Pub Date : 2014-11-01DOI: 10.1109/PEAC.2014.7037838
Zhaoyang Yan, Hongyan He, Jianxia Li, M. Su, Chunjiang Zhang
Under unbalanced grid voltage conditions, negative-sequence will generate the double fundamental frequency in the dq synchronous rotating reference frame. In order to detect the positive-sequence component of the grid voltages fast, this paper proposes a new phase-locked loop method, called double fundamental frequency phase-locked loop (DFF-PLL). The operation principle is analyzed, giving the extract formulas of the positive- and negative-sequence with double fundamental frequency, the process of DFF-PLL and the detection of positive-sequence component of grid voltages. The paper improves the second order generalized integrator quadrature-signals generation (SOGI-QSG), in order to remove the DC bias voltage and guarantee the orthogonality of SOGI-QSG. The performance of DFF-PLL is verified by using simulation and experimental results. Compared with DSOGI-PLL, this method increases the detection speed and accuracy under unbalanced grid voltage conditions.
{"title":"Double fundamental frequency PLL with second order generalized integrator under unbalanced grid voltages","authors":"Zhaoyang Yan, Hongyan He, Jianxia Li, M. Su, Chunjiang Zhang","doi":"10.1109/PEAC.2014.7037838","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037838","url":null,"abstract":"Under unbalanced grid voltage conditions, negative-sequence will generate the double fundamental frequency in the dq synchronous rotating reference frame. In order to detect the positive-sequence component of the grid voltages fast, this paper proposes a new phase-locked loop method, called double fundamental frequency phase-locked loop (DFF-PLL). The operation principle is analyzed, giving the extract formulas of the positive- and negative-sequence with double fundamental frequency, the process of DFF-PLL and the detection of positive-sequence component of grid voltages. The paper improves the second order generalized integrator quadrature-signals generation (SOGI-QSG), in order to remove the DC bias voltage and guarantee the orthogonality of SOGI-QSG. The performance of DFF-PLL is verified by using simulation and experimental results. Compared with DSOGI-PLL, this method increases the detection speed and accuracy under unbalanced grid voltage conditions.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123024899","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 : 2014-11-01DOI: 10.1109/PEAC.2014.7037891
Jiaju Wu, Hongjun Shi, Hangli Hu, Bin Liu
As an example of push-pull SPWM inverter, this paper presents a mathematical model of the push-pull transformer, considers the on-off status of switching devices and discusses the time and space characteristics of the dynamic and effective leakage inductance which means that the leakage inductance within primary/secondary windings of the push-pull transformer has the action time and associated winding in the different situations. Moreover, it clarifies the relationship among the action time, associated winding and the direction of the energy flow within windings. The simulation results are verified by comparison with mathematical analysis. Experimental measurements show a close agreement with the simulation results as well.
{"title":"A new method of modeling and simulation for push-pull SPWM inverter","authors":"Jiaju Wu, Hongjun Shi, Hangli Hu, Bin Liu","doi":"10.1109/PEAC.2014.7037891","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037891","url":null,"abstract":"As an example of push-pull SPWM inverter, this paper presents a mathematical model of the push-pull transformer, considers the on-off status of switching devices and discusses the time and space characteristics of the dynamic and effective leakage inductance which means that the leakage inductance within primary/secondary windings of the push-pull transformer has the action time and associated winding in the different situations. Moreover, it clarifies the relationship among the action time, associated winding and the direction of the energy flow within windings. The simulation results are verified by comparison with mathematical analysis. Experimental measurements show a close agreement with the simulation results as well.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"81 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131133561","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}
In general, Boost circuit is widely used as PFC circuit to achieve high power factor (PF), but the power supply needs to add a Buck circuit in the case of low-voltage output applications. Two-stage circuit requires more components and two control circuits. On the other hand, as the power levels increase, the full-bridge diode rectifier reduces the converter efficiency due to the large conduction losses. This paper presents a novel single-stage (SS) bridgeless Boost&Buck circuit. Boost circuit serves as a PFC stage and Buck as a DC/DC stage. Bridgeless structure can reduce conduction losses effectively, and improve the efficiency of the converter in low-input voltage & high-input current conditions. The proposed DCM + CCM control strategy is used to achieve high PF, high efficiency and step-down capabilities. At last, a prototype with 85~135Vrms input and 75Vdc/150W output was set up to verify the theoretical analysis.
