Phase Control Circuit Timing Extraction for TRIAC Ignition
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Solution Overview
Problem
Existing phase control devices for AC voltage supply networks require large and expensive capacitors due to inefficiencies in energy usage by DIACs, leading to high production costs and reduced thermal stability.
Innovation Solution
A device with a switching element that connects the ignition capacitor to the TRIAC control input after a predefined time, allowing almost all stored energy to be used for ignition, reducing capacitor size and resistor power requirements, and incorporating a voltage-limiting element for improved voltage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DIAC is used to control the ignition capacitor discharge, then the phase control function is achieved, but the capacitor must be large (100 nF) to store sufficient energy
Solution Approach 1:
The patent extracts the timing function from the DIAC and separates it into a dedicated timing circuit. This allows the ignition capacitor to be optimized solely for energy storage rather than兼顾 timing and energy storage, enabling a smaller capacitance value (10 nF) while maintaining reliable ignition through the dedicated timing control that triggers the triac at the correct phase angle.
Solution Approach 2:
The patent segments the ignition control function into two separate components: a timing element that controls when ignition occurs, and an ignition element that executes the ignition. This segmentation allows independent optimization of each function, with the ignition capacitor sized appropriately for energy storage without needing to accommodate timing requirements.
2Reliability
If a large capacitance (100 nF) is used to store sufficient ignition energy, then reliable TRIAC ignition is achieved, but the resistor must be high power (3 W) and large in size
Solution Approach 1:
The patent extracts the timing control function from the resistor-capacitor combination, allowing the resistor to be optimized solely for charging the capacitor rather than controlling discharge timing. This enables the use of a low-power resistor (0.25 W) with a small capacitance value (10 nF), significantly reducing component size and manufacturing cost while maintaining reliable ignition through separate timing control.
Solution Approach 2:
The patent changes the operating parameters of the capacitor from 100 nF to 10 nF, which fundamentally alters the energy storage capacity and corresponding resistor power requirements. This parameter change, enabled by the separated timing and ignition functions, allows the system to use much smaller and cheaper components while achieving the same ignition reliability.
3Ease of operation
If the DIAC blocks after voltage drops by 10 V, then the circuit simplifies operation, but the remaining energy in the capacitor cannot be utilized
Solution Approach 1:
The patent extracts the timing function from the DIAC's voltage-dependent operation and implements it through a dedicated timing element with a reference voltage comparator. This allows precise control of the ignition timing based on the capacitor voltage reaching a reference level, ensuring that the capacitor discharge is timed optimally for triac ignition while utilizing the maximum available energy from the capacitor.
4Productivity
If a resistor and capacitor are used in series for charging, then the phase control is achieved, but production costs increase due to component size and power requirements
Solution Approach 1:
The patent fundamentally changes the operating parameters of the capacitor from 100 nF to 10 nF and the resistor from 3 W to 0.25 W, which directly reduces component size, material costs, and manufacturing complexity. These parameter changes are made possible by the functional separation of timing and ignition control, allowing the use of smaller, cheaper components while maintaining the power control function.
Solution Approach 2:
The patent replaces expensive, large-power components with cheaper, low-power components. The 0.25 W resistor and 10 nF capacitor are significantly cheaper and smaller than the traditional 3 W resistor and 100 nF capacitor, reducing production costs by approximately 10% while maintaining the required power control functionality through optimized timing and ignition control.
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 enables a smaller capacitor (10 nF) and lower power resistors, reducing production costs by 10%, improving thermal stability, and allowing for a softer start with adjustable minimum voltage and increased maximum voltage, while maintaining efficient power control.
Implementation Method 1
an ignition capacitor (22) which is coupled to the ignition device and supplies the energy required to activate the circuit element (12)
Implementation Method 2
a voltage-limiting element (24) having a predetermined maximum voltage value, which is connected in parallel with the ignition capacitor (22) and limits a voltage present at the ignition capacitor (22) to the predetermined maximum voltage value
Data Source
Figure 1~3
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AI summary
A device is disclosed for controlling the power of electric consumers connected to an alternating voltage supply grid, and comprising a circuit element (12, TRIAC) connected in series to the consumer and provided with a control input. The device also comprises a firing system for driving the circuit element and carrying out a phase control operation, and a firing capacitor (22) coupled to the firing system for supplying the energy required for activating the circuit element. The device is characterised in that the firing system comprises a switching element (32) which, when it is activated, establishes a connection between the firing capacitor and the control input of the circuit element, a release element (36) which compares the voltage applied to the firing capacitor with a reference value and generates a release signal, and a timing element (38) which is connected to the release element and activates the switching element (32) in response to the release signal and after a predetermined time period has elapsed, in such a way that the energy stored in the firing capacitor (22) is practically entirely used for firing the circuit element (12, TRIAC).