Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065893
B. Bertoldi, E. F. C. Grabovski, A. B. Lange, M. Heldwein
A variable-step Discrete Fourier Transform with reduced complexity for the electrical quantities of power converters is introduced, as to reduce the time consumption of optimization routines which depend on voltage and current frequency spectrum derived from a complex time domain waveform typically generated by a numeric simulation of a power converter. A variable-step decimation algorithm is also described, reducing the number of points by detecting level transitions and/or derivative discontinuities. The algorithms are validated for a Three-Phase Vienna Interleaved Rectifier voltage and current waveforms employing Discontinuous Pulse Width Modulation.
{"title":"Variable-step DFT Algorithm to Speed Up Optimization Routines Applied to a Three-Phase Interleaved Vienna Rectifier","authors":"B. Bertoldi, E. F. C. Grabovski, A. B. Lange, M. Heldwein","doi":"10.1109/COBEP/SPEC44138.2019.9065893","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065893","url":null,"abstract":"A variable-step Discrete Fourier Transform with reduced complexity for the electrical quantities of power converters is introduced, as to reduce the time consumption of optimization routines which depend on voltage and current frequency spectrum derived from a complex time domain waveform typically generated by a numeric simulation of a power converter. A variable-step decimation algorithm is also described, reducing the number of points by detecting level transitions and/or derivative discontinuities. The algorithms are validated for a Three-Phase Vienna Interleaved Rectifier voltage and current waveforms employing Discontinuous Pulse Width Modulation.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89189959","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065341
Menaouar Berrehil El Kattel, Robson Mayer, Maicon Douglas Possamai, Sérgio Vidal Garcia Oliveira
This paper presents the analysis of a new bucktype interleaved dc-dc non-isolated converter based on the classic interleaved topologies of the buck converter operating in the continuous conduction mode. A simple comparative analysis between the proposed converter and two dc-dc buck converters is conducted. For this purpose, a conventional buck converter, an interleaved buck converter and the proposed converter were compared. In this paper the operation principles, the dc voltage gain, the filters design and the voltage and current stresses are discussed. The proposed converter could replace the conventional dc-dc step-down voltage converter stage with poor power quality and low energy density, such as used in high power ac-dc battery chargers, dc sources among others. In order to validate the theoretical study and to prove the converter performance, some experimental results, obtained from a laboratory prototype of 4 kW, are presented.
{"title":"A Simplified Analysis of Buck-Type Interleaved DC-DC Converter for Battery Chargers Application","authors":"Menaouar Berrehil El Kattel, Robson Mayer, Maicon Douglas Possamai, Sérgio Vidal Garcia Oliveira","doi":"10.1109/COBEP/SPEC44138.2019.9065341","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065341","url":null,"abstract":"This paper presents the analysis of a new bucktype interleaved dc-dc non-isolated converter based on the classic interleaved topologies of the buck converter operating in the continuous conduction mode. A simple comparative analysis between the proposed converter and two dc-dc buck converters is conducted. For this purpose, a conventional buck converter, an interleaved buck converter and the proposed converter were compared. In this paper the operation principles, the dc voltage gain, the filters design and the voltage and current stresses are discussed. The proposed converter could replace the conventional dc-dc step-down voltage converter stage with poor power quality and low energy density, such as used in high power ac-dc battery chargers, dc sources among others. In order to validate the theoretical study and to prove the converter performance, some experimental results, obtained from a laboratory prototype of 4 kW, are presented.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89212947","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065890
Marcus E. T. Souza, F. C. Melo, E. Coelho, L. D. de Freitas
Nowadays, photovoltaic (PV) systems and microgrids are two of the main technologies in electrical engineering researches. Both are important to realize different types of energy management, feeding islanded loads with high reliability, efficiency, social benefits, low cost and environmental impact. This paper assess the possibility of connecting a PV system to a droop-controlled islanded AC microgrid without modified advanced controls, additional components or the use of batteries in a way that only simple standard commercial equipment are used. Two inverters operating with Voltage Control Mode (VCM) employing the droop control method to form an islanded AC microgrid is approached. These inverters function as grid forming converters giving voltage references in order to integrate them with a conventional solar PV system in Current Control Mode (CCM), consolidated technologies which are easily found on the market, since they are used for grid-tie. The proposed complete system is analysed for a typical day, with real measured variations of irradiance and temperature. The computational results of the VCM and CCM inverters integrated is exposed, showing its feasibility and its limitations.
