Commutation in power electronics refers to the process of switching between the phases to energize appropriate windings in order to generate motion in a three-phase linear motor. Commutation is also the process of turning off an SCR (thyristor) in power electronics. Here are some key points about commutation in power electronics:
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SCR Turn OFF: The turn OFF process of an SCR is called commutation. Commutation means transfer of current from one circuit to another.
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Types of Commutation: There are two types of commutation: natural commutation and forced commutation. Natural commutation is used in AC circuits, while forced commutation is used in DC circuits.
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Natural Commutation: In natural commutation, the SCR is turned off due to the natural tendency of AC. No additional circuitry is required in this commutation technique.
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Forced Commutation: In forced commutation, an external circuitry is required to forcibly bring the SCR current below holding current and keep the SCR reversed biased for a period more than the SCR turn off time. This technique is applied for DC circuits.
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Commutation Cell: The commutation cell is the basic structure in power electronics. It is composed of two electronic switches (today, a high-power semiconductor, not a mechanical switch). The purpose of the commutation cell is to "chop" DC power into square wave alternating current.
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SCR Commutation Types: Depending on the process for achieving zero current in the SCR and the arrangement of the commutating components, forced commutation is classified into different types such as Class A, B, C, D, and E.
In summary, commutation in power electronics refers to the process of switching between the phases to energize appropriate windings or turning off an SCR in power electronics. There are two types of commutation: natural and forced commutation, and forced commutation is classified into different types.
