Pub Date : 2014-09-29DOI: 10.1109/EPE.2014.6910686
R. Sudharshan Kaarthik, K. Gopakumar, J. Mathew, T. Undeland
Multilevel inverters with hexagonal voltage space vector structures have improved performance of induction motor drives compared to that of the two level inverters. Further reduction in the torque ripple on the motor shaft is possible by using multilevel dodecagonal (12-sided polygon) voltage space vector structures. The advantages of dodecagonal voltage space vector based PWM techniques are the complete elimination of fifth and seventh harmonics in phase voltages for the full modulation range and the extension of linear modulation range. This paper proposes an inverter circuit topology capable of generating multilevel dodecagonal voltage space vectors with symmetric triangles, by cascading two asymmetric three level inverters with isolated H-Bridges. This is made possible by proper selection of DC link voltages and the selection of resultant switching states for the inverters. In this paper, a simple PWM timing calculation method is proposed. Experimental results have also been presented in this paper to validate the proposed concept.
{"title":"An open-end winding IM drive with multilevel 12-sided polygonal vectors with symmetric triangles","authors":"R. Sudharshan Kaarthik, K. Gopakumar, J. Mathew, T. Undeland","doi":"10.1109/EPE.2014.6910686","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910686","url":null,"abstract":"Multilevel inverters with hexagonal voltage space vector structures have improved performance of induction motor drives compared to that of the two level inverters. Further reduction in the torque ripple on the motor shaft is possible by using multilevel dodecagonal (12-sided polygon) voltage space vector structures. The advantages of dodecagonal voltage space vector based PWM techniques are the complete elimination of fifth and seventh harmonics in phase voltages for the full modulation range and the extension of linear modulation range. This paper proposes an inverter circuit topology capable of generating multilevel dodecagonal voltage space vectors with symmetric triangles, by cascading two asymmetric three level inverters with isolated H-Bridges. This is made possible by proper selection of DC link voltages and the selection of resultant switching states for the inverters. In this paper, a simple PWM timing calculation method is proposed. Experimental results have also been presented in this paper to validate the proposed concept.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"35 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73930579","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 : 2014-09-29DOI: 10.1109/EPE.2014.6910831
T. Krone, T. Koneke, A. Mertens
Manufacturers of power semiconductors and modules intend to rate the maximum junction temperature up to 200°C. This results in higher temperatures at other components of the inverter system as well. In this paper, it is presented a method to identify thermal constraints in an inverter design by combining analytical and numerical analysis of the thermal spreading. Furthermore, an overview of the thermal limits of the inverter's components is given. The resulting thermal constraints of an air-cooled system are discussed, and it is introduced an inverter design to avoid over-temperatures. Finally, the test results achieved from the constructed inverter at 200°C junction temperature are presented.
{"title":"System design for junction temperatures up to 200°C","authors":"T. Krone, T. Koneke, A. Mertens","doi":"10.1109/EPE.2014.6910831","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910831","url":null,"abstract":"Manufacturers of power semiconductors and modules intend to rate the maximum junction temperature up to 200°C. This results in higher temperatures at other components of the inverter system as well. In this paper, it is presented a method to identify thermal constraints in an inverter design by combining analytical and numerical analysis of the thermal spreading. Furthermore, an overview of the thermal limits of the inverter's components is given. The resulting thermal constraints of an air-cooled system are discussed, and it is introduced an inverter design to avoid over-temperatures. Finally, the test results achieved from the constructed inverter at 200°C junction temperature are presented.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"83 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73716185","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 : 2014-09-29DOI: 10.1109/EPE.2014.6910710
V. V. Subrahmanya Kumar Bhajana, P. Drábek, Martin Jara, B. Bednár
This paper proposed a new ZCS single phase ac-ac matrix converter for the traction applications. The proposed soft switching matrix converter is enhanced with an auxiliary resonant circuit in order to achieve the zero current switching for main bidirectional switches of the matrix converter. The main advantage of this proposed topology is soft switching of matrix converter to achieve switching loses limitation. This paper describes the operation of the proposed matrix converter, simulation analysis and experimental validation of the prototype for 50V-16.7Hz-100W-400Hz.
