LED Dimming Control Module PWM Brightness Adjustment
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Solution Overview
Problem
LED light dimming systems face inefficiencies due to total harmonic distortion (THD) and electromagnetic interference (EMI), which existing technologies have not effectively addressed.
Innovation Solution
A system and method for LED light dimming that includes a dimming control module connected to an AC power source via a lighting control device with a power on/off switch and a dimmer, generating a pulse width modulated (PWM) drive signal to progressively adjust brightness levels, minimizing THD and EMI by maintaining sine waveform input current in phase with input voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED dimming methods are used, then brightness control is achieved, but total harmonic distortion (THD) increases and electromagnetic interference (EMI) occurs
Solution Approach 1:
The patent applies periodic action through pulse width modulation (PWM) where the LED is switched on and off at high frequency. The dimming control module generates PWM signals that periodically switch the LED current, achieving brightness control without the harmonic distortion and electromagnetic interference associated with conventional phase-cut dimming methods. This periodic switching maintains sine waveform phase alignment with input voltage while reducing THD and EMI.
2Illumination intensity
If brightness control is implemented, then illumination intensity is adjusted, but power factor decreases
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the duty cycle of the PWM signal to control brightness while maintaining optimal power factor. The dimming control module modifies the on-time proportion of the PWM cycle, allowing brightness adjustment without the power factor degradation typical of conventional dimming circuits. This approach changes the temporal distribution of power consumption rather than reducing overall power efficiency.
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 achieves efficient LED light dimming with increased power factor, reduced THD, and minimized EMI, providing versatile and energy-saving brightness control.
Implementation Method 1
generating a pulse width modulated ('PWM') drive signal based on a selected target brightness level
Data Source
AI summary
A system and method for dimming an LED lighting installation using an AC power source are disclosed. The disclosed LED lighting system includes an LED light having one or more LEDs, a dimming control module for controlling and adjusting brightness level of the LED light toward a desired target brightness, and a user-operated lighting control device including a power on/off switch and a dimmer. The power on/off switch passes or interrupts the AC power fed into the dimming control module. A series of turned-off operations of the power on/off switch of transitory duration causes LED light target brightness levels to be progressively increasing or decreasing leading to a desired target brightness. Operations of the dimmer result in a target brightness setting signal being generated for the dimming control module, representative of a desired target brightness as well.