Pub Date : 2017-11-01DOI: 10.1109/COBEP.2017.8257304
Gabriel A. Fogli, P. M. de Almeida, P. G. Barbosa
This paper analyses operation mode transitions of a dispatchable microgrid based on Diesel gensets connected to back-to-back converter working as grid-supplying or grid-forming. A structure to determine the operation mode is based on abnormal frequency and grid voltage level and its dynamical behaviour is depicted. Besides, a smooth phase adjusting is designed to allow reconnection of grid utility without interruption. Considerations of current and voltage controllers applied in this AC microgrid are addressed. Simulation results are presented to show the effectiveness of proposed scheme, complying with clearing time and synchronization parameter limits recommended by IEEE Std. 1547-2003.
{"title":"Analysis of AC dispatchable microgrid during grid-connected and isolated modes transitions","authors":"Gabriel A. Fogli, P. M. de Almeida, P. G. Barbosa","doi":"10.1109/COBEP.2017.8257304","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257304","url":null,"abstract":"This paper analyses operation mode transitions of a dispatchable microgrid based on Diesel gensets connected to back-to-back converter working as grid-supplying or grid-forming. A structure to determine the operation mode is based on abnormal frequency and grid voltage level and its dynamical behaviour is depicted. Besides, a smooth phase adjusting is designed to allow reconnection of grid utility without interruption. Considerations of current and voltage controllers applied in this AC microgrid are addressed. Simulation results are presented to show the effectiveness of proposed scheme, complying with clearing time and synchronization parameter limits recommended by IEEE Std. 1547-2003.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"28 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116717620","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257380
T. E. P. de Almeida, G. T. de Paula, A. G. de Castro, W. C. Pereira, J. R. Monteiro
Vector control of electrical machines deliver better performance and efficiency when compared to traditional driving methods, however they demand constant precise angular position measurement through sensors that add cost to the system. In this work the vector control of the BLDC machine is investigated, considering the added drawbacks given by the trapezoidal waveform of the BEMF. Position estimation is given through the analysis and adjustment using PLLs of the BEMF estimated by means of a Kalman filter, then Field Oriented Control is applied with the dqx coordinate transform in order to achieve high efficiency and low torque ripple. Simulations of the developed system demonstrate the effectiveness of the estimator, with low estimation error, allowing for good dynamic response of the controller.
{"title":"Sensorless vector control for BLDC machine","authors":"T. E. P. de Almeida, G. T. de Paula, A. G. de Castro, W. C. Pereira, J. R. Monteiro","doi":"10.1109/COBEP.2017.8257380","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257380","url":null,"abstract":"Vector control of electrical machines deliver better performance and efficiency when compared to traditional driving methods, however they demand constant precise angular position measurement through sensors that add cost to the system. In this work the vector control of the BLDC machine is investigated, considering the added drawbacks given by the trapezoidal waveform of the BEMF. Position estimation is given through the analysis and adjustment using PLLs of the BEMF estimated by means of a Kalman filter, then Field Oriented Control is applied with the dqx coordinate transform in order to achieve high efficiency and low torque ripple. Simulations of the developed system demonstrate the effectiveness of the estimator, with low estimation error, allowing for good dynamic response of the controller.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116764226","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257438
Clovis N. L. Gajo, R. A. Prado
The purpose of this document is to discuss the design of medium and high voltage rectifiers with avalanche diodes, pointing out advantages and disadvantages, critical steps and details about them.
