Power Electronic Device, also known as power semiconductor device, is used for high-power (usually tens to thousands of amperes of current and hundreds of volts of voltage) electronic devices in power conversion and power control circuits. It can be divided into semi controlled devices, fully controlled devices and uncontrollable devices. Thyristors are semi controlled devices, with the highest withstand voltage and current capacity among all devices; The power diode is an uncontrollable device with simple structure and principle and reliable operation; It can also be divided into voltage driven devices and current driven devices. GTO and GTR are current driven devices, and IGBT and power MOSFET are voltage driven devices.
1. MCT (MOS Controlled Thyristor): MOS controlled thyristor MCT is a new type of MOS and bipolar composite device. As shown in the figure above. MCT combines the characteristics of MOSFET such as high impedance, low driving diagram, power and fast switching speed with the high-voltage and large current characteristics of thyristor to form a high-power, high-voltage and fast fully controlled device. In essence, MCT is a MOS gate controlled thyristor. It can add a narrow pulse on the gate pole to make it turn on or off. It is composed of countless cells in parallel. Compared with GTR, MOSFET, IGBT, GTO and other devices, it has the following advantages: (1) high voltage, large current capacity, blocking voltage up to 3000 V, peak current up to 1000 A, and maximum turnoff current density of 6000 kA/m2; (2) On state voltage drop is small, loss is small, and on state voltage drop is about 11V; (3) Very high dv/dt and di/dt tolerance, dv/dt has reached 20kV/s, di/dt is 2kA/s; (4) The switching speed is fast, the switching loss is small, the turn on time is about 200ns, and 1000V devices can be turned off within 2s; 2. IGCT (Intergrated Gate Commutated Thyristors) IGCT is a new device developed on the basis of thyristor technology combined with IGBT, GTO and other technologies. It is applicable to high-voltage and high-capacity frequency conversion systems. It is a new power semiconductor device used in giant power electronic complete sets. IGCT integrates GTO chip with anti parallel diode and gate drive circuit, and then connects with its gate driver in a low inductance mode. It combines the advantages of stable turning off capability of transistor and low on state loss of thyristor. In the conduction stage, the performance of the thyristor is displayed, and in the turn off stage, the characteristics of the transistor are displayed. Under the condition that IGCT chips are not connected in series or parallel, the power of two-level inverter is 0.5~3MW and that of three-level inverter is 1~6MW; If the reverse diode is separated and not integrated with IGCT, the power of two-level inverter can be expanded to 4/5MW and three-level inverter 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 the thyristor IGCT of the GCT with a diameter of 88mm, which has the advantages of low loss and fast switching, ensuring that it can be reliably and efficiently used in the 300kW~10MW converter without series and parallel connection. 3. The IEGT (Injection Enhanced Gate Transistor) is an IGBT series power electronic device with a withstand voltage of more than 4kV. By adopting the enhanced injection structure, the low on state voltage is realized, making the large capacity power electronic devices achieve a leap forward development. IEGT has the potential development prospect as a MOS series power electronic device. It has the characteristics of low loss, high speed operation, high voltage withstand, intelligent active gate drive, etc., as well as the characteristics of groove structure and multi chip parallel and self current sharing, which makes it quite potential in further expanding the current capacity. In addition, many derivative products can also be provided through module packaging, which is expected in large and medium capacity converter applications. The IECT developed by Toshiba, Japan, makes use of the electron injection enhancement effect, making it have 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 grid drive power (two orders of magnitude lower than GTO) and high operating frequency. The device adopts a flat plate crimping motor lead out structure with high reliability, and its performance has reached the level of 4.5kV/1500A. 4. IPEM (Intergrated Power Elatronics Modules): Integrated power electronics modules IPEM is a module that integrates many components of power electronics devices. It first encapsulates the semiconductor device MOSFET, IGBT or MCT and the chip of the diode together to form a building block unit, and then stacks these building block units onto the high conductivity insulating ceramic substrate with holes. Below it are copper substrate, beryllium oxide ceramic chip and heat sink in turn. On the upper part of the building block unit, the control circuit, gate drive, current and temperature sensors and protection circuit are integrated on a thin insulating layer through surface mounting. IPEM has realized the intellectualization and modularization of power electronics technology, greatly reduced circuit wiring inductance, system noise and parasitic oscillation, and improved system efficiency and reliability. 