Pub Date : 2009-05-20DOI: 10.1109/CPE.2009.5156026
M. Jasiński, M. Kazmierkowski, M. Bobrowska, P. Okon
This paper investigates problems of grid voltage distortions and their influence on AC-DC-AC converter. A specific control algorithm is presented, which minimizes influence of voltage dips and higher harmonics on the system. Requirements for control of the Line (Grid) Side Converter (LSC) and Machine (Generator) Side Converter (MSC) are discussed. Effectiveness of proposed control scheme is verified with simulations and experimentally on 3kW model. Solution is dedicated to Variable Speed Energy Systems (VSEGS) connected to high impedance grid, particularly wind farms or ocean wave energy converters such as WaveDragon MW.
{"title":"Control of AC-DC-AC converter under unbalanced and distorted input conditions","authors":"M. Jasiński, M. Kazmierkowski, M. Bobrowska, P. Okon","doi":"10.1109/CPE.2009.5156026","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156026","url":null,"abstract":"This paper investigates problems of grid voltage distortions and their influence on AC-DC-AC converter. A specific control algorithm is presented, which minimizes influence of voltage dips and higher harmonics on the system. Requirements for control of the Line (Grid) Side Converter (LSC) and Machine (Generator) Side Converter (MSC) are discussed. Effectiveness of proposed control scheme is verified with simulations and experimentally on 3kW model. Solution is dedicated to Variable Speed Energy Systems (VSEGS) connected to high impedance grid, particularly wind farms or ocean wave energy converters such as WaveDragon MW.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116990206","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156013
P. Mysiak
The article presents the analysis of operation of a coupled three-phase reactor (CTR) used applied in 12-pulse and 18-pulse diode converters. Using sets of coupled three-phase power network reactors, the presented converters make it possible to considerably reduce, at low cost, undesired higher harmonics in the power network current. Selected results of laboratory tests done on a 20kVA 18-pulse diode converter are included.
{"title":"Multipulse diode converters - Frequency domain analysis of operation of the applied coupled three-phase reactor","authors":"P. Mysiak","doi":"10.1109/CPE.2009.5156013","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156013","url":null,"abstract":"The article presents the analysis of operation of a coupled three-phase reactor (CTR) used applied in 12-pulse and 18-pulse diode converters. Using sets of coupled three-phase power network reactors, the presented converters make it possible to considerably reduce, at low cost, undesired higher harmonics in the power network current. Selected results of laboratory tests done on a 20kVA 18-pulse diode converter are included.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126076193","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156070
M. Mehrasa, S. Lesan, Seyed Nima Hoseini Emeni, A. Sheikholeslami
This paper presents the EL modeling of the four-wire 3-level 3-phase NPC voltage source rectifier (VSR). The load current of the four-wire 3-level 3-phase could be expressed in two forms: the load current involving the current of capacitor C1, and the load current involving the current of capacitor C2. So that two EL models will be obtained for four-wire 3-level 3-phase NPC voltage source rectifier. The models are completely in accordance with kirchoffs circuit theory and superposition law of course. One of the rules is utilized to control the voltage of C1 and the other is used to control the voltage of C2. Transforming the EL model from the abc reference frame to dq reference model will completely retain the energy dissipative properties of two models. Having drived the EL models, the control method combined with the techniques of the energy shaping and damping injection applied to the dq frame EL models of the converter. To study the output regulation problem of C1 and C2, the voltage indirect control method has been applied to the passivity based controller. To regulate the internal dynamics of the output voltages of C1 and C2 an outer loop that consisting PI controller is added to both controller models. To verify the ability of the proposed control method different simulations have been carried out by MATLAM/SIMULINK software. The simulation results clarify the abilities of the new method such as: very low THD, unity power factor, decoupled current loop dynamics, low oscillation in the neutral point potential (NPP).
