Review and Comparison of Step-Up Transformerless Topologies for Photovoltaic AC-Module Application

ABSTRACT:

This paper presents a comprehensive review of step-up single phase non isolated inverters suitable for ac-module applications. In order to compare the most feasible solutions of the reviewed topologies, a benchmark is set. This benchmark is based on a typical ac-module application considering the requirements for the solar panels and the grid. The selected solutions are designed and simulated complying with the benchmark obtaining passive and semiconductor components ratings in order to perform a comparison in terms of size and cost. A discussion of the analyzed topologies regarding the obtained ratings as well as ground currents is presented. Recommendations for topological solutions complying with the application benchmark are provided.

KEYWORDS:

  1. AC-module
  2. Photovoltaic(PV)
  3. Step-up Inverter
  4. Transformerless

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

image001

Fig.1 Block diagram of a two stage topology for an ac module

STEP-UP TRANSFORMERLESS INVERTERS:

image002

Fig 2 Boost converter and full bridge inverter

Time sharing boost converter with full bridge inverter

Fig 3 Time sharing boost converter with full bridge inverter

Parallel resonant soft switched boost converter and full bridge inverter

Fig 4 Parallel resonant soft switched boost converter and full bridge inverter

Parallel input series-output bipolar dc output converter and full bridge inverter

Fig 5 Parallel input series-output bipolar dc output converter and full bridge inverter

Boost converter and half bridge inverter

Fig 6 Boost converter and half bridge inverter

Boost converter and neutral point clamped inverter

Fig 7 Boost converter and neutral point clamped inverter

Series combined boost and buck boost and half bridge inverter

Fig 8 Series combined boost and buck boost and half bridge inverter

Center-tapped coupled inductor converter with bipolar output and half bridge inverter

Fig  9 Center-tapped coupled inductor converter with bipolar output and half bridge inverter

Single inductor bipolar output buck-boost converter and half bridge inverter

Fig 10 Single inductor bipolar output buck-boost converter and half bridge inverter

 Boost + FB integrated and dual grounded

Fig  11 Boost + FB integrated and dual grounded

Block diagram of a pseudo-dc-link topology for an ac module

Fig 12 Block diagram of a pseudo-dc-link topology for an ac module

Buck-boost DCM converter and unfolding stage

Fig 13 Buck-boost DCM converter and unfolding stage

Noninverting buck-boost DCM converter and unfolding stage

Fig 14 Noninverting buck-boost DCM converter and unfolding stage

Switched inductor buck boost DCM converter and unfolding stage

Fig 15 Switched inductor buck boost DCM converter and unfolding stage

 Boost buck time sharing converter and unfolding stage

Fig 16 Boost buck time sharing converter and unfolding stage

Block diagram of a single stage topology for an ac module

Fig 17 Block diagram of a single stage topology for an ac module

Universal single stage grid connected inverter

Fig 18 Universal single stage grid connected inverter

image019

Fig 19 Integrated boost converter

image020

Fig 20 Differential boost converter

image021

Fig 21 Boost inverter with improved zero crossing.

image022

Fig 22 Integrated Buck boost inverter

image023

Fig 23 Buck Boost inverter with extended input voltage range

image024

Fig 24 Differential buck boost inverter

image025

Fig 25 Two sourced anti parallel buck boost inverter

image026

Fig 26 Single stage full bridge buck boost inverter

image027

Fig 27 Buck boost based single stage inverter

image028

Fig 28 Switched inductor buck boost based single stage inverter

image029

Fig 29 Single inductor buck boost based inverter

image030

Fig 30 Doubly grounded single inductor buck boost based inverter

image031

Fig 31 Single inductor  buck boost based inverter with dual ground

image032

Fig 32 Three switch buck boost inverter

image033

Fig 33 Coupled inductor buck boost inverter

image034

Fig 34 Impedance-admittance conversion theory based inverter

image035

Fig 35 Single phase Z source inverter

image036

Fig 36 Semi quasi Z source inverter with continuous voltage gain

 

CONCLUSION:

In this paper, a comprehensive review of single phase non isolated inverters for ac module applications is presented. Both the grid connection and the solar panel requirements are analyzed emphasizing the leakage current regulation as it is a main concern in non isolated PV grid connected inverters. In order to compare the most suitable solutions of the reviewed topologies under the same specifications, a benchmark of a typical ac module application is set. These solutions have been designed and simulated, obtaining ratings for the passive and the semiconductor components. These ratings are used for the topology comparison in terms of size and cost. Furthermore, detailed simulations of representative topologies have been performed using semiconductor and inductor models to estimate the efficiency of the reviewed solutions. As a result of the comparison, the required voltage boost necessary for the connection to the European grid is difficult to achieve with transformerless topologies, but it is adequate for U.S. requirements. Two stage topologies, including the solution with dual grounding capability that theoretically avoids the ground leakage currents, are the preferred option for the set benchmark in which switching frequency for the dc-dc stage is set twice than for the dc-ac one. The two stage combination of a step-up dc-dc converter and a step-up inverter should be considered. In addition, the analyzed pseudo-dc-link approaches are an alternative solution in terms of size and cost. Furthermore, ground currents are expected to be low in these solutions because of the line frequency interface and weighted efficiency is the highest due to the flat behavior of the efficiency with the output power. The analyzed single stage topologies have higher cost than the other analyzed solutions and control is expected to be more complex to avoid dc current injection. In addition, DCM operation mode allows smaller solutions, including a solution with dual ground capability, but efficiency is lower due to the high RMS currents.

 

Paper Writing and Paper Publication

The scientific manuscript is a clear written document (Paper Writing) that illustrates a question and then gives a logical answer to this question based on theoretical or experimental or simulation results. A manuscript conveys the technical information to the reader, thus the presentation and discussion should be straightforward.

The origins and development of the scientific and technical press can be traced back to 1665 when the first “modern” scientific papers appeared and were characterized by non standardised form and style. Subsequently, nearly 300 years ago, in an attempt to ensure that articles met the journal’s standards of quality and scientific validity, the peer-reviewed process for scientific manuscripts was born in England and France. Since then, there has been an enormous proliferation of scientific journals and manuscripts so that, at present, the numbers of biomedical papers published annually by over 20,000 journals, at a rate of 5,500 new papers per day, far exceeds 2,000,000.

Published scientific papers and professional meetings are really essential to disseminate relevant information and research findings. However, most of the abstracts of presentations given at scientific meetings are usually available only in conference proceedings. Though they have the potential to be subsequently published as articles in peer-reviewed journals.

Possible reasons for failed publication include lack of time, research still underway, problems with co-authors and negative results. Undoubtedly, lack of the necessary skills and experience in the process of writing and publishing is another possible contributing factor. Also in the field of Transfusion Medicine although the specialists in this discipline are currently adopting the principles and research methodologies. High-level research is actually being carried out at the same rate as in all medical specialties.

There are three broad groups of manuscripts: original scientific articles, reviews and case reports.

We do write research papers and give guidance for publishing papers in good International Journals.

Paper writing

paper writing

Asoka Technologies

A Novel Control Method for Transformerless H-Bridge Cascaded STATCOM with Star Configuration

ABSTRACT

This paper presents a transformerless static synchronous compensator (STATCOM) system based on multilevel H-bridge converter with star configuration. This proposed control methods devote themselves not only to the current loop control but also to the dc capacitor voltage control. With regards to the current loop control, a nonlinear controller based on the passivity-based control (PBC) theory is used in this cascaded structure STATCOM for the first time. As to the dc capacitor voltage control, overall voltage control is realized by adopting a proportional resonant controller. Clustered balancing control is obtained by using an active disturbances rejection controller. Individual balancing control is achieved by shifting the modulation wave vertically which can be easily implemented in a field-programmable gate array. Two actual H-bridge cascaded STATCOMs rated at 10 kV 2 MVA are constructed and a series of verification tests are executed. The experimental results prove that H-bridge cascaded STATCOM with the proposed control methods has excellent dynamic performance and strong robustness. The dc capacitor voltage can be maintained at the given value effectively.

 

KEYWORDS:

Active disturbances rejection controller (ADRC), H-bridge cascaded, passivity-based control (PBC), proportional resonant (PR) controller, shifting modulation wave, static synchronous compensator (STATCOM).

 

SOFTWARE: MATLAB/SIMULINK

 

CONTROL BLOCK DIAGRAM:

image001

Fig. 1. Control block diagram for the 10 kV 2 MVA H-bridge cascaded STATCOM.

 image002

Fig. 2. Block diagram of PBC.

 

EXPERIMENTAL RESULTS:

image003 image004

Fig. 3. Experimental results verify the effect of PBC in steady-state process. (a) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid. (b) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid.

 image005

Fig. 4. Experimental results show the dynamic performance of STATCOM in the dynamic process. Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid.

image006 image007

Fig. 5. Experimental results in the startup process and stopping process. (a) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid. (b) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid.

 

CONCLUSION

This paper has analyzed the fundamentals of STATCOM based on multilevel H-bridge converter with star configuration. And then, the actual H-bridge cascaded STATCOM rated at 10 kV 2 MVA is constructed and the novel control methods are also proposed in detail. The proposed method has the following characteristics.

