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A technique for stabilization of resonant frequency is proposed in this paper. An additional power circuit, a compensator that allows keeping constant resonance frequency was introduced by the authors. In the presented solution the resonant circuit frequency stabilization is achieved by forcing a zero phase shift between the current and the voltage of the main switching module.

Non-thermal plasma reactors offer numerous advantages and are used in a wide variety of applications. Exemplary fields of use include exhaust gas or water quality improvement, surface processing, agriculture, or medical processes. Two of the most popular discharge chamber constructions are dielectric barrier discharge (DBD) and pulsed corona discharge (PCD, barrierless) plasma reactors. Various power supply constructions are presented in the literature with varying complexity and operating principles. A simple, power electronic, pulsed power supply construction is presented in this work, implementing resonant power switch operation, modern silicon carbide (SiC) power semiconductors and a Tesla coil-like transformer design. The power supply construction is immune to short circuits in the reactor and can be used for both types of reactor constructions. The principles of operation, simulation results, and prototype test verifications are presented with main power supply characteristics.

This paper describes the effect of nanosecond pulsed electrical discharges generated in distilled water on cobalt-modified fluorinated polyimide (PI) films derived from hexafluoroisopropylidendiphthalic dianhydride and 4,4’-diamino-3,3’-dimethyl diphenylmethane. The PI films have been characterized by dielectric spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction (XRD) measurements. The relative permittivity of the PI films increased after treatment by water plasma. The XRD analysis has shown a slight increase of the degree of intermolecular ordering and stronger $\pi $ – $\pi $ interactions with the increase of the plasma treatment time. Application of nanosecond high-voltage pulses has induced an increase in concentration of CF3 groups at the polymer surface. A decrease of the cobalt and chlorine fractions, due to their migration into water, and an increase of aliphatic C–C bonds at the film surface may be responsible for the relative permittivity modification after exposure to water plasma.

Propulsion shaft torque measurement is essential in ship energy efficiency evaluation and emission control. Its accuracy and uncertainty influence decision making in terms of voyage optimisation and fuel consumption. For best results, the measuring device should be adjusted and calibrated adequately. This paper analyses the problem of ship propulsion shaft torque meter zero adjustment. Presented results of initial investigation suggest significant unrepeatability of the torque observed when the propulsion unit is at a standstill. Using a recently designed telemetry torque meter and an older analogue device a series of experimental research was conducted on board of a ship and on marine propulsion units installed in a laboratory. A new statistical method for zero adjustment is proposed and evaluated against methods commonly used on ships. The survey results suggest that the new method is burdened with a lower random error compared to presently used methods and uniquely allows for uncertainty evaluation.

The paper describes a novel topology of a highvoltage pulse generator for non-thermal plasma supply. Proposed converter prototype generates high voltage pulses up to 35 kV. Presented article includes the presentation of a new, resonant converter topology with analytical and simulation based description of operation principles and a discussion of most important generator features. Presented topology is well suited for supplying both the Dielectric Barrier Discharge (DBD) and the pulsed corona discharge (PCD) plasma reactors. Its construction is insensitive to short-circuits in the load.

Paper discusses the design idea, construction of the prototype measurement unit and experimental verification of an automated test stand for transformer inrush current identification. Transformers of different size and construction are key components in power systems and power supply units. Proposed test stand construction allows automated inrush current measurement and maximum inrush current identification for tested transformers. Presented experimental results are provided for toroidal core transformers.

Proposed paper gives an overview of the design and performance of a power electronic converter designed to efficiently rectify the alternating voltage of the permanent magnet AC generator to direct current, that may be used to charge batteries and/or power devices from a small hydrogenerator. The generator design is also briefly discussed aimed for electricity generation by the motion of an undersail boat. Simulation results and test — stand results are presented.

Proposed paper discusses a construction and characteristics of a switched mode power controller operating as adjustable load controller. Unique converter topology allows high efficiency operation for a wide range of input voltage change. This feature together with a simple construction make it an interesting choice for applications starting with renewable energy sources up to controllable loads for the testing of performance of electric machines. Natural oscillating character of the input is damped using the averaged current measurement concept. Simulation and experimental results are shown and discussed.

