This paper presents development of a circuit solution design for a bidirectional wireless energy transfer system, based on a resonant self-oscillator. The operation principle of the developed circuit solution in receiving and transmitting mode is described and the elementary circuit diagram is presented together with design ratios. Coil parameters for the resonant circuit are calculated, optimal number of turns in coils is presented, based upon the specified limit value of permissible current. The dependencies of system efficiency from transmitted power, maximum transmitted power, and energy transmission distance are obtained. The developed design, which includes the step-up DC-DC converter, allows to obtain the voltage on the output of the receiving system, equal to or higher than the voltage of the power source of the transmitting system. The specific feature of the proposed system is that it does not require a dedicated control system for operation in resonant mode and changing direction of power transfer. Resonance in transmitting and receiving coils can be maintained, even when their mutual layout is changed, due to utilization of identical resonant circuits and a self-oscillator. Application of the proposed solution is relevant for energy transfer among autonomous robots with limited positioning accuracy, as well as for energy transfer from power supply to robot or in reverse direction.
{"title":"Development of the structure and circuit solution of a bidirectional wireless energy transmission system for swarm robots","authors":"D. K. Krestovnikov, O. E. Cherskikh","doi":"10.2298/sjee2102171k","DOIUrl":"https://doi.org/10.2298/sjee2102171k","url":null,"abstract":"This paper presents development of a circuit solution design for a bidirectional wireless energy transfer system, based on a resonant self-oscillator. The operation principle of the developed circuit solution in receiving and transmitting mode is described and the elementary circuit diagram is presented together with design ratios. Coil parameters for the resonant circuit are calculated, optimal number of turns in coils is presented, based upon the specified limit value of permissible current. The dependencies of system efficiency from transmitted power, maximum transmitted power, and energy transmission distance are obtained. The developed design, which includes the step-up DC-DC converter, allows to obtain the voltage on the output of the receiving system, equal to or higher than the voltage of the power source of the transmitting system. The specific feature of the proposed system is that it does not require a dedicated control system for operation in resonant mode and changing direction of power transfer. Resonance in transmitting and receiving coils can be maintained, even when their mutual layout is changed, due to utilization of identical resonant circuits and a self-oscillator. Application of the proposed solution is relevant for energy transfer among autonomous robots with limited positioning accuracy, as well as for energy transfer from power supply to robot or in reverse direction.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transformer design procedure may vary essentially in respect of the transformer type and its operating frequency (ranging between 50/60 Hz and a few megahertz). This paper presents a simple and straightforward method based on the optimal choice of core geometry of a high frequency transformer (HFT) used in Solid State Transformer (SST) applications. The core of SST is the HFT which largely influences its size and overall performance. The proposed design procedure for HFT focuses on optimizing the core geometry coefficient (in cm5) with a constraint inflicted on loss density. The core geometry coefficient has direct impact on the regulation and copper loss and the procedure results in a robust overall design with minimal footprint. Also, the procedure intends to bring all the operating parameters like regulation, losses and temperature rise within permissible limits while retaining desired efficiency. Thus an energy-efficient design is achieved with minimal footprint. The optimization procedure is implemented using recently developed Moth-flame Optimization (MFO) algorithm. The results of the MFO algorithm are compared with the wellestablished PSO technique. An experimental prototype is built to validate the findings.
