Thyristor converter: operational features and development prospects

The study of the properties of semiconductors made it possible to create new elements that were actively used in various electronic circuits. Gradually appeared more powerful devices, which allowed switching electrical circuits of high power.

A good example is the thyristor converter. From the moment of its appearance, it began to enjoy well-deserved popularity among designers. This device is actively used in various electrical circuits: starting and charging devices, welding machines, heaters, inverters, controlled rectifiers etc. This is not a complete list of devices that use a thyristor converter.

Over time, powerful devices have appeared, with the help of which it became possible to control the speed of electric motors or heat installations. They began to be actively used in production, and in some cases even replaced the traditional "generator-engine" system (GD) at that time.

Improvement of management schemes significantly increased the reliability of these Devices. A powerful thyristor converter is capable of controlling the excitation current or being connected directly to the anchor circuit of the motor. However, the first systems of pulse-phase control (SIFU) often worked with errors. This could lead, say, to the "overturning" of the inverter and the exit of the power elements out of order. The constructive base, too, left much to be desired. Over time, these problems are a thing of the past. There are reliable electronic devices that reliably control and, if necessary, protect the thyristor converter sensitive to overloads. It is also necessary to note the high efficiency, good maintainability and small dimensions of this device in relation to alternative systems.

But, in addition to good performance characteristics, such devices also have some drawbacks with respect to the power circuit:

• The ratio of reactive and active power during their use varies not in the best for the common mains supply side. To save cos φ, it is necessary to use reactive power compensators based on capacitors.

• At the work thyristor converters strongly enough pollute a power network with high-frequency hindrances. To combat this drawback, special RC circuits are used.

With the help of specially developed devices, it is possible to change such a parameter as the frequency of the mains supply. It is used in the work of induction furnaces, in the molding of metals or in other electrical installations. This function is carried out by a thyristor frequency converter specially designed for these purposes . Its creation allowed to significantly improve the existing at that time technology for metal processing in production.

Over time, there were alternative instruments that work quite differently. Schemes are being developed on the basis of powerful IGBT-transistors, which are more used to control small and medium-power engines. They gradually supplant morally obsolete systems.