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:

image001

Figure 1. Configuration of Hybrid Energy System.

EXPECTED SIMULATION RESULTS:

 image002

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

image003

Figure 3. Output Load Voltage.

image004

Figure 4. Output Load Current.

image005

Figure 5. Powers: Line, Wind, Solar.

image006

Figure 6. Output Voltage from Wind System.

image007

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.

 

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.

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 modeled by specific electric blocks from the power system block set. The controllers for the shunt VSC and two series VSCs are presented 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:

UPFC with 60-Pulse GTO-Based Voltage Source Converter

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

EXPECTED SIMULATION RESULTS:

2

 Figure 2. Sixty-pulse VSC output voltage

3

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

4

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

5

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

6

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 accountability, minimum oscillatory behavior, 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 Power 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.

 

 

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:

1

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

 EXPECTED SIMULATION RESULTS:

2

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

3 4

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

 5 6

 Fig. 4 Waveforms and harmonic spectra of 48-pulse converter (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:

 1

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

EXPECTED SIMULATION RESULTS

 2

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

 

3

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

4

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

 

5

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.

A New Control Strategy for Active and Reactive Power Control of Three-Level VSC Based HVDC System

ABSTRACT

This paper presents a new control strategy for real and reactive power control of three-level multipulse voltage source converter based High Voltage DC (HVDC) transmission system operating at Fundamental Frequency Switching (FFS). A three-level voltage source converter replaces the conventional two-level VSC and it is designed for the real and reactive power control is all four quadrants operation. A new control method is developed for achieving the reactive power control by varying the pulse width and by keeping the dc link voltage constant. The steady state and dynamic performances of HVDC system interconnecting two different frequencies network are demonstrated for active and reactive powers control. Total numbers of transformers used in the system are reduced in comparison to two level VSCs. The performance of the HVDC system is also improved in terms of reduced harmonics level even at fundamental frequency switching.

 KEYWORDS 

  1. HVDC
  2. Voltage Source Converter
  3. Multilevel
  4. Multipulse
  5. Dead Angle (β)

 SOFTWARE:  MATLAB/SIMULINK

BLOCK DIAGRAM: 1

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

 

CONTROL SCHEME

2

Fig. 2 Control scheme of three-level VSC based HVDC system using dynamic dead angle (β) Control

EXPECTED SIMULATION RESULTS

3

Fig. 3 Performance of rectifier station during simultaneous real and reactive power control of three-level 24-pulse VSC based HVDC system

4

Fig. 4 Performance of inverter station during simultaneous real and reactive power control of three-level 24-pulse VSC based HVDC system

5

Fig. 5 Variation of angles (δ) and (β) values of three-level 24-pulse VSC based HVDC system during simultaneous real and reactive power control

CONCLUSION

A new control method for three-level 24-pulse voltage source converter configuration has been designed for HVDC system. The performance of this 24-pulse VSC based HVDC system using the control method has been demonstrated in active power control in bidirectional, independent control of the reactive power and power quality improvement. A new dynamic dead angle (β) control has been introduced for three-level voltage source converter operating at fundamental frequency switching. In this control the HVDC system operation is successfully demonstrated and also an analysis of (β) value for various reactive power requirement and harmonic performance has been carried out in detail. Therefore, the selection of converter operation region is more flexible according to the requirement of the reactive power and power quality.

REFERENCES

[1] Gunnar Asplund, Kjell Eriksson and kjell Svensson, “DC Transmission based on Voltage Source Converters,” in Proc. Of CIGRE SC14 Colloquium in South Africa 1997, pp.1-7.

[2] “HVDC Light DC Transmission based on Voltage Source Converter,” ABB Review Manual 1998, pp. 4-9.

[3] Xiao Wang and Boon-Tech Ooi, “High Voltage Direct Current Transmission System Based on Voltage Source Converter,” in IEEEPESC’ 90 Record, vol.1, pp.325-332.

[4] Michael P. Bahrman, Jan G. Johansson and Bo A. Nilsson, “Voltage Source Converter Transmission Technologies-The Right Fit for the Applications,” in Proc. of IEEE-PES General Meeting, Toronto, Canada, July-2003, pp.1840-1847.

[5] 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. Proc of IEEE/PES T & DConf. & Exhibition, Asia and Pacific Dalian, China 2005, pp.1-7.

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.