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. Typical PEBB is shown in the figure above. Although it looks like a power semiconductor module, PEBB includes not only power semiconductor devices, but also gate drive circuits, level conversion, sensors, protection circuits, power supplies and passive devices. PEBB has energy interface and communication interface. Through these two interfaces, several PEBBs can form power electronic systems. These systems can be as simple as small DC-DC converters or as complex as large distributed power systems. In a system, the number of PEBBs can range from one to any number. Multiple PEBB modules can work together to complete system level functions such as voltage conversion, energy storage and conversion, cathodic impedance matching, etc. The most important feature of PEBB is its universality. 6. The power capacity of super power SCR has increased by nearly 3000 times since its birth. Now many countries have been able to stably produce 8kV/4kA thyristors. Japan has now put 8kV/4kA and 6kV/6kA light triggered thyristor (LTT) into production. The United States and Europe mainly produce electrically triggered thyristors. In recent ten years, due to the rapid development of self turning off devices, the application field of thyristor has shrunk. However, due to its high voltage and large current characteristics, it still occupies a very important position in the application of HVDC, static var compensation (SVC), high-power DC power supply and ultra large power and high-voltage variable frequency speed regulation. It is predicted that thyristor will continue to develop in high voltage and high current applications in the next few years. Now, many manufacturers can provide high-voltage high current GTO with rated switching power of 36MVA (6kV/6kA). The typical turn off increment of traditional GTO is only 3-5. The "squeeze effect" caused by the nonuniformity during the GTO switching off must limit the dv/dt to 500~1kV during the switching off period/ μ s。 For this reason, people have to use bulky and expensive absorption circuits. In addition, its gate drive circuit is more complex and requires larger drive power. Up to now, gate controlled power semiconductor devices are most widely used in high-voltage (VBR 3.3kV), high-power (0.5-20MVA) traction, industrial and power inverters. At present, 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 and voltage sources above 1GVA, it is very likely to develop 10kA/12kV GTOs in the near future, and it is possible to solve the technology of more than 30 high-voltage GTOs in series, which is expected to make the application of power electronics technology in the power system to a higher level. 7. Pulse power closing switch Thyristor This device is especially suitable for the discharge closing switch applications that transmit extremely strong peak power (several MW) and extremely short duration (several ns), such as lasers, high-intensity lighting, discharge ignition, electromagnetic transmitters and radar modulators. The device can be quickly opened under several kV high voltage without discharge electrode, has a long service life, small size and relatively low price, and is expected to replace the high-voltage ion thyratron, ignition tube, spark gap switch or vacuum switch currently in use. The unique structure and process characteristics of the device are: the gate cathode boundary is very long and forms a highly interlaced structure. The gate area accounts for 90% of the total chip area, while the cathode area only accounts for 10%; The base hole electron lifetime is very long, and the horizontal distance between gate and cathode is less than a diffusion length. The above two structural features ensure that the cathode area of the device can be 100% applied at the moment of opening. In addition, the cathode electrode of the device adopts a thick metal layer, which can withstand the instantaneous peak current. 8. The new GTO device - integrated gate commutated thyristor currently has two alternatives to conventional GTO: high power IGBT module and new GTO derivative device - integrated gate commutated IGCT thyristor. IGCT thyristor is a new type of high-power device. Compared with conventional GTO thyristor, it has many excellent characteristics, such as reliable shutdown without buffer circuit, short storage time, strong turn-on capability, less gate charge for shutdown, and low total power loss of application system (including all devices and peripheral components such as anode reactor and buffer capacitor). 