Marian K. Kazimierczuk
'%3e%3cpath%20d='M22.1642%2019.0924C21.7317%2018.068%2021.1041%2017.1375%2020.3163%2016.3527C19.5309%2015.5656%2018.6006%2014.9381%2017.5766%2014.5048C17.5674%2014.5002%2017.5582%2014.4979%2017.5491%2014.4933C18.9774%2013.4616%2019.9059%2011.7811%2019.9059%209.88504C19.9059%206.74408%2017.3611%204.19922%2014.2201%204.19922C11.0792%204.19922%208.53429%206.74408%208.53429%209.88504C8.53429%2011.7811%209.46282%2013.4616%2010.8912%2014.4956C10.882%2014.5002%2010.8728%2014.5025%2010.8636%2014.5071C9.83652%2014.9404%208.91487%2015.5617%208.1239%2016.355C7.33685%2017.1404%206.70933%2018.0707%206.276%2019.0947C5.85031%2020.0972%205.62072%2021.172%205.59967%2022.2609C5.59905%2022.2853%205.60335%2022.3097%205.61229%2022.3325C5.62123%2022.3553%205.63465%2022.376%205.65174%2022.3935C5.66883%2022.4111%205.68926%2022.425%205.71182%2022.4345C5.73437%2022.444%205.7586%2022.4489%205.78308%2022.4489H7.15868C7.25956%2022.4489%207.3398%2022.3686%207.3421%2022.2701C7.38795%2020.5001%208.09868%2018.8425%209.35506%2017.5861C10.655%2016.2862%2012.3814%2015.5709%2014.2201%2015.5709C16.0588%2015.5709%2017.7852%2016.2862%2019.0852%2017.5861C20.3415%2018.8425%2021.0523%2020.5001%2021.0981%2022.2701C21.1004%2022.3709%2021.1807%2022.4489%2021.2815%2022.4489H22.6571C22.6816%2022.4489%2022.7058%2022.444%2022.7284%2022.4345C22.751%2022.425%2022.7714%2022.4111%2022.7885%2022.3935C22.8056%2022.376%2022.819%2022.3553%2022.8279%2022.3325C22.8369%2022.3097%2022.8412%2022.2853%2022.8406%2022.2609C22.8176%2021.165%2022.5907%2020.0989%2022.1642%2019.0924ZM14.2201%2013.8284C13.1678%2013.8284%2012.1773%2013.418%2011.4322%2012.6729C10.6871%2011.9278%2010.2767%2010.9374%2010.2767%209.88504C10.2767%208.83271%2010.6871%207.84227%2011.4322%207.09715C12.1773%206.35204%2013.1678%205.94165%2014.2201%205.94165C15.2724%205.94165%2016.2629%206.35204%2017.008%207.09715C17.7531%207.84227%2018.1635%208.83271%2018.1635%209.88504C18.1635%2010.9374%2017.7531%2011.9278%2017.008%2012.6729C16.2629%2013.418%2015.2724%2013.8284%2014.2201%2013.8284Z'%20fill='%238590A2'/%3e%3c/g%3e%3c/svg%3e)
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Academic Career Length
31Years (1996-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications19 June 2018 in IEEE Transactions on Circuits and Systems II: Express Briefs
Journal Article
AAAgasthya Ayachit
Agasthya AyachitMarian K. KazimierczukThis paper proposes an improved averaged smallsignal model of pulse-width modulated (PWM) dc-dc power converters operated in continuous-conduction mode (CCM), which includes a resistance that corresponds to the switching power loss. Through this model, the switching power loss can be incorporated into existing averaged small-signal dynamic models. The proposed approach is based on the principle of conservation of energy. The expressions for the equivalent switching-loss resistance for the basic converter topologies are derived. The improved dc and small-signal models of the switching network are given. A boost dc-dc converter is considered as an example. The effect of the switching-loss resistance on the small-signal control-to-output transfer function is shown. Experimental results are given and the theoretical predictions have been validated.
2 April 2018 in IEEE Transactions on Industry Applications
Journal Article
RWRafal P. Wojda
Rafal P. WojdaMarian K. KazimierczukAn analytical model based on the one-dimensional Dowell's equation for computing the ac-to-dc winding resistance ratio of the litz-wire windings independent of the porosity factor is derived. The model takes into account proximity effect within the bundle and between bundle layers, as well as the skin effect in each strand. Three frequency ranges for the winding resistance characteristics are considered: low-, medium-, and high-frequency range. In each range, the behavior of the ac-to-dc winding resistance ratio F R is different. Moreover, an analytical optimization of the litz-wire winding strand diameter for litz-wire windings conducting sinusoidal and multiharmonic currents independent of the porosity factor is performed.
