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Emerging Hazards: Renewables and Microgrids, U.S. Department of Energy, Energ...
Emerging Hazards: Renewables and Microgrids, U.S. Department of Energy, Energ...AEI / Affiliated Engineers
AEI / Affiliated Engineers presents the Energy Systems Integration Facility, a 182,500 square foot building that provides laboratory and research space for 200 scientists and staff working on promising clean energy technologies and testing their interaction with each other and the grid. Specific areas of research include:
• Smart grids, power electronics.
• Solar: interconnection, parabolic solar concentrators, building integration, and system optimization.
• Buildings: sensors and controls, systems integration, modeling, and Zero Energy Building simulation.
• Hydrogen: electrical interfaces, electrolyzers, storage, quality standards, fueling systems, fuel cell integration.
• Wind: models, generation, and grid interaction, electrical grid analysis.
• Vehicles: grid connected plug-in and vehicle-to-grid electrical integration, battery thermal management, and power electronics.
• Biofuels: generator sets and engines.
• Energy storage: electrical, mechanical, and thermal.
• Microturbines.
AEI’s work included the design of:
• Research Electrical Distribution Bus (REDB): A first-of-its-kind, the REBD is a power integration circuit made up of two AC and two DC ring buses that interconnects testing components across the building’s 15 laboratories. Researchers can test new energy technologies on real and simulated power systems.
• Supervisory Control and Data Acquisition (SCADA) System: Integrated throughout the facility, the SCADA monitors and controls the REDB operations and gathers real-time, high-resolution data for collaboration and visualization. The SCADA also monitors SIL-2 (Safety Integrity Level) rated laboratory PLCs providing emergency stop functionality, gas detection, alarming (horns and lights), and other required safety measures. These systems are all interconnected with the fire alarm, building automation system, and local lab equipment to provide a seamless facility response across systems to various conditions.
Generation of Higher Number of Voltage Levels by Stacking Inverters of Lower ...
This paper proposes a new method of generating higher number of levels in the voltage waveform by stacking multilevel converters with lower voltage space vector structures. An important feature of this stacked structure is the use of low voltage devices while attaining higher number of levels. This will find extensive applications in electric vehicles since direct battery drive is possible. The voltages of all the capacitors in the structure can be controlled within a switching cycle using the switching state redundancies (pole voltage redundancies). This helps in reducing the capacitor size. Also, the capacitor voltages can be balanced irrespective of modulation index and load power factor. To verify the concept experimentally, a 9-level inverter is developed by stacking two 5-level inverters and an induction motor is run using V/f control scheme. Both steady state and transient results are presented.
A generalized multilevel inverter topology with reduction of total standing v...
This paper presents a new multilevel inverter topology with reduced active switches
and total standing voltage. The proposed topology can generate a high number of voltage levels in the symmetric configuration. This topology intuitively generates positive and negative cycles without an additional H-bridge unit, which considerably reduces the total standing voltage of the inverter. A cascaded structure is developed from the proposed topology to create higher voltage levels. To show the novelty of the proposed topology, a thorough comparison between the available and the proposed topologies in terms of the number of switches, standing voltages, and dc-sources is presented. Furthermore, he power loss analysis is carried out for various load values. The feasibility of the proposed nine-level inverter is verified with simulation and experimental results.
Novel symmetric modular hybrid multilevel inverter with reduced number of sem...
In this paper, by using a modular hybrid structure, a new topology for symmetric multilevel inverters (MLI) with a small number of semiconductors and low voltage stress across switches is proposed. Despite many other topologies, this topology can inherently produce negative levels and zero levels without using the H-bridge. The voltage stress across a particular switch of the proposed MLI is inversely proportional to the number of the switching of that switch in a voltage period. The proposed structure is based on two types of module, that is, the f-module and the e-module. The e-module uses a capacitive voltage divider to double the number of non-zero levels. The voltages of the capacitors are approximately balanced without complex control methods. The basic structure of the proposed topology is formed by connecting the f-module and the e-module in series with each other, and the cascaded topology is developed by cascading multiple f-modules with an e-module. To investigate the proposed topology and proving its practicability, simulation results with MATLAB/Simulink, investigation of the capacitor voltages, loss calculations and experimental results are presented. A comparative study is also performed to show the merit of the new multilevel inverter over other topologies.
Recommended
Emerging Hazards: Renewables and Microgrids, U.S. Department of Energy, Energ...