本文的目的是讨论雪崩二极管的中高压整流器的设计，指出其优点和缺点，关键步骤和细节。
{"title":"Design of medium and high voltage rectifiers with avalanche diodes","authors":"Clovis N. L. Gajo, R. A. Prado","doi":"10.1109/COBEP.2017.8257438","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257438","url":null,"abstract":"The purpose of this document is to discuss the design of medium and high voltage rectifiers with avalanche diodes, pointing out advantages and disadvantages, critical steps and details about them.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124799674","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257419
R. Batista, A. Nicolini, F. Carnielutti, H. Pinheiro
Commercial offshore Wind Power Plants (WPP) started in 2002 and the number of installations increases each year, as well as their distances from the coast. For projects more than 70 km far from the coast, the trend is to use HVDC systems, since, in this way, problems with reactive power losses on the insulated cables are avoided. In addition, Modular Multilevel Converters (MMC) are strong candidates to be used in these HVDC systems, since they overcome the main limitation of Line Commutated Converters (LCC). This paper presents a dynamic model for the MMC as well as describes the AC grid forming rectifier and the DC Bus regulator inverter controllers required to implement an offshore HVDC link. The internal control of MMC variables is carried out using the energy concept which simplifies the controllers design. Finally, simulation results are presented to validate the theoretical analysis.
{"title":"Analysis of modular multilevel converters for HVDC connection of offshore wind power plants","authors":"R. Batista, A. Nicolini, F. Carnielutti, H. Pinheiro","doi":"10.1109/COBEP.2017.8257419","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257419","url":null,"abstract":"Commercial offshore Wind Power Plants (WPP) started in 2002 and the number of installations increases each year, as well as their distances from the coast. For projects more than 70 km far from the coast, the trend is to use HVDC systems, since, in this way, problems with reactive power losses on the insulated cables are avoided. In addition, Modular Multilevel Converters (MMC) are strong candidates to be used in these HVDC systems, since they overcome the main limitation of Line Commutated Converters (LCC). This paper presents a dynamic model for the MMC as well as describes the AC grid forming rectifier and the DC Bus regulator inverter controllers required to implement an offshore HVDC link. The internal control of MMC variables is carried out using the energy concept which simplifies the controllers design. Finally, simulation results are presented to validate the theoretical analysis.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125158421","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257416
Gustavo A. Finamor, Diego L. S. Solano, M. Ortmann, Adriano Ruseler, Lucas Munaretto, L. C. Gili, R. Coelho, M. Heldwein
This work presents a stability analysis of a solar photovoltaic (PV) system applied in an experimental smart microgrid. The system totals 20 kW at rated conditions, composed of 10 units of 2 kW, where each unit is fed by a photovoltaic string and a three-state switching cell-based boost dc-dc converter, accordingly connected to the dc-bus of a smart microgrid. Furthermore, with an approach on operation modes, small-signal models are developed to determine the equivalent impedances, used in the stability criteria. As a means to verify the operation and stability of the solar photovoltaic system, experimental results are presented, including a hardware demonstrator of a single dc-dc converter.
{"title":"Stability analysis of a smart microgrid solar photovoltaic system","authors":"Gustavo A. Finamor, Diego L. S. Solano, M. Ortmann, Adriano Ruseler, Lucas Munaretto, L. C. Gili, R. Coelho, M. Heldwein","doi":"10.1109/COBEP.2017.8257416","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257416","url":null,"abstract":"This work presents a stability analysis of a solar photovoltaic (PV) system applied in an experimental smart microgrid. The system totals 20 kW at rated conditions, composed of 10 units of 2 kW, where each unit is fed by a photovoltaic string and a three-state switching cell-based boost dc-dc converter, accordingly connected to the dc-bus of a smart microgrid. Furthermore, with an approach on operation modes, small-signal models are developed to determine the equivalent impedances, used in the stability criteria. As a means to verify the operation and stability of the solar photovoltaic system, experimental results are presented, including a hardware demonstrator of a single dc-dc converter.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"254 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116047978","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257263
A. O. Almeida, Frederico T. Ghetti, Adeilson S. B. Ribeiro, P. M. de Almeida, P. G. Barbosa
This work presents a comparative study of two control strategies proposed to minimize the circulating currents in modular multilevel converters. Different control strategies and algorithms can be used to regulate and equalize the DC voltages of the submodules of modular converters. However, despite of the accurate voltage regulation, circulating currents arise between the positive and negative arms of the converter's branches, as well as between the phases of the converter, due to small imbalances on the terminal and submodules voltages. Thus, a mathematical modeling of the circulating current is presented and the performance of two strategies, one based on dq synchronous reference frame controller and the other based on a resonant controller, are investigated. Simulations results are presented to validate the theoretical analyses and to evaluate the effectiveness of both controllers to minimize the circulating currents of the modular converters.