{"title":"A novel single-stage bridgeless Boost&Buck PFC converter","authors":"Qingliang Zheng, Weiming Lin, Shengjian Liu, Nanbing Wu","doi":"10.1109/PEAC.2014.7037945","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037945","url":null,"abstract":"In general, Boost circuit is widely used as PFC circuit to achieve high power factor (PF), but the power supply needs to add a Buck circuit in the case of low-voltage output applications. Two-stage circuit requires more components and two control circuits. On the other hand, as the power levels increase, the full-bridge diode rectifier reduces the converter efficiency due to the large conduction losses. This paper presents a novel single-stage (SS) bridgeless Boost&Buck circuit. Boost circuit serves as a PFC stage and Buck as a DC/DC stage. Bridgeless structure can reduce conduction losses effectively, and improve the efficiency of the converter in low-input voltage & high-input current conditions. The proposed DCM + CCM control strategy is used to achieve high PF, high efficiency and step-down capabilities. At last, a prototype with 85~135Vrms input and 75Vdc/150W output was set up to verify the theoretical analysis.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115159383","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 : 2014-11-01DOI: 10.1109/PEAC.2014.7037841
Wei Qin, Bo Zhu, Xu Zhang, Xinke Wu
In this paper, a current-feed resonant two-switch forward DC-DC Transformer (DCX) is proposed for high-efficiency and high-density unregulated bus converter applications. With a resonant capacitor in series with the leakage inductance of the transformer, ZCS turn-on and nearly ZCS turn-off can be achieved for the primary switches and there is no body diode and reverse recovery losses in the SR. Meanwhile, the magnetizing current is used to achieve ZVS turn-off for the primary switches. The circuit operating principle and design considerations are discussed. An 110W prototype is built up to verify the theoretical analysis.
{"title":"A novel current-feed soft-switching two-switch forward resonant DC-DC Transformer (DCX)","authors":"Wei Qin, Bo Zhu, Xu Zhang, Xinke Wu","doi":"10.1109/PEAC.2014.7037841","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037841","url":null,"abstract":"In this paper, a current-feed resonant two-switch forward DC-DC Transformer (DCX) is proposed for high-efficiency and high-density unregulated bus converter applications. With a resonant capacitor in series with the leakage inductance of the transformer, ZCS turn-on and nearly ZCS turn-off can be achieved for the primary switches and there is no body diode and reverse recovery losses in the SR. Meanwhile, the magnetizing current is used to achieve ZVS turn-off for the primary switches. The circuit operating principle and design considerations are discussed. An 110W prototype is built up to verify the theoretical analysis.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134026605","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 : 2014-11-01DOI: 10.1109/PEAC.2014.7037964
Biao Liang, G. Zhu, Xiaobin Fu, Wei-Xing Liu, Hao-Ran Wang
The DC current of the single-phase inverter or rectifier contains low frequency ripple whose frequency is twice that of the AC voltage. Traditionally, electrolytic capacitor is used to eliminate these ripple, but it has relatively short lifespan and affect the lifetime of the entire inverter or rectifier system. In this paper, a single-phase bidirectional bridge topology without electrolytic capacitor is presented. The bidirectional topology combines a conventional converter and a pair of additional switches. In addition, the bidirectional bridge topology can control the pulsation power at the ac side due to the two differential capacitors, which is produced by splitting the AC filter capacitor of the conventional inverter or rectifier symmetrically. The DC current ripple of the bridge converter can be significantly reduced without the electrolytic capacitors (E-Cap). Theoretical analysis and results are provided to explain the operation and showcase the performance of the bidirectional bridge topology. All the experimental results are provided to support the feasibility of the proposed work.
