Pub Date : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6871905
T. Roubache, S. Chaouch, M. N. Nait Said
This paper deals with fault tolerant control (FTC) for a high performance induction motor (IM) based on backstepping strategy implicitly tolerant to defects assuming the effect of the fault on the system (IM) can be modeled by an exogenous signal from a stable autonomous system. An additive term is added to the nominal offset and serves to control the effect of the defect (FTC aspect). This additive term is derived from the internal model whose role is to reproduce the signal representing the effect of the defect (FDI aspect). The proposed fault-tolerant controller for IM may be realized in presence of both rotor and stator electrical faults. Simulation tests confirm widely the feasibility and the effectiveness of the proposal FTC of IM based on the backstepping control.
{"title":"Backstepping fault tolerant control for induction motor","authors":"T. Roubache, S. Chaouch, M. N. Nait Said","doi":"10.1109/SPEEDAM.2014.6871905","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871905","url":null,"abstract":"This paper deals with fault tolerant control (FTC) for a high performance induction motor (IM) based on backstepping strategy implicitly tolerant to defects assuming the effect of the fault on the system (IM) can be modeled by an exogenous signal from a stable autonomous system. An additive term is added to the nominal offset and serves to control the effect of the defect (FTC aspect). This additive term is derived from the internal model whose role is to reproduce the signal representing the effect of the defect (FDI aspect). The proposed fault-tolerant controller for IM may be realized in presence of both rotor and stator electrical faults. Simulation tests confirm widely the feasibility and the effectiveness of the proposal FTC of IM based on the backstepping control.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128411790","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6871913
M. Comanescu
The paper discusses the problem of estimating the speed, the flux magnitude and the rotor flux angle of the induction motor (IM) and presents an estimation method based on two Sliding Mode Observers (SMOs) and the Model Reference Adaptive System (MRAS) technique. The method is based on implementation of two SMOs that both yield the magnitude of the rotor flux; one observer is the reference model, the other is the adjustable model. The MRAS method is used to adapt the speed signal which is an input into both SMOs. The reference model is designed using the equations of the IM in the rotating reference frame. It is shown that its estimated flux magnitude is insensitive to the input speed. The adjustable model uses the IM equations in the stationary reference frame. Its output fluxes have magnitudes inverse proportional with the input speed; however, their phases are always accurate (this allows estimation of the flux angle). Using MRAS, the speed is corrected such that the flux magnitudes coming out of the two models match. Based on the structure developed, the paper also a speed estimation method. The simulations validate the theoretical development.
{"title":"An MRAS-type estimator for the speed, flux magnitude and rotor flux angle of the induction motor using sliding mode","authors":"M. Comanescu","doi":"10.1109/SPEEDAM.2014.6871913","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871913","url":null,"abstract":"The paper discusses the problem of estimating the speed, the flux magnitude and the rotor flux angle of the induction motor (IM) and presents an estimation method based on two Sliding Mode Observers (SMOs) and the Model Reference Adaptive System (MRAS) technique. The method is based on implementation of two SMOs that both yield the magnitude of the rotor flux; one observer is the reference model, the other is the adjustable model. The MRAS method is used to adapt the speed signal which is an input into both SMOs. The reference model is designed using the equations of the IM in the rotating reference frame. It is shown that its estimated flux magnitude is insensitive to the input speed. The adjustable model uses the IM equations in the stationary reference frame. Its output fluxes have magnitudes inverse proportional with the input speed; however, their phases are always accurate (this allows estimation of the flux angle). Using MRAS, the speed is corrected such that the flux magnitudes coming out of the two models match. Based on the structure developed, the paper also a speed estimation method. The simulations validate the theoretical development.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134151488","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6872030
V. Calderaro, V. Galdi, G. Graber, A. Piccolo, Dario Cogliano
The calculation of optimal driving speed profiles for metro vehicles that improve energy saving and, thus, reduce costs, are investigated. The optimization problem is solved in two different steps: in the first one, a Dynamic Programming Optimization (DPO) algorithm (including slopes and curves effects) is used to find a set of pseudo-optimal speed cycles; the objective is to minimize the electrical energy used for traction subject to constraints such as travel time, trip distance, acceleration limits, etc. In the second optimization step, the speed profiles set are evaluated in a simulation tool implemented to estimate the power flow among vehicles through the metro network. A test campaign monitoring the saved energy and main electric variables have been implemented and the presented results showing the effectiveness of the performance of the proposed optimization algorithm.
