Pub Date : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579143
Taewon Kang, Beomseok Chae, Y. Suh
This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charge mode, constant-current mode, and constant-voltage mode. The pre-charge mode employs the stair-case shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is specified to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 78A. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system.
{"title":"Control algorithm of bi-directional power flow rapid charging system for electric vehicle using Li-Ion polymer battery","authors":"Taewon Kang, Beomseok Chae, Y. Suh","doi":"10.1109/ECCE-ASIA.2013.6579143","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579143","url":null,"abstract":"This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charge mode, constant-current mode, and constant-voltage mode. The pre-charge mode employs the stair-case shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is specified to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 78A. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122277150","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579286
S. Furukawa, K. Akatsu
This paper proposes a new motor named as a spintronics motor. This is the micro motor which uses GMR elements for the stator side. In this paper, two important examinations for a motor design are performed using FEA, a basic design of the proposed motor is described.
{"title":"A principle of next generation spintronics motor","authors":"S. Furukawa, K. Akatsu","doi":"10.1109/ECCE-ASIA.2013.6579286","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579286","url":null,"abstract":"This paper proposes a new motor named as a spintronics motor. This is the micro motor which uses GMR elements for the stator side. In this paper, two important examinations for a motor design are performed using FEA, a basic design of the proposed motor is described.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"36 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125729534","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}
This paper proposes a new design method of LCL-filter for three-phase PWM voltage source inverter. Maximum converter-side current ripple is calculated by defining different modulation section of the adopted PWM strategy. In this way, the method can be easily extended to different converter topology and PWM strategy. Then the result is used to determine converter-side inductance. Once it is fixed, current attenuation passing from converter to grid at switching frequency and reactive power limitation equations are synthesized to design the minimum grid-side inductance and the proper range of resonance frequency. Then according to adopted PWM converter voltage spectrum, choose final resonance frequency to avoid the harmonic frequency spectrum distribution. A design example is given and the simulation and experiment results demonstrate the effectiveness of the method.
{"title":"LCL-filter design for grid-connected three-phase PWM converter based on maximum current ripple","authors":"Fang Liu, Xing Zhang, Changzhou Yu, Zhangping Shao, Wei Zhao, Hua Ni","doi":"10.1109/ECCE-ASIA.2013.6579165","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579165","url":null,"abstract":"This paper proposes a new design method of LCL-filter for three-phase PWM voltage source inverter. Maximum converter-side current ripple is calculated by defining different modulation section of the adopted PWM strategy. In this way, the method can be easily extended to different converter topology and PWM strategy. Then the result is used to determine converter-side inductance. Once it is fixed, current attenuation passing from converter to grid at switching frequency and reactive power limitation equations are synthesized to design the minimum grid-side inductance and the proper range of resonance frequency. Then according to adopted PWM converter voltage spectrum, choose final resonance frequency to avoid the harmonic frequency spectrum distribution. A design example is given and the simulation and experiment results demonstrate the effectiveness of the method.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"229 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121454907","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579268
Tae-Woong Kim, Choon-Ho Cho, Jae-Ho Choi
Further driving distance has been required in electric vehicles under the limited battery energy. Therefore, inverter which is one of the EV core technologies should secure a higher efficiency. Inverter efficiency is largely dependent on switching commutation. In this paper, inverter SVPWM control scheme with switching loss reduction is proposed by introduction of simplified switching sequence strategy. It is confirmed by simulation and experimental analyses that the proposed modulation scheme has a lower switching loss compared to the conventional 5-step switching sequence based modulations scheme.