1) A PBC theory-based nonlinear controller is first used in STATCOM with this cascaded structure for the current loop control, and the viability is verified by the experimental results.

2) The PR controller is designed for overall voltage control and the experimental result proves that it has better performance in terms of response time and damping profile compared with the PI controller.

3) The ADRC is first used in H-bridge cascaded STATCOM for clustered balancing control and the experimental results verify that it can realize excellent dynamic compensation for the outside disturbance.

4) The individual balancing control method which is realized by shifting the modulation wave vertically can be easily implemented in the FPGA.

The experimental results have confirmed that the proposed methods are feasible and effective. In addition, the findings of this study can be extended to the control of any multilevel voltage source converter, especially those with H-bridge cascaded structure.

 

REFERENCES

[1] B. Gultekin and M. Ermis, “Cascaded multilevel converter-based transmission STATCOM: System design methodology and development of a 12 kV ±12 MVAr power stage,” IEEE Trans. Power Electron., vol. 28, no. 11, pp. 4930–4950, Nov. 2013.

[2] B. Gultekin, C. O. Gerc¸ek, T. Atalik, M. Deniz, N. Bic¸er, M. Ermis, K. Kose, C. Ermis, E. Koc¸, I. C¸ adirci, A. Ac¸ik, Y. Akkaya, H. Toygar, and S. Bideci, “Design and implementation of a 154-kV±50-Mvar transmission STATCOM based on 21-level cascaded multilevel converter,” IEEE Trans. Ind. Appl., vol. 48, no. 3, pp. 1030–1045, May/Jun. 2012.

[3] S. Kouro, M. Malinowski, K. Gopakumar, L. G. Franquelo, J. Pou, J. Rodriguez, B.Wu,M. A. Perez, and J. I. Leon, “Recent advances and industrial applications of multilevel converters,” IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2553–2580, Aug. 2010.

[4] F. Z. Peng, J.-S. Lai, J. W. McKeever, and J. VanCoevering, “A multilevel voltage-source inverter with separateDCsources for static var generation,” IEEE Trans. Ind. Appl., vol. 32, no. 5, pp. 1130–1138, Sep./Oct. 1996.

[5] Y. S. Lai and F. S. Shyu, “Topology for hybrid multilevel inverter,” Proc. Inst. Elect. Eng.—Elect. Power Appl., vol. 149, no. 6, pp. 449–458, Nov. 2002.

Final year academic projects

2015 IEEE ELECTRICAL PROJECTS

  1. A High Gain Input-Parallel Output-Series DC/DC Converter with Dual Coupled Inductors
  2. A High Step-Up Converter with Voltage-Multiplier Modules for Sustainable Energy Applications
  3. A High Step-Up DC to DC Converter Under Alternating Phase Shift Control for Fuel Cell Power System
  4. High-Efficiency MOSFET Transformer-less Inverter for Non-isolated Micro-inverter Applications
  5. A Multi-Input Bridgeless Resonant AC-DC Converter for Electromagnetic Energy Harvesting
  6. A Novel Control Method for Transformer-less H-Bridge Cascaded STATCOM with Star Configuration
  7. A Novel High Step-up DC/DC Converter Based on Integrating Coupled Inductor and Switched-Capacitor Techniques for Renewable Energy Applications

2014 IEEE ELECTRICAL PROJECTS

  1. A Modified Three-Phase Four-Wire UPQC Topology With Reduced DC-Link Voltage Rating
  1. FPGA-Based Predictive Sliding Mode Controller of a Three-Phase Inverter
  2. Pulsewidth Modulation of Z-Source Inverters With Minimum Inductor Current Ripple
  3. Improving the Dynamics of Virtual-Flux-Based Control of Three-Phase Active Rectifiers
  4. Sensorless Induction Motor Drive Using Indirect Vector Controller and Sliding-Mode Observer for Electric Vehicles
  5. Back-Propagation Control Algorithm for Power Quality Improvement Using DSTATCOM
  6. A Zero-Voltage Switching Three-Phase Inverter
  7. Control of Reduced-Rating Dynamic Voltage Restorer With a Battery Energy Storage System
  8. A Combination of Shunt Hybrid Power Filter and Thyristor-Controlled Reactor for Power Quality
  9. A Transformerless Grid-Connected Photovoltaic System Based on the Coupled Inductor Single-Stage Boost Three-Phase Inverter
  10. LCL Filter Design and Performance Analysis for Grid-Interconnected Systems
  11. An Inductively Active Filtering Method for Power-Quality Improvement of Distribution Networks With Nonlinear Loads
  12. A Bidirectional-Switch-Based Wide-Input Range High-Efficiency Isolated Resonant Converter for Photovoltaic Applications
  13. Analysis and Implementation of an Improved Flyback Inverter for Photovoltaic AC Module Applications
  14. Speed Sensorless Vector Controlled Induction Motor Drive Using Single Current Sensor
  15. A Novel Design and Optimization Method of an LCL Filter for a Shunt Active Power Filter
  16. An Active Harmonic Filter Based on One-Cycle Control
  17. A Nine-Level Grid-Connected Converter Topology for Single-Phase Transformerless PV Systems
  18. Modeling and Design of Voltage Support Control Schemes for Three-Phase Inverters Operating Under Unbalanced Grid Conditions
  19. Cascaded Two-Level Inverter-Based Multilevel STATCOM for High-Power Applications