Emerging Hazards: Renewables and Microgrids, U.S. Department of Energy, Energ...AEI / Affiliated Engineers
AEI / Affiliated Engineers presents the Energy Systems Integration Facility, a 182,500 square foot building that provides laboratory and research space for 200 scientists and staff working on promising clean energy technologies and testing their interaction with each other and the grid. Specific areas of research include:
• Smart grids, power electronics.
• Solar: interconnection, parabolic solar concentrators, building integration, and system optimization.
• Buildings: sensors and controls, systems integration, modeling, and Zero Energy Building simulation.
• Hydrogen: electrical interfaces, electrolyzers, storage, quality standards, fueling systems, fuel cell integration.
• Wind: models, generation, and grid interaction, electrical grid analysis.
• Vehicles: grid connected plug-in and vehicle-to-grid electrical integration, battery thermal management, and power electronics.
• Biofuels: generator sets and engines.
• Energy storage: electrical, mechanical, and thermal.
• Microturbines.
AEI’s work included the design of:
• Research Electrical Distribution Bus (REDB): A first-of-its-kind, the REBD is a power integration circuit made up of two AC and two DC ring buses that interconnects testing components across the building’s 15 laboratories. Researchers can test new energy technologies on real and simulated power systems.
• Supervisory Control and Data Acquisition (SCADA) System: Integrated throughout the facility, the SCADA monitors and controls the REDB operations and gathers real-time, high-resolution data for collaboration and visualization. The SCADA also monitors SIL-2 (Safety Integrity Level) rated laboratory PLCs providing emergency stop functionality, gas detection, alarming (horns and lights), and other required safety measures. These systems are all interconnected with the fire alarm, building automation system, and local lab equipment to provide a seamless facility response across systems to various conditions.
Generation of Higher Number of Voltage Levels by Stacking Inverters of Lower ...
This paper proposes a new method of generating higher number of levels in the voltage waveform by stacking multilevel converters with lower voltage space vector structures. An important feature of this stacked structure is the use of low voltage devices while attaining higher number of levels. This will find extensive applications in electric vehicles since direct battery drive is possible. The voltages of all the capacitors in the structure can be controlled within a switching cycle using the switching state redundancies (pole voltage redundancies). This helps in reducing the capacitor size. Also, the capacitor voltages can be balanced irrespective of modulation index and load power factor. To verify the concept experimentally, a 9-level inverter is developed by stacking two 5-level inverters and an induction motor is run using V/f control scheme. Both steady state and transient results are presented.
A generalized multilevel inverter topology with reduction of total standing v...
This paper presents a new multilevel inverter topology with reduced active switches
and total standing voltage. The proposed topology can generate a high number of voltage levels in the symmetric configuration. This topology intuitively generates positive and negative cycles without an additional H-bridge unit, which considerably reduces the total standing voltage of the inverter. A cascaded structure is developed from the proposed topology to create higher voltage levels. To show the novelty of the proposed topology, a thorough comparison between the available and the proposed topologies in terms of the number of switches, standing voltages, and dc-sources is presented. Furthermore, he power loss analysis is carried out for various load values. The feasibility of the proposed nine-level inverter is verified with simulation and experimental results.
Novel symmetric modular hybrid multilevel inverter with reduced number of sem...
In this paper, by using a modular hybrid structure, a new topology for symmetric multilevel inverters (MLI) with a small number of semiconductors and low voltage stress across switches is proposed. Despite many other topologies, this topology can inherently produce negative levels and zero levels without using the H-bridge. The voltage stress across a particular switch of the proposed MLI is inversely proportional to the number of the switching of that switch in a voltage period. The proposed structure is based on two types of module, that is, the f-module and the e-module. The e-module uses a capacitive voltage divider to double the number of non-zero levels. The voltages of the capacitors are approximately balanced without complex control methods. The basic structure of the proposed topology is formed by connecting the f-module and the e-module in series with each other, and the cascaded topology is developed by cascading multiple f-modules with an e-module. To investigate the proposed topology and proving its practicability, simulation results with MATLAB/Simulink, investigation of the capacitor voltages, loss calculations and experimental results are presented. A comparative study is also performed to show the merit of the new multilevel inverter over other topologies.
Energy & Power Signals |Solved Problems|
https://www.youtube.com/watch?v=-bU0TZ3C1XI&list=PLhTuYg-DgnLeD74ravp6pJ0WQeov_0vrq&index=16
A New Family of Step-up Hybrid Switched- Capacitor Integrated Multilevel Inve...
