A Highly Effective Fault-Ride-Through Strategy For a Wind Energy Conversion System with Doubly Fed Induction Generator

ABSTRACT:  

 This paper proposes an improved fault-ride through (FRT) system for a wind turbine with doubly fed induction generator (DFIG) that is based on the proper stator voltage control to address symmetrical as well as unsymmetrical and unbalanced grid voltage sags. This is accomplished by adopting a properly modified topology of the conventional wind energy con-version system (WECS) with DFIG that provides the ability to regulate the stator voltage through the system of the rotor power converters. Therefore, significant improvement of the FRT capability is attained, since any oscillations of both the stator and ro-tor currents that may be caused by the voltage dip can be considerably reduced and they can remain within predefined safety limits. The implementation of the new topology as well as the corresponding control system are cost effective, since no additional hardware is required, and it is accomplished by the reconfiguration of the conventional topology. Selective simulation and experimental results obtained by a high and low scale WECS with DFIG, respectively, are presented to validate the effective-ness of the proposed FRT control method and demonstrate the operational improvements.

KEYWORDS:

1.      Fault-ride through

2.      Doubly-fed induction generator

3.      Wind power generation

4.      Wind turbine

5.      Reliability

6.      Voltage control

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Comparison of the structure of a variable speed WECS with DFIG: (a) conventional and (b) improved FRT capability system.

EXPERIMENTAL RESULTS:

Fig. 2. Simulation results of the performance of the proposed FRT wind sys-tem with DFIG of 1.6-MW, when a symmetrical grid voltage disturbance from 100% to 20% and then 100% of the nominal value occurs, for a low wind speed of 4.5 m/s.

Fig. 3. Simulation results of the performance of the proposed FRT wind system with DFIG of 1.6-MW, when a symmetrical grid voltage disturbance from 100% to 20% and then 100% of the nominal value occurs, for a high wind speed of 9 m/s.

Fig. 4. Zoom of the simulation results of Fig. 5 (WECS with DFIG of 1.6- MW), at the time that the grid voltage disturbance from 100% to 20% of the nominal value occurs (wind speed 9 m/s).

CONCLUSION:

A highly effective FRT control system for a WECS with DFIG has been proposed in this paper. A new WECS topology has been adopted that gives the ability to control the stator of the DFIG. Specifically, by properly controlling the rotor side converter of the DFIG, the stator voltage can be kept constant at the nominal value and thus, a fault diagnosis system is not required. Therefore, the WECS can continue the operation without being affected by any symmetrical, unsymmetrical and unbalanced grid voltage disturbances, and thus, no transient current and voltages are caused. The implementation of the proposed FRT control system does increase the cost of WECS compared to the conventional system, since it is based on the proper modification by replacing expensive components of the conventional system with low cost components and vice-versa. The effectiveness and the high performance of the pro-posed FRT control scheme have been validated with several simulation results obtained by a high power WECS-DFIG of 1.6-MW and experimentally in a laboratory low power scaling emulated WECS with DFIG of 5.5-kW.

REFERENCES:

[1] E. Hau, Wind Turbines: Fundamentals, Technologies, Application, Economics, Springer-Verlag: 2013, 3rd Edition.

[2] A. El-Naggar and I. Erlich, ‘Fault current contribution analysis of dou-bly fed induction generator-based wind turbines’, IEEE Trans. Energy Conv., vol. 30, no. 3, pp. 874-882, Sept. 2015.

[3] D. Xiang, L. Ran, P.J. Tavner, and S. Yang, ‘Control of a doubly fed induction generator in a wind turbine during grid fault ride-through’, IEEE Trans. Energy Conv., vol. 21, no. 3, pp. 652-662, Sep. 2006.

[4] S. Seman, J. Niiranen, and A. Arkkio, ‘Ride-through analysis of doubly fed induction wind-power generator under unsymmetrical network dis-turbance’, IEEE Trans. Power Syst., vol. 21, no. 4, pp. 1782–1789, Nov. 2006.

[5] J. Morren and S.W.H. de Haan, ‘Ridethrough of wind turbines with doubly-fed induction generator during a voltage dip’, IEEE Trans. En-

ergy Conv., vol. 20, no. 2, pp. 435-441, June 2005.