{"title":"A novel ZCS single phase matrix converter for traction applications","authors":"V. V. Subrahmanya Kumar Bhajana, P. Drábek, Martin Jara, B. Bednár","doi":"10.1109/EPE.2014.6910710","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910710","url":null,"abstract":"This paper proposed a new ZCS single phase ac-ac matrix converter for the traction applications. The proposed soft switching matrix converter is enhanced with an auxiliary resonant circuit in order to achieve the zero current switching for main bidirectional switches of the matrix converter. The main advantage of this proposed topology is soft switching of matrix converter to achieve switching loses limitation. This paper describes the operation of the proposed matrix converter, simulation analysis and experimental validation of the prototype for 50V-16.7Hz-100W-400Hz.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"182 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73200709","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 : 2014-09-29DOI: 10.1109/EPE.2014.6911035
L. Kutt, E. Saarijarvi, M. Lehtonen, H. Mõlder, J. Niitsoo
Electric vehicle chargers are mostly power converters with power factor correction and waveform shaping features included. Different vehicle makes and models will likely have different charger control and topology. While the charger charging currents have generally low AC waveform distortions, including variety of chargers at the same time can provide even further lower harmonic currents. This is due to harmonic cancellation brought by different harmonic patterns of different chargers. The present paper analyzes the sine distortions and the sum of the harmonic currents of multiple harmonic sources of such type. The inputs for the analysis are the measurements of the commercial EV's harmonic charging current patterns. It will be shown that remarkable harmonic cancellation will be likely if different vehicle types are included in the pool of vehicles charging at the same time. The results presented here for the EV chargers would be valid also for other similar mains interface converters.
{"title":"Harmonic distortions of multiple power factor compensated EV chargers","authors":"L. Kutt, E. Saarijarvi, M. Lehtonen, H. Mõlder, J. Niitsoo","doi":"10.1109/EPE.2014.6911035","DOIUrl":"https://doi.org/10.1109/EPE.2014.6911035","url":null,"abstract":"Electric vehicle chargers are mostly power converters with power factor correction and waveform shaping features included. Different vehicle makes and models will likely have different charger control and topology. While the charger charging currents have generally low AC waveform distortions, including variety of chargers at the same time can provide even further lower harmonic currents. This is due to harmonic cancellation brought by different harmonic patterns of different chargers. The present paper analyzes the sine distortions and the sum of the harmonic currents of multiple harmonic sources of such type. The inputs for the analysis are the measurements of the commercial EV's harmonic charging current patterns. It will be shown that remarkable harmonic cancellation will be likely if different vehicle types are included in the pool of vehicles charging at the same time. The results presented here for the EV chargers would be valid also for other similar mains interface converters.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"3 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73341035","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 : 2014-09-29DOI: 10.1109/EPE.2014.6910797
Otto Kreutzer, B. Eckardt, M. Mârz
This paper describes the power stage of a non-isolated unidirectional 400 V 100 kW DC-DC converter for fuel cell vehicles that reaches a switching frequency of 150 kHz with industry power modules. The power modules are equipped with custom made DCB-substrate assembled with a combination of fast 600 V superjunction Si-MOSFETs and SiC-Schottky diodes. For all other components like drivers, current sensors and the auxiliary supply converter standard products have been used to facilitate an automotive specification, and a cost efficient production. The inductors are custom-made to reduce choke losses and volume. The converter reaches an efficiency of 98 % at full load (166->400 V, 590 A lowside current). Furthermore a simple and reliable DC-link discharge unit is described that discharges with constant power and is far smaller and faster than a conventional resistor solution. Based on a constant current discharge device using a Power MOSFET in linear operation, it is extended with a small analog circuit to a roughly constant power discharge device.
{"title":"Unidirectional fast switching non-isolated 100 kW fuel cell boost converter","authors":"Otto Kreutzer, B. Eckardt, M. Mârz","doi":"10.1109/EPE.2014.6910797","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910797","url":null,"abstract":"This paper describes the power stage of a non-isolated unidirectional 400 V 100 kW DC-DC converter for fuel cell vehicles that reaches a switching frequency of 150 kHz with industry power modules. The power modules are equipped with custom made DCB-substrate assembled with a combination of fast 600 V superjunction Si-MOSFETs and SiC-Schottky diodes. For all other components like drivers, current sensors and the auxiliary supply converter standard products have been used to facilitate an automotive specification, and a cost efficient production. The inductors are custom-made to reduce choke losses and volume. The converter reaches an efficiency of 98 % at full load (166->400 V, 590 A lowside current). Furthermore a simple and reliable DC-link discharge unit is described that discharges with constant power and is far smaller and faster than a conventional resistor solution. Based on a constant current discharge device using a Power MOSFET in linear operation, it is extended with a small analog circuit to a roughly constant power discharge device.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"30 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72739795","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 : 2014-09-29DOI: 10.1109/EPE.2014.6911047
R. Miftakhutdinov
Paper analyzes substantial Coss behavior differences of FETs using super-junction Si, SiC and GaN technologies versus traditional Si process and suggests new practical models for power losses optimization. These models applied to derive normalized ZVS conditions and boundaries for popular PWM ZVS topologies allowing efficiency optimization at wide operating conditions.
