Pub Date : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395588
Martin Gendrin, Jean-Yves Gauthier, X. Lin-Shi
The use of Electro-Mechanical Actuator to impact an environment is often criticized because of its presumably higher wear. This is due to the naturally high stiffness of the mechanical transmission, that leads to a hard-to-hard impact with the environment. This paper proposes a position-based impedance control using a Finite Control Set Model Predictive Control (FCS-MPC) controller to solve this problem. In comparison to a standard impedance controller, it can achieve the same impedance behavior in steady state, but the reduction of the mechanical losses and of the compression of the transmission are better during the transient. Furthermore, the trade-off between the mechanical losses and the transient time can be modified easily by changing the weighting factors of a cost function.
{"title":"An impedance control using a Finite Control Set Model Predictive Controller","authors":"Martin Gendrin, Jean-Yves Gauthier, X. Lin-Shi","doi":"10.1109/PRECEDE.2015.7395588","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395588","url":null,"abstract":"The use of Electro-Mechanical Actuator to impact an environment is often criticized because of its presumably higher wear. This is due to the naturally high stiffness of the mechanical transmission, that leads to a hard-to-hard impact with the environment. This paper proposes a position-based impedance control using a Finite Control Set Model Predictive Control (FCS-MPC) controller to solve this problem. In comparison to a standard impedance controller, it can achieve the same impedance behavior in steady state, but the reduction of the mechanical losses and of the compression of the transmission are better during the transient. Furthermore, the trade-off between the mechanical losses and the transient time can be modified easily by changing the weighting factors of a cost function.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131908880","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395580
M. Rivera, C. Uribe, L. Tarisciotti, P. Wheeler, P. Zanchetta
This paper proposes a predictive control technique for an indirect matrix converter. The proposed control strategy gives sinusoidal waveforms at both the input and output of the converter without any weighting factor in the cost function and, at the same time, giving operation at a fixed switching frequency. Simulation results with an unbalanced ac-supply validate the proposed method under both steady state and transient conditions.
{"title":"Predictive control of an indirect matrix converter operating at fixed switching frequency and unbalanced AC-supply","authors":"M. Rivera, C. Uribe, L. Tarisciotti, P. Wheeler, P. Zanchetta","doi":"10.1109/PRECEDE.2015.7395580","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395580","url":null,"abstract":"This paper proposes a predictive control technique for an indirect matrix converter. The proposed control strategy gives sinusoidal waveforms at both the input and output of the converter without any weighting factor in the cost function and, at the same time, giving operation at a fixed switching frequency. Simulation results with an unbalanced ac-supply validate the proposed method under both steady state and transient conditions.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"129 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130086822","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395577
R. Fotouhi, Alexey Sorokin, R. Kennel, H. Mouton
Optimal Pulse Patterns (OPPs) permit setting the switching frequency of power converters to a low value without compromising on Total Harmonic Distortion (THD). The optimization, which is performed offline, is a slow procedure and is usually done with the goal of current distortion minimization. This paper proposes a method for online optimization of current distortion based on stator flux trajectory predictions for a five-level inverter.
{"title":"Online optimization of current distortion for MV drives based on stator flux trajectory predictions","authors":"R. Fotouhi, Alexey Sorokin, R. Kennel, H. Mouton","doi":"10.1109/PRECEDE.2015.7395577","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395577","url":null,"abstract":"Optimal Pulse Patterns (OPPs) permit setting the switching frequency of power converters to a low value without compromising on Total Harmonic Distortion (THD). The optimization, which is performed offline, is a slow procedure and is usually done with the goal of current distortion minimization. This paper proposes a method for online optimization of current distortion based on stator flux trajectory predictions for a five-level inverter.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130193648","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395584
C. Hackl
We consider model predictive control (MPC) of disturbed linear time-invariant (LTI) multiple-input multiple-output (MIMO) systems without constraints. For the considered system class, the MPC problem has an analytical solution which allows for prediction horizons with arbitrary length. In addition, we introduce integral error feedback which assures steady-state accuracy for (piece-wise) constant disturbances and reference signals. The proposed MPC scheme is applied to grid-side current control of grid-connected power converters with LCL-filter. Simulation results illustrate and compare the control performance of the proposed MPC scheme with and without integral error feedback under (symmetric) grid perturbations.
