Intro: Trick gadgets in power electronic devices
Silicon-controlled rectifiers (SCRs), also called thyristors, are semiconductor power tools with a four-layer three-way joint structure (PNPN). Considering that its introduction in the 1950s, SCRs have been widely made use of in industrial automation, power systems, home appliance control and other fields due to their high stand up to voltage, huge existing lugging capacity, rapid response and basic control. With the development of innovation, SCRs have progressed right into lots of types, consisting of unidirectional SCRs, bidirectional SCRs (TRIACs), turn-off thyristors (GTOs) and light-controlled thyristors (LTTs). The distinctions between these kinds are not just shown in the framework and functioning concept, however also determine their applicability in various application situations. This post will begin with a technical point of view, incorporated with certain specifications, to deeply examine the major distinctions and typical uses of these four SCRs.
Unidirectional SCR: Basic and secure application core
Unidirectional SCR is the most fundamental and typical type of thyristor. Its structure is a four-layer three-junction PNPN plan, consisting of three electrodes: anode (A), cathode (K) and entrance (G). It only allows existing to stream in one direction (from anode to cathode) and turns on after eviction is caused. As soon as switched on, even if eviction signal is gotten rid of, as long as the anode current is more than the holding current (generally less than 100mA), the SCR continues to be on.
(Thyristor Rectifier)
Unidirectional SCR has solid voltage and current tolerance, with an onward recurring optimal voltage (V DRM) of as much as 6500V and a rated on-state typical current (ITAV) of as much as 5000A. Therefore, it is commonly used in DC motor control, industrial heating systems, uninterruptible power supply (UPS) rectification parts, power conditioning devices and various other occasions that require continual conduction and high power handling. Its benefits are easy framework, inexpensive and high integrity, and it is a core part of numerous conventional power control systems.
Bidirectional SCR (TRIAC): Perfect for air conditioner control
Unlike unidirectional SCR, bidirectional SCR, additionally referred to as TRIAC, can accomplish bidirectional conduction in both favorable and unfavorable half cycles. This structure contains two anti-parallel SCRs, which enable TRIAC to be activated and turned on at any time in the air conditioner cycle without transforming the circuit link technique. The balanced conduction voltage variety of TRIAC is generally ± 400 ~ 800V, the maximum lots current is about 100A, and the trigger current is less than 50mA.
Due to the bidirectional transmission qualities of TRIAC, it is specifically ideal for air conditioning dimming and rate control in house home appliances and consumer electronics. As an example, devices such as lamp dimmers, fan controllers, and air conditioning system follower speed regulators all depend on TRIAC to accomplish smooth power law. On top of that, TRIAC additionally has a lower driving power requirement and appropriates for incorporated design, so it has actually been widely made use of in smart home systems and small devices. Although the power thickness and switching rate of TRIAC are not just as good as those of new power devices, its inexpensive and practical use make it a crucial player in the field of little and medium power AC control.
Entrance Turn-Off Thyristor (GTO): A high-performance rep of energetic control
Gateway Turn-Off Thyristor (GTO) is a high-performance power device established on the basis of conventional SCR. Unlike common SCR, which can only be shut off passively, GTO can be switched off actively by using an unfavorable pulse current to eviction, therefore accomplishing more versatile control. This feature makes GTO perform well in systems that require regular start-stop or fast action.
(Thyristor Rectifier)
The technological specifications of GTO show that it has exceptionally high power handling capability: the turn-off gain has to do with 4 ~ 5, the maximum 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 performance indicators make GTO extensively made use of in high-power scenarios such as electrical locomotive traction systems, big inverters, commercial electric motor frequency conversion control, and high-voltage DC transmission systems. Although the drive circuit of GTO is fairly complex and has high changing losses, its performance under high power and high dynamic feedback requirements is still irreplaceable.
Light-controlled thyristor (LTT): A trusted selection in the high-voltage seclusion atmosphere
Light-controlled thyristor (LTT) makes use of optical signals instead of electrical signals to trigger transmission, which is its largest function that distinguishes it from other kinds of SCRs. The optical trigger wavelength of LTT is usually between 850nm and 950nm, the response time is determined in split seconds, and the insulation level can be as high as 100kV or over. This optoelectronic isolation mechanism considerably improves the system’s anti-electromagnetic disturbance capacity and security.
LTT is mainly utilized in ultra-high voltage straight present transmission (UHVDC), power system relay security gadgets, electro-magnetic compatibility protection in medical tools, and military radar interaction systems and so on, which have exceptionally high demands for security and security. As an example, several converter stations in China’s “West-to-East Power Transmission” task have taken on LTT-based converter valve modules to guarantee stable operation under exceptionally high voltage conditions. Some progressed LTTs can additionally be integrated with gate control to accomplish bidirectional transmission or turn-off functions, further broadening their application variety and making them a suitable selection for fixing high-voltage and high-current control issues.
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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 , please feel free to contact us.(sales@pddn.com)
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