Pub Date : 2018-10-22DOI: 10.23919/IPEC.2018.8507446
Mingshen Li, Yonghao Gui, Zheming Jin, Y. Guan, J. Guerrero
A simple and fast decentralized Current-Voltage (I-V) droop control method under the Synchronous-Reference-Frame (SRF) is proposed to share output current for parallel three-phase inverters with LC filter. The I-V droop characteristic is derived in accordance with the virtual impedance in SRF. Thus, each inverter enables to work in a voltage controlled mode where it controls the filter capacitor voltage. Moreover, a detailed state-space model of two parallel inverters is derived to analyze the control performance. Through the simulation and experiment validation, the proposed method provides accurate current sharing and faster transient response under inverter connection in comparison with the conventional droop control.
{"title":"A Synchronous-Reference-Frame I-V Droop Control Method for Parallel-Connected Inverters","authors":"Mingshen Li, Yonghao Gui, Zheming Jin, Y. Guan, J. Guerrero","doi":"10.23919/IPEC.2018.8507446","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507446","url":null,"abstract":"A simple and fast decentralized Current-Voltage (I-V) droop control method under the Synchronous-Reference-Frame (SRF) is proposed to share output current for parallel three-phase inverters with LC filter. The I-V droop characteristic is derived in accordance with the virtual impedance in SRF. Thus, each inverter enables to work in a voltage controlled mode where it controls the filter capacitor voltage. Moreover, a detailed state-space model of two parallel inverters is derived to analyze the control performance. Through the simulation and experiment validation, the proposed method provides accurate current sharing and faster transient response under inverter connection in comparison with the conventional droop control.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"36 1","pages":"2668-2672"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78343255","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8507645
S. Omori, H. Takami, Masashi Nakamura
We proposed combined electric and dynamic system based on the ILQ optimal control, which has high robust performance for induction motor drive. This method realizes an excellent speed control, even if the response of current-control loop is more than three times of the response of speed-control loop. When the motor parameters are varied, the ILQ optimal controller can hold more robust condition than previous method. This paper presents quantitative evaluations for robust stability and robust performance via μ-analysis. Generalized state equations for μ-analysis are derived and compare the ILQ control method with proposed PI method.
{"title":"μ-Analysis Evaluation of A Novel Combined Current-and-Speed Control for Induction Motors via ILQ Design Method","authors":"S. Omori, H. Takami, Masashi Nakamura","doi":"10.23919/IPEC.2018.8507645","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507645","url":null,"abstract":"We proposed combined electric and dynamic system based on the ILQ optimal control, which has high robust performance for induction motor drive. This method realizes an excellent speed control, even if the response of current-control loop is more than three times of the response of speed-control loop. When the motor parameters are varied, the ILQ optimal controller can hold more robust condition than previous method. This paper presents quantitative evaluations for robust stability and robust performance via μ-analysis. Generalized state equations for μ-analysis are derived and compare the ILQ control method with proposed PI method.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"2187 1","pages":"471-477"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91389695","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8507405
Ryosuke Ota, D. S. Nugroho, N. Hoshi
Many of previous studies have focused on the efficiency of only one component of inductive power transfer (IPT) system, so the efficiency improvement of multiple components of the system has not been considered sufficiently. Therefore, this paper focuses on multiple components, which are the resonant circuit and the secondary-side converter, and proposes a control method to improve the efficiency of these components. As a result, the overall system efficiency is improved. To improve the multiple components’ efficiency, the load impedance control for resonant circuit and switching frequency control to the secondary-side converter were applied. As a result, the combined efficiency of the resonant circuit and the secondary-side converter was raised at the maximum of 1.2 points or 1.3 points with the proposed control where the resonant coil coupling factor was 0.3 or 0.2.