In the low voltage based renewable systems like PV and Fuel cell applications, the step-up of the output voltage to drive the loads is essential. For this, the integration of switched-capacitor (SC) units with the dc-ac converters will have the potential advantages like improved efficiency, optimal switching devices, small size of passive elements (L and C) as compared with traditional two-stage conversion system (dc/dc converter and dc/ac converter). This paper focuses on a new family of step-up multilevel inverter topologies with switched capacitor integration with dual input voltage sources. With the flexibility of 2 dc sources and switching capacitor circuits, four different topologies have been suggested in this paper with features of high voltage gain, reduced component count, reduced voltage stress and self-voltage balancing of the capacitor while achieving a higher number of levels. A detailed analysis of proposed multilevel inverters has been analyzed with the symmetrical and asymmetrical mode of operations and the associated gain, the number of levels, and other performance indices are presented. An in-depth study of all the topologies has been accomplished in this paper with several comparative studies in terms of components count, voltage gain and cost. The effectiveness and practicability of the suggested topology with 13 level output voltage has been explained by the experimental results obtained from a scale down prototype.
A multi cell 21-level hybrid multilevel inverter synthesizes a reduced number...
A multi-cell hybrid 21-Level multilevel inverter is proposed in this paper. The proposed topology includes two-unit; an H-bridge is cascaded with a modified K-type unit to generate an output voltage waveform with 21 levels based only on two unequal DC suppliers. The proposed topology's advantage lies in the fine and clear output voltage waveforms with high output efficiency. Meanwhile, the high number of output voltage waveform levels generates a low level of distortion and reduces the level of an electromagnetic interface (EMI). Moreover, it reduces the voltage stress on the switching devices and gives it a long lifetime. Also, the reduction in the number of components has a noticeable role in saving size and cost. Regarding the capacitors charging, the proposed topology presents an online method for charging and balancing the capacitor's voltage without any auxiliary circuits. The proposed topology can upgrade to a high number of output steps through the cascading connection. Undoubtedly this cascading will increase the power level to medium and high levels and reduce the harmonics content to a neglectable rate. The proposed system has been tested through the simulation results, and an experimental prototype based on the controller dSPACE (DS-1103) hardware unit used to support the simulation results.
A multi cell 21-level hybrid multilevel inverter synthesizes a reduced number...
A multi-cell hybrid 21-Level multilevel inverter is proposed in this paper. The proposed topology includes two-unit; an H-bridge is cascaded with a modified K-type unit to generate an output voltage waveform with 21 levels based only on two unequal DC suppliers. The proposed topology's advantage lies in the fine and clear output voltage waveforms with high output efficiency. Meanwhile, the high number of output voltage waveform levels generates a low level of distortion and reduces the level of an electromagnetic interface (EMI). Moreover, it reduces the voltage stress on the switching devices and gives it a long lifetime. Also, the reduction in the number of components has a noticeable role in saving size and cost. Regarding the capacitors charging, the proposed topology presents an online method for charging and balancing the capacitor's voltage without any auxiliary circuits. The proposed topology can upgrade to a high number of output steps through the cascading connection. Undoubtedly this cascading will increase the power level to medium and high levels and reduce the harmonics content to a neglectable rate. The proposed system has been tested through the simulation results, and an experimental prototype based on the controller dSPACE (DS-1103) hardware unit used to support the simulation results.
A generalized multilevel inverter topology with reduction of total standing v...
This paper presents a new multilevel inverter topology with reduced active switches and total standing voltage. The proposed topology can generate a high number of voltage levels in the symmetric configuration. This topology intuitively generates positive and negative cycles without an additional H-bridge unit, which considerably reduces the total standing voltage of the inverter. A cascaded structure is developed from the proposed topology to create higher voltage levels. To show the novelty of the proposed topology, a thorough comparison between the available and the proposed topologies in terms of the number of switches, standing voltages, and dc-sources is presented. Furthermore, the power loss analysis is carried out for various load values. The feasibility of the proposed nine-level inverter is verified with simulation and experimental results.
A Simplified Space Vector Pulse-Width Modulation Scheme for Three-Phase Casca...
