AC LED Circuit with Phase-Shifted Branches for Flicker Reduction
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Solution Overview
Problem
Existing ACLED devices face challenges in reducing overall flicker index and compliance with mains harmonics regulations due to uncontrolled phase shifts and harmonics in light-emitting diode circuits.
Innovation Solution
The device employs a first branch with a capacitor for phase-shifting the current through a light-emitting diode circuit, while the second branch does not phase-shift the current, using capacitors and resistors to optimize power factor and reduce flicker and harmonics, ensuring the light source operates effectively across both halves of the AC voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a capacitor is used for phase-shifting current in one branch, then the overall flicker index is reduced, but the device complexity increases
Solution Approach 1:
The light-emitting diode circuit is divided into multiple branches (first branch with capacitor for phase-shifting, second branch without), allowing different phase-shifted currents to be generated in parallel. This segmentation enables the reduction of overall flicker index by distributing the phase-shifted current across multiple branches rather than requiring complex control in a single branch.
Solution Approach 2:
Different branches are given different properties: the first branch includes a capacitor for phase-shifting while the second branch does not. This local differentiation allows each branch to contribute differently to the overall flicker reduction, with the phase-shifted branch providing flicker suppression while maintaining simplicity in other branches.
2Object-affected harmful factors
If phase-shifting arrangement is added to reduce flicker, then compliance with mains harmonics regulations is improved, but the device becomes more complex and costly
Solution Approach 1:
The circuit is segmented into branches with and without phase-shifting arrangements. This segmentation allows the system to achieve harmonics compliance through the combined effect of multiple branches, where the phase-shifted branch contributes to harmonics suppression while other branches maintain simpler circuit topologies.
Solution Approach 2:
Multiple branches are merged in parallel to achieve the overall effect of flicker and harmonics reduction. The first branch with capacitor and the second branch without capacitor are combined, allowing the system to leverage the phase-shifted current from one branch while maintaining the simplicity of other branches, thereby achieving compliance without requiring every branch to be complex.
3Volume of moving object
If capacitor is used instead of coil for phase-shifting, then the size is reduced, but the power factor may be affected
Solution Approach 1:
The patent changes the component parameter from coil to capacitor for phase-shifting. This parameter change reduces the size of the phase-shifting arrangement while the overall power factor is managed through the combined effect of multiple branches and the specific configuration of capacitors and resistors in the circuit.
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 results in a reduced overall flicker index and compliance with mains harmonics regulations by smoothing the current and flux, improving stability and reducing third harmonic amplitudes, making the device simpler, cost-effective, and robust.
Implementation Method 1
the first arrangement comprises a capacitor coupled serially to the first light-emitting diode circuit. Use of a capacitor for phase-shifting a current is advantageous
Data Source
AI summary
Devices (1) have branches (20,30) for receiving AC voltages. First branches (20) comprise first light-emitting diode circuits (21) and first arrangements for phase-shifting first currents flowing through the first light-emitting diode circuits (21) with respect to the AC voltages. Second branches (30) comprise second light-emitting diode circuits (31) and do not comprise second arrangements for phase-shifting second currents flowing through the second light-emitting diode circuits (31) with respect to the AC voltages. As a result, an overall flicker index of the device (1) will be smaller than individual flicker indices of the light-emitting diode circuits (21,31). The first arrangements may comprise capacitors (22) coupled serially to the first light-emitting diode circuits (21). The branches (20,30) may further comprise resistors (23,33) coupled serially to or forming part of the light-emitting diode circuits (21,31). The light-emitting diode circuits (21,31) generate light in response to positive and negative halves of the AC voltages.