{"title":"MPC with analytical solution and integral error feedback for LTI MIMO systems and its application to current control of grid-connected power converters with LCL-filter","authors":"C. Hackl","doi":"10.1109/PRECEDE.2015.7395584","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395584","url":null,"abstract":"We consider model predictive control (MPC) of disturbed linear time-invariant (LTI) multiple-input multiple-output (MIMO) systems without constraints. For the considered system class, the MPC problem has an analytical solution which allows for prediction horizons with arbitrary length. In addition, we introduce integral error feedback which assures steady-state accuracy for (piece-wise) constant disturbances and reference signals. The proposed MPC scheme is applied to grid-side current control of grid-connected power converters with LCL-filter. Simulation results illustrate and compare the control performance of the proposed MPC scheme with and without integral error feedback under (symmetric) grid perturbations.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124591436","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395578
O. Yade, Jean-Yves Gauthier, X. Lin-Shi, Martin Gendrin, Abderrahime Zaoui
In order to actively control the power flow in a Dual Active Bridge (DAB) converter, different modulation strategies such as Single Phase Shift (SPS), Triangular Modulation (TRM), Extended Single Phase Shift (ESPS) have been proposed. Each modulation is more suitable for a given range of load power level and has difficulties in working with a wide range of load power level. As these strategies are complementary and their combination can improve the DAB converter yield, in this paper, Finite Control Set Model Predictive Control is used to choose the best modulation strategy at the best moment in order to improve the efficiency of the DAB converter in real time. This choice will be made according to a cost function taking a trade-off of the current across the leakage inductance, the power error and the switching losses.
{"title":"Modulation strategy for a Dual Active Bridge converter using Model Predictive Control","authors":"O. Yade, Jean-Yves Gauthier, X. Lin-Shi, Martin Gendrin, Abderrahime Zaoui","doi":"10.1109/PRECEDE.2015.7395578","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395578","url":null,"abstract":"In order to actively control the power flow in a Dual Active Bridge (DAB) converter, different modulation strategies such as Single Phase Shift (SPS), Triangular Modulation (TRM), Extended Single Phase Shift (ESPS) have been proposed. Each modulation is more suitable for a given range of load power level and has difficulties in working with a wide range of load power level. As these strategies are complementary and their combination can improve the DAB converter yield, in this paper, Finite Control Set Model Predictive Control is used to choose the best modulation strategy at the best moment in order to improve the efficiency of the DAB converter in real time. This choice will be made according to a cost function taking a trade-off of the current across the leakage inductance, the power error and the switching losses.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"553 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127091438","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395507
C. Rojas, S. Kouro, M. Pérez, F. Villarroel
Recently the use of Model Predictive Control (MPC) in electrical motor drives has been reported both theoretically and experimentally. Predictive Torque Control (PTC) has been developed to control induction motor drives, allowing high-performance and fast dynamics. However, the optimization used in PTC is based on a single cost function minimization, where control objectives are merged by using weighting factors. The adjustment of these factors is achieved through a nontrivial process and they are heavily dependent on the system parameters and user requirements, being a complex task in systems where two or three weighting factors must be adjusted. To avoid the well-known time-consuming simulations and branch and bound search process, a Multiobjective Fuzzy Predictive Torque Control (FPTC) is presented for a Three-Level Neutral-Point-Clamped voltage source inverter (3L-NPC). The proposed strategy changes the single cost function with a Multiobjective Optimization based on Fuzzy-Decision-Making. Simulation results are presented to illustrate the behavior of the motor drive under steady-state and dynamic conditions.
