This measurement is necessary because most CMC datasheets lack inductance data versus differential mode current.
In real-world CMCs, the magnetic core can approach saturation due to differential mode inductance and current, reducing core permeability and, consequently, common mode inductance. This reduction affects the CMC's ability to filter common mode noise, especially in applications with high crest factor differential mode currents.
Saturation Characteristics of Common Mode Chokes
TBAIn this document, Vinod Chellat Markose explains an indirect method for measuring the drop in inductance of a CMC at any current using a Bode 100 vector network analyzer.
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Vinod Chellat Markose is a hardware engineer with more than 21 years of experience in hardware design. He graduated with a Bachelor of Engineering in Electrical and Electronics from Visvesvaraya Technological University, India, in 2002. Vinod has worked as a Power Electronics design engineer in industries like Renewable energy, Automotive, Consumer Electronics, and Oil & Gas. He is passionate about analogue electronics, magnetic design, circuit simulations, EMC and protection circuit design with emphasis on robustness to surge.
Vinod enjoys spending extensive time with physical components, analyzing the gap between ideal and real-life component behaviors. Since 2019, he has offered Electronic design consultancy services in Power Electronics and low-power analog (both in product design and root-cause analysis of mass failures). Vinod enjoys involving himself in spiritual and humanitarian activities in his free time.