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KEYNOTE SPEAKER Prof. Poki Chen Doctor of Honoris Causa, Czech Technical University in Prague Visiting Professor, Warsaw University of Technology Professor, Dept. of Electronic and Computer Engineering Automatic Analog Circuit Design Optimization Abstract: System/circuit design always takes extensive work hours with manual labor, and state-of-the-art design optimization algorithms are often need to be more practical due to their multidisciplinary expertise requirements. Taking analog IC design for a good example, software automation is one way to reduce IC design workload, particularly during fine-tuning process. One of the benefits of automating parts of the design process is progress with uptime as high as 24 hours a day, which are infeasible for design engineers. While optimization methods using genetic algorithms and machine learning can improve performance of analog ICs significantly, the operation of such complex methods requires circuit design and software development know-how. However, simple optimization methods such as parameter random spread outlined in this talk have shown to reduce the temperature coefficient of a voltage reference circuit by 25% in a typical corner and 82% in the fast-fast corner. Such performance improvement demonstrates that even a basic automated optimization procedure can help optimize circuits without further human interactions. The circuit optimization consists of 7 steps: simulation parameter determination (Step 1), modification of simulation parameters (Step 2), execution of modified simulations (Step 3), simulation output extraction (Step 4), output data structure reorganization (Step 5), simulation output analysis (Step 6) and determination of simulation continuation (Step 7). Parameter determination in initial runs can vary based on the initialization process [2]. However, Step 1 of subsequent runs generally determines parameters based on previous simulations' results. Step 3 executes batches of simulation set up in Step 2 using parameters obtained in Step 1, and Step 6 analyzes the output results found in Step 4 and organized in Step 5. Step 7 determines whether the simulation should continue in response to the results obtained in Step 6. For an example use case of this algorithm, HSPICE simulation is used for its text-based input and output. The implementation details are as follows. Compared to complex Step 1 operations done in the cited papers, parameter set batches are generated from a simple 20% random spread from the initial set of parameter values made by an IC designer, similar to initializations discussed in prior arts [2]. Step 2 is a text replacer that replaces parameters of interest using a base netlist file and the values obtained in Step 1. Steps 3, 4, and 5 are relatively trivial process executors, directory parsers, and text parsers. Step 6 analysis requires to be fine-tuned to the simulation circuit at hand. Step 7 is manually done by user inspection, simplified by strategic analysis output file naming system. All programs executing Step 1 to Step 6 are written in Python 2.6, which is free of charge on all up-to-date Linux distributions.
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dr inż. Michał Harasimczuk, Politechnika Białostocka Fully Soft-Switched Single-Switch High Step-Up DC–DC Converter with Coupled Inductor Abstract: This presentation concerns a high step-up dc–dc converter dedicated to low-voltage energy sources such as photovoltaic systems, fuel cells, and battery energy storage systems. The proposed converter is based on a coupled inductor and employs only a single active switch, enabling reduced circuit complexity while maintaining high voltage gain and high efficiency. The presented topology utilizes a resonant passive clamp circuit and variable-frequency control based on the valley switching technique. Operation in critical and discontinuous conduction modes enables zero-voltage switching (ZVS) of the transistor during turn-on, while the proposed resonant circuit additionally enables zero-voltage turn-off conditions and limits voltage stress across semiconductor devices. As a result, switching losses are significantly reduced, allowing operation at elevated switching frequencies and increased power density. The presentation will discuss the operating principles of the proposed converter, analytical models describing its operation, and design considerations related to soft-switching conditions and converter control. Experimental validation performed on a 300 W laboratory prototype demonstrated switching frequencies up to 266 kHz, voltage conversion from 30–50 V to 380 V, and peak efficiency reaching 96.6%, confirming the feasibility and effectiveness of the proposed approach. |
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dr inż. Krzysztof Kulikowski, Politechnika Białostocka LLC Resonant Converter with Synchronous Rectifier Abstract: This work presents a 5 kW LLC resonant converter designed for a high-side voltage of 480 V and a low-side voltage of 48 V, operating at a switching frequency of 200 kHz. The main focus is placed on the use of a synchronous rectifier on the low-voltage side, which is a key element for increasing converter efficiency, especially under high output-current conditions. The operation of the converter near the resonant point is discussed, together with the influence of synchronous rectifier transistor control on the current and voltage waveforms in the resonant circuit. The work analyzes the conditions for proper turn-on and turn-off of the synchronous rectifier devices, with particular emphasis on minimizing conduction losses and reducing the risk of undesired reverse current flow. The influence of synchronous rectification on converter efficiency is also presented and compared with conventional diode rectification. In addition, possible methods of bidirectional energy transfer in the LLC topology are discussed, as well as the conditions under which such operation can be achieved using synchronous rectification. Experimental results are presented for an LLC converter with synchronous rectification implemented using two transformer variants: a planar transformer and a transformer based on E-type cores wound with litz wire. The measurement results make it possible to compare the efficiency of the converter operating with synchronous and diode rectification and to evaluate the influence of transformer construction on the operating parameters of the converter. |
