Leszek Jarzębowicz - Publications - Bridge of Knowledge

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Year 2023
Year 2022
  • Application of Traction Supply System for Charging Electric Cars
    Publication

    - ENERGIES - Year 2022

    The development of electromobility involves the development of electric cars charging infrastructure. The increase of the number of chargers poses new demands for the AC power grid, especially in regard to its capacity of delivering high peak power. As an alternative for the public AC power grid, urban electrified transportation systems (trams, trolleybuses, and metro) can be used for supplying electric cars chargers. The article...

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  • Compensation of Voltage Drops in Trolleybus Supply System Using Battery-Based Buffer Station
    Publication

    - ENERGIES - Year 2022

    This paper analyzes the results of a trial operation of a battery-based buffer station supporting a selected section of trolleybus power supply systems in Pilsen, Czech Republic. The buffer station aims to prevent the catenary from excessive voltage drops in a part of the route that is most remote from the traction substation. Compensation of voltage drops is carried out by continuously measuring the catenary voltage and injecting...

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Year 2021
Year 2020
  • Frequency Diagnostics of Transformer Insulating Parameters
    Publication

    - Year 2020

    In the article is presented experimental analysis and diagnostics of insulating system oil-paper for power transformers, mainly by progressive frequency method – dielectric spectroscopy. In the 1-st part of the article is described base theory about measurement and diagnostics insulating part (oil and paper) of power transformers. In the 2-nd part of article is described measuring method of insulating frequency diagnostics - frequency...

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  • Utility analysis and rating of energy storages in trolleybus power supply system
    Publication

    The article discusses two energy storage applications in power supply system of public electrified transport. The first application aims at reducing the peak power of the traction substation. The second application increases effectiveness of using solar power plant to cover partial power demand of traction supply system. These two applications were discussed and analyzed based on trolleybus supply system in Gdynia, where most measurements...

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Year 2019
  • Constant vs. Variable Efficiency of Electric Drive in Train Run Simulations
    Publication

    Train run simulations, which focus on various power- and energy-oriented aspects, should reflect the losses in the electric powertrain. In general, the powertrain efficiency varies with respect to load and speed. Including this relation in simulation requires knowledge about detailed drivetrain parameters, which are often unavailable. This paper verifies the possibility to approximate the drivetrain efficiency in train run simulations...

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  • Derivation of motor mean phase currents in PMSM drives operating with low switching-to-fundamental frequency ratio
    Publication

    Pulse width modulation (PWM) of inverter output voltage causes the waveforms of motor phase cur-rents to consist of distinctive ripples. In order to provide suitable feedback for the motor current con-trollers, the mean value must be extracted from the currents’ waveforms in every PWM cycle. A com-mon solution to derive the mean phase currents is to sample their value at the midpoint of a symmetrical PWM cycle. Using an assumption...

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  • Impact of digital signal processing on FOC current feedback in high-speed PMSM drive
    Publication

    - Year 2019

    In applications where size and weight of the electric motor are among major design concerns, Permanent Magnet Synchronous Motors (PMSMs) with wide operational speed-range are commonly preferred. Due to limited inverter switching frequency, high-speed operation of a drive results in a low ratio between the switching frequency and the fundamental frequency of motor voltage. Such operating conditions have been recently identified...

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  • Quasi-discrete modelling of PMSM phase currents in drives with low switching-to-fundamental frequency ratio
    Publication

    This study proposes a new quasi-discrete approach to modelling the permanent magnet synchronous motor (PMSM). The quasi-discrete modelling reflects the impact of continuous rotor movement, which takes place during a control cycle, on the shape of motor current waveforms. This provides much improvement in current modelling accuracy under inverter low switching-to-fundamental frequency operation. The proposed approach may be used...

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  • Synchronized six-step voltage generation in high-speed PMSM drive
    Publication

    Synchronized voltage generation has already been considered in the context of pulse width modulation (PWM). References prove that synchronized PWM substantially decreases subharmonics in inverter output voltage when operating with low switching-to-fundamental frequency ratio. This paper identifies problems of unsynchronized voltage generation in electric drives under six-step inverter operation. Guidelines for the synchronization...

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Year 2018
Year 2017

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