{"title":"Passivity-based control with dual lagrangian model of four-wire three-level three-phase NPC voltage-source rectifier","authors":"M. Mehrasa, S. Lesan, Seyed Nima Hoseini Emeni, A. Sheikholeslami","doi":"10.1109/CPE.2009.5156070","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156070","url":null,"abstract":"This paper presents the EL modeling of the four-wire 3-level 3-phase NPC voltage source rectifier (VSR). The load current of the four-wire 3-level 3-phase could be expressed in two forms: the load current involving the current of capacitor C1, and the load current involving the current of capacitor C2. So that two EL models will be obtained for four-wire 3-level 3-phase NPC voltage source rectifier. The models are completely in accordance with kirchoffs circuit theory and superposition law of course. One of the rules is utilized to control the voltage of C1 and the other is used to control the voltage of C2. Transforming the EL model from the abc reference frame to dq reference model will completely retain the energy dissipative properties of two models. Having drived the EL models, the control method combined with the techniques of the energy shaping and damping injection applied to the dq frame EL models of the converter. To study the output regulation problem of C1 and C2, the voltage indirect control method has been applied to the passivity based controller. To regulate the internal dynamics of the output voltages of C1 and C2 an outer loop that consisting PI controller is added to both controller models. To verify the ability of the proposed control method different simulations have been carried out by MATLAM/SIMULINK software. The simulation results clarify the abilities of the new method such as: very low THD, unity power factor, decoupled current loop dynamics, low oscillation in the neutral point potential (NPP).","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123245887","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156015
C. Jaen, J. Pou, G. Capella, A. Arias, M. Lamich
Nowadays power supply systems based on photovoltaic cells have two main drawbacks, even the primary energy is free and renewable. They are: production cost and efficiency. In order to increase their efficiency, it should be interesting that the energy transfer between cells and load was done at maximum level. In this paper the use of a sun tracker system is presented as an additional improvement applied to a photovoltaic installation that works under a maximum power point tracking (MPPT) control technique. A 50W-prototype has been assembled. Some experimental results are also included in order to validate the whole system.
{"title":"On the use of sun trackers to improve maximum power point tracking controllers applied to photovoltaic systems","authors":"C. Jaen, J. Pou, G. Capella, A. Arias, M. Lamich","doi":"10.1109/CPE.2009.5156015","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156015","url":null,"abstract":"Nowadays power supply systems based on photovoltaic cells have two main drawbacks, even the primary energy is free and renewable. They are: production cost and efficiency. In order to increase their efficiency, it should be interesting that the energy transfer between cells and load was done at maximum level. In this paper the use of a sun tracker system is presented as an additional improvement applied to a photovoltaic installation that works under a maximum power point tracking (MPPT) control technique. A 50W-prototype has been assembled. Some experimental results are also included in order to validate the whole system.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122677543","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156039
M. Oettmeier, M. Gorski, C. Heising, V. Staudt, A. Steimel
Railway grid interaction is a major concern when developing the power train of a railway traction vehicle and its control. Two main areas have to be taken into account: Line current harmonics and grid stability.
{"title":"LQ-optimized multivariable control for a single-phase 50-kW, 16.7-Hz railway-grid representation featuring variable grid parameters","authors":"M. Oettmeier, M. Gorski, C. Heising, V. Staudt, A. Steimel","doi":"10.1109/CPE.2009.5156039","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156039","url":null,"abstract":"Railway grid interaction is a major concern when developing the power train of a railway traction vehicle and its control. Two main areas have to be taken into account: Line current harmonics and grid stability.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122041509","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156024
G. Kerber, R. Witzmann, Hannes Sappl
The increasing decentralized power generation in the public low voltage grid may lead to a reversed load flow. The common assumption that the highest voltage in a low voltage grid is on the transformer busbar is then no longer appropriate. Therefore the risk of overvoltages rises significantly. A highly effective way to keep the voltage within the allowed bandwidth is to utilize the ability of modern voltage source converters (VSC) to provide or absorb reactive power while feeding active power into the network (4-quadrant operation). With a reactive power consumption while active power is fed in the voltage rise can be limited. For practical use a grid adaptive reactive power control system which works without manual set up or communication requirements is desirable. Therefore an exemplary adaptive control system was designed, modeled in a load flow simulation program and tested on different low voltage (LV) grid models for network classes prone to voltage problems. The results show that simple parameter sets can be found which will work on most grid infrastructures without further adjustment. But they also show the problems to keep the voltage within the limits without decreasing the maximum grid transport capacity by consuming innecessary reactive power.