Comprehensive Study of Single-Phase AC-DC Power Factor Corrected Converters with High-Frequency Isolation

ABSTRACT: Solid-state switch mode AC-DC converters having high-frequency transformer isolation are developed in buck, boost, and buck-boost configurations with improved power quality in terms of reduced total harmonic distortion (THD) of input current, power-factor correction (PFC) at AC mains and precisely regulated and isolated DC output voltage feeding to loads from few Watts to several kW. This paper presents a comprehensive study on state of art of power factor corrected single-phase AC-DC converters configurations, control strategies, selection of components and design considerations, performance evaluation, power quality considerations, selection criteria and potential applications, latest trends, and future developments. Simulation results as well as comparative performance are presented and discussed for most of the proposed topologies.

 

INDEX TERMS: AC-DC converters, harmonic reduction, high-frequency (HF) transformer isolation, improved power quality converters, power-factor correction.

 

SOFTWARE: MATLAB/SIMULINK

image001

Fig. 1. Classification of improved power quality single-phase AC-DC converters with HF transformer isolation.

CIRCUIT CONFIGURATIONS

A. Buck AC-DC Converters

image002         image003

Fig. 2. Buck forward AC-DC converter with voltage follower control.

Fig. 3. Buck push-pull AC-DC converter with voltage follower control.

                                           image004       image005

 

 

 

 

Fig. 4. Half-bridge buck AC-DC converter with voltage follower control.

Fig. 5. Buck full-bridge AC-DC converter with voltage follower control

 B. Boost AC-DC Converters

image006     image007

Fig. 6. Boost forward AC-DC converter with current multiplier control.

Fig. 7. Boost push-pull AC-DC converter with current multiplier control.

image008     image009

Fig. 8. Boost half-bridge AC-DC converter with current multiplier control.

Fig. 9. Boost full-bridge AC-DC converter with current multiplier control.

 C. Buck-Boost AC-DC Converters

image010           image011

Fig. 10. Flyback AC-DC converter with current multiplier control.

Fig. 11. Cuk AC-DC converter with voltage follower control.

image012      image013

Fig. 12. SEPIC AC-DC converter with voltage follower control.

Fig. 13. Zeta AC-DC converter with voltage follower control.

 

SIMULATION RESULTS:

image014

Fig. 14. Current waveforms and its THD for buck AC-DC converter topologies in CCM. (a) Forward buck topology (Fig. 2).( b) Push-pull buck topology (Fig. 3). (c) Half-bridge buck topology (Fig. 4). (d) Bridge buck topology (Fig. 5).

image015

Fig. 15. Current waveforms and its THD for boost AC-DC converter topologies in CCM. (a) Forward boost topology (Fig. 6). (b) Push-pull boost topology (Fig. 7). (c) Half-bridge boost topology (Fig. 8). (d) Bridge boost topology (Fig. 9).

image016

Fig. 16. Current waveforms and its THD for buck-boost AC-DC converter topologies in CCM. (a) Flyback topology (Fig. 10). (b) Cuk topology (Fig. 11). (c) SEPIC topology (Fig. 12). (d) Zeta topology (Fig. 13).

image017

Fig. 17. Current waveforms and its THD for buck AC-DC converter topologies in DCM. (a) Forward buck topology (Fig. 2). (b) Push-pull buck topology (Fig. 3). (c) Half-bridge buck topology (Fig. 4). (d) Bridge buck topology (Fig. 5).

image018

Fig. 18. Current waveforms and its THD for boost AC-DC converter topologies in DCM. (a) Forward boost topology (Fig. 6). (b) Push-pull boost topology (Fig. 7).

image019

Fig. 19. Current waveforms and its THD for buck-boost AC-DC converter topologies in DCM. (a) Flyback topology (Fig. 10). (b) Cuk topology (Fig. 11). (c) SEPIC topology (Fig. 12). (d) Zeta topology (Fig. 13).

