Krzysztof Wrobel

Dr. Krzysztof Wrobel

orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2014 in IET Power Electronics
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KTKrzysztof Tomczewski
Krzysztof Tomczewski
KWKrzysztof Wrobel
Krzysztof Wrobel
This study presents a new power converter for switched reluctance motor‐based drives. In comparison with the standard power systems, the proposed one allows reduction of the switching losses, especially in a low‐speed range, as well as eliminates energy intake from source during the energy discharge process. As a result the efficiency of drive can be increased in the entire range of rotational speed. The computer model of the drive and a detailed study on relationships between the output power and the rotational speed for a sample two‐phase motor‐based drive are presented. To verify simulations results the measurements on the laboratory test‐stand are carried out.

1 August 2012 in IET Power Electronics
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Journal Article
Closed access
KTKrzysztof Tomczewski
Krzysztof Tomczewski
KWKrzysztof Wrobel
Krzysztof Wrobel
This study presents a new configuration of power converter for switched reluctance motor drives. The system allows reduction of the detrimental impact of the commutation processes in motor winding on overall motor performance through enabling reconfiguration of windings connection during operation of motor. Shorter time of commutation, which is the main characteristic of the system, increases the motor average torque particularly in range of operation with high rotational speed. Application of the system in a standard switched reluctance motor-based drive results in extension of range of operation with constant torque and mechanical power as much as two times. The electromechanical characteristics of motor driven from the system are compared with those of the same motor driven from a standard half-bridge converter.

12 March 2021 in Energies
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KWKrzysztof Wrobel
Krzysztof Wrobel
KTKrzysztof Tomczewski
Krzysztof Tomczewski
ASArtur Sliwinski
Artur Sliwinski
ATAndrzej Tomczewski
Andrzej Tomczewski
This article presents a method to adjust the elements of a small wind power plant to the wind speed characterized by the highest annual level of energy. Tests were carried out on the basis of annual wind distributions at three locations. The standard range of wind speeds was reduced to that resulting from the annual wind speed distributions in these locations. The construction of the generators and the method of their excitation were adapted to the characteristics of the turbines. The results obtained for the designed power plants were compared with those obtained for a power plant with a commercial turbine adapted to a wind speed of 10 mps. The generator structure and control method were optimized using a genetic algorithm in the MATLAB program (Mathworks, Natick, MA, USA); magnetostatic calculations were carried out using the FEMM program; the simulations were conducted using a proprietary simulation program. The simulation results were verified by measurement for a switched reluctance machine of the same voltage, power, and design. Finally, the yields of the designed generators in various locations were determined.

5 March 2021 in Energies
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KTKrzysztof Tomczewski
Krzysztof Tomczewski
KWKrzysztof Wrobel
Krzysztof Wrobel
DRDaniel Rataj
Daniel Rataj
GTGrzegorz Trzmiel
Grzegorz Trzmiel
This paper presents a proposal for a new type of regulator for switched reluctance motor (SRM) drives. The proposed regulator enables a significant extension of the rotational speed range and drive output power. This regulator is characterized by a complex structure, including two regulation modules: voltage and phase supply switch-on angle. The voltage module includes a proportional integral derivative (PID) voltage regulator. During its operation, the value of the phase supply switch-on angle and the width of the phase supply range are determined as a result of interpolation of the data previously determined in the simulation program. The other module contains the PID controller of the phase supply switch-on angle. The values of the angles included in the tables have been determined so as to ensure that the drive works with the greatest possible efficiency. The control method is determined based on the current operating parameters of the drive, i.e., torque and speed. The operation of the regulator was simulated in the MATLAB Simulink program. The regulator presented here was implemented in a field programmable gate array (FPGA). Tests of the regulator’s operation in the prototype system were carried out in the field of control of commutation angles.

13 April 2022 in Sensors
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PSPrzemyslaw Strzelczyk
Przemyslaw Strzelczyk
KTKrzysztof Tomczewski
Krzysztof Tomczewski
KWKrzysztof Wrobel
Krzysztof Wrobel
This article presents the possibilities of newly developed middleware dedicated for distributed and modular control systems. The software enables the exchange of information locally, within one control module, and globally, between many modules. The executed information exchange system speed tests confirmed the correct operation of the software. The middleware was used in the control system of the active upper-limb exoskeleton. The upper-limb rehabilitation exoskeleton structure with six degrees of mechanical freedom is presented. The tests were performed using the prototype with three joints. The drives’ models of individual joints were developed and simulated. As a result, the courses of the motion trajectory were shown for different kinds of pressure on the force sensors, and different methods of signal filtering. The tests confirmed a correct operation of middleware and drives control system.

28 October 2024 in Energies
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MŁMarian Łukaniszyn
Marian Łukaniszyn
ŁMŁukasz Majka
Łukasz Majka
BBBernard Baron
Bernard Baron
BKBarbara Kulesz
Barbara Kulesz
KTKrzysztof Tomczewski
Krzysztof Tomczewski
KWKrzysztof Wrobel
Krzysztof Wrobel
This article presents the measurement verification of a novel strategy for inrush current reduction in an unloaded three-phase Dy transformer. The strategy combines appropriate pre-magnetization of transformer cores with an original control switching system using initial phase values of the supply voltage as control variables. Measurements were recorded for primary voltages and currents as well as secondary voltages during transient states at start-up under no-load conditions. Various inrush scenarios were examined across the full angular spectrum of initial phase angles, both polarities, and in regard to different pre-magnetization current values. A detailed analysis of the inrush currents was performed using proprietary automated software based on the recorded data. A comparative study with a nonlinear mathematical model of the transformer was also conducted. Additionally, key technical aspects of the designed system for implementing the proposed pre-magnetization strategy with controlled voltage energization are discussed.