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Power Semiconductor Devices

This article introduces you to the commonly used power semiconductor devices.

MCT (MOS Controlled Thyristor)

MCT is a new type of MOS and bipolar composite device. as the picture shows. MCT combines the high-impedance, low-drive graph MCT power, fast switching speed characteristics of MOSFETs with the high-voltage, high-current characteristics of thyristors to form high-power, high-voltage, fast-controlled devices. Essentially MCT is a MOS gate controlled thyristor. It can be turned on or off by adding a narrow pulse to the gate, which is made up of a myriad of unit cells connected in parallel.

IGCT(Intergrated Gate Commutated Thyristors

IGCT is a new type of device developed on the basis of thyristor technology combined with IGBT and GTO technology. It is suitable for high-voltage large-capacity frequency conversion system. It is a new type of power semiconductor device used in giant power electronics complete sets.

The IGCT integrates the GTO chip with the anti-parallel diode and the gate drive circuit, and then connects its gate driver with low inductance in the periphery, combining the stable turn-off capability of the transistor and the low on-state loss of the thyristor. The performance of the thyristor is exerted during the turn-on phase, and the turn-off phase exhibits the characteristics of the transistor. If the IGCT chip is not in series, the power of the two-level inverter is 0.5~3MW, and the three-level inverter is 1~6MW. If the reverse diode is separated, it is not integrated with the IGCT, and the two-level inverter The power can be expanded to 4/5MW and the three levels are expanded to 9MW.

At present, IGCT has been commercialized. The highest performance parameter of IGCT products manufactured by ABB is 4[1]5kV/4kA, and the highest development level is 6kV/4kA. In 1998, Mitsubishi Corporation of Japan also developed a GCT thyristor with a diameter of 88mm. The IGCT has low loss and fast switching, which ensures that it can be used reliably and efficiently for 300kW~10MW converters without series and parallel connection.

IEGT(Injection Enhanced GateTransistor)

IEGT is an IGBT series power electronic device with a withstand voltage of 4kV or higher. By adopting a structure with enhanced injection, a low on-state voltage is realized, and a large-capacity power electronic device has been rapidly developed.

IEGT has potential development prospects as MOS series power electronic devices, featuring low loss, high speed operation, high withstand voltage, and active gate drive intelligence, as well as the characteristics of self-current sharing using a trench structure and multi-chip parallel connection. It has great potential for further expansion of current capacity. In addition, a number of derivative products are available through module packaging, and are expected to be used in large and medium capacity converter applications.

The IECT developed by Toshiba of Japan utilizes the electron injection enhancement effect, which combines the advantages of both IGBT and GTO: low saturation voltage drop, safe working area (absorption loop capacity is only about one tenth of GTO), low gate Drive power (two orders of magnitude lower than GTO) and higher operating frequency. The device adopts a flat-plate crimping motor lead-out structure with high reliability and performance of 4.5kV/1500A.

IPEM(Intergrated Power Elactronics Modules)

IPEM is a module that integrates many devices of power electronics. It first packs the semiconductor device MOSFET, IGBT or MCT and diode chip together to form a building block unit, and then stacks these building blocks onto the open high-conductivity insulating ceramic substrate, which is followed by Copper substrate, enamel enamel sheet and heat sink. On the upper part of the building block, the control circuit, the gate drive, the current and temperature sensor and the protection circuit are integrated on a thin insulating layer by surface mounting. IPEM realizes the intelligentization and modularization of power electronics technology, which greatly reduces circuit wiring inductance, system noise and parasitic oscillation, and improves system efficiency and reliability.

PEBB(Power Electric Building Block)

PowerElectric Building Block (PEBB) is a device or module that can be integrated with IPEM to process power. PEBB is not a specific semiconductor device, it is the integration of different devices and technologies designed according to the optimal circuit structure and system structure. The typical PEBB is shown above. Although it looks a lot like a power semiconductor module, PEBB includes, in addition to power semiconductor devices, gate drive circuits, level shifting, sensors, protection circuits, power supplies, and passive components.

PEBB has an energy interface and a communication interface. Through these two interfaces, several PEBBs can form a power electronic system. These systems can be as simple as a small DC-DC converter or as complex as a large distributed power system. In a system, the number of PEBBs can range from one to any number. Multiple PEBB modules work together to perform system level functions such as voltage conversion, energy storage and conversion, and yin resistance matching. The most important feature of PEBB is its versatility.

Ultra high power thyristor

Since its inception, the thyristor (SCR) has increased its power capacity by nearly 3,000 times. Many countries have been able to stably produce 8kV/4kA thyristors. Japan has now produced 8kV/4kA and 6kV/6kA light-triggered thyristors (LTTs). Electrically triggered thyristors are primarily produced in the United States and Europe. In the past ten years, due to the rapid development of self-shutdown devices, the application field of thyristors has been reduced, but due to its high voltage and high current characteristics, it is in HVDC, static reactive power compensation (SVC), high-power DC power supply. And ultra-high power and high-voltage variable frequency speed control applications still occupy a very important position. It is expected that thyristors will continue to develop in high voltage and high current applications in the next few years.

Many manufacturers now offer high-voltage, high-current GTOs with rated switching powers of 36MVA (6kV/6kA). The typical GTO’s typical turn-off increment is only 3 to 5. The “squeezing effect” caused by the non-uniformity during GTO shutdown makes it necessary to limit dv/dt to 500 to 1 kV/μs during the off period. For this reason, people have to use large, expensive absorption circuits. In addition, its gate drive circuit is more complicated and requires a larger drive power. So far, gated power semiconductor devices are the most commonly used in high voltage (VBR) 3.3kV, high power (0.5-20MVA) traction, industrial and power inverters. Currently, the highest research level of GTO is 6in, 6kV/6kA and 9kV/10kA. In order to meet the needs of the power system for three-phase inverter power voltage sources above 1GVA, it is very likely that a GTO of 10kA/12kV will be developed in the near future, and it is possible to solve the technology of more than 30 high-voltage GTO series. It is expected that the power electronics technology will be The application aspect in the power system is on the next level.

Pulse power closed switch thyristor

The device is ideal for discharge closed switch applications that deliver extremely high peak power (several MW) and extremely short durations (several ns), such as lasers, high intensity illumination, discharge ignition, electromagnetic transmitters and radar modulators. Wait. The device can be quickly turned on under a high voltage of several kV, does not require a discharge electrode, has a long service life, is small in size, and relatively low in price, and is expected to replace the high-voltage ion thyratron, igniting tube, and spark that are still in use. Gap switch or vacuum switch, etc.

The unique structure and process characteristics of the device are: the gate-cathode perimeter is very long and forms a highly interwoven structure, the gate area accounts for 90% of the total chip area, and the cathode area only accounts for 10%; the hole-electron lifetime of the base region Very long, the horizontal distance between the gate and cathode is less than one diffusion length. The above two structural features ensure that the cathode area can be 100% applied at the turn-on instant. In addition, the device’s cathode electrode uses a thicker metal layer that can withstand transient peak currents.

Type GTO device – integrated gate commutated thyristor

There are currently two alternatives to conventional GTO: high-power IGBT modules, new GTO-derived devices – integrated gate commutated IGCT thyristors. IGCT thyristor is a new type of high-power device. Compared with conventional GTO thyristor, it has many excellent characteristics. For example, it can achieve reliable shutdown without buffer circuit, short storage time, high turn-on capability, and turn off gate charge. Less total application power (including all devices and peripheral components such as anode reactors and snubber capacitors) has a low total power loss.

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