 

CONCLUSION

A comprehensive review of the improved power quality HF transformer isolated AC-DC converters has been made to present a detailed exposure on their various topologies and its design to the application engineers, manufacturers, users and researchers. A detailed classification of these AC-DC converters into 12 categories with number of circuits and concepts has been carried out to provide easy selection of proper topology for a specific application. These AC-DC converters provide a high level of power quality at AC mains and well regulated, ripple free isolated DC outputs. Moreover, these converters have been found to operate very satisfactorily with very wide AC mains voltage and frequency variations resulting in a concept of universal input. The new developments in device technology, integrated magnetic and microelectronics are expected to provide a tremendous boost for these AC-DC converters in exploring number of additional applications. It is hoped that this exhaustive design and simulation of these HF transformer isolated AC-DC converters is expected to be a timely reference to manufacturers, designers, researchers, and application engineers working in the area of power supplies.

 

REFERENCES

[1] IEEE Recommended Practices and Requirements for Harmonics Control in Electric Power Systems, IEEE Standard 519, 1992.

[2] Electromagnetic Compatibility (EMC) – Part 3: Limits- Section 2: Limits for Harmonic Current Emissions (equipment input current 􀀀16 A per phase), IEC1000-3-2 Document, 1st ed., 1995.

[3] A. I. Pressman, Switching Power Supply Design, 2nd ed. New York: McGraw-Hill, 1998.

[4] K. Billings, Switchmode Power Supply Handbook, 2nd ed. NewYork: McGraw-Hill, 1999.

[5] N. Mohan, T. Udeland, and W. Robbins, Power Electronics: Converters, Applications and Design, 3rd ed. New York: Wiley, 2002.

Analysis and Design of Three-Level, 24-Pulse Double Bridge Voltage Source Converter Based HVDC System for Active and Reactive Power Control

ABSTRACT

This paper deals with the analysis, design and control of a three-level 24-pulse Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) system. A three level VSC operating at fundamental frequency switching (FFS) is proposed with 24-pulse VSC structure to improve the power quality and reduce the converter switching losses for high power applications. The design of three-level VSC converter and system parameters such as ac inductor and dc capacitor is presented for the proposed VSC based HVDC system. It consists of two converter stations fed from two different ac systems. The active power is transferred between the stations either way. The reactive power is independently controlled in each converter station. The three-level VSC is operated at optimized dead angle (β). A coordinated control algorithm for both the rectifier and an inverter stations for bidirectional active power flow is developed based on FFS and local reactive power generation. This results in a substantial reduction in switching losses and avoiding the reactive power plant. Simulation is carried to verify the performance of the proposed control algorithm of the VSC based HVDC system for bidirectional active power flow and their independent reactive power control.

 

KEYWORDS

Voltage Source Converter (VSC), Three-level VSC, Fundamental Frequency Switching (FFS), HVDC System, Power Flow Control, Reactive Power Control, Power Quality, Total Harmonic Distortion (THD), Dead Angle (β).

 

SOFTWARE: MATLAB/SIMULINK

 

BLOCK DIAGRAM:

image001

Fig. 1 Three-level 24-pulse double bridge VSC based HVDC system

 

EXPECTED SIMULATION RESULTS:

image002

Fig. 2a Performance of rectifier station during reactive power control of three level 24-pulse VSC HVDC system

image003

Fig. 2b Performance of Inverter station during reactive power control at rectifier station of three-level 24 pulse VSC HVDC system

image004

Fig. 2c Variation of (δ) and (α) values for rectifier and inverter Stations for reactive power variation of a three-level 24-pulse VSC HVDC system

image005

Fig. 3a Rectifier station during active power reversal of three-level 24-pulse VSC HVDC system

image006

Fig. 3b Inverter station during active power reversal of three-level 24-pulse VSC HVDC system

image007

Fig. 3c Variation of (δ) and (α) values during active power reversal of three level 24-pulse VSC HVDC system.

 

CONCLUSION

A new three-level, 24-pulse voltage source converter based HVDC system operating at fundamental frequency switching has been designed and its model has been developed and it is successfully tested for the independent control of active and reactive powers and acceptable level harmonic requirements. The reactive power has been controlled independent of the active power at both conditions. The converter has been successfully operated in all four quadrants of active and reactive powers with the proposed control. The reversal of the active power flow has been implemented by reversing the direction of dc current without changing the polarity of dc voltage which is very difficult in conventional HVDC systems. The power quality of the HVDC system has also improved with three-level 24-pulse converter operation. The harmonic performance of this three-level, 24-pulse VSC has been observed to an equivalent to two-level 48-pulse voltage source converter.

 

REFERENCES

[1] “It’s time to connect,” Technical description of HVDC Light Technology, ABB HVDC Library.

[2] J. Arrillaga, “High Voltage Direct Current Transmission,” 2nd Edition, IEE Power and Energy Series 29, London, 1998.