{"title":"Voltage limitation by autonomous reactive power control of grid connected photovoltaic inverters","authors":"G. Kerber, R. Witzmann, Hannes Sappl","doi":"10.1109/CPE.2009.5156024","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156024","url":null,"abstract":"The increasing decentralized power generation in the public low voltage grid may lead to a reversed load flow. The common assumption that the highest voltage in a low voltage grid is on the transformer busbar is then no longer appropriate. Therefore the risk of overvoltages rises significantly. A highly effective way to keep the voltage within the allowed bandwidth is to utilize the ability of modern voltage source converters (VSC) to provide or absorb reactive power while feeding active power into the network (4-quadrant operation). With a reactive power consumption while active power is fed in the voltage rise can be limited. For practical use a grid adaptive reactive power control system which works without manual set up or communication requirements is desirable. Therefore an exemplary adaptive control system was designed, modeled in a load flow simulation program and tested on different low voltage (LV) grid models for network classes prone to voltage problems. The results show that simple parameter sets can be found which will work on most grid infrastructures without further adjustment. But they also show the problems to keep the voltage within the limits without decreasing the maximum grid transport capacity by consuming innecessary reactive power.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128701502","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156057
B. Franković, Žarko Dubrović, Bojan Jurdana
The territory of the former Trsat Army Barracks in Rijeka was awarded to the Town of Rijeka to be used expressly for the needs of healthcare and higher education. In the Detailed Plan of Urban Development (DPUD) for that area (Susak Clinical Hospital Centre and the future University Campus Trsat) the thermo-technical and thermal energy systems for the intended usage of this area are separated and prejudged in the levels of engineering solutions. To no useful purpose, the plan foresees two autonomous systems: (a) the hospital system at the cogeneration/trigeneration level, (b) the system for the Campus area at the conventional warm water/hot water heating plant. The fact that these systems are located in close proximity of each other further brings into doubt the solution proposed and adopted by the plan. Therefore, the research was made and new solutions prepared. The results of a preliminary study justifying the application of a joint complex municipal thermal power system powered by natural gas for the areas the DPUD covers are elaborated in the paper. The combined thermal power system will serve for heating, steam production, cooling and electrical energy production, primarily for the area of Campus and Clinical Hospital Centre. There is a possibility of increasing the powerproducing capacity of this combined system for the needs of town consumers, which would make the system more efficient. An analysis has been made based on the guidelines for the thermo-technical and thermal power system adopted by the DPUD, the actual state of the distance heating system, and the need for heating, cooling and electrical energy within and outside the zone covered by the plan. Results point to the need to combine the two systems in order to reach an improved technical solution. The solution proposed will help to increase the efficient use of natural gas, the primary energy source, while reducing operating costs and abating environmental pollution.
{"title":"Trigeneration energy system for the campus of the University of Rijeka","authors":"B. Franković, Žarko Dubrović, Bojan Jurdana","doi":"10.1109/CPE.2009.5156057","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156057","url":null,"abstract":"The territory of the former Trsat Army Barracks in Rijeka was awarded to the Town of Rijeka to be used expressly for the needs of healthcare and higher education. In the Detailed Plan of Urban Development (DPUD) for that area (Susak Clinical Hospital Centre and the future University Campus Trsat) the thermo-technical and thermal energy systems for the intended usage of this area are separated and prejudged in the levels of engineering solutions. To no useful purpose, the plan foresees two autonomous systems: (a) the hospital system at the cogeneration/trigeneration level, (b) the system for the Campus area at the conventional warm water/hot water heating plant. The fact that these systems are located in close proximity of each other further brings into doubt the solution proposed and adopted by the plan. Therefore, the research was made and new solutions prepared. The results of a preliminary study justifying the application of a joint complex municipal thermal power system powered by natural gas for the areas the DPUD covers are elaborated in the paper. The combined thermal power system will serve for heating, steam production, cooling and electrical energy production, primarily for the area of Campus and Clinical Hospital Centre. There is a possibility of increasing the powerproducing capacity of this combined system for the needs of town consumers, which would make the system more efficient. An analysis has been made based on the guidelines for the thermo-technical and thermal power system adopted by the DPUD, the actual state of the distance heating system, and the need for heating, cooling and electrical energy within and outside the zone covered by the plan. Results point to the need to combine the two systems in order to reach an improved technical solution. The solution proposed will help to increase the efficient use of natural gas, the primary energy source, while reducing operating costs and abating environmental pollution.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114241007","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156031
W. Koczara, G. Iwański, Zdisialw Chlodnicki
Paper presents features of renewable energy sources (RES) that have unstable nature. Therefore the RES are connected to stiff grid that stabilizes the AC voltage and provides power in case of low level power produced by the RES. The paper proposes to use an adjustable speed generation system operating in common microgrid. The adjustable speed generation system produces high quality AC power with high efficiency that makes whole system more modern. In case of high step load at low speed the adjustable speed system us not able to produce stiff voltage. Therefore a hybrid adjustable speed generation system is applied. Application of energy storage supplying the DC link of the adjustable speed generation system converter makes output AC voltage not sensitive to any step load.