{"title":"Circulating currents suppression strategies for modular multilevel converter","authors":"A. O. Almeida, Frederico T. Ghetti, Adeilson S. B. Ribeiro, P. M. de Almeida, P. G. Barbosa","doi":"10.1109/COBEP.2017.8257263","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257263","url":null,"abstract":"This work presents a comparative study of two control strategies proposed to minimize the circulating currents in modular multilevel converters. Different control strategies and algorithms can be used to regulate and equalize the DC voltages of the submodules of modular converters. However, despite of the accurate voltage regulation, circulating currents arise between the positive and negative arms of the converter's branches, as well as between the phases of the converter, due to small imbalances on the terminal and submodules voltages. Thus, a mathematical modeling of the circulating current is presented and the performance of two strategies, one based on dq synchronous reference frame controller and the other based on a resonant controller, are investigated. Simulations results are presented to validate the theoretical analyses and to evaluate the effectiveness of both controllers to minimize the circulating currents of the modular converters.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122070033","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257432
Gustavo P. de Pontes, S. G. Camila
Most of the distributed generation (DG) controllers have relied on power control (P and Q droop) to achieve reliable operation of the utility grid. Nevertheless, intrinsically, the power control has slow time response and drifts in frequency and voltage level with load changes. This paper proposes a new current droop control and a new method to accurately determine the slope gain based on graphs theory and tellegen theorem. The distributed generation (DG) control operates by means of active curtailment depending on the voltage level and compensation of the voltage drop. The simulation results have proven that the proposed control is cooperative and stable. Further analysis will be performed with different slope gain in order to enhance optimal operation under load variation (nonlinear and linear).
{"title":"A control method for DG connected to the utility grid based on current droop with accurate slope gain","authors":"Gustavo P. de Pontes, S. G. Camila","doi":"10.1109/COBEP.2017.8257432","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257432","url":null,"abstract":"Most of the distributed generation (DG) controllers have relied on power control (P and Q droop) to achieve reliable operation of the utility grid. Nevertheless, intrinsically, the power control has slow time response and drifts in frequency and voltage level with load changes. This paper proposes a new current droop control and a new method to accurately determine the slope gain based on graphs theory and tellegen theorem. The distributed generation (DG) control operates by means of active curtailment depending on the voltage level and compensation of the voltage drop. The simulation results have proven that the proposed control is cooperative and stable. Further analysis will be performed with different slope gain in order to enhance optimal operation under load variation (nonlinear and linear).","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129425397","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257303
João T. de Carvalho Neto, A. Salazar, André H. X. da Costa, A. C. Q. B. Leite, Rafael M. N. de Araújo
The use of PV systems has grown over the recent years around the world. This type of renewable energy has gained space against other types such as wind and biomass because the radiation is directly converted into electricity. One of the most common ways of storing the generated energy is through batteries and in this paper a control strategy is presented that uses a boost converter to charge the batteries and keep them charged when the State of Charge (SOC) is full. The main objective of this work is to present the results of this maximum power point tracker with battery charging using the one cycle control (OCC) technique on same boost converter. The constant voltage method was used because it offers a high reliability, low oscillations and high efficiency in the maximum power point tracking when there are no large temperature variations. OCC provides some advantages such as permanent zero error, rejection of input disturbances and rapid response to change of reference.
