Power semiconductors

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Power semiconductors are semiconductor components that are designed in power electronics for controlling and switching high electrical currents and voltages (more than 1  ampere and voltages of more than about 24  volts ). The upper limit of the size is several thousand amps and volts, respectively.

Different semiconductor components and their maximum currents, voltages and switching frequencies

Adapted variants of normal semiconductor components are required for this, as high currents and voltages would destroy them. The following components are mainly used:

  • Power diodes are switching elements that in principle only allow current to flow in one direction or only above a certain voltage value . They are often used in rectifier circuits.
  • Thyristors are switching elements that allow the switching point to be set flexibly and at will using a controllable voltage on a control electrode. In addition to the rectifier, they are the most typical components in power electronics. They have a wide variety of applications for switching, controlling and regulating.
  • Triacs are two thyristor elements in one component, which are connected in parallel in opposite directions and controlled together. Triacs are primarily used to control and switch alternating currents .
  • Power MOSFETs and IGBT components are transistors with special switching and power properties due to their atomic semiconductor structure.

Practical areas of application for power semiconductors are the control of electrical drives in traffic engineering and mechanical engineering as well as the conversion or adaptation of voltage, current and frequency of an electrical supply system to another or to other values. Power semiconductors are connected in parallel to increase the current carrying capacity ( parallel connection ). Since this is very time-consuming and uneconomical using discrete components in standard housings ( TO220 , TO247), power modules are used for more complex circuits. In addition to the power chips connected in a certain circuit topology, these also contain current measuring resistors ( shunts ) and electrical contacts and in many cases have an electrically insulating, but thermally highly conductive base plate.