{"title":"Optimal design of minimal footprint high frequency transformer","authors":"Jeyapradha Ravichandran Banumathy, Rajini Veeraraghavalu","doi":"10.2298/sjee2103303b","DOIUrl":"https://doi.org/10.2298/sjee2103303b","url":null,"abstract":"Transformer design procedure may vary essentially in respect of the transformer type and its operating frequency (ranging between 50/60 Hz and a few megahertz). This paper presents a simple and straightforward method based on the optimal choice of core geometry of a high frequency transformer (HFT) used in Solid State Transformer (SST) applications. The core of SST is the HFT which largely influences its size and overall performance. The proposed design procedure for HFT focuses on optimizing the core geometry coefficient (in cm5) with a constraint inflicted on loss density. The core geometry coefficient has direct impact on the regulation and copper loss and the procedure results in a robust overall design with minimal footprint. Also, the procedure intends to bring all the operating parameters like regulation, losses and temperature rise within permissible limits while retaining desired efficiency. Thus an energy-efficient design is achieved with minimal footprint. The optimization procedure is implemented using recently developed Moth-flame Optimization (MFO) algorithm. The results of the MFO algorithm are compared with the wellestablished PSO technique. An experimental prototype is built to validate the findings.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dejan Dašić, Miljan Vucetic, Nemanja Ilić, M. Stanković, M. Beko
Operators of modern mobile networks are faced with significant challenges in providing the requested level of service to an ever increasing number of user entities. Advanced machine learning techniques based on deep architectures and appropriate learning methods are recognized as promising ways of tackling the said challenges in many aspects of mobile networks, such as mobile data and mobility analysis, network control, network security and signal processing. Having firstly presented the background of deep learning and related technologies, the paper goes on to present the architectures used for deployment of deep learning in mobile networks. The paper continues with an overview of applications and services related to the new generation of mobile networks that employ deep learning methods. Finally, the paper presents practical use case of modulation classification as implementation of deep learning in an application essential for modern spectrum management. We complete this work by pinpointing future directions for research.
{"title":"Application of deep learning algorithms and architectures in the new generation of mobile networks","authors":"Dejan Dašić, Miljan Vucetic, Nemanja Ilić, M. Stanković, M. Beko","doi":"10.2298/sjee2103397d","DOIUrl":"https://doi.org/10.2298/sjee2103397d","url":null,"abstract":"Operators of modern mobile networks are faced with significant challenges in providing the requested level of service to an ever increasing number of user entities. Advanced machine learning techniques based on deep architectures and appropriate learning methods are recognized as promising ways of tackling the said challenges in many aspects of mobile networks, such as mobile data and mobility analysis, network control, network security and signal processing. Having firstly presented the background of deep learning and related technologies, the paper goes on to present the architectures used for deployment of deep learning in mobile networks. The paper continues with an overview of applications and services related to the new generation of mobile networks that employ deep learning methods. Finally, the paper presents practical use case of modulation classification as implementation of deep learning in an application essential for modern spectrum management. We complete this work by pinpointing future directions for research.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deep Packet Inspection (DPI) of the network traffic is used on a regular basis within the traditional and virtualized environments. But changes in the network architecture with the introduction of containers, microservices, application functions, network functions, and the penetration of 5G access technology are adding more traffic complexity, especially in the so-called east-west flow direction. Network Functions Virtualization (NFV) has become an unavoidable step for further IP network development. In this context, DPI is becoming a challenge. Furthermore, the penetration of 5G allows access of various kinds of devices to the network with cloudification logic which drives them. This paper provides a performance analysis of a selected set of supervised machine learning (ML) algorithms for classification of network traffic within an NFV environment. The goal is to find a suitable algorithm that will classify the traffic from a point of both precision and speed, especially because in the 5G networks any packet delay may compromise the quality of service requirements. The research shows that out of the 6 algorithms tested, Decision Tree algorithm has the best overall performance, from both classification precision and time consumption point of view. It has proved as a reliable classifier that is performing evenly across different classes. Due to the specifics of the virtualized environments and encryption methods, payload data, source, destination, and port information of the network traffic packets are excluded from any statistical operation used for classification by the ML algorithms.