A 500-W Wireless Charging System with Lightweight Pick-Up for Unmanned Aerial Vehicles

ABSTRACT:  

This letter develops a wireless charging system based on a novel orthogonal magnetic structure and primary-side power control to simplify the structure and reduce the weight of on-board pick-up for recharging the unmanned aerial vehicles (UAVs). The novel magnetic structure has a polarized transmitter with a flat U-type core and a perpendicular air-cored receiving coil, guaranteeing the magnetic flux operation space away from UAV body by coil structure itself and also reducing the weight of magnetic receiver. The power flow to the battery is controlled by the primary-side based on charging current and voltage feedback by pick-up. Simulations based on ANSYS Maxwell and experiments are carried out to validate the proposal. The weight of magnetic receiver is 130g. And the system can deliver 500W with a DC-to-Battery efficiency of 90.8%, meanwhile 10A constant current/50V constant voltage charging for 12S lithium-ion battery is achieved by the closed-loop system.

KEYWORDS:

1.      Unmanned aerial vehicles (UAVs)

2.      Wireless charging

3.      Magnetic structure

4.      Primary-side control

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. (a) Wireless charging system structure. (b) The gate drive signals and

output voltage of the inverter. (c) Equivalent circuit model.

 EXPERIMENTAL RESULTS:

Fig. 2. Power transfer ability test. (a) Measured waveforms of system, (b) Input and output power test.

Fig. 3. Closed-loop system operation test. (a) Change the equivalent load  resistance RB from 3 to 33 . (b) Change the equivalent load resistance RB from 3 to 8

CONCLUSION:

A novel orthogonal magnetic structure, which has a lightweight magnetic receiver, for UAVs, has been proposed and verified throughout this letter. The air-cored receiving coil is placed vertically in the middle of a polarized transmitter, possessing a large magnetic flux captured surface for enough power transfer and also constraining magnetic field operation space away from UAV’s body by coil-structure itself. The primary-side power control method is adopted to regulate the power flow to battery, which further reduces the weight of on-board pick-up circuit. A prototype was built for experiment.  It is shown that the system can successfully deliver 500W to UAV with a DC-to-Battery efficiency of 90.8%. The simulation and experimental results confirm the effectiveness of the proposal.

REFERENCES:

[1] T. Kan, R. Mai, P. P. Mercier and C. C. Mi, “Design and Analysis of a Three-Phase Wireless Charging System for Lightweight Autonomous Underwater Vehicles,” IEEE Trans. Power Electron., vol. 33, no. 8, pp. 6622-6632, Aug. 2018.

[2] M. Budhia, J. T. Boys, G. A. Covic and C. Huang, “Development of a  Single-Sided Flux Magnetic Coupler for Electric Vehicle IPT Charging Systems,” IEEE Trans. Ind. Electron., vol. 60, no. 1, pp. 318-328, Jan. 2013.

[3] P. Si, A. P. Hu, S. Malpas and D. Budgett, “A Frequency Control Method for Regulating Wireless Power to Implantable Devices,” IEEE Trans.  Biomed. Circuits Syst., vol. 2, no. 1, pp. 22-29, Mar. 2008.

[4] A. B. Junaid, Y. Lee, Y. Kim, “Design and implementation of  autonomous wireless charging station for rotary-wing UAVs,” Aerospace Science and Technology, vol. 54, pp. 253-266, Apr. 2016.

[5] S. Kumar, Jayprakash, G. K. Mandavi, “Wireless Power Transfer for Unmanned Aerial Vehicle (UAV) Charging,” International Research Journal of Engineering and Technology, vol. 4, no. 8, pp. 1939-1942, Aug. 2017.

Power Quality Analysis and Enhancement of Grid Connected Solar Energy System

ABSTRACT:  

In recent years, renewable energy resources are utilized to meet the growing energy demand. The  integration of renewable energy resources with the grid incorporates power electronic converters for conversion of energy. These power electronic converters introduce power quality issues such as a harmonics, voltage regulation etc. Hence, to improve the power quality issues, this work proposes a new control strategy for a grid interconnected solar system. In this proposed work, a maximum power point tracking (MPPT) scheme has been used to obtain maximum power from the solar system and DC/DC converter is implemented to maintain a constant DC voltage. An active filtering method is utilized to improve the power quality of the grid connected solar system. The proposed system is validated through dynamic simulation using MATLAB/Simulink Power system toolbox and results are delivered to validate the effectiveness of the work.

KEYWORDS:

1.      Power Quality

2.      Active Power Filter

3.      Fuzzy Controller

4.      Harmonics Compensation

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1. Configurations of a photovoltaic interactive shunt active power filter system.

EXPERIMENTAL RESULTS:

Figure 2. Source current for nonlinear load before compensation.

Figure 3. Voltage and current of source after compensation

Figure 4. Voltage and current of source after compensation.

