Triac Control System Using Rectifier for Controller Power
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Solution Overview
Problem
Conventional triac power control systems are costly and unreliable due to the need for robust power supply units that handle high voltages, which increases complexity and size, and often require direct connection to mains voltage, making them prone to failures from surges.
Innovation Solution
A triac power control system that uses a rectifier unit to both transmit control signals and power the controller, coupled with a capacitive network in parallel with the triac, allowing for low power consumption when the triac is off and providing surge protection by triggering the triac to divert potentially damaging surges, thus enabling the use of less robust and cheaper components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a robust power supply unit connected directly to mains voltage is used, then the controller can be powered reliably, but the system cost, complexity and size increase
Solution Approach 1:
The rectifier unit performs dual functions: it rectifies the AC voltage to power the controller and simultaneously generates the trigger pulse for the triac. This multi-functionality eliminates the need for separate power supply and trigger generation circuits, reducing overall system complexity while maintaining reliable controller operation.
Solution Approach 2:
The system uses the mains voltage itself to power the controller through the rectifier unit, rather than requiring an external power supply. The controller is self-powered from the same AC source it controls, eliminating additional power supply components and simplifying the overall system architecture.
2Object-affected harmful factors
If a robust power supply unit with surge protection is used, then the system can withstand voltage surges, but the cost and size of the power supply increase
Solution Approach 1:
The system converts potentially harmful voltage surges into beneficial trigger pulses for the triac. When a surge occurs, the rectifier unit rectifies the surge voltage and uses it to trigger the triac, which then conducts the surge current away from sensitive components, protecting the system while utilizing the surge energy constructively.
3Ease of manufacture
If simple control circuits are used for basic applications, then the system cost is reduced, but the control precision and sophistication are limited
Solution Approach 1:
The system changes the parameter of control signal generation from complex dedicated circuits to a simple rectifier-based pulse generator. The rectifier unit's inherent switching behavior during AC cycles provides sufficient control precision for various applications, from basic on/off control to dimming and motor control, without requiring sophisticated control circuitry.
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 reduces power consumption, especially when the triac is in the off-state, and provides cost-effective and simpler circuitry while offering protective mechanisms against surges, making it suitable for various applications including motor control and lighting.
Implementation Method 1
a rectifier unit (11) comprising at least one rectifier; the rectifier unit being operatively connected between the controller and the control input of the triac unit, and operative: (i) to control the triac unit in accordance with the control signal, and (ii) to transmit electrical power to the controller
Implementation Method 2
A capacitive network is provided in parallel with the triac, and provides another input for the rectifier unit
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A power supply control system is proposed for controlling the supply of power from an alternating current (AC) power source to a load. A triac (T1) in series with the load is controlled by a controller (11), typically an MCU, coupled to the gate terminal of the triac via a rectifier unit comprising at least one rectifier (B1). The rectifier unit transmits a control signal from the controller to the triac, and additionally generates a power signal for powering the controller. Thus, advantageously, a common path can be used for triggering the triac, and powering the controller, so that no sophisticated power supply is required for the controller. This both reduces cost and increase reliability. A capacitive network (ZL, ZH) is provided in parallel with the triac, and electrically connected to an input of the rectifier unit. Optionally, the triac may be additionally triggered in the case of a power surge superimposed on the AC power source, to divert the power surge away from vulnerable components.