The majority of MR (multirotor) UAV (unmanned aerial vehicles) platforms consist of a BLDC (brushless direct current) motors, because of their robustness and high rotation speed capabilities. The ESC's (electronic speed controllers) driving the motors are produced as cost/component efficient inverters. They are motor ambiguous, meaning they should work correctly with any BLDC machine connected to the ESC without any complex tuning procedures. In the paper, a sensorless BLDC driving algorithm is presented, utilizing low cost hardware used in mainstream ESC controllers, thus improving the performance over the typical open-loop control scheme.

The decomposition of various volatile organic compounds (VOCs), namely butyl acetate, styrene, and methanol, by means of non-thermal plasma technology was investigated in different industrial exhaust gases. Although a great deal of effort on the investigation of these VOCs can be found in literature, data regarding the application in real exhaust gases are missing and provided in this contribution. Measurements were performed in an oil shale processing plant in Estonia and in a yacht hall production site in Poland. Up to 71 % of butyl acetate at a specific input energy (SIE) of about 220 J/L and more than 74 % of styrene and methanol at SIE > 300 J/L were decomposed. The energy efficiency of the decomposition processes was analyzed as well as the products formed by the plasma process. Energy constants of k E

Direct and indirect plasma oxidation of NO x was tested in a medium-scale test-bench at gas flows of 50 slm (3 m 3 /h). For direct plasma oxidation the synthetic flue gas was directed through a stacked DBD reactor. For indirect plasma oxidation, a DBD reactor was used to generate ozone from pure O 2 and the plasma treated gas including ozone was mixed with flue gas at the entrance of a 6 m long serpentine-like reaction chamber which allowed reaction times longer than 10 s. At relatively low NO x concentrations of 200 ppm, both oxidation methods gave similar results. However, the temperature increase of the DBD reactor decreased the long-term efficiency of direct plasma oxidation. At the same time, the efficiency of indirect oxidation increased at elevated reactor temperatures. Additional experiments were carried out to investigate the improvement of indirect oxidation by the introduction of catalyst to the reaction zone. Small-scale experiments with TiO 2 powder demonstrated considerable efficiency gain for NO x oxidation while in medium-scale experiments, the efficiency improvement remained negligible.

In presented paper a technique for the secondary side power stabilisation for contactless energy transfer systems is presented. The original part of this approach is the position where stabilisation is performed. Instead of complicated pickup side modifications all additional circuits are located on the systems transmitting side.

Paper describes the system design of modern power electronics laboratory test stands intended for electrical engineering schools and universities. Proposed system design simplifies the configuration of the lab and maximizes the time that the students can use for experimental measurements and converter characterization. System pre-configuration is constant for all exercises so the students do not need to learn the system design of every particular test stand. It also provides clear measurement readings and protection loops so number of errors or damages of the hardware during testing is minimized.

In the paper a stepper motor closed loop driver algorithm is presented which emphasizes the processor overhead minimization in which it is implemented, as well as rotor average torque and set position acquisition. The program was tested as a simulation in MATLAB environment and on a physical driver based on 32 bit microcontroller connected with a motor and an encoder. Exemplary results are introduced in the work.

The presented work gives an overview on simulation and experimental results of the power supply parameters’ influence on DBD discharge uniformity. The proposed study is about the use of quasi-pulsed, power electronic power supply and a saturable inductor in series with the discharge cell [1]. The simulation results are presented with a parallel DBD reactor model with linear critical voltage distribution. A more uniform current waveform is observed, however, due to small reactor capacitances no streamer formation could be verified in calculations. An experimental test stand was prepared with a double dielectric barrier discharge arrangement. The experimental results are presented with regard to the electrical oscilloscope waveforms and ICCD camera imaging. A more homogenous plasma was observed in the case of saturable inductor with saturation current set at the point of discharge formation. Two possible mechanisms are connected with this phenomenon - inductive element current support during discharge and/or current rise-time limitation [1].