A simplified space vector pulse-width modulation (SVPWM) for three-phase cascaded H-bridge (CHB) inverters is presented in this paper. Treating each unit as a three-level inverter and adopting serial calculation mode, a CHB inverter is modulated unit by unit using three-level SVPWM. Duty cycles of real sector are obtained by mapping duty cycles of sector 1, in which the calculation of three-level SVPWM is done. The process to implement multilevel SVPWM is simplified to the process to implement three-level SVPWM. By reusing FPGA chip resource which is used for the calculation of three-level SVPWM, the presented SVPWM can be easily adopted to a CHB inverter with different number of units, while the FPGA chip resource utilization is reduced significantly. In addition, the presented SVPWM provides an effective switching frequency higher than the switching frequency of IGBTs. Simulation and experimental results are provided to verify the feasibility of the presented SVPWM.
Arbitrary representation of sequence
https://www.youtube.com/watch?v=SNiBm-W8G14&list=PLhTuYg-DgnLeD74ravp6pJ0WQeov_0vrq&index=25
A Variable DC Link based Novel Multilevel Inverter Topology for Low Voltage A...
In this paper; a variable dc link based novel multilevel inverter (MLI) topology is proposed. This proposed topology comprises two variable dc links and a modified H-bridge unit. This new single-phase topology offers advantages such as reduction in count of switches; gate drivers and dc sources while simultaneously improving the power quality. The proposed topology has been analyzed for both symmetric and asymmetric modes of operation. A comparative study of the proposed topology with some recent MLI topologies has been presented. The comparative study indicates that the proposed topology requires less number of dc sources; switches and driver circuits as compared to other topologies. The proposed topology has been simulated for 31- level asymmetric configuration in MATLAB/SIMULINK environment to verify the proper operation of proposed topology. Harmonic analysis was also performed for 31-level inverter which showed significant reduction in the total harmonic distortion (THD) for phase voltage and current waveforms. The proposed topology is suitable for low voltage applications such as standalone photovoltaic (PV) systems and hybrid electric vehicles (HEVs).
Power Transfer Improvement without Any Alteration in Existing EHV AC Line wit...
Power Transfer Improvement without Any Alteration in Existing EHV AC Line wit...Shanmuga Priyan Thiagarajan
Enhancing power transfer capability of transmission lines without changing the line facilities is the need of the hour for practicing electrical engineers. As a solution to the problem, the possibility to load the EHV AC transmission lines very close to their thermal limits by transmitting usual ac along with dc super imposed on it is presented. The importance of proposed scheme is that the power transfer improvement is achieved without any alteration in the existing EHV ac line. The main goal is to gain the advantage of parallel ac–dc transmission and to load the line close to its thermal limit. The added dc power flow does not result in any transient instability. This gives the feasibility of converting a double circuit ac line into composite ac–dc power transmission line to get the advantages of parallel ac–dc transmission to improve stability and damping out oscillations. Simulation and experimental studies are carried out for the coordinated control as well as independent control of ac and dc power transmissions. No alterations of conductors, insulator strings, and towers of the original line are needed. The present situation demands the review of traditional power transmission theory and practice, on the basis of new concepts that allow full utilization of existing transmission facilities without decreasing system availability and security. Simultaneous ac–dc power transmission was first proposed through a single circuit ac transmission line. In these proposals Mono-polar dc transmission with ground as return path was used. There were certain limitations due to use of ground as return path. Moreover, the instantaneous value of each conductor voltage with respect to ground becomes higher by the amount of the dc voltage, and more discs are to be added in each insulator string to withstand this increased voltage. In this scheme, the dc power flow is point-to point bipolar transmission system. The proposed new methodology overcomes the problems and allows loading the line to its thermal limit, improving the revenue.LTI system causality and stability
https://www.youtube.com/watch?v=XshP5OkjJq0&list=PLhTuYg-DgnLeD74ravp6pJ0WQeov_0vrq&index=26
Power Electronics Projects Research Assistance
Developed Topics for Power Electronic
Disputes of RES
Essential Parameters in RES
Innovative Areas – Power Electronics
Case study: Ensuring exceptional PV performance with insolar
this case study explains how insolar, our sophisticated solar plant monitoring system, helps achieve exceptional performance of PV plants. With the permission of the owner, we chose a 2 MWp solar plant with over 4 years of operational data to take into consideration for analysing the effect of detailed monitoring in the overall plant performance. Our system monitors every single part of the solar plant from strings, inverters and electrical switchboards to transformers and substations.
Carlson vagus-nerve-stimulation-finite-element-model
Finite element model of vagus nerve stimulation. Finite element analysis of the effect of electric fields on biological tissue (the vagus nerve). Medical device consulting project. Paper: Arle, Carlson, Mei, Investigation of Mechanisms of Vagus Nerve Stimulation for Seizure Using Finite Element Modeling (in review).
