Intro: Secret devices in power electronic devices
Silicon-controlled rectifiers (SCRs), likewise called thyristors, are semiconductor power gadgets with a four-layer three-way joint structure (PNPN). Given that its intro in the 1950s, SCRs have actually been extensively made use of in commercial automation, power systems, home appliance control and various other areas as a result of their high withstand voltage, big current carrying ability, quick feedback and easy control. With the growth of innovation, SCRs have actually progressed right into many 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 only shown in the framework and functioning principle, yet additionally determine their applicability in various application circumstances. This write-up will certainly begin with a technical viewpoint, incorporated with specific criteria, to deeply analyze the main distinctions and regular uses of these 4 SCRs.
Unidirectional SCR: Basic and secure application core
Unidirectional SCR is one of the most basic and usual sort of thyristor. Its structure is a four-layer three-junction PNPN setup, including three electrodes: anode (A), cathode (K) and gate (G). It just allows present to stream in one direction (from anode to cathode) and activates after eviction is activated. As soon as turned on, also if the gate signal is gotten rid of, as long as the anode current is higher than the holding existing (typically less than 100mA), the SCR stays on.
(Thyristor Rectifier)
Unidirectional SCR has strong voltage and current tolerance, with an ahead recurring peak voltage (V DRM) of approximately 6500V and a ranked on-state ordinary present (ITAV) of up to 5000A. For that reason, it is widely made use of in DC electric motor control, industrial heater, uninterruptible power supply (UPS) correction components, power conditioning devices and other celebrations that require constant conduction and high power handling. Its advantages are simple framework, inexpensive and high dependability, and it is a core part of lots of standard power control systems.
Bidirectional SCR (TRIAC): Suitable for air conditioner control
Unlike unidirectional SCR, bidirectional SCR, additionally referred to as TRIAC, can achieve bidirectional transmission in both positive and negative half cycles. This structure contains two anti-parallel SCRs, which enable TRIAC to be activated and switched on at any moment in the a/c cycle without transforming the circuit connection method. The in proportion conduction voltage range of TRIAC is normally ± 400 ~ 800V, the optimum load current has to do with 100A, and the trigger current is much less than 50mA.
Because of the bidirectional conduction characteristics of TRIAC, it is particularly ideal for a/c dimming and rate control in home devices and customer electronics. As an example, gadgets such as lamp dimmers, follower controllers, and air conditioner follower speed regulatory authorities all rely upon TRIAC to accomplish smooth power guideline. On top of that, TRIAC likewise has a lower driving power requirement and is suitable for integrated style, so it has actually been commonly utilized in wise home systems and little home appliances. Although the power thickness and changing speed of TRIAC are not comparable to those of brand-new power gadgets, its affordable and convenient usage make it a crucial player in the area of small and average power a/c control.
Gateway Turn-Off Thyristor (GTO): A high-performance agent of active control
Gate Turn-Off Thyristor (GTO) is a high-performance power device created on the basis of standard SCR. Unlike average SCR, which can just be switched off passively, GTO can be shut off proactively by applying an adverse pulse current to eviction, hence attaining more flexible control. This attribute makes GTO execute well in systems that need frequent start-stop or quick action.
(Thyristor Rectifier)
The technological specifications of GTO show that it has incredibly high power taking care of capacity: the turn-off gain is about 4 ~ 5, the maximum operating voltage can reach 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 efficiency indicators make GTO commonly used in high-power circumstances such as electric engine traction systems, large inverters, commercial electric motor regularity conversion control, and high-voltage DC transmission systems. Although the drive circuit of GTO is fairly complicated and has high switching losses, its performance under high power and high dynamic action requirements is still irreplaceable.
Light-controlled thyristor (LTT): A trusted option in the high-voltage isolation atmosphere
Light-controlled thyristor (LTT) uses optical signals as opposed to electrical signals to activate transmission, which is its largest function that identifies it from various other sorts of SCRs. The optical trigger wavelength of LTT is typically between 850nm and 950nm, the response time is gauged in milliseconds, and the insulation level can be as high as 100kV or above. This optoelectronic seclusion device greatly enhances the system’s anti-electromagnetic interference ability and safety and security.
LTT is mostly used in ultra-high voltage direct present transmission (UHVDC), power system relay defense tools, electromagnetic compatibility security in clinical devices, and military radar interaction systems etc, which have extremely high needs for security and stability. For instance, numerous converter stations in China’s “West-to-East Power Transmission” job have embraced LTT-based converter valve modules to make sure secure operation under very high voltage problems. Some advanced LTTs can likewise be integrated with gateway control to accomplish bidirectional transmission or turn-off functions, even more expanding their application array and making them an excellent 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 scr rectifier, please feel free to contact us.(sales@pddn.com)
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