A Novel High StepUp DCDC Converter Based on Integrating Coupled Inductor and Switched-Capacitor Techniques for Renewable Energy Applications

ABSTRACT

In this paper, a novel high step-up dc/dc converter is presented for renewable energy applications. The suggested structure consists of a coupled inductor and two voltage multiplier cells, in order to obtain high step-up voltage gain. In addition, two capacitors are charged during the switch-off period, using the energy stored in the coupled inductor which increases the voltage transfer gain. The energy stored in the leakage inductance is recycled with the use of a passive clamp circuit. The voltage stress on the main power switch is also reduced in the proposed topology. Therefore, a main power switch with low resistance RDS(ON) can be used to reduce the conduction losses. The operation principle and the steady-state analyses are discussed thoroughly. To verify the performance of the presented converter, a 300-W laboratory prototype circuit is implemented. The results validate the theoretical analyses and the practicability of the presented high step-up converter.

 KEYWORDS:

Coupled inductor, DC/DC converters, High step-up, Switched capacitor.

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

image017

Fig. 1. Circuit configuration of the presented high-step-up converter.

SIMULATION RESULTS:

 image018 image019 image020 image021 image022 image023 image024

Fig. 2. Simulation results under load 300 W.

 CONCLUSION

This paper presents a new high-step-up dc/dc converter for renewable energy applications. The suggested converter is suitable for DG systems based on renewable energy sources, which require high-step-up voltage transfer gain. The energy stored in the leakage inductance is recycled to improve the performance of the presented converter. Furthermore, voltage stress on the main power switch is reduced. Therefore, a switch with a low on-state resistance can be chosen. The steady-state operation of the converter has been analyzed in detail. Also, the boundary condition has been obtained. Finally, a hardware prototype is implemented which converts the 40-V input voltage into 400-V output voltage. The results prove the feasibility of the presented converter.

REFERENCES

[1] F.Nejabatkhah, S. Danyali, S. Hosseini, M. Sabahi, and S. Niapour, “Modeling and control of a new three-input DC–DC boost converter for hybrid PV/FC/battery power system,” IEEE Trans. Power Electron., vol. 27, no. 5, pp. 2309–2324, May 2012.

[2] R. J. Wai and K. H. Jheng, “High-efficiency single-input multiple-output DC–DC converter,” IEEE Trans. Power Electron., vol. 28, no. 2, pp. 886–898, Feb. 2013.

[3] Y. Zhao, X. Xiang, C. Li, Y. Gu, W. Li, and X. He, “Single-phase high step-up converter with improved multiplier cell suitable for half- bridgebased PV inverter system,” IEEE Trans. Power Electron., vol. 29, no. 6, pp. 2807–2816, Jun. 2014.

[4] J.H. Lee, T. J. Liang, and J. F. Chen, “Isolated coupled-inductor-integrated DC–DC converter with non-dissipative snubber for solar energy applications,” IEEE Trans. Ind. Electron., vol. 61, no. 7, pp. 3337–3348, Jul.2014.

[5] C.Olalla, C. Delineand, andD.Maksimovic, “Performance of mismatched PV systems withsubmodule integrated converters,” IEEE J. Photovoltaic, vol. 4, no. 1, pp. 396–404, Jan. 2014.

A Multi-Input Bridgeless Resonant AC-DC Converter for Electromagnetic Energy Harvesting

ABSTRACT

Flapping electromagnetic-reed generators are investigated to harvest wind energy, even at low cut-off wind speeds. Power electronic interfaces are intended to address ac-dc conversion and power conditioning for single- or multiple-channel systems. However, the generated voltage of each generator reed at low wind speed is usually below the threshold voltage of power electronic semiconductor devices, increasing the difficulty and inefficiency of rectification, particularly at relatively low output powers. This manuscript proposes a multi-input bridgeless resonant ac-dc converter to achieve ac-dc conversion, step up voltage and match optimal impedance for a multi-channel electromagnetic energy harvesting system. Alternating voltage of each generator is stepped up through the switching LC network and then rectified by a freewheeling diode. Its resonant operation enhances efficiency and enables miniaturization through high frequency switching. The optimal electrical impedance can be adjusted through resonance impedance matching and pulse-frequency-modulation (PFM) control. A 5-cm×3-cm, six-input standalone prototype is fabricated to address power conditioning for a six-channel BreezBee® wind panel.

 KEYWORDS:

AC-DC conversion, electromagnetic energy harvesting, multi-input converter, resonant converter, wind energy.