{"title":"An algorithm to optimize speed profiles of the metro vehicles for minimizing energy consumption","authors":"V. Calderaro, V. Galdi, G. Graber, A. Piccolo, Dario Cogliano","doi":"10.1109/SPEEDAM.2014.6872030","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872030","url":null,"abstract":"The calculation of optimal driving speed profiles for metro vehicles that improve energy saving and, thus, reduce costs, are investigated. The optimization problem is solved in two different steps: in the first one, a Dynamic Programming Optimization (DPO) algorithm (including slopes and curves effects) is used to find a set of pseudo-optimal speed cycles; the objective is to minimize the electrical energy used for traction subject to constraints such as travel time, trip distance, acceleration limits, etc. In the second optimization step, the speed profiles set are evaluated in a simulation tool implemented to estimate the power flow among vehicles through the metro network. A test campaign monitoring the saved energy and main electric variables have been implemented and the presented results showing the effectiveness of the performance of the proposed optimization algorithm.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123971993","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6871980
M. Aydin, M. Gokasan, S. Bogosyan
This study presents a parameter tuning approach for Extended Kalman Filter (EKF) based observers for the sensorless control of Induction Motor (IM) drives. After an analysis performed on the effect of covariance matrix elements of EKF, the study demonstrates the improved performance of the EKF based estimation (performed for stator currents, rotor flux, rotor speed, stator resistance and load torque), via the developed online parameter tuning approach for different speed and load references. Firstly, it has been demonstrated experimentally that covariance matrices used in EKF algorithm vary with the operation conditions. It has specifically been demonstrated that, among the elements of model covariance matrix, the ones corresponding to the rotor flux components are the most effective in correcting the estimations of the related EKF algorithm. To address this issue, an online fuzzy approach is developed based on different load and speed references, of which the inputs are the estimated speed and estimated load torque, and the output consists of the elements of the model covariance matrix related to the rotor flux. The performance of the proposed Fuzzy EKF has been experimentally tested and the results have demonstrated that the proposed scheme can eliminate biases and yields higher estimation accuracy when compared with the standard EKF where the tuning parameters are fixed to constant values.
{"title":"Fuzzy based parameter tuning of EKF observers for sensorless control of Induction Motors","authors":"M. Aydin, M. Gokasan, S. Bogosyan","doi":"10.1109/SPEEDAM.2014.6871980","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871980","url":null,"abstract":"This study presents a parameter tuning approach for Extended Kalman Filter (EKF) based observers for the sensorless control of Induction Motor (IM) drives. After an analysis performed on the effect of covariance matrix elements of EKF, the study demonstrates the improved performance of the EKF based estimation (performed for stator currents, rotor flux, rotor speed, stator resistance and load torque), via the developed online parameter tuning approach for different speed and load references. Firstly, it has been demonstrated experimentally that covariance matrices used in EKF algorithm vary with the operation conditions. It has specifically been demonstrated that, among the elements of model covariance matrix, the ones corresponding to the rotor flux components are the most effective in correcting the estimations of the related EKF algorithm. To address this issue, an online fuzzy approach is developed based on different load and speed references, of which the inputs are the estimated speed and estimated load torque, and the output consists of the elements of the model covariance matrix related to the rotor flux. The performance of the proposed Fuzzy EKF has been experimentally tested and the results have demonstrated that the proposed scheme can eliminate biases and yields higher estimation accuracy when compared with the standard EKF where the tuning parameters are fixed to constant values.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127648331","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6872042
J. Corcau, L. Dinca
This article presents experimental tests made on a DC to DC Boost Converter of 24 V-48 V. The boost converter was first realized on a laboratory version, regarding it's utility as a voltage source for the E.I.A (Equipments and Installations for Aviation) laboratory of the University of Craiova, and also to be used in teaching activities and for research. During tests it was point out the performances obtained, but also the inconvenient and the limitations of the purposed scheme. The improvements of this schema will be presented in a future study.