Mppt with single dc–dc converter and inverter for grid connected hybrid wind-...
A new topology of a hybrid distributed generator based on photovoltaic and wind-driven permanent magnet synchronous generator is proposed. In this generator, the sources are connected together to the grid with the help of only a single boost converter followed by an inverter. Thus, compared to earlier schemes, the proposed scheme has fewer power converters. A model of the proposed scheme in the d − q-axis reference frame is developed. Two low-cost controllers are also proposed for the new hybrid scheme to separately trigger the dc–dc converter and the inverter for tracking the maximum power from both sources. The integrated operations of both proposed controllers for different conditions are demonstrated through simulation and experimentation. The steady-state performance of the system and the transient response of the controllers are also presented to demonstrate the successful operation of the new hybrid system. Comparisons of experimental and simulation results are given to validate the simulation model.
The Application of Electric Spring in Grid-Connected Photovoltaic System
The characteristics of distributed photovoltaic system power generation system is intermittent and instability. Under the weak grid conditions, when the active power of the PV system injected into the grid is fluctuant, the voltage of supply feeder will increase or decrease, thus affecting the normal use of sensitive load. The electric spring can transfer the energy injected into the supply feeder to the wide-voltage load, which is in series with the ES, to ensure the voltage stability of the sensitive load in the system. In this paper, a grid-connected photovoltaic simulation model with electric spring is built in Matlab / simulink. The voltage waveforms on the ES and sensitive load is obtained under the condition of changing the active power injected into the supply feeder by the grid-connected photovoltaic system. Thought the analysis of the waveforms, we can find that the Electric spring is a kind of effective method to solve the voltage fluctuation of the supply feeder in the grid-connected PV system.
Development of wind and solar based ac microgrid with power quality improveme...
This work proposes a microgrid (μ-grid) integrating wind and solar photovoltaic (PV) resources, along with the battery energy storage (BES) to the three phase grid feeding the nonlinear load. The μ-grid disconcerted by probabilistic nonlinear time dependent parameters and their effects are compensated by cohesive controllers used for utility grid side voltage source converter (GVSC) and machine side VSC (MVSC). The switching controls and the reconfigurability of the μ-grid are addressed on imperative aspects of improving power quality (PQ), power reliability, nonlinear load compensation and economic utilization of resources. The nonlinear load compensation and PQ enhancement are achieved by executing modified version of the adaptive filtering technique including “momentum” based least mean square (MLMS) control technique, utilized for providing the switching control signals to the GVSC. It utilizes two preceding gradient weights for obtaining updated weight thereby improving the convergence rate and overcoming the limitation of conventional control of the same family. The MVSC acquires its switching signals from conventional vector control scheme and the encoderless estimation of speed and rotor position of the synchronous generator (SG) driven by wind turbine through back electromotive force control technique. The external environmental disturbances are overcome by utilizing perturb and observe (P&O) maximum power point (MPP) for wind optimal power extraction and adaptive P&O with variable perturbation step size for solar MPP estimation. Test results are obtained from the laboratory prototype under steady state and dynamic conditions including altering wind speed, intermittent solar insolation and variable load conditions. The PQ issues are addressed and investigated successfully.
Power Electronics UK - 2017/18 Research Themes
Switch Optimisation, Converter Architectures, Heterogeneous Integration, Reliability and Health Management and Virtual Prototyping
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Energy & Power Signals |Solved Problems|
https://www.youtube.com/watch?v=-bU0TZ3C1XI&list=PLhTuYg-DgnLeD74ravp6pJ0WQeov_0vrq&index=16
A New Family of Step-up Hybrid Switched- Capacitor Integrated Multilevel Inve...
In the low voltage based renewable systems like PV and Fuel cell applications, the step-up of the output voltage to drive the loads is essential. For this, the integration of switched-capacitor (SC) units with the dc-ac converters will have the potential advantages like improved efficiency, optimal switching devices, small size of passive elements (L and C) as compared with traditional two-stage conversion system (dc/dc converter and dc/ac converter). This paper focuses on a new family of step-up multilevel inverter topologies with switched capacitor integration with dual input voltage sources. With the flexibility of 2 dc sources and switching capacitor circuits, four different topologies have been suggested in this paper with features of high voltage gain, reduced component count, reduced voltage stress and self-voltage balancing of the capacitor while achieving a higher number of levels. A detailed analysis of proposed multilevel inverters has been analyzed with the symmetrical and asymmetrical mode of operations and the associated gain, the number of levels, and other performance indices are presented. An in-depth study of all the topologies has been accomplished in this paper with several comparative studies in terms of components count, voltage gain and cost. The effectiveness and practicability of the suggested topology with 13 level output voltage has been explained by the experimental results obtained from a scale down prototype.