{"title":"Integration of Solar Photovoltaic (PV) Systems with CCM Inverters into VCM Droop-Controlled Islanded AC Microgrids","authors":"Marcus E. T. Souza, F. C. Melo, E. Coelho, L. D. de Freitas","doi":"10.1109/COBEP/SPEC44138.2019.9065890","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065890","url":null,"abstract":"Nowadays, photovoltaic (PV) systems and microgrids are two of the main technologies in electrical engineering researches. Both are important to realize different types of energy management, feeding islanded loads with high reliability, efficiency, social benefits, low cost and environmental impact. This paper assess the possibility of connecting a PV system to a droop-controlled islanded AC microgrid without modified advanced controls, additional components or the use of batteries in a way that only simple standard commercial equipment are used. Two inverters operating with Voltage Control Mode (VCM) employing the droop control method to form an islanded AC microgrid is approached. These inverters function as grid forming converters giving voltage references in order to integrate them with a conventional solar PV system in Current Control Mode (CCM), consolidated technologies which are easily found on the market, since they are used for grid-tie. The proposed complete system is analysed for a typical day, with real measured variations of irradiance and temperature. The computational results of the VCM and CCM inverters integrated is exposed, showing its feasibility and its limitations.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83922671","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065507
Saulo O. Nascimento, Vinícius M. de Albuquerque, M. C. Fernandes, M. A. Rendón, J. G. Oliveira, P. S. Almeida
This paper studies the aspects of turboelectric system control regarding the power conversion topology. Both Modeling and control of a back-to-back system connected to synchronous machines in both ends are considered. An instantaneous power technique in the αβ-frame is used to control the active rectifier connected to the permanent magnet synchronous generator (PMSG) while the inverter associated in the motor speed control uses synchronous (dq) frame robust control technique. The system considers a synchronous motor of 42kW connected to a 220V PMSG by a 670V DC bus.Mathematical modeling and simulation are used to provide insights on the whole system.
{"title":"Modeling and Control of a Back-to-Back system for turboelectric propulsion","authors":"Saulo O. Nascimento, Vinícius M. de Albuquerque, M. C. Fernandes, M. A. Rendón, J. G. Oliveira, P. S. Almeida","doi":"10.1109/COBEP/SPEC44138.2019.9065507","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065507","url":null,"abstract":"This paper studies the aspects of turboelectric system control regarding the power conversion topology. Both Modeling and control of a back-to-back system connected to synchronous machines in both ends are considered. An instantaneous power technique in the αβ-frame is used to control the active rectifier connected to the permanent magnet synchronous generator (PMSG) while the inverter associated in the motor speed control uses synchronous (dq) frame robust control technique. The system considers a synchronous motor of 42kW connected to a 220V PMSG by a 670V DC bus.Mathematical modeling and simulation are used to provide insights on the whole system.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87881664","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 high frequency (HF) isolation transformer is the core element of a dual-active-bridge (DAB) bi-directional high-power DC-DC converter. At high frequency high power conversion, providing compact and efficient transformer design solutions need to consider the magnetic, electric as well as thermal aspect thoroughly and carefully to ensure the reliability and efficiency of the whole system. Detailed design considerations for a HF isolation transformer in a DAB conversion system are presented in this paper taking into consideration the insulation, high frequency magnetics characteristics, skin-proximity effects at high switching frequency as well as the thermal-fluid interaction analysis. Special attention is paid to the leakage inductance since improper value leads to an undesirable overshoot on the device voltage which may cause the SiC failure. This paper also presents the a multi-objective optimization design methodology applied to a 25kVA/25kHz, 1500V/750V transformer intended for DC-DC stage in 1MVA SiC-based solid state transformer (SST) and the Pareto optimal sets under different cooling methods are derived and analyzed. Comparison between different magnetic materials and different operation conditions are also carried out to find the characteristics variation of the designed transformer. The merit of the optimal design are validated through finite element modeling (FEM) and computational fluid dynamics (CFD) simulations.
