Pub Date : 2014-06-18DOI: 10.1109/SPEEDAM.2014.6871917
B. Deusinger, Marcel Lehr, A. Binder
The determination of the efficiency of electrical machines by direct measurements is often too imprecise if the efficiency exceeds 95 %. For electrically excited synchronous machines a standardized method exists to determine the efficiency by summation of the individual losses. This method needs a variable excitation and therefore cannot be used for permanent magnet synchronous machines. As permanent magnet machines are increasingly used as wind turbine generators and traction motors, there is a large demand for an alternative method. In this project a new procedure is developed, which consists of a calculation of the losses at rated conditions via three different measurement series. The corresponding losses and circuit diagram parameters are determined from measurements at open circuit, measurements with removed rotor and measurements with pure reactive current. In addition to the theoretical calculations direct efficiency measurements are used to validate the efficiency calculation results. The two examined permanent magnet motors with fractional slot winding have a rated power of 45 kW.
{"title":"Determination of efficiency of permanent magnet synchronous machines from summation of losses","authors":"B. Deusinger, Marcel Lehr, A. Binder","doi":"10.1109/SPEEDAM.2014.6871917","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871917","url":null,"abstract":"The determination of the efficiency of electrical machines by direct measurements is often too imprecise if the efficiency exceeds 95 %. For electrically excited synchronous machines a standardized method exists to determine the efficiency by summation of the individual losses. This method needs a variable excitation and therefore cannot be used for permanent magnet synchronous machines. As permanent magnet machines are increasingly used as wind turbine generators and traction motors, there is a large demand for an alternative method. In this project a new procedure is developed, which consists of a calculation of the losses at rated conditions via three different measurement series. The corresponding losses and circuit diagram parameters are determined from measurements at open circuit, measurements with removed rotor and measurements with pure reactive current. In addition to the theoretical calculations direct efficiency measurements are used to validate the efficiency calculation results. The two examined permanent magnet motors with fractional slot winding have a rated power of 45 kW.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"16 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":"124579773","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.2014.6871970
A. Mohammadpour, L. Parsa
An efficient analytical approach is proposed for design of fault-tolerant five-phase permanent-magnet direct-drive linear motor drives for reliability-critical applications. The proposed approach is based on shaping back EMF waveform through a simple closed-from analytical equation to achieve optimal design using a genetic algorithm based optimization. Magnet track and coil assembly parameters are optimized to have a sinusoidal back EMF waveform. Mathematical derivation of optimal fault-tolerant currents for ripple-free operation under open-circuit faults is presented. Proposed methodology can be used to design actuators for high-precision safety-critical applications. Finite-element-analysis and experimental test results are used to verify proposed design method.
{"title":"Optimal design and prototyping of a five-phase direct-drive permanent magnet linear motor","authors":"A. Mohammadpour, L. Parsa","doi":"10.1109/SPEEDAM.2014.6871970","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871970","url":null,"abstract":"An efficient analytical approach is proposed for design of fault-tolerant five-phase permanent-magnet direct-drive linear motor drives for reliability-critical applications. The proposed approach is based on shaping back EMF waveform through a simple closed-from analytical equation to achieve optimal design using a genetic algorithm based optimization. Magnet track and coil assembly parameters are optimized to have a sinusoidal back EMF waveform. Mathematical derivation of optimal fault-tolerant currents for ripple-free operation under open-circuit faults is presented. Proposed methodology can be used to design actuators for high-precision safety-critical applications. Finite-element-analysis and experimental test results are used to verify proposed design method.","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":"131367254","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.2014.6872117
Liao Qingfen, Wang Yifei, Tang Fei, Yang Jian, Liu Yu
Reasonable islanding strategy is significant for avoiding blackout when the power system suffers from major fault. On the basis of this, this paper analyzes the electrical connection between nodes and proposes a new method of islanding strategy searching based on Floyd-warshall and DFS algorithm. By comparing the degree of electrical coupling relationship between load nodes and generator groups, the problem of islanding strategy searching can be mapped to the partition of the shared nodes. Afterwards, the shared nodes can be divided into proper island by further search which takes the minimum unbalanced power in each island after islanding as the objective function. After the above steps, the optimal islanding strategy can be obtained. The proposed method owns the advantage of low computation complexity and high fitness of operational modes. The effectiveness and rapidity are demonstrated through case studies on IEEE-39 test system and IEEE-118 test system.