Effects of plasma assisted waste air treatment from a water treatment plant have been investigated in several field tests. In particular the off-air for a thermal sludge dryer was investigated and treated. The intention of this study was to proof whether plasma assisted technologies are a possible solution for the removal of odour from waster air emitted by wastewater treatment facilities. The plasma treatment was combined with a catalytic (cupper-manganese) unit, a scrubbing unit, or a bio filter in order to demonstrate the abilities for waste air deodorization. The inlet and outlet gas was analysed by means of FTIR, FID, and chemical sensors and the odour removal was investigated by standardized olfactometry. A significant reduction of hydrogen sulphide and methane by means of combined plasma-catalyst-treatment has been measured, but the removal of hydrogen sulphide leads to the formation of unwanted by-products. Main effects of plasma treatment in the field tests can be compared to the results of laboratory studies published in the literature. A significant odour reduction up to about 90% was measured. Aldehydes and other hydrocarbons are marginally removed by plasma treatment as well as by the bio filter. The bio filter released sulphur containing substances (DMS, CS2, DMDS) which can be destroyed by plasma-catalytic treatment. Based on the results of the field tests a reliable concept for an industrial after treatment installation has been designed as described. Due to the high content of H2S a scrubber as the first treatment unit is desired. Downstream the scrubber the plasma/catalytic unit combined with the existing bio filter is proposed for the removal of the hydrocarbons and other odorous constituents.

The application of gas discharge plasmas has assumed an important place in many manufacturing processes. Plasma methods contribute significantly to the economic prosperity of industrialized societies. However, plasma is mainly an enabling method and therefore its role remains often hidden. Hence the success of plasma technologies is described for different examples and commercial areas. From these examples and emerging applications, the potential of plasma technologies is discussed. Economic trends are anticipated together with research needs. The community of plasma scientists strongly believes that more exciting advances will continue to foster innovations and discoveries in the first decades of the 21st century, if research and education will be properly funded and sustained by public bodies and industrial investors.

The paper presents an overview of a method of nanosecond-scale high voltage pulse generation using magnetic compression circuits. High voltage (up to 18 kV) short pulses (up to 1.4 μs) were used for Pulsed Corona Discharge generation. In addition, the control signal of parallel connection of IGBT and MOSFET power transistor influence on system losses is discussed. For a given system topology, an influence of core losses on overall pulse generator efficiency is analysed.

This paper proposes a new topology of a nanosecond, high voltage pulse generator devoted to pulsed corona discharge (PCD) reactor supply. The proposed topology is based on solid state, semiconductor switches and uses parasitic components of transformers. A prototype construction of the proposed generator loaded with a PCD reactor with 6.4-pF capacitance is able to generate high voltage pulses with maximum amplitude of 14 kV (using 5.4-kV supply and up to six modules of proposed topology, each equipped with a MOSFET transistor with 1-kV blocking capability) with voltage steepness of 730 V/ns. Obtained pulses are 65-ns long. The peak power delivered to the PCD reactor is ${>}{\rm 0.3}~{\rm MW}$ while the energy consumed reaches 7 mJ/pulse. This paper also compares two different mechanical constructions of such generators and gives an overview of analytical and numerical voltage waveform analyzes.

Proposed paper presents a fast algorithm for determining static and switching losses of power electronic devices in three-phase DC/AC inverters for different semiconductor materials. This method uses table — form, stored characteristics of individual semiconductor devices, without a necessity of detailed, time resolved analysis of the commutation process. Using such algorithm accelerates total loss calculation, as a result electric machine control strategy can be developed allowing the improvement of the efficiency of the entire propulsion system.

This paper discussed a control system for an HPMSM machine with a stator based field coil aiming at maximum efficiency of the inverter-machine system. A new procedure for efficiency-optimal inverter-machine propulsion system has been introduced. An iterative process for optimal current distribution is described with multidimensional tables of overall losses and efficiencies. Due to high-speed calculations, optimization algorithm can be implemented for various goal functions including classic PMSM drivetrains.