{"title":"Efficient scheme of battery charging based on one cycle control applied in photovoltaic systems","authors":"João T. de Carvalho Neto, A. Salazar, André H. X. da Costa, A. C. Q. B. Leite, Rafael M. N. de Araújo","doi":"10.1109/COBEP.2017.8257303","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257303","url":null,"abstract":"The use of PV systems has grown over the recent years around the world. This type of renewable energy has gained space against other types such as wind and biomass because the radiation is directly converted into electricity. One of the most common ways of storing the generated energy is through batteries and in this paper a control strategy is presented that uses a boost converter to charge the batteries and keep them charged when the State of Charge (SOC) is full. The main objective of this work is to present the results of this maximum power point tracker with battery charging using the one cycle control (OCC) technique on same boost converter. The constant voltage method was used because it offers a high reliability, low oscillations and high efficiency in the maximum power point tracking when there are no large temperature variations. OCC provides some advantages such as permanent zero error, rejection of input disturbances and rapid response to change of reference.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130483077","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257354
Saulo Marcos Torres de Carvalho, G. Campos
The Controller Area Network was designed by Bosch in the mid 80's, whose focus was to provide greater efficiency on the communication of automotive networks at a low cost of implementation. A common problem in a CAN network is that it is unable to guarantee the timing performance of the lower priority messages. When a message miss its deadline, the reliability of the CAN network can be compromised. To avoid this condition many papers, use the Worst Case Response Time (WCRT) analysis to calculate the message response time. This value shall be less than the message deadline. However, the WCRT analysis can lead to a pessimistic approach. This overestimation can increase the cost of the project and reduce the capacity of messages. Hence, the aim of this paper is to assess the pessimism of the WCRT and emphasize its impacts.
{"title":"Worst case response time approach evaluation for computing can messages response time in an automotive network","authors":"Saulo Marcos Torres de Carvalho, G. Campos","doi":"10.1109/COBEP.2017.8257354","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257354","url":null,"abstract":"The Controller Area Network was designed by Bosch in the mid 80's, whose focus was to provide greater efficiency on the communication of automotive networks at a low cost of implementation. A common problem in a CAN network is that it is unable to guarantee the timing performance of the lower priority messages. When a message miss its deadline, the reliability of the CAN network can be compromised. To avoid this condition many papers, use the Worst Case Response Time (WCRT) analysis to calculate the message response time. This value shall be less than the message deadline. However, the WCRT analysis can lead to a pessimistic approach. This overestimation can increase the cost of the project and reduce the capacity of messages. Hence, the aim of this paper is to assess the pessimism of the WCRT and emphasize its impacts.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130641251","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 : 2017-11-01DOI: 10.1109/COBEP.2017.8257422
Ricardo J. F. Bortolini, L. Michels, Lucas V. Belinaso, J. Massing
Multifunctional Photovoltaic Converters (MPVC) are an emerging technology that comprises the advantages of grid-tie and off-grid inverters, as well as Uninterruptable Power Supplies (UPS). MPVCs present several particularities in comparison to grid-tie and off-grid photovoltaic inverters that are not covered by current Brazilian photovoltaic standards. This manuscript analyzes existing conflicts for application of MPVCs in current Brazilian standards and discusses some solutions to mitigate them. This study is important because discuss possible adjustments in current standards to contemplate MPVCs.
{"title":"Compatibilizing multifunctional photovoltaic converters with Brazilian standards: Analysis and discussion","authors":"Ricardo J. F. Bortolini, L. Michels, Lucas V. Belinaso, J. Massing","doi":"10.1109/COBEP.2017.8257422","DOIUrl":"https://doi.org/10.1109/COBEP.2017.8257422","url":null,"abstract":"Multifunctional Photovoltaic Converters (MPVC) are an emerging technology that comprises the advantages of grid-tie and off-grid inverters, as well as Uninterruptable Power Supplies (UPS). MPVCs present several particularities in comparison to grid-tie and off-grid photovoltaic inverters that are not covered by current Brazilian photovoltaic standards. This manuscript analyzes existing conflicts for application of MPVCs in current Brazilian standards and discusses some solutions to mitigate them. This study is important because discuss possible adjustments in current standards to contemplate MPVCs.","PeriodicalId":375493,"journal":{"name":"2017 Brazilian Power Electronics Conference (COBEP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124165140","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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