{"title":"Efficiency Maximization of Inductive Power Transfer System by Impedance and Switching Frequency Control in Secondary-side Converter","authors":"Ryosuke Ota, D. S. Nugroho, N. Hoshi","doi":"10.23919/IPEC.2018.8507405","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507405","url":null,"abstract":"Many of previous studies have focused on the efficiency of only one component of inductive power transfer (IPT) system, so the efficiency improvement of multiple components of the system has not been considered sufficiently. Therefore, this paper focuses on multiple components, which are the resonant circuit and the secondary-side converter, and proposes a control method to improve the efficiency of these components. As a result, the overall system efficiency is improved. To improve the multiple components’ efficiency, the load impedance control for resonant circuit and switching frequency control to the secondary-side converter were applied. As a result, the combined efficiency of the resonant circuit and the secondary-side converter was raised at the maximum of 1.2 points or 1.3 points with the proposed control where the resonant coil coupling factor was 0.3 or 0.2.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"8 1","pages":"3855-3862"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87518941","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8506669
Qin Lei, Chunhui Liu, Yunpeng Si, Yifu Liu
The goal of this paper is to significantly improve the efficiency and power density of medium voltage drive and high-power converters. To achieve the goal, the proposed approach is to replace the high voltage Si IGBT by series connected SiC MOSFETs. Specifically, a game changing and universally applicable standard block of "series connected SiC MOSFET" with excellent dynamic voltage sharing and high reliability is proposed. The core technology in the block is the current source gate driver with device synchronization function. A down-scaled medium voltage drive prototype has been developed to demonstrate the feasibility and advantages of the standard block.
{"title":"A Standard Block of “Series Connected SiC MOSFET” for Medium/High voltage converter","authors":"Qin Lei, Chunhui Liu, Yunpeng Si, Yifu Liu","doi":"10.23919/IPEC.2018.8506669","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8506669","url":null,"abstract":"The goal of this paper is to significantly improve the efficiency and power density of medium voltage drive and high-power converters. To achieve the goal, the proposed approach is to replace the high voltage Si IGBT by series connected SiC MOSFETs. Specifically, a game changing and universally applicable standard block of \"series connected SiC MOSFET\" with excellent dynamic voltage sharing and high reliability is proposed. The core technology in the block is the current source gate driver with device synchronization function. A down-scaled medium voltage drive prototype has been developed to demonstrate the feasibility and advantages of the standard block.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"744 1","pages":"3742-3748"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76888116","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8507988
Shih-Feng Chou, Xiongfei Wang, F. Blaabjerg
This paper presents a design method for LCL filters used in grid-connected voltage source converters (VSCs). The converter-side current feedback and the filter-capacitor voltage feedforward control methods are used. Besides the harmonic current injection limit, the passivity of the input admittance of VSCs is also considered for a co-design of the controller gains and passive filter components. Thus, the stability of current control can be ensured against the grid impedance variation. The effectiveness of the method is confirmed by simulations and experimental tests.
{"title":"Passivity-based LCL Filter Design of Grid-Connected VSCs with Converter Side Current Feedback","authors":"Shih-Feng Chou, Xiongfei Wang, F. Blaabjerg","doi":"10.23919/IPEC.2018.8507988","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507988","url":null,"abstract":"This paper presents a design method for LCL filters used in grid-connected voltage source converters (VSCs). The converter-side current feedback and the filter-capacitor voltage feedforward control methods are used. Besides the harmonic current injection limit, the passivity of the input admittance of VSCs is also considered for a co-design of the controller gains and passive filter components. Thus, the stability of current control can be ensured against the grid impedance variation. The effectiveness of the method is confirmed by simulations and experimental tests.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"212 1","pages":"1711-1718"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76156210","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8507650
Isseki Takahashi, T. Murakami
In recent years, with the declining birthrate and the aging of the population, the demand for nursing care support equipment is increasing. Among them, wheelchairs are already common as nursing care support equipment. Therefore, demand for wheelchair research is high, and electric wheelchair is required to have higher functionality. In this paper, prevention of falling of the wheelchair as a part of enhancing the functionality of the electric wheelchair is described. Several studies on prevention of rollover of electric wheelchairs have already been reported, but since rider motion state is not taken into account in the calculation of rollover conditions, there is a problem that the rollover conditions does not conform to the actual situation. Therefore, the purpose of this study is to estimate the state of the rider by IMU sensor and to calculate accurate rollover condition. Several simulation results are shown to confirm the proposed approach.