A multi cell 21-level hybrid multilevel inverter synthesizes a reduced number...
A multi-cell hybrid 21-Level multilevel inverter is proposed in this paper. The proposed topology includes two-unit; an H-bridge is cascaded with a modified K-type unit to generate an output voltage waveform with 21 levels based only on two unequal DC suppliers. The proposed topology's advantage lies in the fine and clear output voltage waveforms with high output efficiency. Meanwhile, the high number of output voltage waveform levels generates a low level of distortion and reduces the level of an electromagnetic interface (EMI). Moreover, it reduces the voltage stress on the switching devices and gives it a long lifetime. Also, the reduction in the number of components has a noticeable role in saving size and cost. Regarding the capacitors charging, the proposed topology presents an online method for charging and balancing the capacitor's voltage without any auxiliary circuits. The proposed topology can upgrade to a high number of output steps through the cascading connection. Undoubtedly this cascading will increase the power level to medium and high levels and reduce the harmonics content to a neglectable rate. The proposed system has been tested through the simulation results, and an experimental prototype based on the controller dSPACE (DS-1103) hardware unit used to support the simulation results.
A multi cell 21-level hybrid multilevel inverter synthesizes a reduced number...
A multi-cell hybrid 21-Level multilevel inverter is proposed in this paper. The proposed topology includes two-unit; an H-bridge is cascaded with a modified K-type unit to generate an output voltage waveform with 21 levels based only on two unequal DC suppliers. The proposed topology's advantage lies in the fine and clear output voltage waveforms with high output efficiency. Meanwhile, the high number of output voltage waveform levels generates a low level of distortion and reduces the level of an electromagnetic interface (EMI). Moreover, it reduces the voltage stress on the switching devices and gives it a long lifetime. Also, the reduction in the number of components has a noticeable role in saving size and cost. Regarding the capacitors charging, the proposed topology presents an online method for charging and balancing the capacitor's voltage without any auxiliary circuits. The proposed topology can upgrade to a high number of output steps through the cascading connection. Undoubtedly this cascading will increase the power level to medium and high levels and reduce the harmonics content to a neglectable rate. The proposed system has been tested through the simulation results, and an experimental prototype based on the controller dSPACE (DS-1103) hardware unit used to support the simulation results.
A generalized multilevel inverter topology with reduction of total standing v...
This paper presents a new multilevel inverter topology with reduced active switches and total standing voltage. The proposed topology can generate a high number of voltage levels in the symmetric configuration. This topology intuitively generates positive and negative cycles without an additional H-bridge unit, which considerably reduces the total standing voltage of the inverter. A cascaded structure is developed from the proposed topology to create higher voltage levels. To show the novelty of the proposed topology, a thorough comparison between the available and the proposed topologies in terms of the number of switches, standing voltages, and dc-sources is presented. Furthermore, the power loss analysis is carried out for various load values. The feasibility of the proposed nine-level inverter is verified with simulation and experimental results.
A Simplified Space Vector Pulse-Width Modulation Scheme for Three-Phase Casca...
A simplified space vector pulse-width modulation (SVPWM) for three-phase cascaded H-bridge (CHB) inverters is presented in this paper. Treating each unit as a three-level inverter and adopting serial calculation mode, a CHB inverter is modulated unit by unit using three-level SVPWM. Duty cycles of real sector are obtained by mapping duty cycles of sector 1, in which the calculation of three-level SVPWM is done. The process to implement multilevel SVPWM is simplified to the process to implement three-level SVPWM. By reusing FPGA chip resource which is used for the calculation of three-level SVPWM, the presented SVPWM can be easily adopted to a CHB inverter with different number of units, while the FPGA chip resource utilization is reduced significantly. In addition, the presented SVPWM provides an effective switching frequency higher than the switching frequency of IGBTs. Simulation and experimental results are provided to verify the feasibility of the presented SVPWM.
Arbitrary representation of sequence
https://www.youtube.com/watch?v=SNiBm-W8G14&list=PLhTuYg-DgnLeD74ravp6pJ0WQeov_0vrq&index=25
A Variable DC Link based Novel Multilevel Inverter Topology for Low Voltage A...
