Generally sinusoidal alternating current, which is a period of 360 degrees, 180 degrees accounted for the positive half cycle and negative half cycle representing 180 degrees. When an alternating current through the thyristor, so that alternating current can be controlled to be started by conducting at any angle of 0-180 degrees, the so-called controlled rectifier, when added to a positive half cycle of thyristor anode at 180 degrees at a certain angle, the control electrode of the thyristor a trigger pulse is applied, for example, a plus 30-degree pulse, the thyristor current only through the remaining 150 degrees. This makes the thyristor conducting the above-described example, the starting angle of 30 ° is called the control angle, denoted by α. Electrical angle in the thyristor in an ON state is called a power cycle of the conduction angle, expressed by [theta], such as the aforementioned 150 °, so that θ = π-α.
Conduction angle
In the field of power electronics, the conduction angle refers to a period in which the conduction angle of power electronic devices (e.g., thyristors) control.
Generally sinusoidal alternating current, which is a period of 360 degrees, 180 degrees accounted for the positive half cycle and negative half cycle representing 180 degrees. In controlled rectifier SCR for this member, for example, when the alternating current through the diode rectifier element, so that the device 180 through the positive half cycle current, while the negative half cycle of the current can not pass through 180 degrees by, in this way, said a half-wave rectification.
When an alternating current through the thyristor, so that alternating current can be controlled to be started by conducting at any angle of 0-180 degrees, the so-called controlled rectifier, when added to a positive half cycle of thyristor anode at 180 degrees at a certain angle, the control electrode of the thyristor a trigger pulse is applied, for example, a plus 30-degree pulse, the thyristor current only through the remaining 150 degrees. This makes the thyristor conducting angle is referred to the starting conduction angle.
An alternating current cycle of 360 degrees, 180 degrees of the positive half cycle, the negative half cycle 180 degrees, also known as SCR controlled rectifier elements, alternating current through a rectifying element, so that the positive elements 180 kWh by preventing negative by 180 degrees , i.e., a so-called half-wave rectified alternating current through the thyristor, so that the positive half cycle is not electrically through all 180 degrees, i.e., so-called controlled rectifier when a positive half cycle is added to the anode of the thyristor, in a 180 degrees when the angle, the control electrode of thyristor trigger pulse plus one, plus one, for example at 30 ° pulse, the voltage across the thyristor only the remaining 150 degrees. this makes the thyristor conduction angle is referred to the starting electrically conductive angle.
SCR has a variety of classifications.
(A) is turned off by the conduction and control Category: its off thyristor, and control can be turned into an ordinary thyristor, triac, reverse conducting thyristor, gate turn-off more thyristor (GTO), BTG SCR, temperature and light-controlled thyristor SCR.
(B) the pin and the polarity classifier: SCR can be divided according to their polarity and pin diode SCR, three-pole and four-pole thyristor SCR.
(C) the package Category: SCR package can be divided according to their SCR metal packaging, plastic and ceramic packages thyristor SCR three types. Wherein the metal package thyristor is divided into a bolt-shaped, plate-shaped, circular shell-shaped other; SCR divided into plastic finned type heat sink and without the two.
(D) by the current capacity of Category: SCR can be divided by the high-power thyristor current capacity, the power and low-power thyristor SCR three. Typically, multiple high-power thyristor metal shell package, while in low power SCR is to use more plastic or ceramic package.
(E) by the shutdown speed Category: SCR turn-off speed can be divided according to their ordinary and high-frequency thyristor (fast) SCR.
