Bidirectional Dimmer Control for LED Load Phase Accuracy
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Solution Overview
Problem
Existing dimmers are limited in their ability to accommodate a wide range of lighting loads, particularly LED systems, due to inefficiencies in power supply and control mechanisms, leading to issues with light output adjustment and potential errors in phase detection.
Innovation Solution
A dimmer design featuring a bidirectional switch, phase detector, power supply, and controller that modulates the bidirectional switch based on detected AC voltage phases to control light output, ensuring power supply during both halves of the AC cycle and reducing conduction losses, thereby supporting a broader range of loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional dimmer design with unidirectional switch and electrolytic capacitor power supply is used, then the dimmer can provide stable control power, but it is limited in compatibility with various LED lighting loads and produces conduction losses
Solution Approach 1:
The patent inverts the conventional switching approach by using a bidirectional switch that can conduct in both directions, replacing the traditional unidirectional switch. This inversion allows the dimmer to handle AC voltage in both half-cycles efficiently, reducing conduction losses and improving compatibility with various LED lighting loads that require bidirectional current handling capability
2Ease of operation
If phase control is implemented using traditional methods, then light output can be adjusted, but errors in phase detection occur reducing control precision
Solution Approach 1:
The patent incorporates a phase detector that provides feedback on the actual phase of AC voltage to the controller. This feedback mechanism allows the controller to accurately determine the zero-crossing point and adjust the switching timing accordingly, eliminating phase detection errors and enabling precise light output adjustment through accurate phase-controlled rectification
3Reliability
If the power supply operates only during one half cycle of AC voltage, then control power can be generated, but the dimmer cannot maintain stable operation across varying load conditions
Solution Approach 1:
The patent implements a power supply system using a bidirectional switch that can operate during both half-cycles of AC voltage. This multi-functional approach allows the same power supply circuit to generate control power consistently regardless of which half-cycle is active, maintaining stable operation under varying load conditions without requiring separate power supply configurations for different operating modes
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 design enhances the dimmer's compatibility with various loads by maintaining a stable power supply and reducing errors in phase detection, allowing for precise light output adjustment and improved responsiveness to dimming levels.
Implementation Method 1
The power supply has a capacitive device configured to store the control power
Data Source
AI summary
A bidirectional switch is switched so as to conduct and interrupt a bidirectional current between a pair of input terminals. A power supply is electrically connected between the pair of input terminals and produces control power by electric power from an AC power supply. A controller receives the control power from the power supply to be activated. The controller causes the bidirectional switch to be in an off-state from a start point of a half cycle of AC voltage to a first time point when a first time period elapses. The controller causes the bidirectional switch to be in an on-state from the first time point to a second time point when a second time period according to the dimming level elapses. The controller causes the bidirectional switch to be in an off-state from the second time point to an end point of the half cycle.