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mgr inż. Mateusz Wasilewski, prof. dr hab. inż. Andrzej Sikorski, Politechnika Białostocka Reduced-Sensor Control of a Three-Phase Grid-Connected AC-DC Converter with LCL Filter Abstract: The presentation concerns the control system of a three-phase grid-connected AC-DC converter with an LCL filter and a limited number of sensors. An asymptotic Luenberger observer is employed in the system to estimate the currents and voltages of the LCL filter that couples the converter to the power grid. This approach makes it possible to reduce the number of measurement sensors required to implement selected control methods. The mathematical model will be presented, along with the results of laboratory tests of the converter with a reduced number of sensors, for linear control with a PI controller in the rotating dq reference frame, as well as with a multi-resonant controller in the stationary αβ reference frame. |
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mgr inż. Mateusz Daraż, dr hab. inż. Piotr Bogusz, Politechnika Rzeszowska Reduction of supply current ripple in a switched reluctance machine Abstract: The article addresses the problem of high current ripple drawn from the power supply by switched reluctance motors (SRMs), which results from the pulsed excitation of their windings. The authors developed a control algorithm for an active filter placed at the input of the SRM drive controller, which reduces the level of current ripple drawn from the supply source. As part of the research, a shape factor was proposed to evaluate the effectiveness of the power circuit of DC current loads. This factor made it possible to assess the impact of active filtering and changes in the power circuit resistance over the entire investigated operating range of the drive. |
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mgr inż. Piotr Zasowski, dr hab. inż. Piotr Bogusz, Politechnika Rzeszowska On-board charger for an electric vehicle using an SRM drive Abstract: This work presents a solution for an electric drive based on a switched reluctance motor, which facilitates the charging process of a traction battery in an electric vehicle. It employs parts of the motor’s power converter and windings to form part of the charger circuit. In the literature, such solutions are referred to as Integrated On-Board Chargers (IOBCs), and they are applicable to different machine types. Charger integration offers benefits such as simpler drive construction, lower costs, and increased volumetric and gravimetric energy density of the system. In the case of integration using SRM’s windings, one of the key issues is the generation of electromagnetic torque during the charging process. The proposed solution aims to minimize the resultant torque. The main objective is to ensure torque minimization regardless of the current rotor position. This is achieved through appropriate selection of energized winding pairs based on their respective self-inductances at a given rotor angle. The control algorithm selects suitable phases and controls both the charging current and the AC current drawn from the grid, while ensuring power factor correction. |
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mgr inż. Michał Maciesza, Politechnika Warszawska Quad Active Bridge as Partial Power Converter for Bipolar DC Microgrids Abstract: An increasing number of DC-powered devices, higher energy eAiciency due to a reduced number of power conversion stages, the absence of reactive power issues, and the lack of requirement for strict frequency and phase control have led to growing interest in DC microgrids as an alternative to AC systems. Among DC architectures, bipolar DC microgrids deserve particular attention. By providing two voltage levels, they allow for the retention of |
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inż. Piotr Sowiński, Politechnika Warszawska A series-parallel active power filter for improving electric power quality in a low-voltage network Abstract: With the growing demand for electricity and the gradual transition toward renewable energy sources—primarily photovoltaic micro-installations—the load on low-voltage distribution networks is steadily increasing. To ensure the continuous supply of electricity that meets standard quality parameters, modernization of existing lines is necessary in many areas, particularly in rural regions.Traditionally, this would involve costly measures such as replacing conductors with thicker ones or constructing new MV/LV transformers. However, an alternative approach is to improve the quality of transmitted power, thereby enabling the transfer of greater active power through lines with unchanged physical parameters.One such solution is the series-parallel active filter, also known as a Unified Power Quality Conditioner (UPQC). This device is capable of simultaneously controlling both current and voltage in the line where it is installed. By regulating the current, it can compensate for reactive power, suppress higher harmonics, and balance phase currents. Concurrently, by controlling the voltage, the UPQC can compensate voltage drop, ensuring that the voltage at the end of the line remains within required limits.Together, these functionalities allow for better utilization of the existing infrastructure, effectively maximizing the power transfer capability of a given line. As a result, it becomes possible to accommodate increased loads without the immediate need for expensive network upgrades, making this solution both technically and economically attractive.