28 May 2018 in IEEE Transactions on Industrial Electronics
Journal Article
AAAgasthya Ayachit
Agasthya Ayachit
Fabio Corti
Alberto ReattiMarian K. KazimierczukThis paper presents a complete design methodology of a Class-E inverter with a loosely-coupled transformer under zero-voltage switching conditions. At a selected maximum coupling coefficient, the inverter satisfies both zero-voltage switching (ZVS) and zero-derivative switching (ZDS) conditions to achieve a high efficiency. As the coupling coefficient is decreased from its maximum value to zero, the inverter satisfies the ZVS condition over a wide range of load resistance. The proposed method absorbs the magnetizing inductance and the leakage inductance into the inverter topology. The closed-form expressions for all the Class-E inverter parameters are derived in terms of the coupling coefficient including (a) input impedance of the transformer with a complex load impedance, (b) equivalent phase of the resonant circuit for both nominal and sub-optimum operations, and (c) slope of the switch voltage waveform. The relationship between the voltage slope and the coupling coefficient is introduced, which indicates the proximity of the operating point from ZVS and ZDS conditions. A design example of the Class-E inverter is presented to achieve both ZVS and ZDS at an optimum coupling coefficient of 0.77 and ZVS condition for any coupling coefficient lower than 0.77 and over a wide range of load resistance.
21 August 2017 in IEEE Transactions on Industrial Electronics
Journal Article
DSDalvir K. Saini
Dalvir K. SainiAAAgasthya Ayachit
Agasthya AyachitARAlberto Reatti
Alberto Reatti
Marian K. KazimierczukThis paper presents the design, analytical estimation of power losses, and experimental measurement of choke inductors for switched-mode power inverters. The described approach is applicable to a wide variety of circuits such as Class-E inverters and converters. The expressions required to design the magnetic core in the choke inductor using the area-product (Ap) method are given. The equations for the dc resistance, ac resistance at high frequencies, and dc and ac power losses are provided for the solid round winding wire. To validate the presented approach, an example class-E zero-voltage switching power inverter with practical specifications is considered. A core with air gap is selected to avoid core saturation in the choke inductor, which conducts dc current and a small ac current. The gapped core power loss density and power loss are estimated using Steinmetz empirical equation. It is shown that the winding power loss due to the dc current is dominant for the given design. A comparison between the area-product Ap method and the preexisting core geometry coefficient Kg method is presented. The measured magnitude of the inductor impedance has shown that the designed choke is useful up to ten times the switching frequency.
4 April 2017 in IEEE Transactions on Electromagnetic Compatibility
Journal Article
AAAgasthya Ayachit
Agasthya AyachitMarian K. KazimierczukThis letter presents the technique for estimating the self-capacitance of single-layer air-core solenoid inductors with separation between the insulated turns. In single-layer air-core inductors, the self-capacitance is due to the conductor turn-to-turn capacitances. The analytical framework to determine the turn-to-turn capacitances of single-layer air-core inductors with uniformly and nonuniformly separated conductor turns is established. The influence of the wire insulation coating is taken into consideration. A representative design example of a single-layer air-core inductor is presented and its self-capacitance and self-resonant frequency are predicted. The presented analytical approach was tested by experimental measurements on the designed inductor. The derived analytical expressions are useful for designing air-core inductors for high frequency (HF) and very HF applications such as electromagnetic interference/electromagnetic compatibility filters and radio and TV transmitters.
22 May 2018 in IEEE Transactions on Power Electronics
Journal Article
JLJiangtao Liu
Jiangtao Liu
QDQijun Deng
Qijun DengDCDariusz Czarkowski
Dariusz CzarkowskiMarian K. Kazimierczuk
Hong ZhouWHWenshan Hu
Wenshan HuA coil with a high quality factor Q is desired to obtain a high efficiency for inductive power transfer (IPT). Q is proportional to the coil inductance and operating frequency, while it is inversely proportional to the coil resistance, which increases with frequency. An optimized frequency exists to achieve the maximum efficiency. Eddy currents and resulting ac resistance in Litz-wire coils are attributed to magnetic field. Especially, the induction component of the ac resistance is approximately proportional to the squared magnetic field to which the coil is exposed to. FEA simulations are conducted and surface integral method is employed to determine the squared field. Additionally, the volume integral method is proposed to evaluate the overall effect of the field on the induction resistance. The optimized frequency for the maximum efficiency is obtained, using the squared field calculation and resulting ac resistance evaluation. Sample prototype coils are manufactured to verify the resistance analysis methods. An IPT system is built employing these coils. Experiments show that the IPT system achieves the highest efficiency at frequencies closed to the predicted optimized ones.
About Me
Marian K. Kazimierczuk received the M.S., Ph.D., and D.Sci. degrees in electronics engineering from the Department of Electronics, Warsaw University of Technology, Warsaw, Poland, in 1971, 1978, and 1984, respectively. He was a Teaching and Research Assistant with the Department of Electronics, Institute of Radio Electronics, Warsaw University of Technology, from 1972 to 1978, where he was an Assistant Professor from 1978 to 1984. In 1984, he was a Project Engineer with Design Automation Inc., Lexington, MA, USA. From 1984 to 1985, he was a Visiting Professor with the Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA. Since 1985, he has been with the Department of Electrical Engineering, Wright State University, Dayton, OH, USA, where he is currently a University Professor. He is the author/co-author of 7 books, 220 journal papers, and 270 conference papers, and holds 8 patents. He has served as an Associate Editor for IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS, IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, and IET Circuits, Devices, and Systems. His research interests include high-frequency high-efficiency switching-mode tuned-power amplifiers, resonant and PWM dc-dc power converters, dc-ac inverters, high-frequency rectifiers, electronic ballasts, modeling and control of converters, high-frequency magnetics, wireless power transfer, renewable energy sources, and wide bandgap power semiconductor devices.