{"title":"New aspects on analyzing ZVS conditions for converters using super-junction Si and wide bandgap SiC and GaN power FETs","authors":"R. Miftakhutdinov","doi":"10.1109/EPE.2014.6911047","DOIUrl":"https://doi.org/10.1109/EPE.2014.6911047","url":null,"abstract":"Paper analyzes substantial Coss behavior differences of FETs using super-junction Si, SiC and GaN technologies versus traditional Si process and suggests new practical models for power losses optimization. These models applied to derive normalized ZVS conditions and boundaries for popular PWM ZVS topologies allowing efficiency optimization at wide operating conditions.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"97 4","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72632223","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 : 2014-09-29DOI: 10.1109/EPE.2014.6910875
Ivan Kravtzoff, P. Dessante, J. Vannier, P. Manfe, E. Mouni
Hybrids systems benefits are strongly dependent on the system design and the control strategy. The strategy choice strongly affect sizing and vice versa. This phenomenon is not always taken into account which leads to a non-optimal sizing of the system. This paper suggests a new method to optimize the design of hybrid power generator system from the point of view of fuel consumption taking into account this interaction. The main idea is to calculate the optimal control strategy of the system energy flux. Then, we can perform, for a given load profile, an optimization of the whole structure to find the best sizing.
{"title":"Obal optimization of hybrid electrical system to decrease fuel consumption or operating cost","authors":"Ivan Kravtzoff, P. Dessante, J. Vannier, P. Manfe, E. Mouni","doi":"10.1109/EPE.2014.6910875","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910875","url":null,"abstract":"Hybrids systems benefits are strongly dependent on the system design and the control strategy. The strategy choice strongly affect sizing and vice versa. This phenomenon is not always taken into account which leads to a non-optimal sizing of the system. This paper suggests a new method to optimize the design of hybrid power generator system from the point of view of fuel consumption taking into account this interaction. The main idea is to calculate the optimal control strategy of the system energy flux. Then, we can perform, for a given load profile, an optimization of the whole structure to find the best sizing.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"94 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72802208","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 : 2014-09-29DOI: 10.1109/EPE.2014.6910899
Georg Deiml, C. Hahn, W. Winter, M. Luther
This paper discusses a novel model for stability studies of a Multiterminal High Voltage Direct Current system (MT HVDC) as part of an overlay grid in a hybrid AC system. The dynamic model is set up for Multilevel Voltage Sourced Converter (VSC) technology. The new model provides the opportunity to analyse the impact of full- and half-bridge modules during AC and DC faults. In the present paper a radial DC system with four converter stations was built up and simulated in PSS®NETOMAC. In principle the model can be expanded to a multiterminal HVDC system with a higher number of converter stations. Generally the structure of the DC grid does not subject to any restrictions. For steady state control of a MT HVDC system the Voltage Margin Method (VMM) was implemented. The main focus of the presented model is placed on dynamic stability studies in case of DC faults and their effects on the AC grid. But due to the possibility of VSC converters to provide general system services, e.g. to supply reactive power, the effects and advantages of VSC converters during AC faults can also be analysed. In principle Insulated Gate Bipolar Transistor (IGBT) technology offers the possibility of clearing DC faults on the DC side. Depending on the type of modules (full- or half-bridge modules) used in a Multilevel VSC converter the fault clearing strategy and therefore the effects to the AC grid differ enormously. It is essential for the transient stability of a highly stressed AC grid to ensure a very low fault clearance time to keep the system stable. The proposed control design was designed as a two partition macro in PSS®NETOMAC and can be used for planning a Multiterminal DC system in any AC grid. It was applied to a small test grid in order to prove its performance. For more realistic results the model was implemented and applied in a dynamic model of the Continental Europe high voltage power transmission grid.
