Triac Dimming Circuit Stabilizes Conduction Angle via Zero-Cross Feedback

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Solution Overview

Problem

Triac dimming systems experience unstable conduction angles and flicker in lighting due to insufficient maintenance current, leading to uneven waveforms and vibration, which results in noticeable lamp flicker.

Innovation Solution

A triac dimming system incorporating a zero-cross test unit that passes zero-cross signals to the triac dimming circuit, allowing the main control center to adjust the ON/OFF timing and stabilize the conduction angle, combined with a switch power supply, DC power supply control circuit, and dimming control button, to maintain stable waveform and reduce flicker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If triac dimming is used to reduce power consumption, then energy efficiency is improved, but conduction angle instability and waveform unevenness occur due to insufficient maintain current

Engineering Contradiction:

Improvepower consumptionVSAvoidconduction angle stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback mechanism where the microcontroller continuously monitors the triac conduction state and adjusts the firing angle accordingly. The system detects the actual conduction angle and compares it with the target value, then modifies the dimming control signal to maintain stable conduction despite variations in maintain current, thereby resolving the contradiction between energy efficiency and conduction stability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the firing angle parameter based on detected conduction conditions. By changing the firing angle in response to maintain current variations, the system compensates for conduction angle instability while preserving energy efficiency benefits, thus resolving the technical contradiction.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If maintain current is increased to stabilize conduction angle, then conduction stability is improved, but flicker and waveform vibration worsen

Engineering Contradiction:

Improveconduction angle stabilityVSAvoidflicker

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The system uses real-time feedback from waveform detection to adjust the dimming control. When conduction instability is detected, the microcontroller modifies the firing angle to prevent flicker and waveform vibration, rather than simply increasing maintain current. This feedback-based adjustment stabilizes conduction while avoiding the harmful effects of excessive maintain current.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent employs dynamic adjustment of the firing angle based on real-time conduction conditions. Instead of using a fixed high maintain current, the system dynamically adapts the dimming parameters to maintain stable conduction without causing flicker, thus resolving the contradiction between conduction stability and flicker reduction.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If simple triac dimming circuit is used, then device complexity is reduced, but waveform control precision and flicker reduction capability worsen

Engineering Contradiction:

Improvecircuit complexityVSAvoidwaveform control precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces complex analog waveform control circuits with a microcontroller-based digital control system. The microcontroller generates precise dimming control signals through software algorithms, achieving high waveform control precision without requiring complex analog circuitry. This substitution maintains low device complexity while significantly improving waveform control precision and flicker reduction capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effectively stabilizes the conduction angle and waveform, minimizing flicker in lamps, ensuring a smooth dimming experience without noticeable flicker to the user.

Implementation Method 1

Use the rectifier unit to obtain the AC power supply for the AC lamps, convert the AC power into DC power

Methodology Applied

Scientific EffectRectification:

Implementation Method 2

there is a Zener diode-Z1 build in the DC power supply control circuit. Zener diode-Z1 can protect the MOS-Q1

Methodology Applied

Scientific EffectZener breakdown:

Data Source

PatentUS11388803B2Triac dimming system for lighting dimming function

Publication Date: 2022.07.12 NINGBO VEALITE ILLUMINATION CO LTD

AI summary

A triac dimming system for lighting dimming function includes a triac dimming circuit and a zero-cross test unit. The zero-cross test unit connect with triac dimming circuit and pass the zero-cross signal to triac dimming circuit, then the main control center of triac dimming circuit will adjust the ON/OFF timing of triac dimming unit according to the zero-cross signal and the reserved amount to make the conduction angle of triac dimming circuit stable. After precisely controlling the brightness of the AC lamps, it can keep the AC load (AC lamps) flicker within the acceptable level of the user (no flicker feeling by the naked eye).