Intro: Trick gadgets in power electronic devices
Silicon-controlled rectifiers (SCRs), likewise referred to as thyristors, are semiconductor power tools with a four-layer triple joint structure (PNPN). Since its intro in the 1950s, SCRs have actually been commonly used in industrial automation, power systems, home appliance control and various other fields because of their high hold up against voltage, large existing bring ability, quick reaction and easy control. With the development of modern technology, SCRs have advanced right into lots of types, consisting of unidirectional SCRs, bidirectional SCRs (TRIACs), turn-off thyristors (GTOs) and light-controlled thyristors (LTTs). The differences between these kinds are not just reflected in the framework and functioning concept, however also identify their applicability in different application circumstances. This article will begin with a technological viewpoint, integrated with certain specifications, to deeply examine the main differences and common uses these four SCRs.
Unidirectional SCR: Fundamental and stable application core
Unidirectional SCR is one of the most standard and common type of thyristor. Its framework is a four-layer three-junction PNPN arrangement, including three electrodes: anode (A), cathode (K) and gate (G). It just enables existing to flow in one instructions (from anode to cathode) and turns on after eviction is activated. As soon as activated, also 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 strong voltage and current tolerance, with an ahead repeated peak voltage (V DRM) of as much as 6500V and a ranked on-state typical present (ITAV) of up to 5000A. For that reason, it is widely made use of in DC motor control, industrial heating unit, uninterruptible power supply (UPS) rectification components, power conditioning tools and other celebrations that call for continual transmission and high power processing. Its advantages are simple framework, affordable and high integrity, and it is a core part of numerous typical power control systems.
Bidirectional SCR (TRIAC): Perfect for air conditioner control
Unlike unidirectional SCR, bidirectional SCR, also referred to as TRIAC, can attain bidirectional conduction in both positive and adverse fifty percent cycles. This framework consists of two anti-parallel SCRs, which enable TRIAC to be triggered and turned on at any time in the air conditioner cycle without altering the circuit link method. The symmetrical conduction voltage series of TRIAC is normally ± 400 ~ 800V, the maximum load current is about 100A, and the trigger current is less than 50mA.
Because of the bidirectional conduction characteristics of TRIAC, it is especially ideal for a/c dimming and speed control in household home appliances and customer electronics. For example, gadgets such as light dimmers, fan controllers, and ac system follower rate regulatory authorities all depend on TRIAC to achieve smooth power regulation. Additionally, TRIAC also has a lower driving power demand and is suitable for integrated layout, so it has actually been extensively made use of in clever home systems and small home appliances. Although the power thickness and switching speed of TRIAC are not as good as those of brand-new power devices, its affordable and practical use make it a crucial player in the area of small and medium power a/c control.
Entrance Turn-Off Thyristor (GTO): A high-performance rep of active control
Gateway Turn-Off Thyristor (GTO) is a high-performance power device established on the basis of conventional SCR. Unlike regular SCR, which can just be switched off passively, GTO can be switched off proactively by applying an adverse pulse present to the gate, thus achieving even more flexible control. This feature makes GTO do well in systems that require regular start-stop or rapid response.
(Thyristor Rectifier)
The technical parameters of GTO show that it has extremely high power dealing with capacity: the turn-off gain has to do with 4 ~ 5, the optimum operating voltage can reach 6000V, and the maximum operating current depends on 6000A. The turn-on time is about 1μs, and the turn-off time is 2 ~ 5μs. These efficiency signs make GTO widely used in high-power circumstances such as electrical engine traction systems, big inverters, industrial 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 feedback demands is still irreplaceable.
Light-controlled thyristor (LTT): A reliable choice in the high-voltage seclusion setting
Light-controlled thyristor (LTT) uses optical signals as opposed to electrical signals to cause transmission, which is its largest function that identifies it from various other kinds of SCRs. The optical trigger wavelength of LTT is normally between 850nm and 950nm, the feedback time is gauged in split seconds, and the insulation degree can be as high as 100kV or above. This optoelectronic isolation device substantially enhances the system’s anti-electromagnetic disturbance capability and safety and security.
LTT is primarily made use of in ultra-high voltage direct existing transmission (UHVDC), power system relay defense gadgets, electromagnetic compatibility defense in medical tools, and army radar communication systems etc, which have incredibly high requirements for safety and security and stability. As an example, lots of converter terminals in China’s “West-to-East Power Transmission” job have actually adopted LTT-based converter valve modules to make certain steady operation under exceptionally high voltage conditions. Some advanced LTTs can additionally be combined with gateway control to accomplish bidirectional conduction or turn-off features, further expanding their application variety and making them a perfect selection for fixing high-voltage and high-current control problems.
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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 scr controlled, please feel free to contact us.(sales@pddn.com)
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