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

image001

image002

Fig. 1. Multi-channel EMR generators and PEI system: (a) conventional PEI; and (b) proposed multi-input PEI.

CIRCUIT DIAGRAM:

image003

Fig. 2. Illustrative scheme of the proposed multi-input converter (v(i)emf: EMF of #i reed; r(i)EMR: coil resistance; L(i)EMR: self-inductance; i(i)EMR: reed terminal current; v(i)EMR: reed terminal voltage; C(i)r1= C(i)r2: resonant capacitors; Lr: resonant inductor; Q(i)r1, Q(i)r2: MOSFETs; Dr: output diode; Co: output capacitor).

EXPERIMENTAL RESULTS:

image004

  •                                                             (a)
  • image005                                                                    (b)

Fig. 3. Experimental waveforms of power amplifiers: fin = 20 Hz; X-axis: 10 ms/div; Y-axis: (a) vemf = 3 Vrms; Ch1 = output voltage (Vo), 2.5 V/div; Ch2 = terminal voltage (vEMR) of reed #1, 10 V/div; Ch3 = input current (iEMR) of six reeds, 50 mA/div; and (b) vemf = 0.5 Vrms; Ch1 = output voltage (Vo), 0.5 V/div; Ch2 = terminal voltage (vEMR) of reed #1, 5 V/div; Ch3 = sum of the input currents (iEMR) of six reeds, 10 mA/div.

 image006                                                         (a)

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  •                                                           (b)

Fig. 4. Experimental waveforms of power amplifiers with step change: X-axis: 40 ms/div; Y-axis: (a) vemf = from 1 Vrms to 2 Vrms; Ch1 = output voltage (Vo), 1 V/div; Ch2 = terminal voltage (vEMR) of reed #1, 5 V/div; Ch3 = input current (iEMR) of six reeds, 50 mA/div; and (b) fin = from 20 Hz to 50 Hz; Ch1 = output voltage (Vo), 0.5 V/div; Ch2 = terminal voltage (vEMR) of reed #1, 5 V/div; Ch3 = input current (iEMR) of six reeds, 50 mA/div.

image008

(a)

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  •                                                                 (b)

Fig. 5. Experimental waveforms of EMR generators: X-axis: (a) 20 ms/div; (b) 100 ms/div; Y-axis: (a) constant wind speed; (b) wind speed step change; Ch1 = terminal voltage (vEMR) of reed #2, 5 V/div; Ch2 = output voltage (Vo), 1 V/div; Ch3 = terminal voltage (vEMR) of reed #1, 10 V/div; Ch4 = input current (iEMR) of reed #1, 10 mA/div.

 CONCLUSION

This manuscript introduces a multi-input bridgeless resonant ac-dc converter suitable for efficient, low-voltage, low-power, ac-dc power conversion of multiple electromagnetic generators. The multi-input single-stage topology is capable of directly converting independent, low-amplitude, alternative voltages of EMR inductive generators to a stepped-up dc output voltage with relatively high efficiency. Low-frequency alternating voltages of EMR generators are first converted into a high-frequency alternating voltage through an LC network and then rectified into a dc output voltage through a soft-switched diode. Optimal electrical impedance matching is achieved through proper LC network design and PFM control to scavenge maximum power of EMR generators. In addition, high-frequency soft-switching increases the potential of size miniaturization without suffering from switching losses. The converter performance is verified through a 5cm×3cm standalone prototype, which converts ac voltages of six-channel generators into a dc output voltage. A maximum PEI conversion efficiency of 86.3% is measured at 27-mW ac-dc power conversion. The topological concept, presented in this manuscript, can be adapted for rectification of any inductive voltage sources or electromagnetic energy-harvesting device.

REFERENCES

[1] A. Khaligh, P. Zeng, and C. Zheng, “Kinetic energy harvesting using piezoelectric and electromagnetic technologies – state of the art,” IEEE Trans. on Industrial Electronics, vol. 57, no. 3, pp. 850-860, Mar. 2010.

[2] Altenera Technology Inc., accessible online at http://altenera.com/products/.

[3] H. Jung, S. Lee, and D. Jang, “Feasibility study on a new energy harvesting electromagnetic device using aerodynamic instability,” IEEE Trans. on Magnetics, vol. 45, no. 10, pp. 4376-4379, Oct. 2009.