{"title":"Analysis and Optimal Design of Magnetic Components in Dual-Active-Bridge Converter for 1 MVA Solid-State Transformer","authors":"Haonan Tian, Sriram Vaisambhayana, Anshuman Tripathi","doi":"10.1109/COBEP/SPEC44138.2019.9065841","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065841","url":null,"abstract":"The high frequency (HF) isolation transformer is the core element of a dual-active-bridge (DAB) bi-directional high-power DC-DC converter. At high frequency high power conversion, providing compact and efficient transformer design solutions need to consider the magnetic, electric as well as thermal aspect thoroughly and carefully to ensure the reliability and efficiency of the whole system. Detailed design considerations for a HF isolation transformer in a DAB conversion system are presented in this paper taking into consideration the insulation, high frequency magnetics characteristics, skin-proximity effects at high switching frequency as well as the thermal-fluid interaction analysis. Special attention is paid to the leakage inductance since improper value leads to an undesirable overshoot on the device voltage which may cause the SiC failure. This paper also presents the a multi-objective optimization design methodology applied to a 25kVA/25kHz, 1500V/750V transformer intended for DC-DC stage in 1MVA SiC-based solid state transformer (SST) and the Pareto optimal sets under different cooling methods are derived and analyzed. Comparison between different magnetic materials and different operation conditions are also carried out to find the characteristics variation of the designed transformer. The merit of the optimal design are validated through finite element modeling (FEM) and computational fluid dynamics (CFD) simulations.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86671040","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065356
Hao Qiu, Yoshiaki Narusue, Y. Kawahara, T. Sakurai, M. Takamiya
In this paper, a distance detection system that only processes the information in the transmitter (TX) side is proposed. By using the distance detection system, the radius of the digital TX coil can change automatically depending on the distance and thus achieve the maximum efficiency tracking. A wireless power transfer (WPT) prototype is fabricated and experimental results demonstrate that, compared with using the conventional TX coil with a constant radius, the efficiency is improved from 12% to 20% at the distance of 4 times the RX coil radius.
{"title":"Distance Detection System for Digital Transmitter Coil Achieving Distance-Variation-Tolerant Wireless Power Transfer","authors":"Hao Qiu, Yoshiaki Narusue, Y. Kawahara, T. Sakurai, M. Takamiya","doi":"10.1109/COBEP/SPEC44138.2019.9065356","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065356","url":null,"abstract":"In this paper, a distance detection system that only processes the information in the transmitter (TX) side is proposed. By using the distance detection system, the radius of the digital TX coil can change automatically depending on the distance and thus achieve the maximum efficiency tracking. A wireless power transfer (WPT) prototype is fabricated and experimental results demonstrate that, compared with using the conventional TX coil with a constant radius, the efficiency is improved from 12% to 20% at the distance of 4 times the RX coil radius.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86874010","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065497
Andrea Furlan, A. Morentin, G. Fontès, G. Delamare, M. Heldwein, T. Meynard
This work proposes an improvement for the consideration of ac winding losses in the design process of inductors to be employed in power converters, where the geometrical parameters of the inductors are not known before starting the design. The presented method consists of the pre-computation of a homothetic multivariate regular grid surface by finite element simulations, from which the winding resistance can be obtained by direct multivariate linear interpolation. Special attention is given to Dowell’s analytical formulations. These are often used in the design but typically with little details given on how the final expressions are derived. The results with the new method are shown to be more accurate than the analytical calculations over a wide range of design points and, thus, are a useful design tool.
{"title":"Homothetic Method to Compute Winding Losses in the Design of Power Inductors","authors":"Andrea Furlan, A. Morentin, G. Fontès, G. Delamare, M. Heldwein, T. Meynard","doi":"10.1109/COBEP/SPEC44138.2019.9065497","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065497","url":null,"abstract":"This work proposes an improvement for the consideration of ac winding losses in the design process of inductors to be employed in power converters, where the geometrical parameters of the inductors are not known before starting the design. The presented method consists of the pre-computation of a homothetic multivariate regular grid surface by finite element simulations, from which the winding resistance can be obtained by direct multivariate linear interpolation. Special attention is given to Dowell’s analytical formulations. These are often used in the design but typically with little details given on how the final expressions are derived. The results with the new method are shown to be more accurate than the analytical calculations over a wide range of design points and, thus, are a useful design tool.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83651706","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065641
Mukhtiar Singh
This paper deals with the speed and position estimation algorithm for the sensorless control of wind energy conversion system (WECS) having permanent magnet synchronous generator (PMSG) as electromechanical converter. Here, the main purpose is to get rid of the sensors and their issues related to maintenance, connection, tearing and wearing etc. A thorough mathematical modelling of PMSG has been presented. Moreover, Extended Kalman Filter (EKF) based observer has been proposed for the speed and position estimation of PMSG. The proposed PMSG based WECS has been modelled and simulated using the different blocksets of MATLAB/SIMPOWERSYSTEM. An extensive simulation study has been conducted and various results have been discussed and analyzed to validate the EKF based sensorless control of PMSG driven wind turbine.
