the process of turning off of a thyrisror is known as commutation
The term "Forced commutation" is used when a thyristor is turned off using external components. If a thyristor is used in a DC circuit, when first turned on, it will stay on until the current goes to zero. To turn off the thyristor it is possible to use a Forced commutation circuit. The circuit creates a reverse voltage over the thyristor (and a small reverse current) for a short time, but long enough to turn off the thyristor. A simple circuit consist of a precharged capacitor and a switch (e.g. another thyristor) parallel to the thyristor. When the switch is closed, the current is supplied by the capacitor for a short while. This cause a reversed voltage over the thyristor, and the thyristor is turned off.
One voltage is greater in thyristor whether forward breakover or reverse breakdown voltage. The greater of the two voltages in thyristor is forward breakover voltage.
It is stated that one of the voltage is greater in thyristor whether it be forward breakover or reverse breakdown voltage. It is also stated that the greater of the 2 voltages in thyristor is the forward breakover voltage.
Function of a thyristorA thyristor - also known as an SCR (silicon controlled rectifier) - is like a very fast static switch and is good for controlling large amounts of power (called power regulation) and for controlling the speed of dc motors. Another typical application is to make dimmers for lighting circuits.How it worksA thyristor is semiconductor device having 3 electrodes:an anodea cathodea gateNo current can travel from the anode to the cathode until a pulse which has the right amount of voltage (called the "trigger voltage") has been applied to the gate for the right minimum amount of time (called the "trigger duration") which causes the thyristor to switch on to allow current to flow through it from the source to the load.After being triggered, current continues to flow through the thyristor from the source to the load until either:the load gets disconnected from the thyristor by some other means orthe supply of current from the source to the thyristor gets turned off by some other means.
It can be. I have a heap of them in my irrigation system. You need to state what kind of interface you are asking about.
it is a type of forced commutation technique of thyristor
it is the natural commutation ...by making open circuit or short circuit on the thyristor to make it turn off.
The term "Forced commutation" is used when a thyristor is turned off using external components. If a thyristor is used in a DC circuit, when first turned on, it will stay on until the current goes to zero. To turn off the thyristor it is possible to use a Forced commutation circuit. The circuit creates a reverse voltage over the thyristor (and a small reverse current) for a short time, but long enough to turn off the thyristor. A simple circuit consist of a precharged capacitor and a switch (e.g. another thyristor) parallel to the thyristor. When the switch is closed, the current is supplied by the capacitor for a short while. This cause a reversed voltage over the thyristor, and the thyristor is turned off.
Voltage commutation: This is possible in ac circuits...The thyristor gets turned off by reverse bias (negative half cycle) voltage applied across it. This is also called line commutation. Current Commutation: This is possible in dc circuits ...This type of commutation makes use of auxiliary circuit which contains inductor,capacitor,diode and even a thyristor(auxiliary). This is called Forced commutation.
i think i know this answer...line commutation is the commutation in single phase inverters/converters when there is current flow back to the source.. It can also refer to a method of turning of a semiconductor device known as a Thyristor or SCR, sometimes called natural commutation. In this method the current between the anode and cathode is interrupted or dropped to a point where the Thyristor can no longer maintain its latch or keep conducting, shutting the device off.
a Heumann chopper is nothing but the Class D commutation of a thyristor.refer to the following link on class d commutationhttp://www.slideshare.net/prathikm/thyristor-commutation-techniques
it is one of method to turn off scr. resonating LC component is used to turn off scr
L. J. Berman has written: 'A classification of thyristor commutation circuits for static invertors'
Commutation in a rectifier: Refers to the process of transfer of current from one device (diode or thyristor) to the other in a rectifier. The device from which the current is transferred is called the "out going device" and the device to which the current is transferred is called the "incoming device". The incoming device turns on at the beginning of commutation while the out going device turns off at the end of commutation.Commutation failure: Refers to the situation where the out going device fails to turn off at the end of commutation and continues to conduct current.
Two types of commutation process 1) Natural commutation 2) Forced commutation
Generally there are two methods of improving Commutation :- 1.Resistance Commutation 2.Emf or Voltage Commutation The Commutation can also be improve by using interpoles and compensating windings.
Overlap angle of a rectifier (μ): The commutation process in a practical rectifier is not instantaneous. During the period of commutation, both the incoming and the outgoing devices conduct current simultaneously. This period, expressed in radians, is called the overlap angle "μ" of a rectifier. It is easily verified that α + μ + γ = π radian.α= Firing angelμ=Overlap angelγ =extiction angel