Intro: Secret devices in power electronics
Silicon-controlled rectifiers (SCRs), also known as thyristors, are semiconductor power tools with a four-layer triple joint structure (PNPN). Considering that its intro in the 1950s, SCRs have actually been commonly used in commercial automation, power systems, home device control and various other areas because of their high stand up to voltage, huge present carrying ability, rapid action and easy control. With the growth of modern technology, SCRs have evolved right into lots of types, consisting of unidirectional SCRs, bidirectional SCRs (TRIACs), turn-off thyristors (GTOs) and light-controlled thyristors (LTTs). The differences in between these types are not just mirrored in the framework and working principle, however likewise determine their applicability in various application circumstances. This article will certainly start from a technical viewpoint, incorporated with details specifications, to deeply evaluate the main differences and common uses of these 4 SCRs.
Unidirectional SCR: Standard and stable application core
Unidirectional SCR is the most basic and usual type of thyristor. Its framework is a four-layer three-junction PNPN setup, consisting of three electrodes: anode (A), cathode (K) and gate (G). It just enables existing to flow in one instructions (from anode to cathode) and activates after eviction is activated. As soon as turned on, even if eviction signal is gotten rid of, as long as the anode current is more than the holding existing (normally less than 100mA), the SCR remains on.
(Thyristor Rectifier)
Unidirectional SCR has solid voltage and present tolerance, with an ahead repetitive top voltage (V DRM) of as much as 6500V and a ranked on-state average existing (ITAV) of approximately 5000A. Therefore, it is commonly used in DC motor control, commercial furnace, uninterruptible power supply (UPS) correction components, power conditioning gadgets and other celebrations that call for constant transmission and high power handling. Its advantages are straightforward framework, inexpensive and high integrity, and it is a core component of many standard power control systems.
Bidirectional SCR (TRIAC): Perfect for AC control
Unlike unidirectional SCR, bidirectional SCR, additionally referred to as TRIAC, can attain bidirectional conduction in both favorable and adverse half cycles. This framework includes two anti-parallel SCRs, which enable TRIAC to be activated and activated any time in the air conditioning cycle without transforming the circuit connection technique. The balanced transmission voltage variety of TRIAC is usually ± 400 ~ 800V, the maximum tons current is about 100A, and the trigger current is much less than 50mA.
Due to the bidirectional transmission qualities of TRIAC, it is especially ideal for AC dimming and speed control in household appliances and customer electronic devices. As an example, devices such as lamp dimmers, follower controllers, and ac system fan rate regulators all rely on TRIAC to achieve smooth power policy. In addition, TRIAC additionally has a reduced driving power requirement and appropriates for integrated layout, so it has been commonly utilized in clever home systems and tiny appliances. Although the power thickness and switching rate of TRIAC are not like those of new power devices, its low cost and practical usage make it a crucial player in the field of little and moderate power air conditioner control.
Gateway Turn-Off Thyristor (GTO): A high-performance agent of energetic control
Gate Turn-Off Thyristor (GTO) is a high-performance power device established on the basis of typical SCR. Unlike normal SCR, which can only be switched off passively, GTO can be shut off proactively by applying an adverse pulse present to eviction, therefore accomplishing more versatile control. This function makes GTO execute well in systems that need regular start-stop or fast feedback.
(Thyristor Rectifier)
The technical specifications of GTO reveal that it has exceptionally high power dealing with capacity: the turn-off gain has to do with 4 ~ 5, the optimum operating voltage can get to 6000V, and the maximum operating current is up to 6000A. The turn-on time has to do with 1μs, and the turn-off time is 2 ~ 5μs. These performance indications make GTO commonly used in high-power circumstances such as electric locomotive grip systems, huge inverters, commercial motor regularity conversion control, and high-voltage DC transmission systems. Although the drive circuit of GTO is reasonably intricate and has high changing losses, its efficiency under high power and high dynamic response requirements is still irreplaceable.
Light-controlled thyristor (LTT): A trustworthy selection in the high-voltage isolation environment
Light-controlled thyristor (LTT) utilizes optical signals rather than electrical signals to activate transmission, which is its biggest function that distinguishes it from various other kinds of SCRs. The optical trigger wavelength of LTT is generally in between 850nm and 950nm, the response time is measured in split seconds, and the insulation level can be as high as 100kV or over. This optoelectronic isolation device significantly boosts the system’s anti-electromagnetic disturbance capacity and safety and security.
LTT is mostly utilized in ultra-high voltage straight existing transmission (UHVDC), power system relay protection gadgets, electromagnetic compatibility protection in medical devices, and army radar interaction systems etc, which have extremely high needs for safety and security. For example, several converter stations in China’s “West-to-East Power Transmission” task have adopted LTT-based converter shutoff components to guarantee secure operation under very high voltage problems. Some advanced LTTs can also be combined with entrance control to achieve bidirectional transmission or turn-off functions, even more expanding their application range and making them an optimal selection for fixing high-voltage and high-current control troubles.
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Luoyang Datang Energy Tech Co.Ltd focuses on the research, development, and application of power electronics technology and is devoted to supplying customers with high-quality transformers, thyristors, and other power products. Our company mainly has solar inverters, transformers, voltage regulators, distribution cabinets, thyristors, module, diodes, heatsinks, and other electronic devices or semiconductors. If you want to know more about semiconductor controlled rectifier, please feel free to contact us.(sales@pddn.com)
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