{"title":"Single-phase bidirectional bridge topology without electrolytic capacitor at the DC side","authors":"Biao Liang, G. Zhu, Xiaobin Fu, Wei-Xing Liu, Hao-Ran Wang","doi":"10.1109/PEAC.2014.7037964","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037964","url":null,"abstract":"The DC current of the single-phase inverter or rectifier contains low frequency ripple whose frequency is twice that of the AC voltage. Traditionally, electrolytic capacitor is used to eliminate these ripple, but it has relatively short lifespan and affect the lifetime of the entire inverter or rectifier system. In this paper, a single-phase bidirectional bridge topology without electrolytic capacitor is presented. The bidirectional topology combines a conventional converter and a pair of additional switches. In addition, the bidirectional bridge topology can control the pulsation power at the ac side due to the two differential capacitors, which is produced by splitting the AC filter capacitor of the conventional inverter or rectifier symmetrically. The DC current ripple of the bridge converter can be significantly reduced without the electrolytic capacitors (E-Cap). Theoretical analysis and results are provided to explain the operation and showcase the performance of the bidirectional bridge topology. All the experimental results are provided to support the feasibility of the proposed work.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131985836","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 : 2014-11-01DOI: 10.1109/PEAC.2014.7037948
Feng-wu Zhou, Huipin Lin, Jin Hu, Zhengyu Lv, Bin Qian, Jun Xu
Series-connected lithium batteries can be charged in pack mode that is most widely used in lithium battery application field. But pack charging mode will lead to cell unbalanced charging because of cell differences among series-connected batteries in electrochemical characteristic. On the other hand, the cell charging mode can avoid the imbalance problem by charging each cell independently as a result of reducing the charge efficiency and raising the cost. In this paper, a novel balancing strategy is proposed with pack charging mode and cell charging mode mixed to implement balancing algorithm. The proposed balancing system is based on the distributed power supply technology and the power bus technology. A DC voltage bus and an AC quasi-square wave voltage bus are built by relevant converters. The proposed method aims to solve the problem of charge imbalance with simple balancing algorithm and make the charge efficiency stay as high as possible.
{"title":"A novel balancing strategy for series-connected lithium batteries based on mixed charging mode","authors":"Feng-wu Zhou, Huipin Lin, Jin Hu, Zhengyu Lv, Bin Qian, Jun Xu","doi":"10.1109/PEAC.2014.7037948","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037948","url":null,"abstract":"Series-connected lithium batteries can be charged in pack mode that is most widely used in lithium battery application field. But pack charging mode will lead to cell unbalanced charging because of cell differences among series-connected batteries in electrochemical characteristic. On the other hand, the cell charging mode can avoid the imbalance problem by charging each cell independently as a result of reducing the charge efficiency and raising the cost. In this paper, a novel balancing strategy is proposed with pack charging mode and cell charging mode mixed to implement balancing algorithm. The proposed balancing system is based on the distributed power supply technology and the power bus technology. A DC voltage bus and an AC quasi-square wave voltage bus are built by relevant converters. The proposed method aims to solve the problem of charge imbalance with simple balancing algorithm and make the charge efficiency stay as high as possible.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130299497","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}
In this paper, a novel power electronic transformer (PET) structure for dc power distribution system is proposed. The proposed converter can achieve very high voltage conversion ratio with high frequency isolation and bidirectional energy flow, thus it can be used as the interface equipment of high voltage and low voltage dc power grid. Different from the conventional structure, only one high frequency transformer is used in the proposed structure, reducing the fabricating cost. Based on the proposed topology, phase shift control method is introduced to output the required power and balance the submodule voltage. A 100kW simulation model is built up in Simulink/MATLAB. The simulation results verify the proposed converter and control method.
{"title":"Power electronic transformer for dc power distribution network","authors":"Zhaohui Wang, Zhen Zhang, Junming Zhang, Kuang Sheng","doi":"10.1109/PEAC.2014.7037961","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037961","url":null,"abstract":"In this paper, a novel power electronic transformer (PET) structure for dc power distribution system is proposed. The proposed converter can achieve very high voltage conversion ratio with high frequency isolation and bidirectional energy flow, thus it can be used as the interface equipment of high voltage and low voltage dc power grid. Different from the conventional structure, only one high frequency transformer is used in the proposed structure, reducing the fabricating cost. Based on the proposed topology, phase shift control method is introduced to output the required power and balance the submodule voltage. A 100kW simulation model is built up in Simulink/MATLAB. The simulation results verify the proposed converter and control method.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"335 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115668712","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 : 2014-11-01DOI: 10.1109/PEAC.2014.7038071
Zhonghua Zhu, Yongai Zheng, Yu Fang, Pan Xu
This paper analyzes the necessity of establishing the dc bus voltage of the Dual Active Bridge (Dual Active Bridge, DAB) converter when starting up. And the startup method that the DC-bus voltage is built up only by high-voltage-side body diode of the DAB converter rectifying is proposed in the paper. The detailed steps and the software realization method are elaborated. The saturation phenomenon of the inductor and the current surge can be effectively avoided in this way and the method presented in this paper implemented only by digital control, so this method does not need to add extra hardware. Finally, the experimental results verify the method.
