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.

Improved P-F/Q-V And P-V/Q-F Droop Controllers For Parallel Distributed Generation Inverters In AC Microgrid

ABSTRACT:

Distributed generation inverters are generally operated in parallel with P-f/Q-V and P-V/Q-f droop control strategies. Due to mismatched resistive and inductive line impedance, power sharing and output voltage of the parallel DG inverters deviate from the reference value. This leads to instability in the microgrid system. Adding virtual resistors and virtual inductors in the control loop of droop controllers improve the power sharing and stability of operation. But, this leads to voltage drop. Therefore, an improved P-f/Q-V and P-V/Q-f droop control is proposed. Simulation results demonstrate that the proposed control and the selection of parameters enhance the output voltage of inverters.

KEYWORDS:

1.      Distributed generation inverters

2.      Droop control

3.      Microgrid

4.      Output impedance

5.      Virtual resistors

6.      Virtual inductors

SOFTWARE: MATLAB/SIMULINK

 DROOP CONTROL BLOCK DIAGRAM.:

Fig. 1. Droop control block diagram.

EXPERIMENTAL RESULTS:

Fig. 2. Parallel inverter output voltage using P-V/Q-f droop control with virtual resistor under resistive line impedance.

Fig. 3. Active power sharing using secondary control with virtual resistor under resistive line impedance.

Fig. 4. Reactive power sharing using secondary control with virtual resistor under resistive line impedance.

Fig. 5. Parallel inverter output frequency using secondary control with virtual resistor under resistive line impedance.

Fig. 6. Parallel inverter output voltage using secondary control with virtual resistor under resistive line impedance.

Fig. 7. Active power sharing using P-V/Q-f droop control under inductive line impedance.

Fig. 8. Reactive power sharing using P-V/Q-f droop control under inductive line impedance.

Fig. 9. Active power sharing using P-f/Q-V droop control with virtual inductor under inductive line impedance.

Fig. 10. Reactive power sharing using P-f/Q-V droop control with virtual inductor under inductive line impedance. 

Fig. 11. Parallel inverter output frequency using P-f/Q-V droop control with virtual inductor under inductive line impedance.

Fig. 12. Parallel inverter output voltage using P-f/Q-V droop control with virtual inductor under inductive line impedance.

Fig. 13. Active power sharing using secondary control with virtual inductor under inductive line impedance.

Fig. 14. Reactive power sharing using secondary control with virtual inductor under inductive line impedance.

Fig. 15. Parallel inverter output frequency using secondary control with virtual inductor under inductive line impedance.

Fig. 16. Parallel inverter output voltage using secondary control with virtual inductor under inductive line impedance.

Fig. 17. Active power sharing using secondary control with different DG ratings under resistive line impedance.

Fig. 18. Reactive power sharing using secondary control with different DG ratings under resistive line impedance.

Fig. 19. Parallel inverter output frequency using secondary control with different DG ratings under resistive line impedance.

Fig. 20. Parallel inverter output voltage using secondary control with different DG ratings under resistive line impedance.

Fig. 21. Active power sharing using secondary control with different DG ratings under inductive line impedance.

Fig. 22. Reactive power sharing using secondary control with different DG ratings under inductive line impedance.

Fig. 23. Parallel inverter output frequency using secondary control with different DG ratings under inductive line impedance.

Fig. 24. Parallel inverter output voltage using secondary control with different DG ratings under inductive line impedance.

CONCLUSION:

In this paper, analysis of improved P-f/Q-V and P-V/Q-f droop control with secondary control for DG parallel inverters in microgrid is proposed considering line and output impedance. Proportional integral controller is adopted to ensure accurate tracking of the output voltage of the inverter to the reference value and the influence of the controller parameters on the voltage closed loop transfer function and the equivalent output impedance of the inverter is analyzed. In order to match the total output impedance of the inverter and line impedance in parallel, the P-V/Q-f and P-f/Q-V droop control strategy based on the inductive and resistive virtual impedance is adopted to improve the total output impedance of the inverter through the virtual impedance. The proposed P-f/Q-V and P-V/Q-f droop control, adaptively compensates the virtual resistor and inductor voltage drop to improve output voltage amplitude accuracy to the reference value. Simulation results show the rationality and effectiveness of the proposed improved control method.

REFERENCES:

Brabandere, K. D., Bolsens, B., & Van, J. (2007). A voltage and frequency droop control method for parallel inverters. IEEE Transactions on Power Electronics, 22(4), 1107–1115.

Chandorkar, M. C., Divan, D. M., & Adapa, R. (1993). Control of parallel connected inverters in standalone ac supply systems. IEEE Transactions on Industry Applications, 29(1), 136–143.

Chengshan, W., Zhaoxia, X., & Shouxiang, W. (2009). Multiple feedback loop control scheme for inverters of the microsource in microgrids. Transactions of China Electro Technical Society, 24(2), 100–107 [in Chinese].

Chengshan, W., Zhangang, Y., Shouxiang, W., & Yanbo, C. (2010). Analysis of structural characteristics and control approaches of experimental microgrid systems. Automation of Electric Power Systems, 34(1), 99–105 [in Chinese].

Chowdhury, A. A. S., & Agarwal, K. (2003). Dono Koval Reliability modeling of distributed generation in conventional distribution systems planning and analysis. IEEE Transactions on Industry Applications, 39(5), 1493–1498.