lighting pattern while reducing the average frequency to lower stress on LED components, thus resolving the contradiction between avoiding stroboscopic effects and extending component service life
Solution Approach 2:
The patent changes the frequency parameter from a fixed high value to a dynamically varying value within a specific range. By continuously adjusting the modulation frequency within a defined band, the system avoids the stroboscopic effect without requiring consistently high frequencies, thereby reducing stress on semiconductor components and extending their service life
2Object-affected harmful factors
If a constant high modulation frequency is used to avoid the stroboscopic effect, then the stroboscopic effect is avoided, but electromagnetic compatibility issues arise
Solution Approach 1:
The system dynamically varies the modulation frequency within a defined band rather than maintaining a constant high frequency. This continuous variation prevents the formation of constant lighting patterns that cause stroboscopic effects, while the reduced average frequency lowers electromagnetic interference and improves EMC compatibility
3Object-affected harmful factors
If a high modulation frequency is used to avoid the stroboscopic effect, then the stroboscopic effect is avoided, but the average control frequency remains high causing stress on components
Solution Approach 1:
The patent changes the frequency parameter from a fixed high value to a dynamically varying value within a specific range. By continuously adjusting the modulation frequency within a defined band, the system avoids the stroboscopic effect without requiring consistently high frequencies, thereby reducing stress on semiconductor components and extending their service life
Data Source
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AI summary
Method for operating a motor vehicle lighting device comprising at least one LED and a control device that controls the LED by pulse width modulation, wherein the modulation frequency is continuously varied.