{"title":"Extended Kalman Filter based Speed Estimation for the Control of PMSG","authors":"Mukhtiar Singh","doi":"10.1109/COBEP/SPEC44138.2019.9065641","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065641","url":null,"abstract":"This paper deals with the speed and position estimation algorithm for the sensorless control of wind energy conversion system (WECS) having permanent magnet synchronous generator (PMSG) as electromechanical converter. Here, the main purpose is to get rid of the sensors and their issues related to maintenance, connection, tearing and wearing etc. A thorough mathematical modelling of PMSG has been presented. Moreover, Extended Kalman Filter (EKF) based observer has been proposed for the speed and position estimation of PMSG. The proposed PMSG based WECS has been modelled and simulated using the different blocksets of MATLAB/SIMPOWERSYSTEM. An extensive simulation study has been conducted and various results have been discussed and analyzed to validate the EKF based sensorless control of PMSG driven wind turbine.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77212189","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065823
Nicolas Parma Rios, Guilherme Márcio Soares, E. C. Teixeira
This paper presents the design of an integrated circuit devised to control an LED driver with visible light communication (VLC) capability. The chip was designed for a standard 0.5-μm CMOS technology and it is applied to control a buck converter. The adopted communication strategy is the variable pulse position modulation (VPPM), which allows the LEDs dimming and the data transmission at rates up to 266.6 kbit/s. The building blocks of the proposed integrated circuit are described, and SPICE simulation results are shown.
{"title":"Design of an Integrated Circuit for LED Driving in Visible Light Communication Applications","authors":"Nicolas Parma Rios, Guilherme Márcio Soares, E. C. Teixeira","doi":"10.1109/COBEP/SPEC44138.2019.9065823","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065823","url":null,"abstract":"This paper presents the design of an integrated circuit devised to control an LED driver with visible light communication (VLC) capability. The chip was designed for a standard 0.5-μm CMOS technology and it is applied to control a buck converter. The adopted communication strategy is the variable pulse position modulation (VPPM), which allows the LEDs dimming and the data transmission at rates up to 266.6 kbit/s. The building blocks of the proposed integrated circuit are described, and SPICE simulation results are shown.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76921225","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}
Pub Date : 2019-12-01DOI: 10.1109/COBEP/SPEC44138.2019.9065676
V. Gruner, Lucas Fiamoncini, Lenon Schmitz, D. Martins, Roberto Francisco Coelho
This paper presents a DC-DC converter capable of dealing with low voltage and high input current sources. The proposed topology is based on Forward converters with inputs connected in parallel and outputs connected in series. This configuration allows a natural sharing of the input current and provides high static gain to the converter. The phase-shift modulation is applied to reduce size and volume of the single output filter presented at the topology. The study carried out in this work includes the converter operation stages, equation, theoretical waveforms and modelling. In addition, experimental results performed from a 1-kW prototype are presented and discussed in order to validate the proposed converter operation in closed loop.
{"title":"High Step-Up DC-DC Converter with Input Current Sharing Based on the Forward Converter","authors":"V. Gruner, Lucas Fiamoncini, Lenon Schmitz, D. Martins, Roberto Francisco Coelho","doi":"10.1109/COBEP/SPEC44138.2019.9065676","DOIUrl":"https://doi.org/10.1109/COBEP/SPEC44138.2019.9065676","url":null,"abstract":"This paper presents a DC-DC converter capable of dealing with low voltage and high input current sources. The proposed topology is based on Forward converters with inputs connected in parallel and outputs connected in series. This configuration allows a natural sharing of the input current and provides high static gain to the converter. The phase-shift modulation is applied to reduce size and volume of the single output filter presented at the topology. The study carried out in this work includes the converter operation stages, equation, theoretical waveforms and modelling. In addition, experimental results performed from a 1-kW prototype are presented and discussed in order to validate the proposed converter operation in closed loop.","PeriodicalId":69617,"journal":{"name":"电力电子","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82664620","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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