{"title":"Experimental tests regarding the functionality of a DC to DC Boost Converter","authors":"J. Corcau, L. Dinca","doi":"10.1109/SPEEDAM.2014.6872042","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872042","url":null,"abstract":"This article presents experimental tests made on a DC to DC Boost Converter of 24 V-48 V. The boost converter was first realized on a laboratory version, regarding it's utility as a voltage source for the E.I.A (Equipments and Installations for Aviation) laboratory of the University of Craiova, and also to be used in teaching activities and for research. During tests it was point out the performances obtained, but also the inconvenient and the limitations of the purposed scheme. The improvements of this schema will be presented in a future study.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128671430","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6872102
F. Palone, M. Rebolini, C. Bruzzese, F. Ielpo, S. Lauria, A. Vitiello
An innovative design of a device embedding the functions of both power transformer and shunt reactor is presented. The device is thought for installation onboard substation platforms of long HV/EHV AC cable connected offshore wind plants. The compact design saves much space on the hosting offshore platform, which can be sized smaller and cheaper. Machine sizing as well as cost saving considerations are exposed in this paper.
{"title":"An integrated transformer-shunt reactor operation device for the connection of off-shore wind-farms","authors":"F. Palone, M. Rebolini, C. Bruzzese, F. Ielpo, S. Lauria, A. Vitiello","doi":"10.1109/SPEEDAM.2014.6872102","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872102","url":null,"abstract":"An innovative design of a device embedding the functions of both power transformer and shunt reactor is presented. The device is thought for installation onboard substation platforms of long HV/EHV AC cable connected offshore wind plants. The compact design saves much space on the hosting offshore platform, which can be sized smaller and cheaper. Machine sizing as well as cost saving considerations are exposed in this paper.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114524715","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6872068
P. Zito, D. A. Lampasi, G. Maffia, G. Candela
This paper presents a novel digital controller purposely developed for nuclear fusion power supply systems and a MATLAB/Simulink model to simulate its behavior. Nuclear fusion experiments, as ITER, JT-60SA, FAST and DTT, require high current AC/DC converters, typically implemented in 4-quadrant 12-pulse back-to-back configurations, able to follow a desired current profile (scenario). With respect to a classic PID controller, the new digital controller features: a simple and robust feedback loop control of current by using two digital PID-based current controllers, an adapted and flexible direct control of the circulating current, good accuracy and stability during the current circulation to avoid dangerous oscillations, faster dynamic response, sequential control, variable firing angle limits, lower reactive power and reduced harmonic distortion. The controller and the developed simulation models were used to design and analyze the power supply systems for JT-60SA, an international fusion research project that is under construction with the joint contribution of Japanese and European researchers. The JT-60SA converters are designed to supply a DC current up to ±20 kA with an accuracy of ±1%.
{"title":"A novel digital controller for 12-pulse back-to-back AC/DC converters in nuclear fusion experiments","authors":"P. Zito, D. A. Lampasi, G. Maffia, G. Candela","doi":"10.1109/SPEEDAM.2014.6872068","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872068","url":null,"abstract":"This paper presents a novel digital controller purposely developed for nuclear fusion power supply systems and a MATLAB/Simulink model to simulate its behavior. Nuclear fusion experiments, as ITER, JT-60SA, FAST and DTT, require high current AC/DC converters, typically implemented in 4-quadrant 12-pulse back-to-back configurations, able to follow a desired current profile (scenario). With respect to a classic PID controller, the new digital controller features: a simple and robust feedback loop control of current by using two digital PID-based current controllers, an adapted and flexible direct control of the circulating current, good accuracy and stability during the current circulation to avoid dangerous oscillations, faster dynamic response, sequential control, variable firing angle limits, lower reactive power and reduced harmonic distortion. The controller and the developed simulation models were used to design and analyze the power supply systems for JT-60SA, an international fusion research project that is under construction with the joint contribution of Japanese and European researchers. The JT-60SA converters are designed to supply a DC current up to ±20 kA with an accuracy of ±1%.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115728663","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6871981
D. Popa, D. Fodorean
The paper deals with the study of a high speed induction motor to be used for the propulsion of an electric vehicle. A 40 kW machine, operating at a rated speed of 40500 r/min is designed and analyzed in the paper. After exposing the reasons which determined the choice of the induction motor for such an application, a particular topology is analyzed here. The aspects that arise during the design procedure and operation of such a motor are discussed in detail in the paper. Various choices which are influencing the performances of the machine are analyzed, both by analytical and numerical methods. Given the challenges of such an application, the numerical analysis has a very important role, to validate the choices made in the design process and to proof the capability of the machine to respond to the applications' demands.
