LED Luminescence Apparatus With Phase Switching For Power Factor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED luminescence apparatus using AC power faces issues with power factor and Total Harmonics Distortion (THD) due to non-sinusoidal waveforms of AC voltage, leading to inefficient light emission and flicker phenomena.
Innovation Solution
The apparatus incorporates a rectification circuit, multiple LED units connected in series with switch units and constant current control circuits, and a current comparison unit to generate switching control signals, ensuring a specific current magnitude and minimizing the LED OFF interval by using different driving voltages for each LED unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple reduction in LED driving voltage is applied, then circuit complexity is reduced, but power factor and THD requirements are not fulfilled
Solution Approach 1:
The LED string is divided into multiple groups connected in series, with each group controlled by a separate phase switch. This segmentation allows progressive turning on of LED groups as input voltage increases, enabling better control of current waveform and power factor without requiring complex circuitry throughout the entire LED string.
Solution Approach 2:
The phase switches dynamically control the connection of different LED groups based on the instantaneous input voltage level. As voltage increases, additional groups are sequentially activated, creating a dynamic response that maintains optimal operating conditions across varying voltage conditions while improving power factor and reducing THD.
2Use of energy by moving object
If AC power with distorted waveform is used, then power consumption is reduced, but light emission efficiency varies significantly
Solution Approach 1:
The system utilizes the periodic nature of AC power by implementing phase switches that operate in synchronization with the AC cycle. Each phase switch activates LED groups at specific phases of the voltage waveform, ensuring that LEDs receive optimized driving current during each half-cycle, thereby maintaining consistent light emission efficiency despite waveform distortion.
Solution Approach 2:
The invention changes the operating parameters of LED groups based on the instantaneous AC voltage characteristics. By adjusting which groups are active and at what current levels according to the distorted waveform parameters, the system maintains efficient light emission across varying voltage conditions.
3Adaptability or versatility
If multiple circuits are added to drive LEDs with AC power, then AC compatibility is improved, but device complexity increases
Solution Approach 1:
The AC driving circuit is segmented into modular phase switch units, each controlling a specific LED group. This segmentation allows the system to achieve AC compatibility through simple, repeatable circuit modules rather than complex integrated circuits, maintaining adaptability while controlling overall system complexity.
Solution Approach 2:
Each phase switch unit serves multiple functions: it controls current magnitude, provides AC compatibility, enables progressive LED activation, and contributes to power factor improvement. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting complexity growth despite enhanced AC adaptability.
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 configuration improves power factor, reduces THD, and increases light output efficiency by minimizing the LED OFF interval, resulting in more consistent and efficient LED operation.
Implementation Method 1
a rectification circuit unit to receive an alternating current (AC) power voltage and rectify the AC power voltage to output a unidirectional ripple voltage
Implementation Method 2
a plurality of LED units connected in series, each of the plurality of LED units comprising an anode and a cathode, the plurality of LED units being configured to receive the unidirectional ripple voltage
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An LED luminescence apparatus includes a plurality of LED units connected in series which are configured to receive a unidirectional ripple voltage, a plurality of switch units, one end of each being connected to the cathode of one of the plurality of LED units, a plurality of constant current control circuit units, one end of each being connected to an another end of a respective switch unit to receive a current from the respective switch unit, each of the constant current control circuit units being configured to output a current control signal to the respective switch unit to control a magnitude of the received current to have a specific value, and a current comparison unit to receive currents flowing from the plurality of switching units, and generate a plurality of switching control signals for the respective switch units to sequentially drive the plurality of constant current control circuit units.