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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Hagen, C.W. (author), Kruit, P. (author)In electron optics, calculation of the electric field plays a major role in all computations and simulations. Accurate field calculation methods such as the finite element method (FEM), boundary element method and finite difference method, have been used for years. However, such methods are computationally very expensive and make the computer...journal article 2024
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Heidary, Amir (author), Ghaffarian Niasar, M. (author), Popov, M. (author)The rapid increase of integrated distributed generators results in higher fault currents in the future modern grids. A remedy for the concern is employing series reactors as fault current limiters. This paper elaborates on a ferromagnetic core series reactor, which, when saturated, adversely affects the operation of the series reactor during...journal article 2024
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Ganeshpure, D.A. (author), Soeiro, Thiago Batista (author), Ghaffarian Niasar, M. (author), Kulkarni, Nitish Milind (author), Bauer, P. (author), Vaessen, P.T.M. (author)This article proposes a new configuration of a modular multilevel converter (MMC) and a Marx generator to generate fast-rising impulse waveforms. This new configuration improves the capabilities of the MMC-based high voltage arbitrary wave shape generator to generate fast-rising impulse since the MMC topology faces many inherent limitations....journal article 2024
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Zhao, W. (author), Ghafoor, S. (author), Lagerweij, Gijs Willem (author), Rietveld, Gert (author), Vaessen, P.T.M. (author), Ghaffarian Niasar, M. (author)This paper comprehensively reviews several techniques that address the static and dynamic voltage balancing of series-connected MOSFETs. The effectiveness of these techniques was validated through simulations and experiments. Dynamic voltage-balancing techniques include gate signal delay adjustment methods, passive snubbers, passive clamping...journal article 2024
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Heidary, Amir (author), Ghaffarian Niasar, M. (author), Popov, M. (author)This paper introduces an innovative Magnetic Switch (MFS) designed to control and alter magnetic flux within energy system components, offering an alternative to conventional power electronic devices. The MFS comprises a low-current control coil, a control core, and a high-density magnetic flux-carrying main core combined with a main coil energy...journal article 2024
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Chen, Y. (author), Castro Heredia, L.C. (author), Smit, J.J. (author), Ghaffarian Niasar, M. (author), Ross, Robert (author)Partial discharge (PD) detection is a standardized technique to qualify the insulation condition in power equipment. The main purpose of the article is to evaluate the performance of an extra high-sensitivity adapted giant magneto-resistive (xMR) sensor for non-contacting PD detection. First, compensation and signal conditioning circuits of...journal article 2023
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Chen, Y. (author), Castro Heredia, L.C. (author), Smit, J.J. (author), Ghaffarian Niasar, M. (author), Ross, Robert (author)Partial discharges (PD) detection is an effective diagnostic method to assess the insulation condition of electrical power equipment in the high-voltage laboratory or field tests. This paper presents a non-contacting PD detection method for power equipment. The method is based on an extra high-sensitivity adapted giant magneto-resistive (xMR)...journal article 2023
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Mathew, P. (author), Ghaffarian Niasar, M. (author), Vaessen, P.T.M. (author)Penetration of power electronics in the grid has produced a new species of stresses, characterized by fast-rising pulsed waveforms with microsecond rise times repeating at several tens of kilohertz. Analyzing their impact on existing and future insulation systems requires pulse modulators, most often with pulse transformers (PTs), to perform...journal article 2023
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Heidary, Amir (author), Popov, M. (author), Moghim, Ali (author), Ghaffarian Niasar, M. (author), Lekić, A. (author)The significance of battery energy storage systems (BESSs) technology has been growing rapidly, mostly due to the need for microgrid applications and the integration of renewables. Relevant to the importance of utilization of BESS in microgrids, the protection of the BESS during microgrid faults has become a concern too. The short circuit in...journal article 2023
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Zhou, Xiaochuan (author), Ganeshpure, D.A. (author), Soeiro, Thiago B. (author), Ghaffarian Niasar, M. (author), Wu, Y. (author), Vaessen, P.T.M. (author)In order to damp the resonance in the MMC-based Arbitrary Wave shape Generator (AWG) used for high voltage testing, an active damping control methodology is proposed in this paper instead of the passive damping with an arm resistor. It is vital to ensure the system’s stability when such an active damping closed loop control is implemented....conference paper 2023