{"title":"Design and performances evaluation of a high speed induction motor used for the propulsion of an electric vehicle","authors":"D. Popa, D. Fodorean","doi":"10.1109/SPEEDAM.2014.6871981","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871981","url":null,"abstract":"The paper deals with the study of a high speed induction motor to be used for the propulsion of an electric vehicle. A 40 kW machine, operating at a rated speed of 40500 r/min is designed and analyzed in the paper. After exposing the reasons which determined the choice of the induction motor for such an application, a particular topology is analyzed here. The aspects that arise during the design procedure and operation of such a motor are discussed in detail in the paper. Various choices which are influencing the performances of the machine are analyzed, both by analytical and numerical methods. Given the challenges of such an application, the numerical analysis has a very important role, to validate the choices made in the design process and to proof the capability of the machine to respond to the applications' demands.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"19 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120999055","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6872121
R. Laia, H. Pousinho, R. Melício, M. Collares-Pereira, V. Mendes
This paper proposes a stochastic mixed-integer linear approach to deal with a short-term unit commitment problem with uncertainty on a deregulated electricity market that includes day-ahead bidding and bilateral contracts. The proposed approach considers the typically operation constraints on the thermal units and a spinning reserve. The uncertainty is due to the electricity prices, which are modeled by a scenario set, allowing an acceptable computation. Moreover, emission allowances are considered in a manner to allow for the consideration of environmental constraints. A case study to illustrate the usefulness of the proposed approach is presented and an assessment of the cost for the spinning reserve is obtained by a comparison between the situation with and without spinning reserve.
{"title":"Spinning reserve and emission unit commitment through stochastic optimization","authors":"R. Laia, H. Pousinho, R. Melício, M. Collares-Pereira, V. Mendes","doi":"10.1109/SPEEDAM.2014.6872121","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872121","url":null,"abstract":"This paper proposes a stochastic mixed-integer linear approach to deal with a short-term unit commitment problem with uncertainty on a deregulated electricity market that includes day-ahead bidding and bilateral contracts. The proposed approach considers the typically operation constraints on the thermal units and a spinning reserve. The uncertainty is due to the electricity prices, which are modeled by a scenario set, allowing an acceptable computation. Moreover, emission allowances are considered in a manner to allow for the consideration of environmental constraints. A case study to illustrate the usefulness of the proposed approach is presented and an assessment of the cost for the spinning reserve is obtained by a comparison between the situation with and without spinning reserve.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127024450","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 : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6871990
M. Andriollo, A. Tortella, S. Kallio
The paper analyzes a “fork connection” arrangement enabling to achieve the benefits of multiple star windings overcoming the constraints on slot number imposed by conventional configurations. A suitable optimization technique yields both the required emf phase displacement and the optimal armature mmf profile, minimizing its harmonic content and consequently torque ripple and rotor losses due to eddy currents. Results of an example of application will be presented.
{"title":"Optimized “fork connection” arrangement for multiple star windings","authors":"M. Andriollo, A. Tortella, S. Kallio","doi":"10.1109/SPEEDAM.2014.6871990","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871990","url":null,"abstract":"The paper analyzes a “fork connection” arrangement enabling to achieve the benefits of multiple star windings overcoming the constraints on slot number imposed by conventional configurations. A suitable optimization technique yields both the required emf phase displacement and the optimal armature mmf profile, minimizing its harmonic content and consequently torque ripple and rotor losses due to eddy currents. Results of an example of application will be presented.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131580446","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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