Introduction: Trick tools in power electronic devices

Silicon-controlled rectifiers (SCRs), also referred to as thyristors, are semiconductor power tools with a four-layer three-way junction framework (PNPN). Given that its introduction in the 1950s, SCRs have been extensively used in industrial automation, power systems, home appliance control and various other areas because of their high stand up to voltage, large current carrying capacity, quick response and easy control. With the growth of modern technology, SCRs have developed into several 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 shown in the structure and working concept, yet likewise determine their applicability in various application scenarios. This article will certainly start from a technical point of view, incorporated with specific specifications, to deeply analyze the main differences and typical uses these four SCRs.

Unidirectional SCR: Standard and steady application core

Unidirectional SCR is one of the most basic and typical type of thyristor. Its framework is a four-layer three-junction PNPN plan, including 3 electrodes: anode (A), cathode (K) and gateway (G). It only enables current to stream in one instructions (from anode to cathode) and turns on after the gate is set off. As soon as turned on, also if the gate signal is eliminated, as long as the anode current is greater than the holding existing (normally less than 100mA), the SCR stays on.

(Thyristor Rectifier)

Unidirectional SCR has strong voltage and present resistance, with an ahead repetitive height voltage (V DRM) of approximately 6500V and a ranked on-state average existing (ITAV) of up to 5000A. As a result, it is extensively utilized in DC electric motor control, industrial heater, uninterruptible power supply (UPS) correction components, power conditioning tools and various other celebrations that need continuous transmission and high power processing. Its advantages are easy structure, affordable and high reliability, and it is a core part of lots of standard power control systems.

Bidirectional SCR (TRIAC): Perfect for a/c control

Unlike unidirectional SCR, bidirectional SCR, additionally called TRIAC, can attain bidirectional transmission in both favorable and unfavorable fifty percent cycles. This structure includes 2 anti-parallel SCRs, which allow TRIAC to be caused and turned on at any moment in the air conditioning cycle without transforming the circuit link approach. The balanced conduction voltage series of TRIAC is normally ± 400 ~ 800V, the maximum lots current has to do with 100A, and the trigger current is less than 50mA.

Due to the bidirectional conduction characteristics of TRIAC, it is particularly suitable for air conditioner dimming and rate control in household home appliances and consumer electronic devices. For example, devices such as light dimmers, fan controllers, and air conditioning unit fan rate regulatory authorities all rely upon TRIAC to attain smooth power law. In addition, TRIAC likewise has a lower driving power need and appropriates for incorporated design, so it has been commonly used in clever home systems and small appliances. Although the power thickness and changing rate of TRIAC are not just as good as those of brand-new power tools, its low cost and hassle-free usage make it a crucial player in the field of tiny and moderate power air conditioner control.

Gateway Turn-Off Thyristor (GTO): A high-performance rep of active control

Gate Turn-Off Thyristor (GTO) is a high-performance power gadget developed on the basis of traditional SCR. Unlike normal SCR, which can only be turned off passively, GTO can be turned off actively by using a negative pulse existing to the gate, hence accomplishing even more adaptable control. This attribute makes GTO do well in systems that require constant start-stop or rapid feedback.

(Thyristor Rectifier)

The technical parameters of GTO reveal that it has very high power taking care of capability: 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 indicators make GTO commonly utilized in high-power situations such as electrical engine grip systems, big inverters, commercial electric motor regularity conversion control, and high-voltage DC transmission systems. Although the drive circuit of GTO is reasonably complicated and has high changing losses, its efficiency under high power and high dynamic action demands is still irreplaceable.

Light-controlled thyristor (LTT): A dependable selection in the high-voltage seclusion atmosphere

Light-controlled thyristor (LTT) uses optical signals instead of electrical signals to trigger conduction, which is its most significant function that differentiates it from other sorts of SCRs. The optical trigger wavelength of LTT is generally between 850nm and 950nm, the response time is gauged in milliseconds, and the insulation level can be as high as 100kV or over. This optoelectronic seclusion device substantially enhances the system’s anti-electromagnetic interference capability and safety.

LTT is mostly used in ultra-high voltage direct current transmission (UHVDC), power system relay protection gadgets, electromagnetic compatibility security in medical equipment, and army radar interaction systems etc, which have exceptionally high demands for security and security. As an example, many converter terminals in China’s “West-to-East Power Transmission” job have actually adopted LTT-based converter valve components to guarantee secure procedure under incredibly high voltage problems. Some advanced LTTs can likewise be combined with gate control to accomplish bidirectional transmission or turn-off functions, further increasing their application array and making them a suitable choice for solving 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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