{"title":"Classification of network traffic using supervised machine learning algorithms within NFV environment","authors":"G. Ilievski, P. Latkoski","doi":"10.2298/sjee2102237i","DOIUrl":"https://doi.org/10.2298/sjee2102237i","url":null,"abstract":"Deep Packet Inspection (DPI) of the network traffic is used on a regular basis within the traditional and virtualized environments. But changes in the network architecture with the introduction of containers, microservices, application functions, network functions, and the penetration of 5G access technology are adding more traffic complexity, especially in the so-called east-west flow direction. Network Functions Virtualization (NFV) has become an unavoidable step for further IP network development. In this context, DPI is becoming a challenge. Furthermore, the penetration of 5G allows access of various kinds of devices to the network with cloudification logic which drives them. This paper provides a performance analysis of a selected set of supervised machine learning (ML) algorithms for classification of network traffic within an NFV environment. The goal is to find a suitable algorithm that will classify the traffic from a point of both precision and speed, especially because in the 5G networks any packet delay may compromise the quality of service requirements. The research shows that out of the 6 algorithms tested, Decision Tree algorithm has the best overall performance, from both classification precision and time consumption point of view. It has proved as a reliable classifier that is performing evenly across different classes. Due to the specifics of the virtualized environments and encryption methods, payload data, source, destination, and port information of the network traffic packets are excluded from any statistical operation used for classification by the ML algorithms.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miloš Milovanović, Jordan Radosavljević, Bojan Perović
In this paper, a novel hybrid phasor particle swarm optimization and gravitational search algorithm, namely the hybrid PPSOGSA algorithm, is proposed to find the optimal size and location of shunt capacitors in distribution systems with non-linear loads. The performance of PPSOGSA are studied and evaluated using the IEEE 9- and 85-bus test systems with the objective of minimizing the total annual cost of the system. The procedure is conducted taking into account effects of harmonic distortion and discrete size of capacitors available in the market. Simulation results are compared with those obtained by other optimization techniques, and verified using the Electrical Transient Analysis Program (ETAP). It was established that that the hybrid PPSOGSA algorithm provides better solutions in terms of convergence and accuracy.
{"title":"Optimal placement and sizing of shunt capacitors in distorted distribution systems using a hybrid algorithm","authors":"Miloš Milovanović, Jordan Radosavljević, Bojan Perović","doi":"10.2298/SJEE2101115M","DOIUrl":"https://doi.org/10.2298/SJEE2101115M","url":null,"abstract":"In this paper, a novel hybrid phasor particle swarm optimization and gravitational search algorithm, namely the hybrid PPSOGSA algorithm, is proposed to find the optimal size and location of shunt capacitors in distribution systems with non-linear loads. The performance of PPSOGSA are studied and evaluated using the IEEE 9- and 85-bus test systems with the objective of minimizing the total annual cost of the system. The procedure is conducted taking into account effects of harmonic distortion and discrete size of capacitors available in the market. Simulation results are compared with those obtained by other optimization techniques, and verified using the Electrical Transient Analysis Program (ETAP). It was established that that the hybrid PPSOGSA algorithm provides better solutions in terms of convergence and accuracy.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Mekaladevi, Devi Nirmala Manickam, M. Jayakumar
The design and realization of a wideband substrate-integrated waveguide (SIW) cavity-backed slot antenna operating at 2.45 GHz for WLAN applications are presented. Dual dumbbell-shaped slots with rectangular slots are used to achieve increased bandwidth. The bandwidth observed is 160 MHz with the dumbbell-shaped slots. Further, it has been improved up to 9.2% by adding a rectangular slot. The wideband antenna is analyzed using ANSYS HFSS and fabricated on FR-4 substrate. The measured results of the proposed design are in good agreement with the simulation results and comparable with the reported results.
