Electric power conversion
Power converters (dormant ) plants for the conversion of an electrical current type into another by means of electronic components such as transistors, in particular IGBT, IGCT, MOSFET, diodes or thyristors. Previously also vacuum tubes, mercury arc rectifying and thyratrons were used.
On the other hand refers to plants in which the conversion is effected by means driven by electric motors, generators, when (rotating ) transformers. For new constructions, especially large systems this have now been displaced by power converters.
Converter for converting alternating current into direct current hot rectifier, for converting DC to AC inverter or (English ) inverter. For the conversion of an AC type in a different inverters are used; a typical representative of the frequency converter, which basically is used to change the frequency of an alternating current.
Much like a transformer, a converter transforms electric energy, but shall not unlike that as an electric machine.
Converter transformers are transformers that are connected downstream of a converter at the Wechsel-/Drehstromseite forward or backward. They are used for voltage matching and harmonic attenuation.
Typical applications of power converters are electrical power supplies: For this the device input side usually supplied with AC voltage at the output they usually supply a DC voltage with fixed or adjustable voltage value.
Further power converters are used for the control or regulation of the variable-speed electric motors. Typical applications are in the range of simpler types of drives such as pumps and fans. Another important special field of power converters are used in electrically powered rail and road vehicles such as cars, locomotives and trams.
In addition, controlled -powered three-phase synchronous motors are fed by power converters. As control variables are used mostly for the speed, the rotational position or the torque to be output. Typical applications include machine tools and production machines.
Another special application of power converters are electrolysis and melting processes in the metal industry. Here, an AC voltage of a few volts is generated by a transformer, which is redirected (in the range of several thousands of amperes ) due to high power rectifier, the required DC low voltage ( in volt range ) and very high currents.
In recent decades, high-voltage direct -current transmission of electrical energy has found more widespread. Here too, the DC and the AC directing the electric current is carried by power converters. The connected by HVDC power systems can thereby even have different frequencies.