9. Nowadays, the IGBT cells in high-power IGBT modules usually use grooved gate IGBT. Compared with the plane gate structure, the grooved gate structure usually adopts 1 μ M machining accuracy, thus greatly improving the cell density. Due to the existence of gate channel, the junction field-effect transistor effect between adjacent cells in the planar gate structure device is eliminated, and a certain electron injection effect is introduced, which makes the on resistance decrease. It creates conditions for increasing the thickness of long base region and improving the withstand voltage of devices. Therefore, IGBT devices with high voltage withstand and high current appeared in recent years all adopt this structure. In 1996, Mitsubishi and Hitachi successfully developed 3.3kV/1.2kA IGBT modules with huge capacity. Compared with the conventional GTO, the switching time is reduced by 20%, and the grid drive power is only 1/1000 of the GTO. In 1997, Fuji Electric Corporation successfully developed a 1kA/2.5kV flat plate IGBT. As the collector and emitter junction adopt a flat plate crimping structure similar to GTO, a more efficient heat dissipation mode at both ends of the chip is adopted. It is particularly meaningful to avoid a large number of electrode leads inside the high current IGBT module, improve the reliability and reduce the lead inductance. The disadvantage is that the chip area utilization is reduced. Therefore, the high-voltage and high current IGBT module with the flat plate crimping structure can also be expected to become the preferred power device of the high power and high voltage converter. 10. In recent years, Toshiba Corporation of Japan has developed the IEGT (Injection Enhanced Gate Transistor). Like IGBT, it also has two structures: planar gate and grooved gate. The former is about to come out, while the latter is still under development. IEGT has some advantages of both IGBT and GTO: low saturation voltage drop, wide safe working area (absorption loop capacity is only about 1/10 of GTO), low grid drive power (2 orders of magnitude lower than GTO) and high operating frequency. In addition, the device adopts a flat plate crimping electrode lead out structure, which is expected to have high reliability. Compared with IGBT, the main feature of IEGT structure is that the grid length Lg is longer, and the lateral resistance near the grid side of the N-long base area is higher. Therefore, holes in the N-long base area are injected from the collector. Unlike in IGBT, holes flow into the emitter through the P-area smoothly, but a hole accumulation layer is formed in this area. In order to maintain the electrical neutrality of this region, the emitter must inject a large number of electrons into the N long base region through the N channel. In this way, the emitter side of the N-long base region also forms a high concentration carrier accumulation, forming a carrier distribution similar to that in GTO in the N-long base region, so as to better solve the contradiction between high current and high withstand voltage. At present, the device has reached the level of 4.5kV/1kA. 11. MOS Gated Thyristor The MOS gate controlled thyristor makes full use of the good on state characteristics, excellent opening and closing characteristics of the thyristor, which is expected to have excellent self closing dynamic characteristics, very low on state voltage drop and high voltage resistance, and become a high-voltage high-power device with a promising future in power devices and power systems. At present, more than ten companies in the world are actively carrying out research on MCT. MOS gated thyristor mainly has three structures: MOS field controlled thyristor (MCT), base resistance controlled thyristor (BRT) and emitter switched thyristor (EST). Among them, EST is probably the most promising structure of MOS gated thyristor. However, it will take quite a long time for this device to become a commercial and practical device to replace GTO. 12. With the increasing switching frequency of the converter, the requirements for fast recovery diodes are also increasing. As we all know, it has superior high-frequency switching characteristics than silicon diode, but due to process technology and other reasons, the withstand voltage of GaAs diode is low, and its practical application is limited. In order to meet the requirements of high-voltage, high-speed, high efficiency and low EMI applications, high-voltage GaAs high-frequency rectifier diodes have been successfully developed in Motorola. Compared with silicon fast recovery diode, this new diode has the following remarkable characteristics: small change of reverse leakage current with temperature, low switching loss, and good reverse recovery characteristics. 13. Silicon carbide and silicon carbide (SiC) power devices Among the power devices made of new semiconductor materials, the most promising is silicon carbide (SiC) power devices. Its performance index is an order of magnitude higher than that of GaAs devices. Compared with other semiconductor materials, silicon carbide has the following excellent physical characteristics: high band gap, high saturated electron drift speed, high breakdown strength, low dielectric constant and high thermal conductivity. These excellent physical properties determine that silicon carbide is an ideal semiconductor material for high temperature, high frequency and high power applications. Under the same withstand voltage and current conditions, the drift resistance of SiC devices is 200 times lower than that of silicon. Even the conduction voltage drop of high withstand voltage SiC FETs is much lower than that of unipolar and bipolar silicon devices. Moreover, the switching time of SiC devices can reach the order of 10nS, and it has a very superior FBSOA. SiC can be used to manufacture RF and microwave power devices