Intro: Key gadgets in power electronics
Silicon-controlled rectifiers (SCRs), additionally called thyristors, are semiconductor power gadgets with a four-layer three-way joint structure (PNPN). Because its introduction in the 1950s, SCRs have actually been commonly made use of in industrial automation, power systems, home appliance control and various other fields as a result of their high stand up to voltage, big existing bring capacity, rapid reaction and straightforward control. With the growth of technology, SCRs have developed into lots of types, consisting of unidirectional SCRs, bidirectional SCRs (TRIACs), turn-off thyristors (GTOs) and light-controlled thyristors (LTTs). The differences between these types are not just mirrored in the framework and functioning principle, but likewise establish their applicability in various application situations. This article will start from a technical point of view, incorporated with specific criteria, to deeply assess the main differences and common uses these 4 SCRs.
Unidirectional SCR: Basic and secure application core
Unidirectional SCR is the most standard and common type of thyristor. Its structure is a four-layer three-junction PNPN plan, consisting of three electrodes: anode (A), cathode (K) and gateway (G). It just enables existing to flow in one direction (from anode to cathode) and activates after the gate is caused. Once switched on, even if the gate signal is removed, as long as the anode current is greater than the holding current (typically much less than 100mA), the SCR stays on.
(Thyristor Rectifier)
Unidirectional SCR has solid voltage and current tolerance, with an onward repeated optimal voltage (V DRM) of up to 6500V and a ranked on-state ordinary current (ITAV) of up to 5000A. As a result, it is extensively made use of in DC motor control, commercial heating unit, uninterruptible power supply (UPS) correction parts, power conditioning devices and various other events that call for continual transmission and high power processing. Its benefits are basic structure, inexpensive and high reliability, and it is a core part of many typical power control systems.
Bidirectional SCR (TRIAC): Suitable for air conditioning control
Unlike unidirectional SCR, bidirectional SCR, likewise known as TRIAC, can achieve bidirectional conduction in both positive and unfavorable fifty percent cycles. This structure contains two anti-parallel SCRs, which permit TRIAC to be activated and turned on at any time in the air conditioning cycle without transforming the circuit link method. The symmetrical transmission voltage series of TRIAC is usually ± 400 ~ 800V, the maximum tons current has to do with 100A, and the trigger current is less than 50mA.
Because of the bidirectional transmission characteristics of TRIAC, it is especially ideal for air conditioning dimming and rate control in home devices and customer electronics. For instance, tools such as lamp dimmers, fan controllers, and a/c fan speed regulators all rely on TRIAC to achieve smooth power regulation. Furthermore, TRIAC additionally has a lower driving power need and appropriates for integrated layout, so it has been extensively made use of in wise home systems and tiny home appliances. Although the power density and switching rate of TRIAC are not like those of new power devices, its affordable and convenient usage make it an important gamer in the field of tiny and moderate power air conditioner control.
Entrance Turn-Off Thyristor (GTO): A high-performance agent of energetic control
Gateway Turn-Off Thyristor (GTO) is a high-performance power device established on the basis of standard SCR. Unlike normal SCR, which can only be switched off passively, GTO can be shut off actively by applying a negative pulse existing to eviction, therefore achieving even more adaptable control. This feature makes GTO perform well in systems that call for constant start-stop or rapid reaction.
(Thyristor Rectifier)
The technical parameters of GTO reveal that it has incredibly high power managing capacity: the turn-off gain has to do with 4 ~ 5, the optimum operating voltage can reach 6000V, and the optimum 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 indicators make GTO commonly made use of in high-power situations such as electric engine traction systems, huge inverters, industrial electric motor frequency conversion control, and high-voltage DC transmission systems. Although the drive circuit of GTO is reasonably complex and has high changing losses, its performance under high power and high vibrant response needs is still irreplaceable.
Light-controlled thyristor (LTT): A dependable selection in the high-voltage seclusion environment
Light-controlled thyristor (LTT) makes use of optical signals as opposed to electrical signals to trigger conduction, which is its largest function that differentiates it from other types of SCRs. The optical trigger wavelength of LTT is generally between 850nm and 950nm, the feedback time is gauged in nanoseconds, and the insulation degree can be as high as 100kV or over. This optoelectronic seclusion mechanism substantially improves the system’s anti-electromagnetic interference ability and safety and security.
LTT is mainly made use of in ultra-high voltage direct existing transmission (UHVDC), power system relay security tools, electro-magnetic compatibility security in medical tools, and armed forces radar interaction systems etc, which have exceptionally high needs for safety and security. For instance, many converter stations in China’s “West-to-East Power Transmission” project have embraced LTT-based converter valve modules to guarantee steady operation under exceptionally high voltage conditions. Some progressed LTTs can also be integrated with gate control to accomplish bidirectional transmission or turn-off features, even more expanding their application array and making them a perfect choice for resolving high-voltage and high-current control troubles.
Vendor
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 silicon controlled rectifier has, please feel free to contact us.(sales@pddn.com)
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