{"title":"An islanding surface searching approach based on Floyd-warshall and DFS algorithm","authors":"Liao Qingfen, Wang Yifei, Tang Fei, Yang Jian, Liu Yu","doi":"10.1109/SPEEDAM.2014.6872117","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872117","url":null,"abstract":"Reasonable islanding strategy is significant for avoiding blackout when the power system suffers from major fault. On the basis of this, this paper analyzes the electrical connection between nodes and proposes a new method of islanding strategy searching based on Floyd-warshall and DFS algorithm. By comparing the degree of electrical coupling relationship between load nodes and generator groups, the problem of islanding strategy searching can be mapped to the partition of the shared nodes. Afterwards, the shared nodes can be divided into proper island by further search which takes the minimum unbalanced power in each island after islanding as the objective function. After the above steps, the optimal islanding strategy can be obtained. The proposed method owns the advantage of low computation complexity and high fitness of operational modes. The effectiveness and rapidity are demonstrated through case studies on IEEE-39 test system and IEEE-118 test system.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"65 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":"129836410","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.2014.6872011
G. Carpinelli, A. Russo, P. Varilone
Modern distribution grids are rapidly evolving toward complex systems (Smart Grids) due to the increasing level of penetration of distributed energy systems and information and communication technologies. In this context, Power Quality (PQ) becomes an important concern and advanced technical solutions to PQ problems are needed. The waveform distortions are one of the most important PQ disturbances and active filters are considered an useful technical solution to this disturbance. This paper deals with multi-converter distribution systems and formulates the problem of siting and sizing of active filters as a multi-objective optimization problem. The problem includes also the control strategies of the active compensators among the problem variables. A heuristic simplified approach based on a trade-off analysis is proposed to solve the multi-objective optimization problem with the aim of minimizing several objectives while meeting proper equality and inequality constraints. The proposed approach is applied to a 17-busbars distribution test system giving evidence of its effectiveness.
{"title":"Active filters: A multi-objective approach for the optimal allocation and sizing in distribution networks","authors":"G. Carpinelli, A. Russo, P. Varilone","doi":"10.1109/SPEEDAM.2014.6872011","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872011","url":null,"abstract":"Modern distribution grids are rapidly evolving toward complex systems (Smart Grids) due to the increasing level of penetration of distributed energy systems and information and communication technologies. In this context, Power Quality (PQ) becomes an important concern and advanced technical solutions to PQ problems are needed. The waveform distortions are one of the most important PQ disturbances and active filters are considered an useful technical solution to this disturbance. This paper deals with multi-converter distribution systems and formulates the problem of siting and sizing of active filters as a multi-objective optimization problem. The problem includes also the control strategies of the active compensators among the problem variables. A heuristic simplified approach based on a trade-off analysis is proposed to solve the multi-objective optimization problem with the aim of minimizing several objectives while meeting proper equality and inequality constraints. The proposed approach is applied to a 17-busbars distribution test system giving evidence of its effectiveness.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"50 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":"125633608","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.2014.6872070
C. Buccella, Carlo Cecati, M. G. Cimoroni, K. Razi
A new procedure to mitigate some harmonics is presented for a 5-level cascaded inverter, varying the modulation index. The two switching angles α1 and α2 are computed by using a procedure based on graphycal analysis by using Chebyshev polynomials and the Waring's formulae. The proposed mitigation technique is applied to reduce a pair of harmonics among third, fifth and seventh in inverter output voltage according to standard code requirements. Experimental results are also extracted by the prototype built at the laboratory. The measured results confirm the quality of the presented procedure.