{"title":"Switching loss reduction modulation scheme based inverter for electric vehicle","authors":"Tae-Woong Kim, Choon-Ho Cho, Jae-Ho Choi","doi":"10.1109/ECCE-ASIA.2013.6579268","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579268","url":null,"abstract":"Further driving distance has been required in electric vehicles under the limited battery energy. Therefore, inverter which is one of the EV core technologies should secure a higher efficiency. Inverter efficiency is largely dependent on switching commutation. In this paper, inverter SVPWM control scheme with switching loss reduction is proposed by introduction of simplified switching sequence strategy. It is confirmed by simulation and experimental analyses that the proposed modulation scheme has a lower switching loss compared to the conventional 5-step switching sequence based modulations scheme.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133988021","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579279
Rakesh Sharma, V. Agarwal
A high gain DC-DC converter is proposed in this paper. This converter combines the basic boost converter with voltage doubler circuit to achieve high voltage gain with high efficiency. The novel topology makes use of a single switch to achieve high voltage gain. The voltage appearing across the switch is much lower than the output voltage. Hence, a low voltage rating switch with low on state resistance can be used for this converter. The operation of the converter is explained and steady state analysis is included. Voltage gain equation and expression for voltage across the switch is derived. Representative simulation results are included along with the preliminary experimental results.
{"title":"A high gain dc-dc converter with voltage multiplier","authors":"Rakesh Sharma, V. Agarwal","doi":"10.1109/ECCE-ASIA.2013.6579279","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579279","url":null,"abstract":"A high gain DC-DC converter is proposed in this paper. This converter combines the basic boost converter with voltage doubler circuit to achieve high voltage gain with high efficiency. The novel topology makes use of a single switch to achieve high voltage gain. The voltage appearing across the switch is much lower than the output voltage. Hence, a low voltage rating switch with low on state resistance can be used for this converter. The operation of the converter is explained and steady state analysis is included. Voltage gain equation and expression for voltage across the switch is derived. Representative simulation results are included along with the preliminary experimental results.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133639220","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579223
K. Rouzbehi, A. Miranian, A. Luna, P. Rodríguez
This paper proposes a novel control strategy in multi-terminal DC (MTDC) grids with offshore wind generation based on the idea of generalized voltage droop (GVD). In the proposed strategy, the GVD characteristics are assigned to the voltage-regulating converter station, enhancing their control maneuverability and enabling them to perform necessary DC voltage control and power sharing tasks. By adjusting the coefficients of the corresponding GVD characteristic, a converter station can be operated in three operating modes, namely (1) fixed active power control mode, (2) conventional voltage droop control mode or (3) fixed DC voltage control mode. Results of simulations on a test four-terminal DC grid including two offshore wind farm and two AC grids show the capabilities of the proposed control strategy. Moreover, simulation results confirmed stable operation of the GVD control in transition from one operating mode to another.
{"title":"A novel approach for voltage control of multi-terminal DC grids with offshore wind farms","authors":"K. Rouzbehi, A. Miranian, A. Luna, P. Rodríguez","doi":"10.1109/ECCE-ASIA.2013.6579223","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579223","url":null,"abstract":"This paper proposes a novel control strategy in multi-terminal DC (MTDC) grids with offshore wind generation based on the idea of generalized voltage droop (GVD). In the proposed strategy, the GVD characteristics are assigned to the voltage-regulating converter station, enhancing their control maneuverability and enabling them to perform necessary DC voltage control and power sharing tasks. By adjusting the coefficients of the corresponding GVD characteristic, a converter station can be operated in three operating modes, namely (1) fixed active power control mode, (2) conventional voltage droop control mode or (3) fixed DC voltage control mode. Results of simulations on a test four-terminal DC grid including two offshore wind farm and two AC grids show the capabilities of the proposed control strategy. Moreover, simulation results confirmed stable operation of the GVD control in transition from one operating mode to another.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132502794","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579111
Xiaolei Hu, K. Tseng, Yitao Liu, S. Yin, Mengqi Zhang
In applications of modern power distribution with distributed energy resources, grid-tied energy storage systems (ESS) will be increasingly incorporated. Energy storage devices (ESD) such as lithium-ion battery or super-capacitor cells however have low DC terminal voltages. It is essential to develop a bidirectional DC/AC converter to interface ESS based on low voltage cells to the higher voltage grid without using high number of cells in series. In this paper a bidirectional current-fed converter with high frequency transformer isolation is proposed. In this proposed topology, a current source inverter (CSI) is used to interface to the grid. A DC/DC converter with High frequency(HF) transformer is used to feed the current to CSI. Low voltage and high voltage side of DC/DC converter can be either Push-Pull or Full-Bridge. The proposed topology has the advantage of reduced component count and simple control strategy. Simulation and hardware results have shown that the proposed circuit can work in charging and discharging of the ESS and the control strategy is effective.