[3] Vijay K. Sood, “HVDC and FACTS Controllers – Applications of Static Converters in Power Systems,” Kluwer Academic Publishers, Masachusetts, 2004.

[4] J. Arrillaga, Y. H. Liu and N. R. Waston, “Flexible Power Transmission- The HVDC Options,” John Wiley & Sons, Ltd, Chichester, UK, 2007.

[5] J. Arrillaga and M. E. Villablanca, “A modified parallel HVDC convertor for 24 pulse operation,” IEEE Trans. on Power Delivery, vol. 6, no. 1, pp. 231-237, Jan 1991.

H6-type Single Phase Full-Bridge PV Grid-Tied Transformerless Inverters

ABSTRACT:
Photovoltaic (PV) generation systems are widely employed in transformer less inverters, in order to achieve the benefits of high efficiency and low cost. Safety requirements of leakage currents are met by proposing the various transformers less inverter topologies. In this paper, three transformer less inverter topologies are illustrated such as a family of H6 transformer less inverter topologies with low leakage currents is proposed, and the intrinsic relationship between H5 topology, highly efficient and reliable inverter concept (HERIC) topology. The proposed H6 topology has been discussed as well. For a detailed analysis with operation modes and modulation strategy one of the proposed H6 inverter topologies is taken as an example. Comparison among the HERIC, the H5, and the proposed H6 topologies is been done for the power device costs and power losses. For evaluating their performances in terms of power efficiency and leakage currents characteristics, a universal prototype is built for these three topologies mentioned. Simulation results show that the proposed HERIC topology and the H6 topology achieve similar performance in leakage currents, which is slightly worse than that of the H5 topology, but it features higher efficiency than that of H5 topology.

KEYWORDS:
1. Common-mode voltage
2. Grid-tied inverter
3. Leakage current
4. Photovoltaic (PV) generation system
5. Transformerless inverter

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

image002

Fig. 1. Leakage current path for transformerless PV inverters

EXPECTED SIMULATION RESULTS:

image004 image006

Fig. 2. CM voltage and leakage current in H6 topology. (a) CM voltage. (b) Leakage current.

image008 image010

Fig. 3. Drain–source voltages in H6 topology. (a) Voltage stress on S5 and S6 . (b) Detailed waveforms.

image012

Fig. 4. DM characteristic of H6 topology.

image014

Fig. 5. Efficiency comparison of H5, HERIC and H6 topologies.

CONCLUSION:

In this paper, based on the H5 topology, a new current path is formed by inserting a power device between the terminals of PV array and the midpoint of one of bridge legs. As a result, a family of single-phase transformerless full-bridge H6 inverter topologies with low leakage currents is derived. The proposed H6 topologies have the following advantages and evaluated by simulation results:
1) The conversion efficiency of the novel H6 topology is better than that of the H5 topology, and its thermal stress distribution is better than that of the H5 topology;
2) The leakage current is almost the same as HERIC topology, and meets the safety standard;
3) The excellent DM performance is achieved like the isolated full-bridge inverter with uniploar SPWM. Therefore, the proposed H6 topologies are good solutions for the single phase transformerless PV grid-tied inverters.

REFERENCES:
[1] S. B. Kjaer, J. K. Pederson, and F. Blaabjerg, “A review of single-phase grid-connected inverters for photovoltaic modules,” IEEE Trans. Ind. Appl., vol. 41, no. 5, pp. 1292–1306, Sep/Oct. 2005.
[2] F. Blaabjerg, Z. Chen, and S. B. Kjaer, “Power electronics as efficient interface in dispersed power generation systems,” IEEE Trans. Power Electron., vol. 19, no. 5, pp. 1184–1194, Sep. 2004.
[3] B. Sahan, A. N. Vergara, N. Henze, A. Engler, and P. Zacharias, “A single stage PVmodule integrated converter based on a low-power current source inverter,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2602–2609, Jul.2008.
[4] M. Calais, J. Myrzik, T. Spooner, and V. G. Agelidis, “Inverters for single phase grid connected photovoltaic systems—An overview,” in Proc. IEEE PESC, 2002, vol. 2, pp. 1995–2000.
[5] F. Blaabjerg, Z. Chen, and S. B. Kjaer, “Power electronics as efficient interface in dispersed power generation systems,” IEEE Trans. Power Electron., vol. 19, no. 5, pp. 1184–1194, Sep. 2004.