{"title":"Harmonic mitigation technique for multilevel inverters in power systems","authors":"C. Buccella, Carlo Cecati, M. G. Cimoroni, K. Razi","doi":"10.1109/SPEEDAM.2014.6872070","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872070","url":null,"abstract":"A new procedure to mitigate some harmonics is presented for a 5-level cascaded inverter, varying the modulation index. The two switching angles α1 and α2 are computed by using a procedure based on graphycal analysis by using Chebyshev polynomials and the Waring's formulae. The proposed mitigation technique is applied to reduce a pair of harmonics among third, fifth and seventh in inverter output voltage according to standard code requirements. Experimental results are also extracted by the prototype built at the laboratory. The measured results confirm the quality of the presented procedure.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"3 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":"120863612","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.2014.6871967
Daniel Strassberger, Paolo Mercorelli, A. Georgiadis
This paper proposes a controller for motion control of the Robotino. The proposed controller takes under consideration a noninteracting control strategy realized using a geometric approach and the flatness of the DC-Drives. Horizon, Vertical and Angular motions are considered and once the decoupling between these motions is obtained, a Model Predictive Control (MPC) strategy is used in combination with a preselecting matrix. Simulation results using real data of Robotino are shown.
{"title":"Using the flatness of DC-Drives to emulate a generator for a decoupled MPC using a geometric approach for motion control in Robotino","authors":"Daniel Strassberger, Paolo Mercorelli, A. Georgiadis","doi":"10.1109/SPEEDAM.2014.6871967","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871967","url":null,"abstract":"This paper proposes a controller for motion control of the Robotino. The proposed controller takes under consideration a noninteracting control strategy realized using a geometric approach and the flatness of the DC-Drives. Horizon, Vertical and Angular motions are considered and once the decoupling between these motions is obtained, a Model Predictive Control (MPC) strategy is used in combination with a preselecting matrix. Simulation results using real data of Robotino are shown.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"108 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":"126925523","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.2014.6872008
A. C. Moreira, L. D. da Silva, H. K. Morales Paredes
This article proposes the use of PSCAD/EMTDC to model and simulate a three-phase x-ray machine. The model is an alternative tool to power quality studies, load connection impact analysis and power factor correction in the electric power distribution systems. The developed model is used to identify and quantify potential impacts of the X-ray machine in the electric power distribution system. Analyzes and discussions are based on actual measurements obtained in an X-ray apparatus terminals.
{"title":"Electrical modelling and power quality analysis of three-phase X-ray apparatus","authors":"A. C. Moreira, L. D. da Silva, H. K. Morales Paredes","doi":"10.1109/SPEEDAM.2014.6872008","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872008","url":null,"abstract":"This article proposes the use of PSCAD/EMTDC to model and simulate a three-phase x-ray machine. The model is an alternative tool to power quality studies, load connection impact analysis and power factor correction in the electric power distribution systems. The developed model is used to identify and quantify potential impacts of the X-ray machine in the electric power distribution system. Analyzes and discussions are based on actual measurements obtained in an X-ray apparatus terminals.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"16 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":"133659127","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.2014.6872076
V. Boscaino, G. Cipriani, V. Di Dio, R. Lauricella, A. Marcotulli, R. Miceli
Distributed power generation units are experiencing an impressive growth. Consequently, the amount of energy injected by non-linear loads as power converters is expected to increase. Stability and quality of the overall grid are heavily affected by performances of grid-side converters. In this paper, an overview of grid-synchronization technique is proposed. The grid-side inverter is implemented in MATLAB/Simulink® environment including current control and grid-synchronization section. Both Synchronous Reference Frame (SRF) and Decoupled Double Synchronous Reference Frame (DDSRF) PLL algorithms are implemented. A performance comparison is carried out under ideal and unbalanced utility conditions. A modify of DDSRF architecture is proposed to enhance performances of DDSRF under distorted conditions. Simulation results are shown and discussed.
