Inductor ripple current

Naveen's picture

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Joined: Nov 27, 2019

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Inductor ripple current
November 27, 2019 - 7:57am

Can you please let me know why we use inductor ripple current as 20 to 40% of load current? 

Also what will be the boundary condition between CCM and DCM. 

In CCM mode, inductor current will not reach zero, what is the value of onductor current above zero in CCM mode

Bradyen's picture

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Joined: Aug 14, 2018

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Question not clear!!
November 28, 2019 - 11:01am

Which project are you talking about and about which circuit? How do you expect people to help you, when your quesion itself is not clear 

Sourav Gupta's picture

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Inductor ripple current
December 2, 2019 - 11:25pm

Because Inductor works when changes in current occur. During these changes, a circuit is not an ideal one, it is much more complex. Therefore, to tolerate with the peak current condition, a larger value inductor is used.

The word CCM and DCM is just a meaningless word if you do not include the term "Switching frequency".  As told you earlier that the inductor works only when there is a change in the flow of current, a switch always changes its state to control the current flow through the inductor. Therefore if the switch turns OFF or ON in a situation where the inductor current flow set to a static level (No changes) in the switching cycle is called as discontinuous conduction mode and if the current flow through an inductor never gets into a static level it is called continuous conduction mode. Therefore, CCM and DCM have a boundary condition of switching frequency or how the switch changes its state and what is the condition of current change inside the inductor.

 

Zero is not static in Electronics. There is nothing called Zero in the practical world. The Inductor current never gets zero until or unless the power of supply is disconnected physically. However, again its depends on the used components, depends on the switching cycle (As it is CCM), depends on the inductor's value and many other crucial factors.