Conducted EMI in Power Electronics Systems

A typical conducted EMI measurement setup for a power converter is shown below. Common-mode (CM) noise first flows through the parasitic capacitors between the converter and the ground plane. Most of the CM noise is then bypassed by the EMI filter through the ground point of the CM filter. At last, the remaining CM noise flows through the ground plane, the line impedance stabilization networks (LISNs), the power interconnects, and back to the EMI filter and the converter. In order to efficiently bypass CM noise, the grounding impedance of the CM filter should be as small as possible. On the other hand, the differential-mode (DM) noise is first attenuated by the DM filter and then flows between two power interconnects through LISNs. The noise is measured from the voltage drops of the noise current on the 50-Ω input impedances of the noise separator. Learn more, please download.

Design of Inductor Winding Capacitance Cancellation for EMI Suppression

The parasitics in both differential-mode (DM) and common-mode (CM) inductors are discussed. The methods for both DM and CM inductor winding capacitance cancellation are then proposed. Prototypes are designed and tested, using a network analyzer. Finally, the prototypes are applied to practical power converters and electromagnetic interference (EMI) is measured. Both small signal measurement and practical EMI measurement prove that the proposed methods can efficiently reduce the effects of winding capacitance and therefore improve the inductor’s filtering performance. Learn more, please download.

More posts of our conducted EMI research pending

Radiated EMI in Power Electronics Systems

With ever-increasing development on high switching frequency and high power density of power electronics, electromagnetic interference (EMI) is becoming more and more serious. For power electronics applications including power adapters and electric vehicles, radiated EMI is regulated by international standards, e.g. CISPR 22 and CISPR 25. Modeling and reduction of radiated EMI in power converters become increasingly important.

Semi-anechoic Chamber for the Radiated EMI Testing

Learn about the semi-anechoic chamber facility owned and operated by our lab, please download.

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In GaN IC-based Active Clamp Flyback Converters, Radiated EMI Modeling and Reduction Techniques

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In Non-isolated Power Converters, Radiated EMI Modeling and Reduction Techniques

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More posts pending