Non-Isolated Thyristor Trigger Circuit for Compact AC Grid Driving
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Solution Overview
Problem
Existing thyristor driving apparatuses for AC power grids face issues with high-frequency pollution, large space occupation, low cost-effectiveness, and poor reliability due to reliance on transformers and high-voltage electronic switches.
Innovation Solution
A thyristor driving apparatus utilizing a non-isolated power supply circuit and throttling circuit that eliminates the need for transformers and high-voltage electronic switches, featuring a simple circuit design, low power consumption, and high cost-effectiveness, with a throttling circuit that detects the turn-on state of the thyristor and controls the trigger signal accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transformer is used to drive the thyristor in an isolated manner, then the thyristor can be triggered, but the circuit occupies large space and generates high-frequency pollution
Solution Approach 1:
The patent extracts and eliminates the transformer from the traditional isolated driving circuit, replacing it with a non-isolated power supply circuit that directly interfaces with the AC power grid. This removes the source of high-frequency pollution and reduces circuit space while maintaining triggering functionality through a simplified circuit topology.
Solution Approach 2:
The patent replaces the electromagnetic transformation mechanism (transformer) with a direct electrical connection approach using a non-isolated power supply circuit. This substitution eliminates the need for magnetic coupling and high-frequency switching components, thereby reducing space occupation and eliminating high-frequency pollution.
2Reliability
If a transformer and multiple circuits are used to drive the thyristor, then the thyristor can be triggered, but the circuit complexity increases and cost-effectiveness decreases
Solution Approach 1:
The patent merges the power supply function and triggering signal generation into a single non-isolated power supply circuit. The capacitor in this circuit serves dual purposes: power factor correction and triggering signal generation, thereby simplifying the overall circuit structure and improving cost-effectiveness while maintaining reliable thyristor triggering.
Solution Approach 2:
The capacitor in the non-isolated power supply circuit performs multiple functions simultaneously: it acts as a power factor correction element, a energy storage device for triggering signal generation, and a timing element for controlling the triggering moment. This multi-functionality reduces the total component count and simplifies the circuit.
3Power
If high-voltage electronic switches are used to drive the thyristor, then the thyristor can be triggered at high voltage, but the reliability decreases and the switches are prone to breakdown
Solution Approach 1:
The patent replaces expensive and unreliable high-voltage electronic switches with a simpler, more robust circuit topology using standard components like capacitors and resistors in the non-isolated power supply circuit. This approach uses components that are less prone to breakdown and more reliable in high-voltage AC environments.
Solution Approach 2:
The non-isolated power supply circuit generates the triggering signal automatically from the AC power grid voltage itself, without requiring external high-voltage switches. The circuit uses the inherent characteristics of the AC power supply to generate appropriate triggering signals, eliminating the need for vulnerable high-voltage switching components.
Data Source
AI summary
An apparatus for driving a thyristor in an alternating-current power grid includes a non-isolated power supply circuit and a throttling circuit. One terminal of a power supply input of the non-isolated power supply circuit is connected to a first terminal of the thyristor. The other terminal of the power supply input is connected to another phase of the power supply relative to the first terminal or a neutral lead. The non-isolated power supply circuit forms a signal trigger loop through the throttling circuit, a second terminal of the thyristor and the first terminal of the thyristor. A control terminal of the throttling circuit is connected to a third terminal of the thyristor. The apparatus of the present invention has advantages of occupying a small space and having a simple circuit, a great instantaneous triggering current, a high cost effectiveness, and a low power consumption.