Phase Cut Angle Converter for LED Dimming Range
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Solution Overview
Problem
Phase cut dimmers are unable to control LED luminaire brightness over the entire range of achievable brightness due to limitations in passing AC mains power, typically unable to pass 100% or less than 10% of the AC mains power sine wave, and require a constant current power source, which is not directly compatible with LED lighting.
Innovation Solution
A controller is implemented to detect the range of operating angles of the phase cut dimmer and adjust the brightness of the LED luminaire accordingly, using a phase cut angle converter with a flyback converter, phase cut angle detector, and signal adjustment functionality to convert the phase cut angle to a dimming signal, ensuring the LED luminaire operates within the achievable brightness range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a phase cut dimmer is used to control LED luminaire brightness, then brightness control is achieved, but the control range is limited and cannot cover the entire achievable brightness range
Solution Approach 1:
The patent introduces a controller as an intermediary device between the phase cut dimmer and the LED luminaire. The controller detects the phase cut angle from the dimmer's effect on the AC mains power sine wave and converts it into an appropriate dimming signal that the LED driver can process. This intermediary function resolves the incompatibility between phase cut dimmers (designed for resistive loads) and LED drivers (requiring constant current control), enabling full brightness range control while maintaining LED operating requirements.
2Illumination intensity
If phase cut dimmer blocks portion of AC mains power sine wave, then brightness control is achieved, but minimum and maximum brightness limits are imposed
Solution Approach 1:
The controller performs preliminary detection of the phase cut angle by analyzing the AC mains power sine wave before generating the dimming signal. By detecting the phase cut angle φ in advance and using it to calculate the appropriate PWM duty cycle or analog dimming level, the controller ensures that the LED luminaire brightness accurately reflects the user's dimmer adjustment across the entire achievable range, eliminating the minimum and maximum brightness limits imposed by direct phase cut connection.
3Device complexity
If direct connection between phase cut dimmer and LED luminaire is used, then system simplicity is maintained, but brightness control precision is reduced
Solution Approach 1:
The controller implements feedback by continuously monitoring the phase cut angle φ through detection of the AC mains power sine wave characteristics. This feedback mechanism allows the controller to adjust the dimming signal in real-time based on the actual phase cut angle, ensuring precise brightness control. The feedback loop compensates for variations in phase cut angle and ensures accurate mapping between dimmer position and LED brightness, achieving high precision control while maintaining relatively simple system structure.
Data Source
AI summary
A phase cut angle converter with range detection for a phase cut dimmer constituted of: a phase cut angle detector arranged to detect the phase cut angle presented by the phase cut dimmer blocking a portion of an alternating current mains power sine wave from reaching a power converter, and output a signal whose value is responsive to the detected phase cut angle; a storage functionality constituted of a memory in communication with the phase cut angle detector, the storage functionality arranged to detect each of a minimum value and a maximum value for the detected phase cut angle of the phase cut angle detector and store the minimum value and the maximum value on the memory; and a signal adjustment functionality arranged to convert the detected phase cut angle to a dimming signal responsive to the stored minimum value and the maximum value for the detected phase cut angle.