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Monday 25 July 2016

Modeling and Simulation of Hybrid Wind Solar Energy System using MPPT


 ABSTRACT:
The main objective of this paper is to enhance the power transfer capability of grid interfaced hybrid generation system. Generally, this hybrid system is a combination of solar and wind energy systems. In order to get maximum and constant output power from these renewable energy systems at any instant of time, this paper proposes the concept of maximum power tracking techniques. The main concept of this maximum power point tracking controller is used for controlling the Direct Current (DC) to DC boost converter. Finally, the performance of this Maximum Power Point Tracking (MPPT) based Hybrid system is observed by simulating using Matlab/Simulink.

KEYWORDS: MPPT Technique, Solar Energy System, Wind Turbine System

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Figure 1. Configuration of Hybrid Energy System.

EXPECTED SIMULATION RESULTS:


Figure 2. Simulation Diagram for Hybrid Wind-PV System.

Figure 3. Output Load Voltage.

Figure 4. Output Load Current.

Figure 5. Powers: Line, Wind, Solar.

Figure 6. Output Voltage from Wind System.

Figure 7. Output Voltage from Wind System.

CONCLUSION:
Output from solar and a wind system is converted into AC power output by using inverter. In the given time additional load of 5 KW is connected by using Circuit Breaker. Under all operating conditions to meet the load the hybrid system is controlled to give maximum output power. Battery is supporting to wind or solar system to meet the load and Also, simultaneous operation for the same load.

 REFERENCES:
1.   Huil J, Bakhshai A, Jain PK. A hybrid wind-solar energy system: A new rectifier stage topology. 2010 25th Annual IEEE Proceedings of Applied Power Electronics Conference and Exposition (APEC); 2010 Feb 21–25. p. 156–61.
2.  Kim SK, Jeon JH, Cho CH, Ahn JB, Kwon SH. Dynamic modeling and control of a grid-connected hybrid genera­tion system with versatile power transfer. IEEE Transactions on Industrial Electronics. 2008 Apr; 55(4):1677–88.
3. Ezhilarasan S, Palanivel P, Sambath S. Design and devel­opment of energy management system for DG source allocation in a micro grid with energy storage system. Indian Journal of Science and Technology. 2015 Jun; 8(13):58252.
4.   Patel MR. Wind and solar power systems design analysis and operation. 2nd ed. Taylor and Francis Group Publishing Co. 2006; 30(3):265–6.
5. Chen YM, Liu YC, Hung SC, Cheng CS. Multi-input inverter for grid-connected hybrid PV/wind power system. IEEE Transactions on Power Electronics. 2007 May; 22(3):1070–7.


Saturday 23 July 2016

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
                                                    

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 ô€€€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.

Wednesday 13 July 2016

Digital Simulation of the Generalized Unified Power Flow Controller System with 60-Pulse GTO-Based Voltage Source Converter


ABSTRACT:


 The Generalized Unified Power Flow Controller (GUPFC) is a Voltage Source Converter (VSC) based Flexible AC Transmission System (FACTS) controller for shunt and series compensation among the multiline transmission systems of a substation. The paper proposes a full model comprising of 60-pulse Gate Turn-Off thyristor VSC that is constructed becomes the GUPFC in digital simulation system and investigates the dynamic operation of control scheme for shunt and two series VSC for active and reactive power compensation and voltage stabilization of the electric grid network. The complete digital simulation of the shunt VSC operating as a Static Synchronous Compensator (STATCOM) controlling voltage at bus and two series VSC operating as a Static Synchronous Series Capacitor (SSSC) controlling injected voltage, while keeping injected voltage in quadrature with current within the power system is performed in the MATLAB/Simulink environment using the Power System Block set (PSB). The GUPFC, control system scheme and the electric grid network are modelled by specific electric blocks from the power system block set. The controllers for the shunt VSC and two series VSCs are pre-sented in this paper based on the decoupled current control strategy. The performance of GUPFC scheme connected to the 500-kV grid is evaluated. The proposed GUPFC controller scheme is fully validated by digital simulation.