{"title":"A high frequency isolated current-fed bidirectional DC/AC converter for grid-tied energy storage system","authors":"Xiaolei Hu, K. Tseng, Yitao Liu, S. Yin, Mengqi Zhang","doi":"10.1109/ECCE-ASIA.2013.6579111","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579111","url":null,"abstract":"In applications of modern power distribution with distributed energy resources, grid-tied energy storage systems (ESS) will be increasingly incorporated. Energy storage devices (ESD) such as lithium-ion battery or super-capacitor cells however have low DC terminal voltages. It is essential to develop a bidirectional DC/AC converter to interface ESS based on low voltage cells to the higher voltage grid without using high number of cells in series. In this paper a bidirectional current-fed converter with high frequency transformer isolation is proposed. In this proposed topology, a current source inverter (CSI) is used to interface to the grid. A DC/DC converter with High frequency(HF) transformer is used to feed the current to CSI. Low voltage and high voltage side of DC/DC converter can be either Push-Pull or Full-Bridge. The proposed topology has the advantage of reduced component count and simple control strategy. Simulation and hardware results have shown that the proposed circuit can work in charging and discharging of the ESS and the control strategy is effective.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128343626","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579072
A. M. Razali, M. Rahman, N. Rahim
This paper investigates a new approach in developing a current control method utilizing the grid virtual flux estimation technique for reducing the number of sensors and to enhance the control performance of the grid connected three phase ac-dc converter system. Accordingly, a virtual flux oriented control (VFOC) with the improvement of virtual flux estimation technique has been proposed in this work. The virtual flux components obtained from the grid virtual flux estimation technique is used to extract the grid voltage information from the converter switching states, the dc-link output voltage and the three phase input currents. The VFOC structure is developed by incorporating the grid virtual flux components in modeling the ac-dc converter. The steady state as well as the dynamic performances of the proposed VFOC are presented and analyzed by using Matlab/Simulink and experimentally verified in real-time. The results show that the ac-dc converter utilizing the proposed VFOC is able to produce a fixed switching frequency, almost sinusoidal with low total harmonic distortion of the line currents, unity power factor operation and adjustable dc-link output voltage.
{"title":"An analysis of current control method for grid connected front-end three phase AC-DC converter","authors":"A. M. Razali, M. Rahman, N. Rahim","doi":"10.1109/ECCE-ASIA.2013.6579072","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579072","url":null,"abstract":"This paper investigates a new approach in developing a current control method utilizing the grid virtual flux estimation technique for reducing the number of sensors and to enhance the control performance of the grid connected three phase ac-dc converter system. Accordingly, a virtual flux oriented control (VFOC) with the improvement of virtual flux estimation technique has been proposed in this work. The virtual flux components obtained from the grid virtual flux estimation technique is used to extract the grid voltage information from the converter switching states, the dc-link output voltage and the three phase input currents. The VFOC structure is developed by incorporating the grid virtual flux components in modeling the ac-dc converter. The steady state as well as the dynamic performances of the proposed VFOC are presented and analyzed by using Matlab/Simulink and experimentally verified in real-time. The results show that the ac-dc converter utilizing the proposed VFOC is able to produce a fixed switching frequency, almost sinusoidal with low total harmonic distortion of the line currents, unity power factor operation and adjustable dc-link output voltage.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132019067","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579258
H. Geng, Geng Yang
Grid codes require wind farm to ride through disturbances such as faults and support the grid during such events. Doubly fed induction generator (DFIG) based wind farm with conventional design has limited capability to ride through severe asymmetrical faults due to low capacity of the rotor-side-converter (RSC). DFIG wind turbine with series grid-side converter (SGSC) can help to extend the operation areas during the fault and satisfy the future grid codes. This paper addresses the capacity design and coordinating control scheme of the SGSC-DFIG based wind farm to ride through the severe asymmetrical fault and support the power grid. Considering the control capability of the RSC and the requirements of the present grid code, the SGSC capacity can be minimized if it is employed to compensate part of the negative-sequence grid voltages. By coordinating the control of SGSC and the DFIG, the positive- and negative-sequence reactive current can be carefully regulated to support the grid and satisfy the code requirements. At the same time, the torsional oscillation of the generator shaft can be mitigated by the negative current control. Simulation results verify the effectiveness of the design and scheme.
