Constant-Current LED Module with Rectifier and Capacitor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-power LEDs driven by alternating current experience significant heat degradation, luminance loss, and efficiency issues due to sudden current conduction, leading to flicker phenomena, low power factor, and increased total harmonic distortion.
Innovation Solution
A constant-current-drive LED module device that includes a rectifier, a unidirectional or bidirectional LED module unit, and a constant current unit with a switching unit, control voltage output unit, and a constant current driver, utilizing components like FETs and zener diodes to regulate current and maintain constant current levels, even with fluctuating AC input voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-power LEDs are driven with large drive current, then luminance output is improved, but heat generation increases causing luminance degradation
Solution Approach 1:
The LED module divides high-power LEDs into multiple strings connected in series, with each string containing multiple LEDs. This segmentation allows the total drive current to be distributed across multiple parallel strings, reducing the current burden on each individual LED string while maintaining overall luminance output.
Solution Approach 2:
The patent applies different connection configurations (series/parallel combinations) to different LED strings based on their specific requirements. Each string can be optimized with appropriate series resistors and connection methods to manage local heat generation while maintaining overall system luminance.
2Device complexity
If LED modules operate only when input voltage exceeds forward threshold voltage, then simple circuit configuration is maintained, but flicker phenomenon and low power factor occur
Solution Approach 1:
The patent introduces a capacitor connected in parallel with the LED module that charges during voltage peaks and discharges during voltage valleys, providing preliminary energy storage action. This smoothing action prevents flicker and maintains continuous operation even when instantaneous voltage drops below the forward threshold voltage.
Solution Approach 2:
The capacitor acts as an intermediary energy storage element between the AC power source and the LED module. It mediates the voltage fluctuations by storing energy when voltage is high and releasing it when voltage is low, ensuring continuous LED operation and eliminating flicker.
3Device complexity
If resistor is used to determine current magnitude in LED module, then simple current control is achieved, but power factor degradation and high harmonic distortion occur
Solution Approach 1:
The capacitor serves as an intermediary reactive power compensation element that improves power factor by providing leading reactive power to counterbalance the lagging reactive power of the resistive LED load. This reduces harmonic distortion and improves overall power quality without complicating the current control mechanism.
Solution Approach 2:
The patent changes the electrical parameters of the circuit by introducing capacitive reactance in parallel with the resistive LED load. This parameter change transforms the overall load characteristics, improving power factor and reducing harmonic distortion while maintaining the simplicity of resistive current control.
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 solution suppresses flicker phenomena, improves light efficiency, and enhances the power factor by maintaining consistent current flow, reducing harmonic distortion, and stabilizing luminance despite AC voltage fluctuations, thereby extending LED lifespan and improving overall performance.
Implementation Method 1
a rectifier configured to receive and rectify an alternating current power source
Implementation Method 2
a constant current driver configured to be controlled by the driving voltage of the first or second level to provide constant current
Data Source
AI summary
A constant-current-drive LED module device includes a rectifier configured to receive and rectify an alternating current power source; a unidirectional LED module unit configured to connect to one end of the rectifier; and a constant current unit configured to connect between the unidirectional LED module unit and the other end of the rectifier to control constant current.