{"title":"A novel dynamic model for Multiterminal HVDC systems based on self-commutated full- and half-bridge Multilevel Voltage Sourced Converters","authors":"Georg Deiml, C. Hahn, W. Winter, M. Luther","doi":"10.1109/EPE.2014.6910899","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910899","url":null,"abstract":"This paper discusses a novel model for stability studies of a Multiterminal High Voltage Direct Current system (MT HVDC) as part of an overlay grid in a hybrid AC system. The dynamic model is set up for Multilevel Voltage Sourced Converter (VSC) technology. The new model provides the opportunity to analyse the impact of full- and half-bridge modules during AC and DC faults. In the present paper a radial DC system with four converter stations was built up and simulated in PSS®NETOMAC. In principle the model can be expanded to a multiterminal HVDC system with a higher number of converter stations. Generally the structure of the DC grid does not subject to any restrictions. For steady state control of a MT HVDC system the Voltage Margin Method (VMM) was implemented. The main focus of the presented model is placed on dynamic stability studies in case of DC faults and their effects on the AC grid. But due to the possibility of VSC converters to provide general system services, e.g. to supply reactive power, the effects and advantages of VSC converters during AC faults can also be analysed. In principle Insulated Gate Bipolar Transistor (IGBT) technology offers the possibility of clearing DC faults on the DC side. Depending on the type of modules (full- or half-bridge modules) used in a Multilevel VSC converter the fault clearing strategy and therefore the effects to the AC grid differ enormously. It is essential for the transient stability of a highly stressed AC grid to ensure a very low fault clearance time to keep the system stable. The proposed control design was designed as a two partition macro in PSS®NETOMAC and can be used for planning a Multiterminal DC system in any AC grid. It was applied to a small test grid in order to prove its performance. For more realistic results the model was implemented and applied in a dynamic model of the Continental Europe high voltage power transmission grid.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"112 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77259312","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 : 2014-09-29DOI: 10.1109/EPE.2014.6910926
G. Farivar, V. Agelidis, B. Hredzak
In this paper a generalized scheme for capacitors voltage estimation for multilevel converters based on the converter switching states and using only a single voltage sensor at the AC side of the converter is proposed. The estimation of the capacitors voltage is performed after a capacitor is switched on or off and hence the estimation frequency is dependent on the converter switching frequency. In between the switching periods, the scheme can keep track of the capacitors voltage by monitoring the current flowing through the capacitor until the next transition. The effectiveness of the proposed scheme is demonstrated on a single-phase 7-level cascaded H-Bridge multilevel converter based STATCOM by simulation in the Matlab/Simulink environment.
{"title":"A generalized capacitors voltage estimation scheme for multilevel converters","authors":"G. Farivar, V. Agelidis, B. Hredzak","doi":"10.1109/EPE.2014.6910926","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910926","url":null,"abstract":"In this paper a generalized scheme for capacitors voltage estimation for multilevel converters based on the converter switching states and using only a single voltage sensor at the AC side of the converter is proposed. The estimation of the capacitors voltage is performed after a capacitor is switched on or off and hence the estimation frequency is dependent on the converter switching frequency. In between the switching periods, the scheme can keep track of the capacitors voltage by monitoring the current flowing through the capacitor until the next transition. The effectiveness of the proposed scheme is demonstrated on a single-phase 7-level cascaded H-Bridge multilevel converter based STATCOM by simulation in the Matlab/Simulink environment.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"190 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79755104","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 : 2014-09-29DOI: 10.1109/EPE.2014.6910723
Jian Fu, Bo Zhang, D. Qiu, Wenxun Xiao
This paper proposes a novel single-switch dc-dc converter with voltage gain D/(1-D)2 by cascading a Boost converter and a Buck-boost converter. The proposed converter has the advantages of simple circuit structure and extended voltage conversion ratio. The operating principle and steady-state analysis of the proposed converter are discussed in detail. Finally, a prototype is implemented to verify theoretical analysis.
{"title":"A novel single-switch cascaded DC-DC converter of Boost and Buck-boost converters","authors":"Jian Fu, Bo Zhang, D. Qiu, Wenxun Xiao","doi":"10.1109/EPE.2014.6910723","DOIUrl":"https://doi.org/10.1109/EPE.2014.6910723","url":null,"abstract":"This paper proposes a novel single-switch dc-dc converter with voltage gain D/(1-D)2 by cascading a Boost converter and a Buck-boost converter. The proposed converter has the advantages of simple circuit structure and extended voltage conversion ratio. The operating principle and steady-state analysis of the proposed converter are discussed in detail. Finally, a prototype is implemented to verify theoretical analysis.","PeriodicalId":6508,"journal":{"name":"2014 16th European Conference on Power Electronics and Applications","volume":"37 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2014-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79805786","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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