Category | Switches

Loss Reduction in Power Electronics Switches by Soft Switching

Posted on 19 April 2020

              Soft switching is a possible way of reducing losses in power electronic switches. The expression "soft switching" actually refers to the operation of power electronic switches as zero-voltage switches (ZVS) or zero-current switches (ZCS). The many different converter circuits that working according to these principles are generally assigned [...]

Switching Loss Reduction Networks - Snubber Circuits

Posted on 06 March 2020

              Power electronic switches with conventional thyristors or GTOs require snubber circuits in order to guarantee operation within the safe operating area, i.e., these networks are indispensable if the components are to live up to their basic functions during switching. In contrast to this, the SOA (Safe Operating Area) [...]

Gate Resistors – Principles and Applications

Posted on 23 July 2020

    This article provides information on the use of gate resistors (RG) to control IGBT switching. The information given in this application note contains tips only and does not constitute complete design rules; the information is not exhaustive. The responsibility for proper design remains with the user.   Introduction The switching behaviour of power [...]

Basic Operating Modes of Power Semiconductors

Posted on 21 May 2020

  With the exception of a few special applications, power semiconductors are used predominantly in switching applications. Their switching sequences are either inductive (current-impressed) or capacitive (voltage-impressed). A switch used in an inductive circuit can actively turn on at any given time. For an infinitely short switching time, no power losses occur in the switch. If [...]

Four Types of Switching Processes

Posted on 03 May 2020

              For current and voltage characteristics related to semiconductors and the associated power losses, it is possible to distinguish between four types of switching processes: hard switching, soft switching, resonant switching and neutral switching. Hard turn-on is characterized by a total commutation voltage drop over the current-carrying switch at [...]

Power Electronic Switches: Neutral Switches

Posted on 25 April 2020

              A commutation process is started or ended by neutral turn-on or turn-off of a neutral switch. At the moment of switching, the voltage and current at the switch are both zero. These switching properties are inherent in diodes. Neutral switches can also be implemented using actively switchable power [...]

An Advantage of Hard Switching

Posted on 23 April 2020

              An actively switchable power electronic switch integrates a combination of power semiconductor and driver (driver stage). On the one hand, the parameters of a switch result from the behaviour of the power semiconductors. On the other hand, the driver unit is responsible for all main parameters of the [...]

Power Electronic Switches: Zero Voltage Switching and Zero Voltage Resonant Switches

Posted on 20 April 2020

              Switching sequences in power electronics are either inductive (current-impressed) or capacitive (voltage-impressed). Zero-voltage switches (ZVS) can be actively turned off. They are passively turned on in the zero-crossing of the switch voltage (Vsub>S= 0). Active turn-off produces very low losses if a sufficiently high parallel capacitance is selected. [...]