{"title":"Multiobjective Fuzzy Predictive Torque Control of an induction machine fed by a 3L-NPC inverter","authors":"C. Rojas, S. Kouro, M. Pérez, F. Villarroel","doi":"10.1109/PRECEDE.2015.7395507","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395507","url":null,"abstract":"Recently the use of Model Predictive Control (MPC) in electrical motor drives has been reported both theoretically and experimentally. Predictive Torque Control (PTC) has been developed to control induction motor drives, allowing high-performance and fast dynamics. However, the optimization used in PTC is based on a single cost function minimization, where control objectives are merged by using weighting factors. The adjustment of these factors is achieved through a nontrivial process and they are heavily dependent on the system parameters and user requirements, being a complex task in systems where two or three weighting factors must be adjusted. To avoid the well-known time-consuming simulations and branch and bound search process, a Multiobjective Fuzzy Predictive Torque Control (FPTC) is presented for a Three-Level Neutral-Point-Clamped voltage source inverter (3L-NPC). The proposed strategy changes the single cost function with a Multiobjective Optimization based on Fuzzy-Decision-Making. Simulation results are presented to illustrate the behavior of the motor drive under steady-state and dynamic conditions.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123666367","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395592
M. Tomlinson, T. Mouton, R. Kennel
In this paper a finite-control-set model predictive control (FCS-MPC) scheme for achieving a fixed switching frequency is compared with a linear regulator for current control of a single-leg inverter driving a resistive-inductive load with a back-EMF. This comparison is motivated by the fact that finite-control-set MPC is often regarded as having an inferior output waveform quality compared to PWM due to a variable switching frequency. In this paper, an oversampled FCS-MPC control scheme that achieves a fixed switching frequency through hard constraints is compared to an oversampled and well-tuned linear resonant regulator. It will be shown that by oversampling the predictive controller and forcing a fixed switching frequency scheme, the output waveform quality of FCS-MPC can produce results similar to that of a PWM-based controller. It will further be shown that the typical one-sample delay during reference step changes and the effects of model uncertainties such a DC bus ripple are greatly reduced if the predictive controller is sampled at a much higher rate than the switching frequency.
{"title":"Finite-control-set model predictive control with a fixed switching frequency vs. linear control for current control of a single-leg inverter","authors":"M. Tomlinson, T. Mouton, R. Kennel","doi":"10.1109/PRECEDE.2015.7395592","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395592","url":null,"abstract":"In this paper a finite-control-set model predictive control (FCS-MPC) scheme for achieving a fixed switching frequency is compared with a linear regulator for current control of a single-leg inverter driving a resistive-inductive load with a back-EMF. This comparison is motivated by the fact that finite-control-set MPC is often regarded as having an inferior output waveform quality compared to PWM due to a variable switching frequency. In this paper, an oversampled FCS-MPC control scheme that achieves a fixed switching frequency through hard constraints is compared to an oversampled and well-tuned linear resonant regulator. It will be shown that by oversampling the predictive controller and forcing a fixed switching frequency scheme, the output waveform quality of FCS-MPC can produce results similar to that of a PWM-based controller. It will further be shown that the typical one-sample delay during reference step changes and the effects of model uncertainties such a DC bus ripple are greatly reduced if the predictive controller is sampled at a much higher rate than the switching frequency.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133591522","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395508
M. Pérez, C. Garcia
Model predictive control has several advantages for power converter applications such as a simple theoretical concept, a straightforward implementation and a high dynamical response regardless the high switching frequency it generates which is one of its main drawbacks. In this paper a virtual first order filter is modeled in the predictive algorithm and its output is included into the cost function in order to modify the switching states selection and reduce the switching frequency. The proposed algorithm generates a reduction of the average switching frequency but it does not deteriorate the dynamical response of predictive control. Additionally, it has a simple implementation because it does not require frequency transformations, the virtual filter can be easily designed and the algorithm does not require additional memory to save the switching pattern to count the commutations. Results that confirm the performance of the proposed algorithm are given.
