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1. Mitigating Optical Module Emi Using Common- and Differential-Mode Filters

   https://doi.org/10.1109/EMCSIPI52291.2025.11170239  

   Singh, Shivali; Gopalaiah, Rakshith Kumar; Li, Di; Tejasvi, Mokshit; Shipra, Shipra; Khilkevich, Victor (August 2025, IEEE)

   A strategy to mitigate electromagnetic interference in quad/octal small form-factor pluggable interfaces using a common-mode/differential-mode filter is presented in this research. Differential source imbalance produces significant common- and differential-mode noise in the differential pseudorandom binary sequence signal. EMI associated with this noise can be reduced by incorporating a bandstop filter onto the differential line on a printed circuit board. Two kinds of filters were tested: common mode and common/differential mode. It was demonstrated that the application of a common-mode/differential-mode filter is more advantageous than a common-mode filter and allows to achieve the suppression of the total radiated power by 17 dB to 7 dB in the frequency range from 10 GHz to 26 GHz. 

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2. HIL Testbed-Based Design and Implementation of DER-Integrated-MMC for Extreme Fast Charger

   https://doi.org/10.1109/NAPS61145.2024.10741783  

   Yadav, Ankit; Gelli, Ravikumar (October 2024, IEEE)

   The limited availability of affordable and rapid charging infrastructure slows the adoption of electric vehicles (EVs). The modular multilevel converter (MMC) based approach can provide a viable solution for future extreme-fast charging (XFC) infrastructure. Additionally, distributed energy resources (DER) can be integrated to minimize grid dependency and increase availability and reliability. We propose a DER-integrated-MMC for extreme fast charger (MMC-DER-XFC) that incorporates a dual-active bridge (DAB) for EV charging and DER within the sub-module (SM). While some researchers have explored related studies, the absence of access to the SM capacitor terminals limits the integration with DAB and DER. To address this challenge, this paper proposes an innovative and optimal design of MMC-DER-XFC and implements and validates it using an OpalRT real-time simulator-based HIL testbed. This model can act as a testbed for various studies and control developments. This paper simulates a testbed with 60 EVs and DERs, but it can support up to 300 EVs and DERs. Additionally, any number of EVs and DERs can be activated or deactivated for a specified duration. Furthermore, distinct EV charging/discharging and DER generation profiles can be independently defined for each unit. The developed testbed has been evaluated using a standard MMC controller. This paper examines the internal dynamics of the MMC-DER-XFC under different scenarios: (1) only DERs are operational, (2) only EVs are functioning in either grid-to-vehicle (G2V) or vehicle-to-grid (V2G) mode, and (3) both DERs and EVs (G2V and V2G) are active. The testbed demonstrates harmonic distortion at low power levels, but these distortions are eliminated under full load conditions. 

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3. Active Filtering for Differential Mode EMI

   Mulumudi, Guru Abhilash (April 2024, ASU)

   Switch-mode power converters operate at frequencies ranging from tens to hundreds of kilohertz and tend to generate significant conducted EMI within the regulated frequency band of 0.15-30 MHz. Converters typically require an input filter to comply with electromagnetic compatibility standards to prevent high-frequency currents from traveling through the power source conductors. The traditional EMI filters are usually made of passive components, which are substantial in size, sometimes occupying as much as onethird to one-fourth of the total volume, limiting the power density of the power converters. An alternative to bulky passive EMI filters is the utilization of active electronics, which inject voltages or currents to counteract the interference signal. The work introduces a boost converter in conjunction with a synchronized switch mode Active EMI Filter (AEF), which reduces energy storage requirements compared to passive EMI filters. The proposed AEF operating at a frequency of 30 MHz effectively mitigates additional EMI into the system as its operational frequency lies beyond the typical range of conducted EMI. The AEF is realized using a synchronous buck converter with a series resonant tank and the current configuration is designed to counteract the ripple component of the boost converter. Firstly, this work presents the comprehensive analytical modeling of the AEF circuit consisting of a series resonant tank to determine the variation of AEF current magnitude to circuit parameters, and duty-controlled switching in the proposed AEF is implemented using high-speed analog circuits to generate pulse width modulated (PWM) signals for the filter. The proposed methodology controls the magnitude of AEF current to a desired value ii in an open loop to reduce the complexity of the circuit. Further, the AEF is employed in a (6-12)V-to-24V boost converter switching at 150 kHz and has been found to attenuate the fundamental ripple component. From the experimental results, an attenuation of 23dB is achieved using the proposed AEF and a reduction of LC product by a factor of 16 in the AEF and the effective volume of the AEF by 47% compared to that of a single-stage fully passive LC filter. 

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4. A 25kW Silicon Carbide 3kV/540V Series-Resonant Converter for Electric Aircraft Systems

   https://doi.org/10.1109/APEC42165.2021.9487328  

   Du, Xinyuan; Diao, Fei; Zhao, Zhe; Zhao, Yue (June 2021, 2021 IEEE Applied Power Electronics Conference and Exposition (APEC))

   In this work, a 25 kW all silicon carbide (SiC) series-resonant converter (SRC) design is proposed to enable a single stage dc to dc conversion from 3kV to 540V (±270V) for future electric aircraft applications. The proposed SRC consists of a 3-level neutral-point-clamped (NPC) converter using 3.3kV discrete SiC MOSFETs on the primary side, a H-bridge converter using 900V SiC MOSFET modules on the secondary side and a high frequency (HF) transformer. The detailed design methods for the SRC power stage and the HF transformer are presented. Especially, a tradeoff between the complexity for the cooling system and the need for power density is addressed in the transformer design, leading to a novel multi-layer winding layout. To validate the effectiveness of the proposed SRC design, a converter prototype has been developed and comprehensive experimental studies are performed. 

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5. EMI Mitigation, Material Characterization, Transformer Equivalent Circuit Modeling

   Vahdani, Reza (May 2025, Missouri S&T Library)

   Modern high-frequency electronic systems demand precise characterization and modeling techniques to ensure signal integrity and electromagnetic compatibility. This thesis presents three core studies focused on real-world challenges in high-speed and power electronics: EMI mitigation using 3D printed absorbers, wideband liquid dielectric charac- terization, and accurate transformer modeling. The first study demonstrates a targeted approach to mitigating electromagnetic in- terference (EMI) in a commercial router. By using holography imaging to identify radiation hotspots, custom absorber structures were designed with commercially available materials, fabricated via 3D printing, and applied directly to emission sources. Radiated emission tests in a reverberation chamber showed up to 9 dB reduction in EMI, validating the method’s effectiveness for practical applications. The second study proposes a wideband method (up to 30 GHz) to characterize liquid dielectrics using a differential microstrip line and the Djordjevic-Sarkar model. Dielectric constant (DK) and dissipation factor (Df) were extracted by comparing S-parameters of air and liquid-immersed conditions between measurement and simulation results. Experi- mental validation with PAO4 and DC-15 liquids showed strong agreement with traditional cavity resonance methods, with DK deviations under 1.5%. The third study addresses transformer modeling across 100 kHz to 30 MHz by developing an equivalent circuit model that accurately captures winding effects, parasitic capacitance, and leakage inductance. The approach incorporates an optimized coupling coefficient based on physical parameters. Validation with air-core inductors demonstrated high model accuracy, with an average relative error of 2.2%. 

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