In this paper; a variable dc link based novel multilevel inverter (MLI) topology is proposed. This proposed topology comprises two variable dc links and a modified H-bridge unit. This new single-phase topology offers advantages such as reduction in count of switches; gate drivers and dc sources while simultaneously improving the power quality. The proposed topology has been analyzed for both symmetric and asymmetric modes of operation. A comparative study of the proposed topology with some recent MLI topologies has been presented. The comparative study indicates that the proposed topology requires less number of dc sources; switches and driver circuits as compared to other topologies. The proposed topology has been simulated for 31- level asymmetric configuration in MATLAB/SIMULINK environment to verify the proper operation of proposed topology. Harmonic analysis was also performed for 31-level inverter which showed significant reduction in the total harmonic distortion (THD) for phase voltage and current waveforms. The proposed topology is suitable for low voltage applications such as standalone photovoltaic (PV) systems and hybrid electric vehicles (HEVs).
Power Transfer Improvement without Any Alteration in Existing EHV AC Line wit...
Power Transfer Improvement without Any Alteration in Existing EHV AC Line wit...Shanmuga Priyan Thiagarajan
Enhancing power transfer capability of transmission lines without changing the line facilities is the need of the hour for practicing electrical engineers. As a solution to the problem, the possibility to load the EHV AC transmission lines very close to their thermal limits by transmitting usual ac along with dc super imposed on it is presented. The importance of proposed scheme is that the power transfer improvement is achieved without any alteration in the existing EHV ac line. The main goal is to gain the advantage of parallel ac–dc transmission and to load the line close to its thermal limit. The added dc power flow does not result in any transient instability. This gives the feasibility of converting a double circuit ac line into composite ac–dc power transmission line to get the advantages of parallel ac–dc transmission to improve stability and damping out oscillations. Simulation and experimental studies are carried out for the coordinated control as well as independent control of ac and dc power transmissions. No alterations of conductors, insulator strings, and towers of the original line are needed. The present situation demands the review of traditional power transmission theory and practice, on the basis of new concepts that allow full utilization of existing transmission facilities without decreasing system availability and security. Simultaneous ac–dc power transmission was first proposed through a single circuit ac transmission line. In these proposals Mono-polar dc transmission with ground as return path was used. There were certain limitations due to use of ground as return path. Moreover, the instantaneous value of each conductor voltage with respect to ground becomes higher by the amount of the dc voltage, and more discs are to be added in each insulator string to withstand this increased voltage. In this scheme, the dc power flow is point-to point bipolar transmission system. The proposed new methodology overcomes the problems and allows loading the line to its thermal limit, improving the revenue.LTI system causality and stability
https://www.youtube.com/watch?v=XshP5OkjJq0&list=PLhTuYg-DgnLeD74ravp6pJ0WQeov_0vrq&index=26
Power Electronics Projects Research Assistance
Developed Topics for Power Electronic
Disputes of RES
Essential Parameters in RES
Innovative Areas – Power Electronics
Case study: Ensuring exceptional PV performance with insolar
this case study explains how insolar, our sophisticated solar plant monitoring system, helps achieve exceptional performance of PV plants. With the permission of the owner, we chose a 2 MWp solar plant with over 4 years of operational data to take into consideration for analysing the effect of detailed monitoring in the overall plant performance. Our system monitors every single part of the solar plant from strings, inverters and electrical switchboards to transformers and substations.
Carlson vagus-nerve-stimulation-finite-element-model
Finite element model of vagus nerve stimulation. Finite element analysis of the effect of electric fields on biological tissue (the vagus nerve). Medical device consulting project. Paper: Arle, Carlson, Mei, Investigation of Mechanisms of Vagus Nerve Stimulation for Seizure Using Finite Element Modeling (in review).
Mppt with single dc–dc converter and inverter for grid connected hybrid wind-...
A new topology of a hybrid distributed generator based on photovoltaic and wind-driven permanent magnet synchronous generator is proposed. In this generator, the sources are connected together to the grid with the help of only a single boost converter followed by an inverter. Thus, compared to earlier schemes, the proposed scheme has fewer power converters. A model of the proposed scheme in the d − q-axis reference frame is developed. Two low-cost controllers are also proposed for the new hybrid scheme to separately trigger the dc–dc converter and the inverter for tracking the maximum power from both sources. The integrated operations of both proposed controllers for different conditions are demonstrated through simulation and experimentation. The steady-state performance of the system and the transient response of the controllers are also presented to demonstrate the successful operation of the new hybrid system. Comparisons of experimental and simulation results are given to validate the simulation model.