[4] A. Bansal, D. A. Howey, and A. S. Holmes, “CM-scale air turbine and generator for energy harvesting from low-speed flows,” in Proc. Solid-State Sensors, Actuators and Microsystems Conf., Jun. 2009, pp. 529-532.

[5] D. Rancourt, A. Tabesh, and L. G. Fréchette, “Evaluation of centimeter-scale micro windmills: aerodynamics and electromagnetic power generation,” in Proc. PowerMEMS, 2007, pp. 93-96.

 

High-Efficiency MOSFET Transformerless Inverter for Non-isolated Microinverter Applications

ABSTRACT

State-of-the-art low-power-level metal–oxide–semiconductor field-effect transistor (MOSFET)-based transformerless photovoltaic (PV) inverters can achieve high efficiency by using latest super junction MOSFETs. However, these MOSFET-based inverter topologies suffer from one or more of these drawbacks: MOSFET failure risk from body diode reverse recovery, increased conduction losses due to more devices, or low magnetics utilization. By splitting the conventional MOSFET based phase leg with an optimized inductor, this paper proposes a novel MOSFET-based phase leg configuration to minimize these drawbacks. Based on the proposed phase leg configuration, a high efficiency single-phase MOSFET transformerless inverter is presented for the PV microinverter applications. The pulsewidth modulation (PWM) modulation and circuit operation principle are then described. The common-mode and differential-mode voltage model is then presented and analyzed for circuit design. Experimental results of a 250Whardware prototype are shown to demonstrate the merits of the proposed transformerless inverter on non-isolated two-stage PV microinverter application.

 KEYWORDS: Microinverter, MOSFET inverters, photovoltaic (PV) inverter, transformerless inverter.

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

image001

Fig. 1. Two-stage nonisolated PV microinverter.

CIRCUIT DIAGRAM:

image002

Fig. 2. Proposed transformerless inverter topology with (a) separated magnetic and (b) integrated magnetics.

 EXPERIMENTAL RESULTS:

image003

Fig. 3. Output voltage and current waveforms.

image004

Fig. 4. PWM gate signals waveforms.

image005

Fig. 5. Inverter splitting inductor current waveform.

image006

Fig. 6. Waveforms of voltage between grid ground and DC ground (VEG ).

CONCLUSION

This paper proposes a MOSFET transformerless inverter with a novel MOSFET-based phase leg, which achieves:

1) high efficiency by using super junction MOSFETs and SiC diodes;

2) minimized risks from the MOSFET phase leg by splitting the MOSFET phase leg with optimized inductor and minimizing the di/dt from MOSFET body diode reverse recovery;

3) high magnetics utilization compared with previous high efficiency MOSFET transformerless inverters in [21], [22], [25], which only have 50% magnetics utilization.

The proposed transformerless inverter has no dead-time requirement, simple PWM modulation for implementation, and minimized high-frequency CMissue. A 250Whardware prototype has been designed, fabricated, and tested in two-stage nonisolated microinverter application. Experimental results demonstrate that the proposed MOSFET transformerless inverter achieves 99.01% peak efficiency at full load condition and 98.8% CEC efficiency and also achieves around 98% magnetic utilization. Due to the advantages of high efficiency, low CM voltage, and improved magnetic utilization, the proposed topology is attractive for two-stage nonisolated PV microinverter applications and transformerless string inverter applications.

 REFERENCES

[1] 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.

[2] S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “A review of singlephase grid-connected inverters for photovoltaic modules,” IEEE Trans. Ind. Appl., vol. 41, no. 5, p. 1292, Sep. 2005.

[3] Q. Li and P. Wolfs, “A review of the single phase photovoltaic module integrated converter topologies with three different dc link configurations,” IEEE Trans. Power Electron., vol. 23, no. 3, pp. 1320–1333, May 2008.

[4] Y. Xue, L. Chang, S. B. Kjaer, J. Bordonau, and T. Shimizu, “Topologies of single-phase inverters for small distributed power generators: An overview,” IEEE Trans. Power Electron., vol. 19, no. 5, pp. 1305–1314, 2004.

[5] W. Yu, J. S. Lai, H. Qian, and C. Hutchens, “High-efficiency MOSFET inverter with H6-type configuration for photovoltaic non-isolated AC-module applications,” IEEE Trans. Power Electron., vol. 56, no. 4, pp. 1253–1260, Apr. 2011.