{"title":"Performances of the adjustable speed decoupled generation systems","authors":"W. Koczara, G. Iwański, Zdisialw Chlodnicki","doi":"10.1109/CPE.2009.5156031","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156031","url":null,"abstract":"Paper presents features of renewable energy sources (RES) that have unstable nature. Therefore the RES are connected to stiff grid that stabilizes the AC voltage and provides power in case of low level power produced by the RES. The paper proposes to use an adjustable speed generation system operating in common microgrid. The adjustable speed generation system produces high quality AC power with high efficiency that makes whole system more modern. In case of high step load at low speed the adjustable speed system us not able to produce stiff voltage. Therefore a hybrid adjustable speed generation system is applied. Application of energy storage supplying the DC link of the adjustable speed generation system converter makes output AC voltage not sensitive to any step load.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114517313","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156017
V. Minambres, M. I. Milanés, B. Vinagre, E. Romero
The analysis and design of a three-phase Phase Locked Loop system to synchronize to the electrical grid is presented. The whole phase locked loop model is obtained and a Proportional Integral, a Proportional Integral Derivative and a novel Fractional Proportional Integral controllers in continuous time domain are proposed to solve the phase tracking by improving time response, phase error and overshoot. The performance of the three controllers is analyzed under distorted utility conditions, such as imbalance, harmonics and phase and/or frequency variations. The phase locked loop is totally implemented by software, and tested by simulation via SIMULINK and experimentally via xPCTarget, in a three phase Autoadjustable Synchronous Reference Frame application. A comparison in the dynamic and steady state of the phase locked loop parameters like accurate, robustness and fastness is carried out for the three different controllers.
{"title":"Comparison of controllers for a three-phase Phase Locked Loop system under distorted conditions","authors":"V. Minambres, M. I. Milanés, B. Vinagre, E. Romero","doi":"10.1109/CPE.2009.5156017","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156017","url":null,"abstract":"The analysis and design of a three-phase Phase Locked Loop system to synchronize to the electrical grid is presented. The whole phase locked loop model is obtained and a Proportional Integral, a Proportional Integral Derivative and a novel Fractional Proportional Integral controllers in continuous time domain are proposed to solve the phase tracking by improving time response, phase error and overshoot. The performance of the three controllers is analyzed under distorted utility conditions, such as imbalance, harmonics and phase and/or frequency variations. The phase locked loop is totally implemented by software, and tested by simulation via SIMULINK and experimentally via xPCTarget, in a three phase Autoadjustable Synchronous Reference Frame application. A comparison in the dynamic and steady state of the phase locked loop parameters like accurate, robustness and fastness is carried out for the three different controllers.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117076585","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 : 2009-05-20DOI: 10.1109/CPE.2009.5156076
I. Quesada, A. Lázaro, C. Martínez, C. Lucena, A. Barrado, R. Vazquez, I. Gonzalez, N. Herreros
AC voltage generation in rail applications (auxiliary services), usually employs optimized PWM feedforward schemes in order to control the inverter. In this kind of applications the THD reduction of the filtered output voltage together with the reduced weight of the static converters are the main goals to be reached. In order to achieve these objectives, the most commonly used optimized PWM techniques are going to be compared in terms of Total Harmonic Distortion (THD), Weighted Total Harmonic Distortion (WTHD) and IGBT losses.
{"title":"Improved modulator for THD reduction in onboard generation of three phase AC voltage","authors":"I. Quesada, A. Lázaro, C. Martínez, C. Lucena, A. Barrado, R. Vazquez, I. Gonzalez, N. Herreros","doi":"10.1109/CPE.2009.5156076","DOIUrl":"https://doi.org/10.1109/CPE.2009.5156076","url":null,"abstract":"AC voltage generation in rail applications (auxiliary services), usually employs optimized PWM feedforward schemes in order to control the inverter. In this kind of applications the THD reduction of the filtered output voltage together with the reduced weight of the static converters are the main goals to be reached. In order to achieve these objectives, the most commonly used optimized PWM techniques are going to be compared in terms of Total Harmonic Distortion (THD), Weighted Total Harmonic Distortion (WTHD) and IGBT losses.","PeriodicalId":272748,"journal":{"name":"2009 Compatibility and Power Electronics","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123657088","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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