{"title":"Overview and performance comparison of grid synchronization algorithms","authors":"V. Boscaino, G. Cipriani, V. Di Dio, R. Lauricella, A. Marcotulli, R. Miceli","doi":"10.1109/SPEEDAM.2014.6872076","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6872076","url":null,"abstract":"Distributed power generation units are experiencing an impressive growth. Consequently, the amount of energy injected by non-linear loads as power converters is expected to increase. Stability and quality of the overall grid are heavily affected by performances of grid-side converters. In this paper, an overview of grid-synchronization technique is proposed. The grid-side inverter is implemented in MATLAB/Simulink® environment including current control and grid-synchronization section. Both Synchronous Reference Frame (SRF) and Decoupled Double Synchronous Reference Frame (DDSRF) PLL algorithms are implemented. A performance comparison is carried out under ideal and unbalanced utility conditions. A modify of DDSRF architecture is proposed to enhance performances of DDSRF under distorted conditions. Simulation results are shown and discussed.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"6 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":"130527847","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.2014.6871964
S. Atiq, T. Lipo, B. Kwon
Field weakening control is a key technique for high speed operation of electrical machines. A novel Current Regulated Voltage Source Inverter (CRVSI) operation strategy is adopted in this paper to achieve high speed operation from Surface Mounted Permanent Magnet Synchronous Motor (SMPMSM). This strategy avoids any kind of previously proposed winding switching and achieves same benefits of high flux weakening. Machine operation is divided into two modes: two 3-phase CRVSI operation and three single phase CRVSI operation. During first mode of operation machine can be operated at maximum torque conditions as well as d-axes current control is applied for first stage of flux weakening. In second mode of operation, when machine reaches its constant power operation limit, CRVSIs operation is modified. Three 1-phase CRVSI are established such that machine operation reverts to achieve unity internal power factor at the elevated speed. Again d-axes current control is adopted to achieve second stage of flux weakening. Suitability of suggested current flow paths for the proposed topology is supported by inductance variation calculations. Furthermore effect of slot per pole per phase configuration on this flux weakling topology is discussed. Also constant power capability of the machine is examined for high speed operation. Initial experimental results are provided to validate the simulation results.
{"title":"Novel field weakening technique for Surface Mounted Permanent Magnet machine using Current Regulated Voltage Source Inverters","authors":"S. Atiq, T. Lipo, B. Kwon","doi":"10.1109/SPEEDAM.2014.6871964","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871964","url":null,"abstract":"Field weakening control is a key technique for high speed operation of electrical machines. A novel Current Regulated Voltage Source Inverter (CRVSI) operation strategy is adopted in this paper to achieve high speed operation from Surface Mounted Permanent Magnet Synchronous Motor (SMPMSM). This strategy avoids any kind of previously proposed winding switching and achieves same benefits of high flux weakening. Machine operation is divided into two modes: two 3-phase CRVSI operation and three single phase CRVSI operation. During first mode of operation machine can be operated at maximum torque conditions as well as d-axes current control is applied for first stage of flux weakening. In second mode of operation, when machine reaches its constant power operation limit, CRVSIs operation is modified. Three 1-phase CRVSI are established such that machine operation reverts to achieve unity internal power factor at the elevated speed. Again d-axes current control is adopted to achieve second stage of flux weakening. Suitability of suggested current flow paths for the proposed topology is supported by inductance variation calculations. Furthermore effect of slot per pole per phase configuration on this flux weakling topology is discussed. Also constant power capability of the machine is examined for high speed operation. Initial experimental results are provided to validate the simulation results.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"1 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":"131282611","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.2014.6871907
A. Lebsir, R. Rebbah, M. Larakeb, H. Djeghloud, A. Bentounsi
This paper presents the finite element modelling of a three-phase synchronous machine (3 kW-1500 rpm). In addition to analyzing the electromagnetic behaviour of the machine, various tests (no-load, short-circuit and load tests) was performed virtually using Maxwell software and validated experimentally. This work aims to parametric identification of machines and creation of a virtual laboratory of machine tests at Dept. of Electrical Engineering at the University of Constantine 1, Algeria.
{"title":"Modeling and analysis of a salient poles synchronous machines using finite-elements method","authors":"A. Lebsir, R. Rebbah, M. Larakeb, H. Djeghloud, A. Bentounsi","doi":"10.1109/SPEEDAM.2014.6871907","DOIUrl":"https://doi.org/10.1109/SPEEDAM.2014.6871907","url":null,"abstract":"This paper presents the finite element modelling of a three-phase synchronous machine (3 kW-1500 rpm). In addition to analyzing the electromagnetic behaviour of the machine, various tests (no-load, short-circuit and load tests) was performed virtually using Maxwell software and validated experimentally. This work aims to parametric identification of machines and creation of a virtual laboratory of machine tests at Dept. of Electrical Engineering at the University of Constantine 1, Algeria.","PeriodicalId":344918,"journal":{"name":"2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion","volume":"3 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":"128116729","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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