 CONCLUSION:

This work has presented a novel control of an existing grid interfacing inverter to improve the quality of power at PCC. It has been proved that the grid-interfacing inverter can be effectively utilized for power conditioning without affecting its normal operation of real power transfer. This approach eliminates the need for additional power conditioning equipment to improve the quality of power. Extensive MATLAB/Simulink simulation results have validated the proposed approach and have shown that the grid-interfacing inverter can be utilized as a multi-function device.

REFERENCES:

[1] Akagi, H. (2006) Modern Active Filters and Traditional Passive Filters. Bulletin of the Polish Academy of Sciences Technical Sciences, 54, 255-269.

[2] Kazem, H.A. (2013) Harmonic Mitigation Techniques Applied to Power Distribution Networks. Advances in Power Electronics. http://dx.doi.org/10.1155/2013/591680

[3] Ravindra, S., Veera Reddy, V.C., Sivanagaraju, S. and Gireesh Kumar, D. (2012) Design of Shunt Active Power Filter to Eliminate the Harmonic Currents and to Compensate the Reactive Power under Distorted and or Imbalanced Source Voltages in Steady State. International Journal of Engineering Trends and Technology, 3, 1-6.

[4] Kumar, A. and Singh, J. (2013 Harmonic Mitigation and Power Quality Improvement Using Shunt Active Power Filter. International Journal of Electrical, Electronics and Mechanical Control, 2, 13 p.

[5] Gligor, A. (2009) Design and Simulation of a Shunt Active Filter in Application for Control of Harmonic Levels. Acta Universitatis Sapientiae, Electrical and Mechanical Engineering, 53-63.

Investigations On Shunt Active Power Filter In A PV-Wind-FC Based Hybrid Renewable Energy System To Improve Power Quality Using Hardware-In-The loop Testing Platform

ABSTRACT:  

The current power distribution system involves usage of nonlinear loads that cause power quality problems.Further, the penetration of renewable energy sources is increasing in the power networks to satisfy the consistently rising energy demand, which changes the traditional network plan and control drastically. This paper presents an intelligently controlled hybrid energy system (HES) integrated with shunt active power filter (SAPF) to address the power quality problems. Renewable sources like-Wind, PV and fuel cell (FC) are integrated into HES and are regulated using artificial intelligence techniques that are also implemented for maximum power point tracking (MPPT) in both PV and wind energy systems. The dynamic performance of SAPF is optimized using fuzzy logic, neural network and adaptive neuro-fuzzy inference system (ANFIS) based control algorithms. These controllers provide the smooth DC-link voltage and minimize the total harmonic distortion (THD) produced by the balanced/unbalanced and nonlinear loads. Comparison of these reveal that the ANFIS based algorithm provides minimum THD. The system is tested in real-time using hardware-in-the-loop (HIL) setup. The control schemes are executed on FPGA based OPAL-RT4510computational engine with microsecond step.

KEYWORDS:

Renewable energy

Photovoltaic

Wind energy

Fuel cell

Maximum power point tracking

Adaptive neuro-fuzzy inference system

Shunt active power filter

SOFTWARE: MATLAB/SIMULINK

PROPOSED SYSTEM CONFIGURATION:

Fig. 1. Proposed system configuration.

EXPERIMENTAL RESULTS:

Fig. 2. Performance of system balanced & nonlinear load.

Fig. 3. Harmonic spectrum of source current.

Fig. 4. Harmonic spectrum of load current.

Fig. 5. Performance of system under unbalanced & nonlinear load.

Fig. 6. Harmonic spectrum of source current.

Fig. 7. Harmonic spectrum of load current.

Fig. 8. Performance under dynamically load changes.

Fig. 9. DC bus voltage behavior under switching operation of RESs.

 CONCLUSION:

In this paper, a PV-Wind-FC based adaptive HES has been proposed which is further integrated with SRF based SAPF to eliminate the current  harmonics in the source current. The system injected the compensating current and decreased the harmonic level when balanced/unbalanced &  nonlinear loads have been applied. Various control strategies like fuzzy  logic, BP-ANN, RBF-ANN, and ANFIS has been employed for SAPF control  and MPPT control. The ANFIS based strategies regulating the DC-link  capacitor voltage have made it more robust and less susceptible to system transients. The proposed control scheme based on ANFIS has been validated  through an HIL using the hardware controller OPAL-RT. The performance of the combined system had also been evaluated for dynamical switching (on/off) for different renewable energy sources with different types of load. The proposed design has; mitigated harmonics, minimized voltage variations, allowed feeding of surplus power to the grid, better utilized the renewable energy sources, and hence has improved the performance of the grid.

