We know that power devices are the core of electric energy conversion and circuit control in electronic devices. They change the voltage, frequency, phase and DC/AC conversion functions in electronic devices by using the characteristics of unidirectional semiconductor conduction. Power devices are divided into many categories based on controllability and other usage factors. Common classifications include:
MOS Controlled Thyristor (MCT)
MCT is a new type of MOS and bipolar device. MCT is the MOSFET high impedance, low drive MCT power, fast switching speed characteristics and thyristor high voltage, high current characteristics combined to form a high power, high voltage, fast full control device. MCT is essentially a MOS gate controlled thyristor. It can be turned on or off by adding a narrow pulse to the gate, and it consists of numerous single cells in parallel.
IGCT Intergrated Gate Commutated Thyristors
IGCT is a new type device developed on the basis of thyristor technology combined with IGBT and GTO technology. It has the characteristics of high current, high blocking voltage, high switching frequency, high reliability, compact structure and low conduction loss. It is a new type of power semiconductor device used in huge power electronic equipment. It is suitable for high voltage and large capacity frequency conversion system with low cost and high yield. It has good application prospect.
IGCT integrates THE GTO chip with the reverse parallel diode and gate driver circuit, and then connects with the gate driver externally in a low inductance mode, combining the advantages of stable turn-off capability of the transistor and low on-state loss of the thyristor. The performance of thyristor is displayed in the on-off stage, and the characteristics of transistor are displayed in the off-off stage.
Intergrated Power Elactronics Modules (IPEM)
IPEM is a module that integrates many components of power electronic devices. It starts with semiconductor devices MOSFET, IGBT or MCT and diode chips encapsulated together to form a building block unit, and then these building blocks are stacked on an open insulating ceramic substrate with high conductivity, followed by a copper substrate, beryllium oxide porcelain and heat sink. On the upper part of the building block unit, the control circuit, gate drive, current and temperature sensor, and protection circuit are integrated on a thin insulating layer by surface mount.
IPEM realizes the intellectualization and modularization of power electronics technology, greatly reduces the inductance of circuit wiring, system noise and parasitic oscillation, and improves system efficiency and reliability.
PEBB (Power Electric Building Block)
PEBB is a device or module developed on the basis of IPEM which can deal with power integration. PEBB is not a specific semiconductor device, but an integration of different devices and technologies designed according to optimal circuit and system architecture.
In addition to power semiconductor devices, it also contains a gate drive circuit, level conversion, sensor, protection circuit, power supply and passive devices. PEBB has an energy interface and a communication interface through which several PEBbs can form a power electronics system. These systems can be as simple as a small DC-DC converter or as complex as a large distributed power system.
The number of PEBbs in a system can vary from one to any number. Multiple PEBB modules working together can complete voltage conversion, energy storage and conversion, negative and reactive matching and other system-level functions. The most important feature of PEBB is its versatility.
Injection Enhanced Gate Transistor IEGT
IEGT is a series of IGBT power electronic devices which can withstand voltage up to 4kV. By adopting the structure of enhanced injection, it realizes low on-state voltage and makes the development of large capacity power electronic devices by leaps and leaps. IEGT has the potential development prospect as MOS series power electronic devices. It has the characteristics of low loss, high-speed action, high voltage resistance, intelligent active gate drive and so on. It also has the characteristics of groove structure and multi-chip parallel and self-equalizing current, so it has great potential in further expanding current capacity. In addition, many derivative products can be provided by module encapsulation, which are expected to be applied in large and medium capacity converters.
Super power thyristor
The power capacity of the thyristor (SCR) has increased nearly 3,000 times since its inception. In recent years, due to the rapid development of self-switching devices, the application of thyristor has been reduced, but because of its high voltage, high current characteristics, it still plays a very important role in HVDC, static reactive power compensation (SVC), high power DC power supply and super power and high voltage frequency conversion speed regulation applications.
The unique structure and process characteristics of the device are as follows: the gate and cathode perimeter is very long and forms a highly intertwined structure. The gate area accounts for 90% of the total chip area, while the cathode area only accounts for 10%. The hole-electron lifetime in the base region is very long, and the horizontal distance between gate and cathode is less than one diffusion length. The above two structural characteristics ensure that 100% of the cathode area can be applied when the device is turned on. In addition, the cathode electrode of the device uses a thick metal layer, which can withstand instantaneous peak current.
High power TrenchIGBT (IGBT) module
Nowadays, the IGBT cell in high power IGBT module usually adopts the grooved gate structure IGBT. Compared with planar grid structure, groove grid structure usually adopts 1μm machining precision, thus greatly improving cell density. Due to the existence of gate groove, the junction fET effect between adjacent cells in planar gate structure device is eliminated, and some electron injection effect is introduced to reduce the conduction resistance. It creates conditions for increasing the thickness of long base region and improving the voltage resistance of device. Therefore, in recent years, IGBT devices with high voltage and high current all adopt this structure.
Silicon carbide and silicon carbide (SiC) power devices
Silicon carbide (SiC) power devices are the most promising power devices made of new semiconductor materials. Its performance index is one order of magnitude higher than gallium arsenide devices. Compared with other semiconductor materials, silicon carbide has the following excellent physical characteristics: high band gap width, high saturated electron drift velocity, high breakdown strength, low dielectric constant and high thermal conductivity. These excellent physical characteristics, determine the silicon carbide in high temperature, high frequency, high power applications is an ideal semiconductor material.
Under the same voltage and current conditions, the drift resistance of SiC devices is 200 times lower than that of silicon, and even the conduction voltage drop of SiC mosFETS with high voltage resistance is much lower than that of monopole and bipolar silicon devices. Moreover, the switching time of SiC devices can be up to the order of 10nS and has a very superior FBSOA. SiC can be used to manufacture rf and microwave power devices, various high-frequency rectifiers, MESFETS, MOSFETS and JFETS, etc.
These are common power semiconductor devices. The power level of power electronic converter covers a wide range, including small power range: such as laptop computer, refrigerator, washing machine, air conditioning, etc.; Medium power range electric transmission, new energy power generation, etc. High power range: such as HVDC transmission system, the development of science and technology also put forward more and more, higher and higher performance requirements for power semiconductor devices.