{"title":"Design and analysis of dual dumbbell and rectangular slots SIW cavity-backed antenna at 2.45 GHz","authors":"V. Mekaladevi, Devi Nirmala Manickam, M. Jayakumar","doi":"10.2298/sjee2102211v","DOIUrl":"https://doi.org/10.2298/sjee2102211v","url":null,"abstract":"The design and realization of a wideband substrate-integrated waveguide (SIW) cavity-backed slot antenna operating at 2.45 GHz for WLAN applications are presented. Dual dumbbell-shaped slots with rectangular slots are used to achieve increased bandwidth. The bandwidth observed is 160 MHz with the dumbbell-shaped slots. Further, it has been improved up to 9.2% by adding a rectangular slot. The wideband antenna is analyzed using ANSYS HFSS and fabricated on FR-4 substrate. The measured results of the proposed design are in good agreement with the simulation results and comparable with the reported results.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Bouarroudj, T. Abdelkrim, Maissa Farhat, V. Feliu-Batlle, B. Benlahbib, D. Boukhetala, F. Boudjema
Conventionally, the parameters of a fuzzy logic controller (FLC) are obtained by a trial and error method or by human experience. In this paper, the problem of designing a FLC for maximum power point tracking (MPPT) of a photovoltaic system (PV) that consists of a PV generator, a DC-DC boost converter and a lead-acid battery is studied. The normalization gains, the membership functions and the fuzzy rules are automatically adjusted using a particles swarm optimization algorithm (PSO) in order to maximize the criterion based on the integration of the PV module power under standard temperature condition (STC) (T=25?C and S=1000 W/m2). The robustness test of the optimized fuzzy logic MPPT controller (FLC-MPPT) is carried out under different scenarios. Simulation results of the system clearly show that the proposed optimized FLCMPPT controller outperforms in terms of maximum efficiency the FLC-MPPT controller not optimized, the FLC-MPPT controller with optimized normalization gains and the FLC-MPPT controller with optimized normalization gains and membership functions.
{"title":"Fuzzy logic controller based maximum power point tracking and its optimal tuning in photovoltaic systems","authors":"N. Bouarroudj, T. Abdelkrim, Maissa Farhat, V. Feliu-Batlle, B. Benlahbib, D. Boukhetala, F. Boudjema","doi":"10.2298/sjee2103351b","DOIUrl":"https://doi.org/10.2298/sjee2103351b","url":null,"abstract":"Conventionally, the parameters of a fuzzy logic controller (FLC) are obtained by a trial and error method or by human experience. In this paper, the problem of designing a FLC for maximum power point tracking (MPPT) of a photovoltaic system (PV) that consists of a PV generator, a DC-DC boost converter and a lead-acid battery is studied. The normalization gains, the membership functions and the fuzzy rules are automatically adjusted using a particles swarm optimization algorithm (PSO) in order to maximize the criterion based on the integration of the PV module power under standard temperature condition (STC) (T=25?C and S=1000 W/m2). The robustness test of the optimized fuzzy logic MPPT controller (FLC-MPPT) is carried out under different scenarios. Simulation results of the system clearly show that the proposed optimized FLCMPPT controller outperforms in terms of maximum efficiency the FLC-MPPT controller not optimized, the FLC-MPPT controller with optimized normalization gains and the FLC-MPPT controller with optimized normalization gains and membership functions.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the challenges of the power quality management is a need for reliable harmonic identification in grids with multiple non-linear loads. This paper proposes a novel method to accurately determine time-varying harmonic contributions of non-linear loads to the total grid voltage distortion. The use of the invasive measurement approach and ternary pulse sequence as a stimuli guarantees an accurate assessment of harmonic contribution with the account for timevariating harmonic impacts. The application of proposed approach is demonstrated by means of time-domain grid simulation with implemented white-box model of a pulse sequence generator. Statistical estimation of the accuracy of the proposed approach as well as comparison with typical harmonic identification methods justify its effectiveness under non-stationary network conditions.