The Application of Electric Spring in Grid-Connected Photovoltaic System
The characteristics of distributed photovoltaic system power generation system is intermittent and instability. Under the weak grid conditions, when the active power of the PV system injected into the grid is fluctuant, the voltage of supply feeder will increase or decrease, thus affecting the normal use of sensitive load. The electric spring can transfer the energy injected into the supply feeder to the wide-voltage load, which is in series with the ES, to ensure the voltage stability of the sensitive load in the system. In this paper, a grid-connected photovoltaic simulation model with electric spring is built in Matlab / simulink. The voltage waveforms on the ES and sensitive load is obtained under the condition of changing the active power injected into the supply feeder by the grid-connected photovoltaic system. Thought the analysis of the waveforms, we can find that the Electric spring is a kind of effective method to solve the voltage fluctuation of the supply feeder in the grid-connected PV system.
Development of wind and solar based ac microgrid with power quality improveme...
This work proposes a microgrid (μ-grid) integrating wind and solar photovoltaic (PV) resources, along with the battery energy storage (BES) to the three phase grid feeding the nonlinear load. The μ-grid disconcerted by probabilistic nonlinear time dependent parameters and their effects are compensated by cohesive controllers used for utility grid side voltage source converter (GVSC) and machine side VSC (MVSC). The switching controls and the reconfigurability of the μ-grid are addressed on imperative aspects of improving power quality (PQ), power reliability, nonlinear load compensation and economic utilization of resources. The nonlinear load compensation and PQ enhancement are achieved by executing modified version of the adaptive filtering technique including “momentum” based least mean square (MLMS) control technique, utilized for providing the switching control signals to the GVSC. It utilizes two preceding gradient weights for obtaining updated weight thereby improving the convergence rate and overcoming the limitation of conventional control of the same family. The MVSC acquires its switching signals from conventional vector control scheme and the encoderless estimation of speed and rotor position of the synchronous generator (SG) driven by wind turbine through back electromotive force control technique. The external environmental disturbances are overcome by utilizing perturb and observe (P&O) maximum power point (MPP) for wind optimal power extraction and adaptive P&O with variable perturbation step size for solar MPP estimation. Test results are obtained from the laboratory prototype under steady state and dynamic conditions including altering wind speed, intermittent solar insolation and variable load conditions. The PQ issues are addressed and investigated successfully.
Power Electronics UK - 2017/18 Research Themes
Switch Optimisation, Converter Architectures, Heterogeneous Integration, Reliability and Health Management and Virtual Prototyping
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- 1. Robert Miller MailingAddress: Email: rzm4hf@mst.edu 106 Aintree St. Phone: 417-456-2340 Rolla,MO 65401 Objective To obtainan internshipinthe field of Electrical Engineering Education Missouri Universityof Science andTechnology Spring2016 B.S.Electrical Engineering GPA 3.0/4.0 Experience Wolf CreekNuclearOperationsCorporation Burlington,KS Engineering Co-op May – December, 2014 Workedon electrical loadcalculationsforcablesthroughoutthe plant Updatedplantrecords:analyzed, diagnosed, fixed,andreported errors&discrepancies Shadowed supervisorandmanagermeetingsaboutmajorplantdecisionsandchanges Modeledcircuits,&generatedloadflow information,aswell astime/currentdamage curvesfor equipmentusingthe ETAPprogram CompletedanEvaluationCalculationconcerningwaterlevelsandpowersupplyof the sumppumpsin manholesaroundthe facility Coffeyville Resources Coffeyville,Ks Electrical Engineering Intern Summer,2013 Managed electromechanical/solid-staterelayproject Workedinthe fieldtodiagnose andrepairelectrical equipmentinthe plant Updatedelectrical groundmaps Assistedinplanningandimplementingplacementof anew transformer MC TelephoneCompany Pineville,MO In House Line Design/Mapper Summer,2012 Managed andupdatedcompanyelectronicmapsusingAuto-Cad Updatedplantrecords Repairof telephone andmediasystems Analyzed,diagnosed, fixed,andreportedErrors& discrepancies Computer AutoCad; Mat-Lab; ETAP; Curator;Empac; Setroute;Enterprise; C++Programming; Skills MicrosoftOffice- Word,Excel,PowerPoint,Access Honors & IEEE Activities Engineersw/oBorders BackpackingClub IM Sports; Various volunteereventsresultingin100+ hours