In parallel with the study of the properties of semiconductors, there was an improvement in the technology for manufacturing devices based on them. Gradually, new elements appeared, with good performance. The first IGBT transistor appeared in 1985 and combined the unique properties of a bipolar and field structure. As it turned out, these two types of semiconductor devices known at that time could well "get along" together. They formed a structure that became innovative and gradually gained immense popularity among electronic circuit developers. The very abbreviation IGBT (Insulated Gate Bipolar Transistors) refers to the creation of a hybrid circuit based on bipolar and field effect transistors. Moreover, the ability to work with large currents in the power circuits of one structure was combined with a high input resistance of another.
The modern IGBT is different from its predecessor. The fact is that the technology of their production has been gradually improved. Since the appearance of the first element with such a structure, its main parameters have changed for the better:
- Switching voltage increased from 1000V to 4500V. This allowed the use of power modules when working in high voltage circuits. Discrete elements and modules have become more reliable in working with inductance in the power circuit and more protected from impulse noise.
- The switching current for discrete elements has grown to 600A in discrete and up to 1800A in modular design. This made it possible to switch current circuits of high power and use an IGBT transistor to work with motors, heaters, various industrial installations, etc.
- The direct voltage drop in the open state fell to 1V. This allowed to reduce the area of ββheat sink radiators and at the same time reduce the risk of failure from thermal breakdown.
- The switching frequency in modern devices reaches 75 Hz, which allows them to be used in innovative drive control circuits. In particular, they are successfully used in frequency converters. Such devices are equipped with a PWM controller, which works in conjunction with a module, the main element of which is an IGBT transistor. Frequency inverters are gradually replacing traditional drive control circuits.
- The performance of the device has also increased significantly. Modern IGBTs have a di / dt = 200ΞΌs. This refers to the time taken to enable / disable. Compared with the first samples, the performance has increased five times. An increase in this parameter affects the possible switched frequency, which is important when working with devices that implement the principle of PWM control.
The electronic circuits that controlled the IGBT transistor were also improved. The main requirements that apply to them are to ensure safe and reliable device switching. They must take into account all the weaknesses of the transistor, in particular, its "fear" of overvoltage and static electricity.