{"title":"Real-time harmonic identification under varying grid conditions","authors":"A. E. Bulycheva, A. S. Yanchenko","doi":"10.2298/SJEE2101029B","DOIUrl":"https://doi.org/10.2298/SJEE2101029B","url":null,"abstract":"One of the challenges of the power quality management is a need for reliable harmonic identification in grids with multiple non-linear loads. This paper proposes a novel method to accurately determine time-varying harmonic contributions of non-linear loads to the total grid voltage distortion. The use of the invasive measurement approach and ternary pulse sequence as a stimuli guarantees an accurate assessment of harmonic contribution with the account for timevariating harmonic impacts. The application of proposed approach is demonstrated by means of time-domain grid simulation with implemented white-box model of a pulse sequence generator. Statistical estimation of the accuracy of the proposed approach as well as comparison with typical harmonic identification methods justify its effectiveness under non-stationary network conditions.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The results of experimental research and thermal analysis of several types of cooling of brushless electric motors with nominal power 10-12kW (PMAC), suitable for ?light? EV/HEV vehicles are presented in the research paper. The studied motors have permanent magnets, a double stator and an axial magnetic flux with air or liquid cooling. The Motor-CAD software performed the presented thermal analysis. The experimental study was made on the basis of precision results, obtained from the measurement of process temperatures during operation in a real-world environment. For this purpose, the electric motors were equipped with a number of thermocouples with which the temperatures are measured. The precise measurement and recording of the heat flux temperatures is performed using LabVIEW software. The calculations from the thermal analysis coincide with the experimental results and can be used to predict the heat fluxes in different designs and types of cooling systems. The possibilities for improving the cooling and power of standard PMAC electric motors with double stators have been studied and analyzed.
{"title":"Experimental study and thermal analysis of cooling systems for brushless motors with double stator and axial gap","authors":"B. Velev, I. Ivanov, V. Kamenov","doi":"10.2298/sjee2103333v","DOIUrl":"https://doi.org/10.2298/sjee2103333v","url":null,"abstract":"The results of experimental research and thermal analysis of several types of cooling of brushless electric motors with nominal power 10-12kW (PMAC), suitable for ?light? EV/HEV vehicles are presented in the research paper. The studied motors have permanent magnets, a double stator and an axial magnetic flux with air or liquid cooling. The Motor-CAD software performed the presented thermal analysis. The experimental study was made on the basis of precision results, obtained from the measurement of process temperatures during operation in a real-world environment. For this purpose, the electric motors were equipped with a number of thermocouples with which the temperatures are measured. The precise measurement and recording of the heat flux temperatures is performed using LabVIEW software. The calculations from the thermal analysis coincide with the experimental results and can be used to predict the heat fluxes in different designs and types of cooling systems. The possibilities for improving the cooling and power of standard PMAC electric motors with double stators have been studied and analyzed.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Harmonic contributions of utility and customer may feature significant variations due to network switchings and changing operational modes. In order to correctly define the impacts on the grid voltage distortion the frequency dependent impedance characteristic of the studied network should be accurately measured in the real-time mode. This condition can be fulfilled by designing a stimuli generator measuring the grid impedance as a response to injected interference and producing time-frequency plots of harmonic contributions during considered time interval. In this paper a prototype of a stimuli generator based on programmable voltage source inverter is developed and tested. The use of ternary pulse sequence allows fast wide-band impedance measurements that meet the requirements of real-time assessment of harmonic contributions. The accuracy of respective analysis involving impedance determination and calculation of harmonic contributions is validated experimentally using reference characteristics of laboratory test set-up with varying grid impedance.
{"title":"Experimental assessment of harmonic contributions using a ternary pulse sequence","authors":"E. Bulycheva, S. Yanchenko","doi":"10.2298/sjee2103271b","DOIUrl":"https://doi.org/10.2298/sjee2103271b","url":null,"abstract":"Harmonic contributions of utility and customer may feature significant variations due to network switchings and changing operational modes. In order to correctly define the impacts on the grid voltage distortion the frequency dependent impedance characteristic of the studied network should be accurately measured in the real-time mode. This condition can be fulfilled by designing a stimuli generator measuring the grid impedance as a response to injected interference and producing time-frequency plots of harmonic contributions during considered time interval. In this paper a prototype of a stimuli generator based on programmable voltage source inverter is developed and tested. The use of ternary pulse sequence allows fast wide-band impedance measurements that meet the requirements of real-time assessment of harmonic contributions. The accuracy of respective analysis involving impedance determination and calculation of harmonic contributions is validated experimentally using reference characteristics of laboratory test set-up with varying grid impedance.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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