Proposed paper deals with the subject of plasma power measurement in dielectric barrier discharge (DBD) reactors. Four approaches are compared including analytical, electrical, Lissajous figure and comparative methods. Discussion is led regarding measurement sensors, digital oscilloscope time base resolution and measurement capacitor technology. Lissajous curve approach gives results that are very comparable to definition based power calculation. Analytical approach, due to technical reasons, is inadequate, comparative approach gives slightly elevated values with respect to other methods. Measurement capacitor value should be of comparable capacitance to reactors overall capacitance, a pulsed technology capacitor should be used for measurements.

Effects of space vector modulation strategy on hybrid (Si-SiC) inverter lossesThis work summarizes efficiency measurement results of a full bridge, 3 phase inverter composed of state-of-the-art Si IGBT transistors and Si or SiC diodes. Different (symmetrical and discontinuous) space vector modulation strategies were chosen in order to examine their influence (together with modulation frequency) on inverter losses. Induction machine was used as load, different load points were examined. Results clearly show, that proper modulation strategy, minimizing the switching losses of semiconductor switches, can increase the overall output efficiency at about 1% in case of both silicon and hybrid constructions. The drawback of DPWM approach is connected with the decreased quality of inverter output current. Hybrid technology can also improve the output efficiency at about 1% when compared to traditional constructions, but only in case of elevated switching frequencies. At low frequencies (below 10 kHz) modern semi-conductors offer comparable results at much lower device costs.

PurposeThe purpose of this paper is to introduce a unique multilevel, one‐phase inverter (in the multiplied full‐bridge configuration, cascaded‐type) with unequal voltage distribution among the voltage levels.Design/methodology/approachNumerical and experimental results are discussed and the topology thereafter evaluated.FindingsUnequal voltage distribution among voltage stages of the converter leads to increase of the output voltage resolution while simplifying the converter construction and minimizing the power switch losses. Simplorer numerical analyses as well as test stand measurements were led in order to verify properties of the system. Using the voltage distribution in the proportion of 6/2/1 leads to improved utilisation of power switches used in the means of voltage, current and switching frequency. FFT analysis was implemented in order to explore the frequency domain properties of the control apparatus.Practical implicationsThe results allow improvement of power switch utilisation and output voltage resolution of cascaded, three‐stage multilevel converter topologies and voltage output filter optimisation for multilevel power electronic converters.Originality/valueA new concept of voltage distribution is provided and described, a dedicated DSP‐based control system was developed as well as a small‐scale converter prototype, test stand measurement results are provided.

Voltage – current characteristics of photovoltaic (PV) generators rely on many auxiliary conditions as irradiance, temperature or load profile. Independently on the type of installation (stand-alone, grid connected, hybrid) a solar panel generation system should always be operated at it's maximum electrical power point under defined conditions. Many algorithms have been proposed as maximum power point seeking techniques. A comparison of two methods is described considering an iterative approach and a fuzzy logic controller. Both dynamical properties and tracking accuracy are analyzed based on laboratory experiments and measurements led on an exemplary installation. In addition a misinterpretation avoidance apparatus is proposed for flat-topped power characteristics under partial shading or low irradiance. Power electronic system is described as well as the control system prototype based on a fixed-point microcontroller. Measurement results are presented and conclusions are given.

Contactless power supply systems are of high interest in small power and large power applications. Many high efficiency contactless systems use the resonant operation mode. A parallel compensation system is presented enlarging overall system safety and allowing for resonant system parameter change while maintaining zero current switching (ZCS) operation. Basics of digital control unit construction and operation are presented. Simulation and experimental results are given for control system operation. Systems performance allows for large resonant circuit parameter drift. Modern DSP control unit minimizes the necessary external circuitry and time delays in case of most important operations. DOI: http://dx.doi.org/10.5755/j01.eee.20.10.4989

This paper presents the topology of the high voltage, pulsed converter using transformer parasitic parameters. The converter uses solid-state switches and generates (in no load conditions) a voltage pulse with an amplitude of 20 kV with 5kV supply. The steepness of the voltage rise without load is 1.36 kV/ns and the pulse duration is less than 100ns.