{"title":"Fall Prevention and Vibration Suppression of Wheelchair Using Rider Motion State","authors":"Isseki Takahashi, T. Murakami","doi":"10.23919/IPEC.2018.8507650","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507650","url":null,"abstract":"In recent years, with the declining birthrate and the aging of the population, the demand for nursing care support equipment is increasing. Among them, wheelchairs are already common as nursing care support equipment. Therefore, demand for wheelchair research is high, and electric wheelchair is required to have higher functionality. In this paper, prevention of falling of the wheelchair as a part of enhancing the functionality of the electric wheelchair is described. Several studies on prevention of rollover of electric wheelchairs have already been reported, but since rider motion state is not taken into account in the calculation of rollover conditions, there is a problem that the rollover conditions does not conform to the actual situation. Therefore, the purpose of this study is to estimate the state of the rider by IMU sensor and to calculate accurate rollover condition. Several simulation results are shown to confirm the proposed approach.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"316 1","pages":"575-582"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74544742","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8507597
Tomoyuki Mannen, K. Wada
This paper proposes a control method of initial charging of the dc-capacitor in voltage source power converters. The proposed method is suitable for the power converter equipped with a small dc capacitor and is capable of removing the initial charge circuit. The proposed method makes a leg short-circuit by using power devices in the power converter, which discharges the dc capacitor and suppresses its overvoltage due to the initial charge. The short-circuit operation is a short time period and is used one time in each leg for distributing the loss to each power devices. The experimental verification using a 200-V, 5-kVA three-phase converter shows that the proposed method can reduce the peak voltage of the dc capacitor from 520 V to 420 V. The experimental results exhibit a good capability of the proposed method of suppressing the overvoltage due to the initial charge without fatal damage to the power devices. As a result, the proposed method makes it possible to remove the initial charge circuit resulting in a reduction in the size and cost of power converters.
{"title":"A Control Method of Overvoltage Suppression across the DC Capacitor in a Grid-Connection Converter Using Leg Short-Circuit of Power MOSFETs during the Initial Charge","authors":"Tomoyuki Mannen, K. Wada","doi":"10.23919/IPEC.2018.8507597","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507597","url":null,"abstract":"This paper proposes a control method of initial charging of the dc-capacitor in voltage source power converters. The proposed method is suitable for the power converter equipped with a small dc capacitor and is capable of removing the initial charge circuit. The proposed method makes a leg short-circuit by using power devices in the power converter, which discharges the dc capacitor and suppresses its overvoltage due to the initial charge. The short-circuit operation is a short time period and is used one time in each leg for distributing the loss to each power devices. The experimental verification using a 200-V, 5-kVA three-phase converter shows that the proposed method can reduce the peak voltage of the dc capacitor from 520 V to 420 V. The experimental results exhibit a good capability of the proposed method of suppressing the overvoltage due to the initial charge without fatal damage to the power devices. As a result, the proposed method makes it possible to remove the initial charge circuit resulting in a reduction in the size and cost of power converters.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"25 1","pages":"1866-1871"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90516307","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8507527
Takaaki Tanaka, Huai Wang, F. Blaabjerg
This paper proposes a capacitor voltage oscillation reduction method by using third harmonic zero-sequence current for Modular Multilevel Cascade Converter (MMCC) with Single Delta Bridge Cells (SDBC). A practical case study on an 80 MVar/ 33 kV MMCC-SDBC based STATCOM is used to demonstrate the method. The impact of the third harmonic zero-sequence current level of the capacitor oscillation reduction and the electro-thermal stresses on IGBT modules is investigated. An optimal parameter of the current level is obtained by compromising the above two performance factors. The capacitor bank volume is reduced by 23 % by applying the proposed method.
{"title":"A DC-link Capacitor Voltage Oscillation Reduction Method for a Modular Multilevel Cascade Converter with Single Delta Bridge Cells (MMCC-SDBC)","authors":"Takaaki Tanaka, Huai Wang, F. Blaabjerg","doi":"10.23919/IPEC.2018.8507527","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507527","url":null,"abstract":"This paper proposes a capacitor voltage oscillation reduction method by using third harmonic zero-sequence current for Modular Multilevel Cascade Converter (MMCC) with Single Delta Bridge Cells (SDBC). A practical case study on an 80 MVar/ 33 kV MMCC-SDBC based STATCOM is used to demonstrate the method. The impact of the third harmonic zero-sequence current level of the capacitor oscillation reduction and the electro-thermal stresses on IGBT modules is investigated. An optimal parameter of the current level is obtained by compromising the above two performance factors. The capacitor bank volume is reduced by 23 % by applying the proposed method.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"27 1","pages":"2604-2610"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82942583","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 : 2018-10-22DOI: 10.23919/IPEC.2018.8507729
J. Imaoka, M. Shoyama
This paper proposes a novel leakage flux cancellation technique suitable for series-parallel combined resonant circuits with asymmetric rotary transformer used for ultrasonic spindles drive. An asymmetric rotary transformer is utilized in the ultrasonic spindle in order to realize automated tool change. However, an asymmetric rotary transformer is likely to occur much leakage fluxes in secondly core due to asymmetric core structures. This large leakage inductance affects a drive circuit using a series-parallel combined resonant circuit, and the resonant characteristics in the drive circuit become very steep. In this state, the resonance circuit does not realize the desired function when the drive frequency fluctuates or the error of resonance parameters occurs. Therefore, this paper proposes a novel leakage flux cancellation technique used for ultrasonic spindle drive. The effectiveness of the proposed method is discussed from the theoretical analysis and experimental test.