IEEE Electrical Engineering Projects for BTech and MTech

Asoka Technologies (IEEE electrical engineering projects)                                                           (B.TECH/M.TECH IEEE ELECTRICAL ENGINEERING PROJECTS USING MATLAB/SIMULINK)
WE OFFER ACADEMIC MATLAB SIMULATION PROJECTS FOR
1. ELECTRICAL AND ELECTRONICS ENGINEERING [EEE]
2. POWER ELECTRONICS AND DRIVES [PED]
3. POWER SYSTEMS [PS]….etc

We will develop your OWN IDEAS and your IEEE Papers with extension if necessary and also we give guidance for publishing papers…

For Further Details Call Us :

0-9347143789/9949240245

For Abstracts of IEEE papers and for any Queries mail to: asokatechnologies@gmail.com and also visit our Blog: www.asokatechnologies.blogspot.com and website www.asokatechnologies.in for more IEEE

IEEE Electrical engineering projects.

 

Electrical engineers typically hold a degree in electrical engineering or electronic engineering. Practicing engineers may have professional certification and be members of a professional body. Such bodies include the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (professional society) (IET).

Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range from basic circuit theory to the management skills required of a project manager. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple voltmeter to a top end analyzer to sophisticated design and manufacturing software.

BTech and MTech EEE projects  can be done in different domains. They are power electronics and drives,  power systems, electrical machines and drives etc. Each of these domains use many technologies and areas.

We understand the importance of IEEE papers for BTech and M.Tech EEE projects. Hence we hand pick IEEE projects for BTech and M.Tech EEE. We ensure that the IEEE papers and projects have enough scope for a two semister project work or for a final year project work. If needed an improvement over the simulated results by newer and better techniques for MTech EEE can also be done. The Matlab / Simulink software is used for doing EEE projects. We do give guidance for paper writing and suggest journals.

BTech and MTech EEE projects of various domains are available at Asoka Technologies. We also develop your own ideas. We deliver the projects within the time frame given by the students. Visit our website and blogspot for more papers.

 

A Unified Control Strategy for Three-Phase Inverter in Distributed Generation

ABSTRACT:
This paper presents a unified control strategy that enables both islanded and grid-tied operations of three-phase inverter in distributed generation, with no need for switching between two corresponding controllers or critical islanding detection. The proposed control strategy composes of an inner inductor current loop, and a novel voltage loop in the synchronous reference frame. The inverter is regulated as a current source just by the inner inductor current loop in grid-tied operation, and the voltage controller is automatically activated to regulate the load voltage upon the occurrence of islanding. Furthermore, the waveforms of the grid current in the grid-tied mode and the load voltage in the islanding mode are distorted under nonlinear local load with the conventional strategy. And this issue is addressed by proposing a unified load current feedforward in this paper. Additionally, this paper presents the detailed analysis and the parameter design of the control strategy. Finally, the effectiveness of the proposed control strategy is validated by the simulation results.

KEYWORDS:
1. Distributed generation (DG)
2. Islanding
3. Load current
4. Seamless transfer
5. Three-phase inverter
6. Unified control

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:
image002
Fig. 1. Overall block diagram of the proposed unified control strategy.

EXPECTED SIMULATION RESULTS:
image004
Fig. 2. Simulation waveforms of load voltage vC a , grid current iga, and inductor current iLa when DG is in the grid-tied mode under condition of the step down of the grid current reference from 9 A to 5 A with: (a) conventional voltage mode control, and (b) proposed unified control strategy.

image006
Fig. 3. Simulation waveforms of load voltage vC a , grid current iga, and inductor current iLa when DG is transferred from the grid-tied mode to the islanded mode with: (a) conventional hybrid voltage and current mode control, and (b) proposed unified control strategy.

CONCLUSION:
A unified control strategy was proposed for three-phase inverter in DG to operate in both islanded and grid-tied modes, with no need for switching between two different control architectures or critical islanding detection. A novel voltage controller was presented. It is inactivated in the grid-tied mode, and the DG operates as a current source with fast dynamic performance. Upon the utility outage, the voltage controller can automatically be activated to regulate the load voltage. Moreover, a novel load current feed forward was proposed, and it can improve the waveform quality of both the grid current in the grid-tied mode and the load voltage in the islanded mode. The proposed unified control strategy was verified by the simulation results.
REFERENCES:
[1] R. C. Dugan and T. E. McDermott, “Distributed generation,” IEEE Ind. Appl. Mag., vol. 8, no. 2, pp. 19–25, Mar./Apr. 2002.
[2] R. H. Lasseter, “Microgrids and distributed generation,” J. Energy Eng., vol. 133, no. 3, pp. 144–149, Sep. 2007.
[3] C. Mozina, “Impact of green power distributed generation,” IEEE Ind. Appl. Mag., vol. 16, no. 4, pp. 55–62, Jul./Aug. 2010.
[4] IEEE Recommended Practice for Utility Interface of Photovoltaic(PV) Systems, IEEE Standard 929-2000, 2000.
[5] IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems, IEEE Standard 1547-2003, 2003.