 KEYWORDS:

 60-Pulse GTO Thyristor Model VSC, UPFC, GUPFC,Active and Reactive Compensation, Voltage Stability

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:


Figure 1. Three-bus system with the GUPFC at bus B5 and B2


EXPECTED SIMULATION RESULTS:




Figure 2. Sixty-pulse VSC output voltage



Figure 3. Simulated results of the GUPFC .shunt converter operation for DC voltage with Qref = 0.3pu; 0.5 pu


Figure 4. Simulated results of the GUPFC series converter operation Pref=8.7pu; 10pu, Qref=-0.6pu; 0.7pu


Figure 5. Simulated results of the GUPFC series converter operation Pref=7.7pu; 9.0pu, Qref=-0.5pu; 0.9pu


Figure 6. Digital simulation results for the decoupled current controller schemes for the shunt VSC in a weak power system

CONCLUSION:

The paper presents and proposes a novel full 60-pulse GTO voltage source converter that it constructed becomes GUPFC FACTS devices. It comprises the full 60-pulse VSC-cascade models connected to the grid network through the coupling transformer. These full descriptive digital models are validated for voltage stabilization, active and reactive compensation and dynamically power flow control using three decoupled current control strategies. The control strategies implement decoupled current control switching technique to ensure controllability, minimum oscillatory behaviour, minimum inherent phase locked loop time delay as well as system instability reduced impact due to a weak interconnected ac system and ensures full dynamic regulation of the bus voltage (VB), the series voltage injected and the dc link voltage Vdc. The 60-pulse VSC generates less harmonic distortion and reduces power quality problems in comparison to other converters such as (6,12,24 and 36) pulse. In the synchronous reference frame, a complete model of a GUPFC has been presented and control circuits for the shunt and two series converters have been described. The simulated results presented confirm that the performance of the proposed GUPFC is satisfactory for active and reactive power flow control and independent shunt reactive compensation.

REFERENCES:

[1] K. K. Sen, “SSSC-static synchronous series compensator. Theory, modeling and application”, IEEE Transactions on Pwer Delivery, Vol. 13, No. 1, pp. 241-246, January 1998.
[2] B. Fardanesh, B. Shperling, E. Uzunovic, and S. Zelingher, "Multi-Converter FACTS Devices: The Generalized Unified Power Flow Controller (GUPFC)," in IEEE 2000 PES Summer Meeting, Seattle, USA, July 2000.
[3] N. G. Hingorani and L. Gyugyi, “Understanding FACTS, Concepts and Technology of Flexible AC Transmission Systems. Pscataway, NJ: IEEE Press. 2000.
[4] X. P. Zang, “Advanced Modeling of the Multicontrol Func-tional Static Synchronous Series Compensator (SSSC) in Newton Power Flow” , IEEE Transactions on Power Systems, Vol. 20, No. 4, pp. 1410-1416, November 2005,
[5] A. H. Norouzi and A. M. Sharaf, Two Control Schemes to Enhance the Dynamic Performance of the Statcom and Sssc”, IEEE Transactions on Power Delivery, Vol. 20, No. 1, pp. 435-442, January 2005.



Sunday 10 July 2016

A Two-Level, 48-Pulse Voltage Source Converter for HVDC Systems


ABSTRACT

This paper deals with an analysis, modeling and control of a two level 48-pulse voltage source converter for High Voltage DC (HVDC) system. A set of two-level 6-pulse voltage source converters (VSCs) is used to form a 48-pulse converter operated at fundamental frequency switching (FFS). The performance of the VSC system is improved in terms of reduced harmonics level at FFS and THD (Total Harmonic Distribution) of voltage and current is achieved within the IEEE 519 standard. The performance of the VSC is studied in terms of required reactive power compensation, improved power factor and reduced harmonics distortion. Simulation results are presented for the designed two level multipulse converter to demonstrate its capability. The control algorithm is disused in detail for operating the converter at fundamental frequency switching.

KEYWORDS

Two-Level Voltage Source Converter, HVDC Systems, Multipulse, Fundamental Frequency Switching, Harmonics.

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:


Fig. 1 A 48-Pulse voltage source converter based HVDC system configuration


EXPECTED SIMULATION RESULTS:



Fig. 2 Steady state performance of proposed 48-pulse voltage source converter




Fig. 3 Dynamic performance of proposed 48-pulse voltage source converter





Fig. 4 Waveforms and harmonic spectra of 48-pulse covnerter (a) supply voltage (b) supply current (c) converter voltage



CONCLUSION

A 48-pulse two-level voltage source converter has been designed, modeled and controlled for back-to-back HVDC system. The transformer connections with appropriate phase shift have been used to realize a 48-pulse converter along with a control scheme using a set of two level six pulse converters. The operation of the designed converter configuration has been simulated and tested in steady sate and transient conditions which have demonstrated the quite satisfactory converter operation. The characteristic harmonics of the system has also improved by the proposed converter configuration.

