The working principle and function analysis of thyristor

Silicon Controlled Rectifier (SCR) is a high-power electrical component, also known as thyristor. It has the advantages of small size, high efficiency and long life. In the automatic control system, it can be used as a high-power drive device to control high-power devices with low-power controls. It has been widely used in AC and DC motor speed control systems, power adjustment systems and servo systems.

The working principle of thyristor is:

To turn on the thyristor, first, apply a forward voltage between its anode A and cathode K, and second, input a forward trigger voltage between its gate G and cathode K. After the thyristor is turned on, release the push button switch to remove the trigger voltage and still maintain the conduction state.

If the anode or the control electrode is applied with a reverse voltage, the thyristor cannot be turned on. The role of the gate is to turn the thyristor on by applying a positive trigger pulse, but it does not turn it off. By turning off the turned-on thyristor, the anode power supply can be turned off or the anode current can be made less than the minimum value that maintains conduction (referred to as holding current). If an alternating voltage or a pulsating DC voltage is applied between the thyristor anode and the cathode, the thyristor will turn itself off when the voltage crosses zero.

The role of thyristors in the circuit is as follows:

Converter/rectification

Pressure regulation

frequency conversion

switch

One of the most important functions of thyristors is to stabilize the flow. SCR has a wide range of applications in automatic control and control, electromechanical, industrial electrical and home appliances. A thyristor is an active switching element that is normally kept in a non-pass state until it is triggered or "ignited" by a lesser control signal, and it remains on the ignition signal once it is ignited. The pass state is such that it can be reversed between its anode and cathode or reduce the current flowing through the thyristor diode below a certain value.