Adaptive PI Control of STATCOM for Voltage Regulation

ABSTRACT:

STATCOM can provide fast and efficient reactive power support to maintain power system voltage stability. In the literature, various STATCOM control methods have been discussed including many applications of proportional-integral (PI) controllers. However, these previous works obtain the PI gains via a trial-and-error approach or extensive studies with a tradeoff of performance and applicability. Hence, control parameters for the optimal performance at a given operating point may not be effective at a different operating point. This paper proposes a new control model based on adaptive PI control, which can self-adjust the control gains during a disturbance such that the performance always matches a desired response, regardless of the change of operating condition. Since the adjustment is autonomous, this gives the plug-and-play capability for STATCOM operation. In the simulation test, the adaptive PI control shows consistent excellence under various operating conditions, such as different initial control gains, different load levels, change of transmission network, consecutive disturbances, and a severe disturbance. In contrast, the conventional STATCOM control with tuned, fixed PI gains usually perform fine in the original system, but may not perform as efficient as the proposed control method when there is a change of system conditions.

KEYWORDS:
1. Adaptive control
2. Plug and play
3. Proportional-integral (PI) control
4. Reactive power compensation
5. STATCOM
6. Voltage stability.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:
image001
Figure 1 Studied system

image004
Fig.2 Results of (a) voltages and (b) output reactive power using the same network and loads as in the original system.
image006
Fig.3 Results of using the same network and loads as in the original system.
image008
Fig. 4. Results of (a) voltages and (b) output reactive power with changed PI control gains
image010
Fig. 5. Results of (a) voltages and (b) output reactive power with a change of load
image012
Fig. 6. Results of with changed PI control gains.
image014
Fig. 7. Results of α with a change of load.
image008
Fig. 8. Results of α(a) voltages and (b) output reactive power with a change of transmission network.
image018
Fig. 9. Results of α with a change of transmission network.
image020
Fig. 10. Results of α (a) voltages and (b) output reactive power with two consecutive disturbances.
image022
Fig. 11. Results of α with two consecutive disturbances.

CONCLUSION:
In the literature, various STATCOM control methods have been discussed including many applications of PI controllers. However, these previous works obtain the PI gains via a trialand- error approach or extensive studies with a tradeoff of performance and applicability. Hence, control parameters for the optimal performance at a given operating point may not always be effective at a different operating point. To address the challenge, this paper proposes a new control model based on adaptive PI control, which can self-adjust the control gains dynamically during disturbances so that the performance always matches a desired response, regardless of the change of operating condition. Since the adjustment is autonomous, this gives the “plug-and-play” capability for STATCOM operation.
In the simulation study, the proposed adaptive PI control for STATCOMis compared with the conventional STATCOM control with pretuned fixed PI gains to verify the advantages of the proposed method. The results show that the adaptive PI control gives consistently excellent performance under various operating conditions, such as different initial control gains, different load levels, change of the transmission network, consecutive disturbances, and a severe disturbance. In contrast, the conventional STATCOM control with fixed PI gains has acceptable performance in the original system, but may not perform as efficient as the proposed control method when there is a change of system conditions.
Future work may lie in the investigation of multiple STATCOMs since the interaction among different STATCOMs may affect each other. Also, the extension to other power system control problems can be explored.

REFERENCES:
[1] F. Li, J. D. Kueck, D. T. Rizy, and T. King, “A preliminary analysis of the economics of using distributed energy as a source of reactive power supply,” Oak Ridge, TN, USA, First Quart. Rep. Fiscal Year, Apr. 2006, Oak Ridge Nat. Lab.
[2] A. Jain, K. Joshi, A. Behal, and N. Mohan, “Voltage regulation with STATCOMs:Modeling, control and results,” IEEE Trans. Power Del., vol. 21, no. 2, pp. 726–735, Apr. 2006.
[3] D. Soto and R. Pena, “Nonlinear control strategies for cascaded multilevel STATCOMs,” IEEE Trans. Power Del., vol. 19, no. 4, pp. 1919–1927, Oct. 2004.
[4] F. Liu, S. Mei, Q. Lu, Y. Ni, F. F. Wu, and A. Yokoyama, “The nonlinear internal control of STATCOM: Theory and application,” Int. J. Elect. Power Energy Syst., vol. 25, no. 6, pp. 421–430, 2003.
[5] C. Hochgraf and R. H. Lasseter, “STATCOM controls for operation with unbalanced voltage,” IEEE Trans. Power Del., vol. 13, no. 2, pp. 538–544, Apr. 1998.