{"title":"Reduced switching frequency operation of power converters using virtual model based MPC","authors":"M. Pérez, C. Garcia","doi":"10.1109/PRECEDE.2015.7395508","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395508","url":null,"abstract":"Model predictive control has several advantages for power converter applications such as a simple theoretical concept, a straightforward implementation and a high dynamical response regardless the high switching frequency it generates which is one of its main drawbacks. In this paper a virtual first order filter is modeled in the predictive algorithm and its output is included into the cost function in order to modify the switching states selection and reduce the switching frequency. The proposed algorithm generates a reduction of the average switching frequency but it does not deteriorate the dynamical response of predictive control. Additionally, it has a simple implementation because it does not require frequency transformations, the virtual filter can be easily designed and the algorithm does not require additional memory to save the switching pattern to count the commutations. Results that confirm the performance of the proposed algorithm are given.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132981729","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395591
M. Vijayagopal, L. Empringham, L. de Lillo, L. Tarisciotti, P. Zanchetta, P. Wheeler
This paper investigates a novel model- predictive control strategy to control an induction motor fed by a matrix converter with multi-objective control capability. The proposed control method combines the features of the classical Model Predictive Control and the Space Vector Modulation technique into a Modulated Model Predictive Control. This new solution maintains all the characteristics of Model Predictive Control (such as fast transient response, multi-objective control using only one feedback loop, easy inclusion of nonlinearities and constraints of the system, the flexibility to include other system requirements in the controller) adding the advantages of working at fixed switching frequency and improving the quality of the controlled waveforms. Simulation results employing the control method to control the stator current and input reactive power of a direct matrix converter induction motor drive are presented.
{"title":"Current control and reactive power minimization of a direct matrix converter induction motor drive with Modulated Model Predictive Control","authors":"M. Vijayagopal, L. Empringham, L. de Lillo, L. Tarisciotti, P. Zanchetta, P. Wheeler","doi":"10.1109/PRECEDE.2015.7395591","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395591","url":null,"abstract":"This paper investigates a novel model- predictive control strategy to control an induction motor fed by a matrix converter with multi-objective control capability. The proposed control method combines the features of the classical Model Predictive Control and the Space Vector Modulation technique into a Modulated Model Predictive Control. This new solution maintains all the characteristics of Model Predictive Control (such as fast transient response, multi-objective control using only one feedback loop, easy inclusion of nonlinearities and constraints of the system, the flexibility to include other system requirements in the controller) adding the advantages of working at fixed switching frequency and improving the quality of the controlled waveforms. Simulation results employing the control method to control the stator current and input reactive power of a direct matrix converter induction motor drive are presented.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116226646","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 : 2015-10-01DOI: 10.1109/PRECEDE.2015.7395594
V. Yaramasu, M. Rivera, Bin Wu, José R. Rodríguez
In this paper, finite control-set model predictive control of two-level and three-level four-leg voltage source converters (VSCs) is presented. The predictive current control (PCC) and predictive voltage control (PVC) schemes are presented considering grid-connected and standalone distributed generation applications respectively. The discrete-time model of load currents, load voltages, DC-link capacitors voltage and VSC terminal voltages is formulated in terms of four-leg converter switching states. A cost function is defined with the PCC scheme to minimize the error between reference and predicted load currents. Similarly, in PVC scheme, the cost function deals with the minimization of error between reference and predicted load voltages. The balancing of split DC-link capacitors voltage is considered with the three-level four-leg VSCs. The optimal switching states which minimize the cost function are chosen and applied to the four-leg VSC directly without involving linear regulators and modulation stage. The proposed PCC and PVC strategies are verified through simulation results considering single-/three-phase, balanced/unbalanced and linear/nonlinear loads.
{"title":"Predictive control of four-leg power converters","authors":"V. Yaramasu, M. Rivera, Bin Wu, José R. Rodríguez","doi":"10.1109/PRECEDE.2015.7395594","DOIUrl":"https://doi.org/10.1109/PRECEDE.2015.7395594","url":null,"abstract":"In this paper, finite control-set model predictive control of two-level and three-level four-leg voltage source converters (VSCs) is presented. The predictive current control (PCC) and predictive voltage control (PVC) schemes are presented considering grid-connected and standalone distributed generation applications respectively. The discrete-time model of load currents, load voltages, DC-link capacitors voltage and VSC terminal voltages is formulated in terms of four-leg converter switching states. A cost function is defined with the PCC scheme to minimize the error between reference and predicted load currents. Similarly, in PVC scheme, the cost function deals with the minimization of error between reference and predicted load voltages. The balancing of split DC-link capacitors voltage is considered with the three-level four-leg VSCs. The optimal switching states which minimize the cost function are chosen and applied to the four-leg VSC directly without involving linear regulators and modulation stage. The proposed PCC and PVC strategies are verified through simulation results considering single-/three-phase, balanced/unbalanced and linear/nonlinear loads.","PeriodicalId":271130,"journal":{"name":"2015 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130223544","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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