Volatile organic compounds (VOCs) in industrial exhaust gases were treated by a dielectric barrier discharge (DBD) operated with two different mobile power supplies. Together with the plasma source various gas diagnostics were used, namely fourier transform infrared (FTIR) spectroscopy, flame ionization detector (FID) and GC-MS. The analysis revealed that some exhaust gases consist of a rather complex mixture of hydrocarbons and inorganic compounds and also vary in pollutants concentration and flow rate. Thus, analysis of removal efficiencies and byproduct concentrations is more demanding than under laboratory conditions. This contribution presents the experimental apparatus used under the harsh conditions of industrial exhaust systems as well as the mobile power source used. Selected results obtained in a shale oil processing plant, a polymer concrete production facility and a yacht hull factory are discussed. In the case of total volatile organic compounds in oil processing units, up to 60% were removed at input energy of 21–37 J/L when the concentrations were below 500 mg/m 3 . In the yacht hull factory up to 74% of styrene and methanol were removed at specific input energies around 300 J/L. In the polymer concrete production site 195 ppm of styrene were decomposed with the consumption of 1.8 kJ/L. These results demonstrate the feasibility of plasma assisted methods for treatment of VOCs in the investigated production processes but additional analysis is needed to improve the energy efficiency.

In the article a converter topology for high voltage, nanosecond pulse generation is introduced. Proposed topology uses parasitic parameters of autotransformers as circuit components. Introduced converter was used to generate Pulsed Corona Discharge (PCD). Numerical analysis and results of laboratory measurements of the properties of proposed topology are presented. The voltage pulse was obtained with a duration less than 100ns, voltage amplitude of 15.3kV, with the power of 4kV. The peak power delivered to the reactor amounted to 260kW.

Nowadays non-thermal plasma technologies are state of the art for the generation of ozone as an important oxidant for water cleaning or bleaching, the incineration of waste gases or for the removal of dust from flue gases in electrostatic precipitators. Furthermore their possibilities of gas depollution are well known. Plasmas contain reactive species, in particular ions, radicals or other oxidizing compounds, which can decompose pollutant molecules, organic particulate matter or soot. Electron beam flue gas treatment is another plasma-based technology which has been successfully demonstrated on industrial scale coal fired power plants. This chapter aims a comprehensive description of plasma-based air remediation technologies. The possibilities of exhaust air pollution control by means of non-thermal plasmas generated by gas discharges and electron beams will be summarized. Therefore plasma as the 4th state of matter, its role in technology and the principle of plasma-based depollution of gases the will be described. After an overview on plasma-based depollution technologies the main important techniques, namely electron beam flue gas treatment, gas discharge generated plasmas including plasma-enhanced catalysis and injection methods will be described in separate sections. In these sections selected examples of commercially available or nearly commercialised processes for flue gas treatment or the removal of volatile organic compounds and deodorization will be described, too. Current trends and concepts will be discussed.

For non-thermal plasma technology corona discharge devices high-voltage, high-current pulses are used with very high demands considering rising voltage slopes. Many solid state pulse power modulator (SSPPM) system topologies are known however most include a high power transformer compromising the overall system efficiency. A modified Fitch generator topology is introduced enlarging the output voltage to supply voltage ratio to theoretically the factor of three. Moreover the output voltage waveform enables the magnetic pulse compressor cross-section minimization with the factor of 0,67 due to a unique output voltage waveform. Test stand results are given for a 10-stage construction and a single stage magnetic compressor, power switch dynamic parameters influence on systems efficiency is discussed.

Preliminary results are given regarding black pepper powder decontamination using dielectric barrier discharge (DBD) plasma in atmospheric pressure. Three different DBD reactor constructions were investigated, both packaged and unpackaged material was treated. Due to potential, industrial applications, in addition to microbiological results, water activity, loss of mass and the properties of packaging material, regarding barrier properties were investigated. Argon based treatment of packed pepper with DBD reactor configuration is proposed and satisfactory results are presented for treatment time of 5 min or less.

This document gives an overview of a power supply construction suitable for dielectric barrier discharge (DBD) reactor excitation. The influence of temperature and voltage change on DBD reactor parameters is discussed. A power electronic supply system topology allowing for continuous resonant frequency tracking is proposed together with simulation and test stand results of operation. An additional feature of proposed topology is the output peak to peak voltage control.