{"title":"A Leakage Flux Cancellation Technique for Series-Parallel Combined Resonant Circuits with Asymmetric Rotary Transformers Used for Ultrasonic Spindle Drive","authors":"J. Imaoka, M. Shoyama","doi":"10.23919/IPEC.2018.8507729","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507729","url":null,"abstract":"This paper proposes a novel leakage flux cancellation technique suitable for series-parallel combined resonant circuits with asymmetric rotary transformer used for ultrasonic spindles drive. An asymmetric rotary transformer is utilized in the ultrasonic spindle in order to realize automated tool change. However, an asymmetric rotary transformer is likely to occur much leakage fluxes in secondly core due to asymmetric core structures. This large leakage inductance affects a drive circuit using a series-parallel combined resonant circuit, and the resonant characteristics in the drive circuit become very steep. In this state, the resonance circuit does not realize the desired function when the drive frequency fluctuates or the error of resonance parameters occurs. Therefore, this paper proposes a novel leakage flux cancellation technique used for ultrasonic spindle drive. The effectiveness of the proposed method is discussed from the theoretical analysis and experimental test.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"167 1","pages":"1554-1561"},"PeriodicalIF":0.0,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86744661","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 : 2018-06-15DOI: 10.23919/IPEC.2018.8507675
A. Mattsson, P. Nuutinen, T. Kaipia, P. Peltoniemi, J. Karppanen, V. Tikka, A. Lana, P. Pinomaa, P. Silventoinen, J. Partanen
This paper presents an approach to power electronic converter design in which the objective is to minimize the life cycle cost when the converter is used to supply a residential customer. In the paper, the life cycle cost is defined as the sum of the cost of the main components of the power stage and the cost of the losses during the utilization period. The semiconductor switches, output filtering, heat sink, gate drivers, and DC link capacitance are included in the analysis, whereas their parameters are freed in the optimization process. The behavior of the load of an average residential customer is taken as one of the inputs in the calculation. It is shown that parameters such as the optimal silicon area, filter inductance, and switching frequency can differ significantly from the industry norm in which a high weight factor is given to the performance near the nominal power.
{"title":"Design of Customer-End Converter Systems for Low Voltage DC Distribution from a Life Cycle Cost Perspective","authors":"A. Mattsson, P. Nuutinen, T. Kaipia, P. Peltoniemi, J. Karppanen, V. Tikka, A. Lana, P. Pinomaa, P. Silventoinen, J. Partanen","doi":"10.23919/IPEC.2018.8507675","DOIUrl":"https://doi.org/10.23919/IPEC.2018.8507675","url":null,"abstract":"This paper presents an approach to power electronic converter design in which the objective is to minimize the life cycle cost when the converter is used to supply a residential customer. In the paper, the life cycle cost is defined as the sum of the cost of the main components of the power stage and the cost of the losses during the utilization period. The semiconductor switches, output filtering, heat sink, gate drivers, and DC link capacitance are included in the analysis, whereas their parameters are freed in the optimization process. The behavior of the load of an average residential customer is taken as one of the inputs in the calculation. It is shown that parameters such as the optimal silicon area, filter inductance, and switching frequency can differ significantly from the industry norm in which a high weight factor is given to the performance near the nominal power.","PeriodicalId":6610,"journal":{"name":"2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia)","volume":"1 1","pages":"2948-2955"},"PeriodicalIF":0.0,"publicationDate":"2018-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82247827","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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