{"title":"Ride-through and grid support of the DFIG based wind farm during asymmetrical faults","authors":"H. Geng, Geng Yang","doi":"10.1109/ECCE-ASIA.2013.6579258","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579258","url":null,"abstract":"Grid codes require wind farm to ride through disturbances such as faults and support the grid during such events. Doubly fed induction generator (DFIG) based wind farm with conventional design has limited capability to ride through severe asymmetrical faults due to low capacity of the rotor-side-converter (RSC). DFIG wind turbine with series grid-side converter (SGSC) can help to extend the operation areas during the fault and satisfy the future grid codes. This paper addresses the capacity design and coordinating control scheme of the SGSC-DFIG based wind farm to ride through the severe asymmetrical fault and support the power grid. Considering the control capability of the RSC and the requirements of the present grid code, the SGSC capacity can be minimized if it is employed to compensate part of the negative-sequence grid voltages. By coordinating the control of SGSC and the DFIG, the positive- and negative-sequence reactive current can be carefully regulated to support the grid and satisfy the code requirements. At the same time, the torsional oscillation of the generator shaft can be mitigated by the negative current control. Simulation results verify the effectiveness of the design and scheme.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133186853","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 : 2013-06-03DOI: 10.1109/ECCE-ASIA.2013.6579099
D. Pan, Yang Wang, T. Lipo
Permanent magnet synchronous generators have been shown to be lower cost, lighter in weight and more efficient when compared to a wound-field synchronous generator with a brushless exciter. However, due to the fact that the field from the magnets cannot be adjusted, PM machines have seen less application when operated in the generation mode. In this paper, it is proposed to regulate the load side voltage of an open-winding permanent magnet synchronous generator by injecting reactive power in a series fashion as the rotor speed and load level vary. The var source is a voltage source inverter that is directly connected in series to the generator. The operating principle will be explained. A detailed comparison between the proposed topology and existing shunt regulated system will be presented. In addition, the dimensioning of the compensation inverter will be discussed. The control method of the proposed system will be proposed and validated by simulation and experimental study.
{"title":"A series regulated open-winding PM generator based constant voltage, variable frequency AC distribution system","authors":"D. Pan, Yang Wang, T. Lipo","doi":"10.1109/ECCE-ASIA.2013.6579099","DOIUrl":"https://doi.org/10.1109/ECCE-ASIA.2013.6579099","url":null,"abstract":"Permanent magnet synchronous generators have been shown to be lower cost, lighter in weight and more efficient when compared to a wound-field synchronous generator with a brushless exciter. However, due to the fact that the field from the magnets cannot be adjusted, PM machines have seen less application when operated in the generation mode. In this paper, it is proposed to regulate the load side voltage of an open-winding permanent magnet synchronous generator by injecting reactive power in a series fashion as the rotor speed and load level vary. The var source is a voltage source inverter that is directly connected in series to the generator. The operating principle will be explained. A detailed comparison between the proposed topology and existing shunt regulated system will be presented. In addition, the dimensioning of the compensation inverter will be discussed. The control method of the proposed system will be proposed and validated by simulation and experimental study.","PeriodicalId":301487,"journal":{"name":"2013 IEEE ECCE Asia Downunder","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122685889","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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