本文分析了双有源桥式(Dual Active Bridge, DAB)变换器启动时建立直流母线电压的必要性。提出了仅靠DAB变换器的高压侧体二极管整流来建立直流母线电压的启动方法。阐述了具体步骤和软件实现方法。这种方法可以有效地避免电感的饱和现象和电流浪涌，而且本文的方法仅通过数字控制实现，因此不需要增加额外的硬件。最后，通过实验验证了该方法的有效性。
{"title":"Analysis of the startup method for building up DC voltage via body diode rectifying in Dual Active Bridge converter","authors":"Zhonghua Zhu, Yongai Zheng, Yu Fang, Pan Xu","doi":"10.1109/PEAC.2014.7038071","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7038071","url":null,"abstract":"This paper analyzes the necessity of establishing the dc bus voltage of the Dual Active Bridge (Dual Active Bridge, DAB) converter when starting up. And the startup method that the DC-bus voltage is built up only by high-voltage-side body diode of the DAB converter rectifying is proposed in the paper. The detailed steps and the software realization method are elaborated. The saturation phenomenon of the inductor and the current surge can be effectively avoided in this way and the method presented in this paper implemented only by digital control, so this method does not need to add extra hardware. Finally, the experimental results verify the method.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"16 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114125628","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 : 2014-11-01DOI: 10.1109/PEAC.2014.7037995
Qiqi Zhao, Yu Fang, Mingming Ma, Jun Wang, Yong Xie
A fuzzy control strategy is presented to implement the neutral-point (NP) potential balance based on the power stage of three-level Boost dc-dc converter in this paper. The presented fuzzy controller can solve the imbalance problem of NP potential in the process of starting up and can suppress the influence of inverter circuit modulation strategy on NP potential. It is the fuzzy controller that can adaptively change duty cycle ratio to implement the balance between the output capacitor voltages, not only in the process of starting up, but also in steady operation state. The fuzzy controller has been designed in this paper and the control rules have been given to achieve perfect dynamic and steady performance. Finally, the simulation and experimental results verify the feasibility and reliability of this methods way and the method presented in this paper implemented only by digital control, so this method does not need to add extra hardware. Finally, the experimental results verify the method.
{"title":"Study on a fuzzy controller for the balance of capacitor voltages of three-level boost dc-dc converter","authors":"Qiqi Zhao, Yu Fang, Mingming Ma, Jun Wang, Yong Xie","doi":"10.1109/PEAC.2014.7037995","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7037995","url":null,"abstract":"A fuzzy control strategy is presented to implement the neutral-point (NP) potential balance based on the power stage of three-level Boost dc-dc converter in this paper. The presented fuzzy controller can solve the imbalance problem of NP potential in the process of starting up and can suppress the influence of inverter circuit modulation strategy on NP potential. It is the fuzzy controller that can adaptively change duty cycle ratio to implement the balance between the output capacitor voltages, not only in the process of starting up, but also in steady operation state. The fuzzy controller has been designed in this paper and the control rules have been given to achieve perfect dynamic and steady performance. Finally, the simulation and experimental results verify the feasibility and reliability of this methods way and the method presented in this paper implemented only by digital control, so this method does not need to add extra hardware. Finally, the experimental results verify the method.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114468650","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 : 2014-11-01DOI: 10.1109/PEAC.2014.7038018
Dongbin Zhao, F. Lin, Zhongping Yang
In this paper, the mathematical model of the PMSM (permanent magnet synchronous motor) traction drive system is established. After the linearization of the model, the equation of state which takes the fluctuations of the DC traction voltage as input is deduced. Then the effects of the distance between the substation and the motor, the speed of the motor and the dc-link inductor on the PMSM traction drive system are analyzed by using the zero-pole map when the voltage of the DC traction network waved. At last, the simulation results proves the validity of the analysis.
{"title":"Effects of the traction network voltage fluctuation on the permanent magnet synchronous traction drive system","authors":"Dongbin Zhao, F. Lin, Zhongping Yang","doi":"10.1109/PEAC.2014.7038018","DOIUrl":"https://doi.org/10.1109/PEAC.2014.7038018","url":null,"abstract":"In this paper, the mathematical model of the PMSM (permanent magnet synchronous motor) traction drive system is established. After the linearization of the model, the equation of state which takes the fluctuations of the DC traction voltage as input is deduced. Then the effects of the distance between the substation and the motor, the speed of the motor and the dc-link inductor on the PMSM traction drive system are analyzed by using the zero-pole map when the voltage of the DC traction network waved. At last, the simulation results proves the validity of the analysis.","PeriodicalId":309780,"journal":{"name":"2014 International Power Electronics and Application Conference and Exposition","volume":"187 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123358246","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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