REFERENCES:

 [1] M.C. Falvo, F. Foiadelli, Preliminary analysis for the design of an energy-efficient and environmental sustainable integrated mobility system, IEEE PES Gen. Meet. PES (2010) (2010) 1–7, https://doi.org/10.1109/PES.2010.5589545.

[2] T. Vigneysh, N. Kumarappan, Autonomous operation and control of photovoltaic/ solid oxide fuel cell/battery energy storage based microgrid using fuzzy logic controller, Int. J. Hydrogen Energy 41 (2015) 1877–1891, https://doi.org/10.  1016/j.ijhydene.2015.11.022.

[3] P. Chaudhary, M. Rizwan, Voltage regulation mitigation techniques in distribution system with high PV penetration: a review, Renewable Sustain. Energy Rev. 82  (2018) 3279–3287, https://doi.org/10.1016/j.rser.2017.10.017.

[4] Y. Sawle, S.C. Gupta, A. Kumar Bohre, W. Meng, PV-wind hybrid system: a review with case study, Cogent Eng. 3 (2016) 1189305, , https://doi.org/10.1080/  23311916.2016.1189305.

[5] M.P. an Brenna, F. Foiadelli, G. Manzolini, Grid connection of MCFC applied to power plant with CO2 capture, Int. J. Electr. Power Energy Syst. 53 (2013) 980–986, https://doi.org/10.1016/j.ijepes.2013.06.016.

Design and Control of Wind integrated Shunt Active Power Filter to Improve Power Quality

ABSTRACT:   

In this paper wind energy conservation system (WECS) with shunt active power filter (SAPF) is proposed for harmonics elimination, power factor correction, reactive power compensation and grid current balancing. Adaptive neuro  fuzzy inference system (ANFIS) based controller is implemented at WECS side to control the boost converter to achieve MPP and at SAPF sides to minimize voltage variations and enhance power quality. Here, synchronous reference frame (SRF) theory based reference current generation technique is employed in SAPF. The proposed scheme is implemented in MATLAB/Simulink. The results confirm that this method has better performance and can maintain total harmonic distortion (THD) level of the system within the IEEE standard 519.

KEYWORDS:

1.      Shunt active power filter

2.      Synchronous reference frame theory

3.      Wind energy

4.      Power quality

5.       Renewable energy

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

                   

Fig.1. Power circuit of WECS integrated SAPF

 EXPERIMENTAL RESULTS:

Fig. 2. Performance of system balanced & nonlinear load

Fig. 3. Harmonics spectrum of grid current

Fig. 4. Harmonics spectrum of load current

Fig. 5. Performance of system unbalanced & nonlinear load

Fig. 6. Harmonics spectrum of grid current

Fig. 7. Harmonic spectrum of load current

Fig. 8. WECS performance under variable wind speed

CONCLUSION:

The topology of a double stage WECS integrated SAPF has been designed and implemented. The proposed controller has two purposes, namely, extracting the maximum power from  the WECS and filtering out the harmonics. Here, a DC-DC  boost converter with an ANFIS based MPPT control algorithm  is developed to track the MPP of WECS. Further, SRF based ANFIS tuned SAPF is also implemented to improve the power quality. The proposed system provides smooth regulation to DC-link capacitor voltage, improves the power factor and system performance during dynamic loading conditions. This strategy brings down the THD level to 4.14 % and 4.68 % in grid currents for balanced and unbalanced nonlinear loading conditions respectively, which meets the IEEE standard 519.

REFERENCES:

[1] J. et al. Carrasco, “Power-Electronic Systems for the Grid Integration of Renewable Energy Sources: A Survey,” IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1002–1016, 2006.

[2] B. Bhattacharya, A., Chakraborty, C., “Shunt Compensation: Reviewing Traditional Methods of Reference Current Generation,” IEEE Ind. Electron. Mag, pp. 38–49, 2009.

[3] R. Kumar, P. Chaturvedi, H. O. Bansal, and P. K. Ajmera, “Adaptive Artificial Neural Network Based Control Strategy forShunt Active Power Filter,” Int. Conf. Electr. Power Energy Syst., pp. 194–199, 2016.

[4] A. Hoseinpour, S. Masoud Barakati, and R. Ghazi, “Harmonic

reduction in wind turbine generators using a Shunt Active Filter  based on the proposed modulation technique,” Int. J. Electr. Power Energy Syst., vol. 43, no. 1, pp. 1401–1412, 2012.

[5] M. Boutoubat, L. Mokrani, and M. Machmoum, “Control of a wind energy conversion system equipped by a DFIG for active power generation and power quality improvement,” Renew. Energy, vol.   50, pp. 378–386, 2013.