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Nasirpour, F. (author), Heidary, Amir (author), Ghaffarian Niasar, M. (author), Lekić, A. (author), Popov, M. (author)High local electric field intensity in transformer windings originating from transient signals is one of the reasons for transformer failures. Due to the integration of renewable energy sources into the power grids and the increased number of transients, the likelihood of transformer catastrophic failure increases accordingly. Therefore, to...journal article 2023
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Heidary, Amir (author), Ghaffarian Niasar, M. (author), Popov, M. (author), Lekić, A. (author)Due to the extension of the power grid with many complex and compact pieces of power equipment, transformers will be more exposed to fast transient, resulting from various resonance conditions. Transformer resonance can result in severe overvoltage on internal parts of the winding, leading to insulation failure and, consequently, transformer...journal article 2023
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Ganeshpure, D.A. (author), Soeiro, Thiago B. (author), Ghaffarian Niasar, M. (author), Vaessen, P.T.M. (author)A Modular Multilevel Converter (MMC)-based Arbitrary Wave shape Generator (AWG) for High Voltage (HV) testing faces challenges in the control hardware to generate kHz-range high-frequency waveforms. Real Time Simulators (RTS) provide a simple way to implement the control of the MMC-based AWG in the FPGA. One of the commercially available RTS...conference paper 2023
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Ganeshpure, D.A. (author), Soeiro, Thiago B. (author), Gagic, Mladen (author), Ghaffarian Niasar, M. (author), Bauer, P. (author), Vaessen, P.T.M. (author)To test high-voltage (HV) equipment with increasingly complex transients obtained from various power system studies, this article demonstrates a hardware implementation of a medium-voltage (MV) submodule (SM) to be used in a modular multilevel converter (MMC)-based HV arbitrary wave shape generator (AWG). The MV SM is scalable with its own...journal article 2023
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Mirzadarani, R. (author), Ghaffarian Niasar, M. (author), Li, Z. (author), Qin, Z. (author), Vaessen, P.T.M. (author), Bauer, P. (author), Van Lieshout, Lou (author)Green hydrogen production uses renewable energies to energise the electrolysers for hydrogen production. The present paper compares possible solutions and configurations of a medium-frequency transformer (MFT) as part of a solid-state transformer (SST) in green hydrogen production applications. The single-phase and three-phase MFTs are compared...conference paper 2023
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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Hagen, C.W. (author), Kruit, P. (author)The design of electrostatic electron lenses involves the choice of many geometrical parameters for the lens electrodes as well as the choice of voltages applied to the electrodes. The purpose of the design is to focus the electrons at a specific point and to minimize the aberrations of the lens. In a previous study, genetic algorithm...conference paper 2023
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Li, Z. (author), Qin, Z. (author), Mirzadarani, R. (author), Ghaffarian Niasar, M. (author), Itraj, M.S. (author), Van Lieshout, Lou (author), Bauer, P. (author)For electrolyzer applications, traditional solutions using line frequency transformers plus rectifiers are bulky, heavy and have low controllability. The Solid State Transformer (SST) could be a promising solution to solve the mentioned issues. This paper compares the semiconductor ratings and capacitance of five different Modular Multilevel...conference paper 2023
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Luo, T. (author), Ghaffarian Niasar, M. (author), Vaessen, P.T.M. (author)Litz wire, which is used to suppress eddy current, always have complex structure. Solving its 3-D finite element model (FEM) requires high computational resources. This article presents a 2.5-D loss calculation method for round Litz wires, which do not need mesh. One pitch of Litz wire is set as an object. The exact structure is constructed...journal article 2023
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Luo, T. (author), Ghaffarian Niasar, M. (author), Vaessen, P.T.M. (author)In this article, an approach combining semi-empirical equations and the method of images is proposed for round conductor layer windings with un-gapped core. The new equation for proximity effect can convert the constant field strength from the magneto-motive force (MMF) across the core window into a frequency-dependent uniform background...journal article 2023
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Luo, T. (author), Ghaffarian Niasar, M. (author), Vaessen, P.T.M. (author)Magnetic components are essential parts in many power electronic applications. Their characteristics deeply impact the performances of the applications. This article proposed a 2-D calculation method for frequency-dependent winding losses and leakage inductance of magnetic components of round conductors. The method does not have any...journal article 2023