REFERENCES

[1] J. Arrillaga, Y. H. Liu and N. R. Waston, “Flexible Power Transmission, The HVDC Options,” John Wiley & Sons, Ltd, Chichester, UK, 2007.
[2] Gunnar Asplund Kjell Eriksson and kjell Svensson, “DC Transmission based on Voltage Source Converter,” in Proc. of CIGRE SC14 Colloquium in South Africa 1997, pp.1-8.
[3] Y. H. Liu R. H. Zhang, J. Arrillaga and N. R. Watson, “An Overview of Self-Commutating Converters and their Application in Transmission and Distribution,” in Conf. IEEE/PES Trans. and Distr.Conf. & Exhibition, Asia and Pacific Dalian, China 2005.
[4] B. R. Anderson, L. Xu, P. Horton and P. Cartwright, “Topology for VSC Transmission,” IEE Power Engineering Journal, vol.16, no.3, pp142- 150, June 2002.

[5] G. D. Breuer and R. L. Hauth, “HVDC’s Increasing Poppularity”, IEEE Potentials, pp.18-21, May 1988.

A Two-Level 24-Pulse Voltage Source Converter with Fundamental Frequency Switching for HVDC System


ABSTRACT

This paper deals with the performance analysis of a two-level, 24-pulse Voltage Source Converters (VSCs) for High Voltage DC (HVDC) system for power quality improvement. A two level VSC is used to realize a 24-pulse converter with minimum switching loss by operating it at
fundamental frequency switching (FFS). The performance of this converter is studied on various issues such as steady state operation, dynamic behavior, reactive power compensation, power factor correction, and harmonics distortion. Simulation results are presented for a two level 24-pulse converter to demonstrate its capability.

KEYWORDS

1.      Two-Level Voltage Source Converter
2.       HVDC
3.      Multipulse
4.      Fundamental Frequency Switching
5.       Harmonics

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:



Fig. 1 A 24-Pulse voltage source converter based HVDC system
Configuration

 EXPECTED SIMULATION RESULTS



Fig. 2 Synthesis of Stepped AC voltage waveform of 24-pulse VSC.



Fig. 3 Steady state performance of proposed 24-pulse voltage source
Converter





Fig. 4 Dynamic performance of proposed 24-pulse voltage source converter







Fig. 5 Waveforms and harmonic spectra of 24-pulse covnerter i) supply
voltage ii) supply current (iii) converter voltage

CONCLUSION

A two level, 24-pulse voltage source converter has been designed and its performance has been validated for HVDC system to improve the power quality with fundamental frequency switching. Four identical transformers have been used for phase shift and to realize a 24-pulse converter along with control scheme using a two level voltage source converter topology. The steady state and dynamic performance of the designed converter configuration has been demonstrated the quite satisfactory operation and found suitable for HVDC system. The characteristic harmonics of the converter system has also improved by the proposed converter configuration with minimum switching losses without using extra filtering requirements compared to the conventional 12-pulse thyristor converter.

REFERENCES

[1] J. Arrillaga, “High Voltage Direct Current Transmission,” 2nd Edition, IEE Power and Energy Series29, London, UK-1998.
[2] J. Arrilaga and M. Villablanca, “24-pulse HVDC conversion,” IEE Proceedings Part-C, vol. 138, no. 1, pp. 57–64, Jan. 1991..
[3] Lars Weimers, “HVDC Light: a New Technology for a better Environment,” IEEE Power Engineering Review, vol.18, no. 8, pp. 1920-1926, 1989.
[4] Vijay K. Sood, “HVDC and FACTS Controller, Applications of Static Converters in Power Systems”, Kluwar Academic Publishers, The Netherlands, 2004.

[5] Gunnar Asplund Kjell Eriksson and kjell Svensson, “DC Transmission based on Voltage Source Converters, in Proc. of CIGRE SC14 Colloquium in South Africa 1997.