ABSTRACT:

This paper presents a inclusive review of step-up single phase non isolated inverters suitable for ac-module use. In order to measure the most feasible solutions of the reviewed topologies, a benchmark is set.

SEMICONDUCTOR

This benchmark is based on a typical ac-module application considering the want for the solar panels and the grid.The selected solutions are produce and simulated complying with the benchmark get passive and semiconductor components ratings in order to perform a comparison in terms of size and cost.

TOPOLOGIES

A discussion of the analyzed topologies concerning the get ratings as well as ground currents is given. Advice for topological solutions submit with the application benchmark are supply.

KEYWORDS:

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

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

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

STEP-UP TRANSFORMERLESS INVERTERS:

Fig 2 Boost converter and full bridge inverter

Fig 3 Time sharing boost converter with full bridge inverter

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

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

Fig 6 Boost converter and half bridge inverter

Fig 7 Boost converter and neutral point clamped inverter

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

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

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

Fig  11 Boost + FB integrated and dual grounded

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

Fig 13 Buck-boost DCM converter and unfolding stage

Fig 14 Noninverting buck-boost DCM converter and unfolding stage

Fig 15 Switched inductor buck boost DCM converter and unfolding stage

Fig 16 Boost buck time sharing converter and unfolding stage

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

Fig 18 Universal single stage grid connected inverter

Fig 19 Integrated boost converter

Fig 20 Differential boost converter

Fig 21 Boost inverter with improved zero crossing.

Fig 22 Integrated Buck boost inverter

Fig 23 Buck Boost inverter with extended input voltage range

Fig 24 Differential buck boost inverter

Fig 25 Two sourced anti parallel buck boost inverter

Fig 26 Single stage full bridge buck boost inverter

Fig 27 Buck boost based single stage inverter

Fig 28 Switched inductor buck boost based single stage inverter

Fig 29 Single inductor buck boost based inverter

Fig 30 Doubly grounded single inductor buck boost based inverter

Fig 31 Single inductor  buck boost based inverter with dual ground

Fig 32 Three switch buck boost inverter

Fig 33 Coupled inductor buck boost inverter

Fig 34 Impedance-admittance conversion theory based inverter

Fig 35 Single phase Z source inverter

Fig 36 Semi quasi Z source inverter with continuous voltage gain

CONCLUSION:

In this paper, a inclusive review of single phase non isolated inverters for ac module use is given. Both the grid relation and the solar panel want are analyzed stress the leakage current regulation as it is a main disturb in non isolated PV grid connected inverters.

SEMICONDUCTOR

In order to compare the most suitable solutions of the reviewed topologies under the same requirement, a benchmark of a typical ac module use is set.These solutions have been designed and simulated, get ratings for the passive and the semiconductor components. These ratings are used for the topology comparison in terms of size and cost.

TRANSFORMERLESS

Furthermore, detailed simulations of typical topologies have been achieve 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 able for U.S. want.

DC-DC

Two stage topologies, including the solution with dual grounding efficiency that in theory avoids the ground leakage currents, are the chosen option for the set benchmark in which switching density for the dc-dc stage is set twice than for the dc-ac one.

INVERTER

The two stage combination of a step-up dc-dc converter and a step-up inverter should be thought-out In addition, the consider pseudo-dc-link reach  are an alternative solution in terms of size and cost.

DCM

Moreover, ground currents are normal to be low in these solutions because of the line density interface and weighted ability is the highest due to the flat behavior of the ability with the output power. The consider single stage topologies have higher cost than the other consider solutions and control is normal to be more complex to avoid dc current injection.

RMS

In addition, DCM operation mode allows smaller solutions, including a solution with dual ground efficiency, but ability is lower due to the high RMS currents.

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.

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Asoka Technologies

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

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

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

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

CIRCUIT CONFIGURATIONS

A. Buck AC-DC Converters

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

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

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

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

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

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

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

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

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

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

SIMULATION RESULTS:

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).

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).

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).

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).

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).

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.

ABSTRACT:
Photovoltaic (PV) generation systems are broadly employed in transformer less inverters, in order to produce the benefits of high efficiency and low cost. Safety want of leakage currents are met by request the various transformers less inverter topologies. In this paper, three transformer less inverter topologies are decorated such as a family of H6 transformer less inverter topologies with low leakage currents is planned, and the intrinsic relationship between H5 topology, highly efficient and reliable inverter concept (HERIC) topology.

H6 INVERTER

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 captured 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.

HERIC

For decide their performances in terms of power efficiency and leakage currents component, a universal prototype is built for these three topologies noticed. Simulation results show that the proposed HERIC topology and the H6 topology achieve similar performance in leakage currents, which is a little bad than that of the H5 topology, but it features higher ability 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:

Fig. 1. Leakage current path for transformerless PV inverters

EXPECTED SIMULATION RESULTS:

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

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

Fig. 4. DM characteristic of H6 topology.

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.

PV ARRAY

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:

H6  TOPOLOGY

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.

ABSTRACT:

STATCOM can provide fast and active and reactive power support to maintain power system voltage support. In the research, various STATCOM control methods have been look at including many applications of proportional-integral (PI) controllers. However, these previous works obtain the PI gains via a trial-and-error reach or large studies with a tradeoff of performance and applicability.

PI  CONTROL

Hence, control parameters for the optimal performance at a given operating point may not be active 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.

STATCOM

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.

CONVENTIONAL

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:

Figure 1 Studied system

Fig.2 Results of (a) voltages and (b) output reactive power using the same network and loads as in the original system.

Fig.3 Results of using the same network and loads as in the original system.

Fig. 4. Results of (a) voltages and (b) output reactive power with changed PI control gains

Fig. 5. Results of (a) voltages and (b) output reactive power with a change of load

Fig. 6. Results of with changed PI control gains.

Fig. 7. Results of α with a change of load.

Fig. 8. Results of α(a) voltages and (b) output reactive power with a change of transmission network.

Fig. 9. Results of α with a change of transmission network.

Fig. 10. Results of α (a) voltages and (b) output reactive power with two consecutive disturbances.

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.

AUTONOMOUS

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.

CONTROL

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.

PERFORMANCE

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.