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mgr inż. Mikołaj Kądzielawski, Politechnika Warszawska Robust Control of Grid-Forming Converter Under Varying Load Conditions Abstract: The ongoing transition toward decentralized, inverter-based power systems highlights the critical role of grid-forming (GFM) power converters. This poses new challenges due to the fact that the converter needs to create the grid itself, providing a stable sinusoidal voltage to the mains across a wide range of possible load conditions. To achieve the goal of stable and safe operation, a control algorithm based on a robust control paradigm for an LCL-filtered, 4-leg, three-phase converter is presented. The issue of weight selection for control synthesis is addressed. Synthesis weight selection using Particle Swarm Optimization (PSO) is proposed and evaluated in the presence of linear and non-linear loads. The case of a leading power factor, which is often omitted in the literature, and its influence on control stability are analyzed. The presented work also covers fault conditions during the operation of the converter, such as overloads and short circuits. Different approaches to peak limiting are presented, and further issues regarding converter current limitation are discussed.
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mgr inż. Krzysztof Kalinowski, Politechnika Warszawska Energy Storage Systems and Bidirectional Electric Vehicle Charging Stations as Key Components for Enhancing Power System Resilience and Flexibility Abstract: The increasing penetration of renewable energy sources, particularly photovoltaic (PV) systems, and the rapid development of electromobility introduce significant challenges for modern power systems. Enhancing system flexibility and resilience has therefore become essential. This presentation discusses the role of energy storage systems and bidirectional electric vehicle charging technologies (Vehicle-to-Grid, V2G) as key enablers of these capabilities. Their coordinated orchestration enables more efficient balancing of supply and demand, supports renewable energy integration, and improves system response to disturbances. The presentation also outlines selected technical, economic, and regulatory challenges related to large-scale deployment. Additionally, demonstrators of energy storage technologies at Warsaw University of Technology will be presented as practical responses to the identified challenges. |
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mgr inż. Jakub Duk, Politechnika Lubelska Analysis of DC bus current pulsations influence on electrochemical power cells aging and state of charge estimator Abstract: The article presents the results of work related to the modeling of electrochemical cells and charging/discharging processes, as well as the development of a laboratory test station. The first part discusses issues related to the estimation of the State of Charge (SoC) in systems using asymmetrically operating AC/DC power converters. The problem of phase current asymmetry and the reasons for applying such solutions are presented. It is indicated that the use of converters enabling energy transfer between phases allows the asymmetry problem to be reduced; however, this comes at the cost of power pulsations occurring on the DC bus, to which the energy storage system is most commonly connected. The influence of current oscillations on lithium-ion electrochemical batteries has not yet been clearly determined, which motivates aging studies of cells subjected to such operating conditions. The main objective of the article is to develop a Kalman filter that takes into account the influence of 100 Hz oscillations on the battery State of Charge (SoC) and State of Health (SoH). The following section presents battery modeling using an Equivalent Circuit Model (ECM), together with a description of its parameters. Based on this model, state-space equations used in the Extended Kalman Filter (EKF) were developed. The current status of the measurement test bench development is also presented. The concept of the research setup is described, followed by the implementation status of the individual system components. The current converter installed in the control cabinet together with the measurement equipment, the test setup during operation, and the thermal chamber are presented.
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mgr inż. Ernest Przychodzki, Politechnika Lubelska Analysis of the Impact of Electric Vehicle Charging Infrastructure with V2G Functionality on Power System Operation, selection of power electronics topology Abstract: This presentation addresses the development of future motorway service stations for electric vehicles with Vehicle-to-Grid functionality. The work begins with an estimation of the current and future power demand of charging infrastructure, based on motorway service station data and the expected growth trend of electromobility. On this basis, the required power level for future charging and refuelling stations is assessed. Particular attention is paid to the impact of V2G operation, which enables bidirectional energy flow between vehicles and the power system. This functionality allows the charging infrastructure to operate not only as a high-power load, but also as an active element supporting power balancing, grid stability, and more effective use of available energy resources. The presentation also discusses requirements for future self-sufficient charging and refuelling stations, including the necessary installed power, scalability, flexibility, and readiness for integration with additional energy infrastructure. The considered approach provides a basis for selecting a scalable power electronics architecture suitable for future high-power transport infrastructure. |
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mgr inż. Maciej Rudawski, Politechnika Lubelska Medium-Frequency Multiport DC/DC Converter for Modular Energy Storage Systems: High-Turns-Ratio Transformer Design Abstract: The presentation focuses on the analysis of a multi-port medium-frequency DC/DC converter designed for modular energy storage systems. The topology, which allows for the individual connection of cells via H-bridges and galvanic isolation using a multi-winding transformer, is discussed. The main focus is on the problem of designing a transformer with a very high turns ratio, whose operation is severely limited by parasitic capacitance, leakage inductance, and resonance phenomena. The results of analyses and measurements for several structural variants are presented: a single high-turns-ratio transformer, a cascade configuration, a structure with summing of secondary winding voltages, and a hybrid system with an intermediate voltage level of 48 V.
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