A Fuzzy Logic Control Method for MPPT of PV Systems

ABSTRACT:

Maximum power point trackers are so important in photovoltaic systems to increase their efficiency. Many methods have been proposed to achieve the maximum power that the PV modules are capable of producing under different weather conditions. This paper proposed an intelligent method for maximum power point tracking based on fuzzy logic controller. The system consists of a photovoltaic solar module connected to a DC-DC Buck-boost converter. The system has been experienced under disturbance in the photovoltaic temperature and irradiation level. The simulation results show that the proposed maximum power tracker could track the maximum power accurately and successfully in all condition tested. Comparison of different performance parameters such as: tracking efficiency and response time of the system shows that the proposed method gives higher efficiency and better performance than the conventional perturbation and observation method.

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Block diagram of the stand-alone PV system

EXPECTED SIMULATION RESULTS:

Fig. 2: case 1: changing the solar radiation

Fig. 3: Case 1: performance of FLC method

 

Fig. 4: Case I: performance of P&O method

Fig, 5: Case 2: changing the solar radiation

Fig, 6: Case 2: performance of FLC method

Fig, 7: Case 2: performance of P&O method

Fig, 8: Changing the temperature

Fig, 9: Performance of FLC method

Fig, 10: Performance of P&O method

 CONCLUSION:

 Photovoltaic model using Matlab/STMULTNK and design of appropriate DC-DC buck-boost converter with a maximum power point tracking facility are presented in this paper. A new method for MPPT based fuzzy logic controller is presented and compared with the conventional P&O MPPT method. The models are tested under disturbance in both solar radiation and photovoltaic temperature. Simulation results show that the proposed method effectively tracks the maximum power point under different ambient conditions. The oscillation around MPP is decreased and the response is faster in compared with the conventional methods. Comparing the tracking efficiency of both methods indicates that the proposed method has a higher efficiency than the conventional P&O MPPT method.

 REFERENCES:

[1] Jancarle L. Dos Santos, Fernando L. M. Antunes and Anis Chehab, “A Maximum Power Point Tracker for PV Systems Using a High Performance Boost Converter”, Solar Energy, Issue 7, Vol. 80, pp. 772- 778,2005.

[2] Ting-Chung Yu and Tang-Shiuan Chien, “Analysis and Simulation of Characteristics and Maximum Power Point Tracking for Photovoltaic Systems”, Conference,P prpo.c 1e3ed3i9n g- s1 3o4f4 ,PT aoiwpeeri, 2E0l0e9c.t ronics and Drive Systems

[3] Roberto Faranda, Sonia Leva, “Energy Comparison of MPPT techniques for PV Systems”, Wseas Transctions on Power System, Issue 6, Vol. 3, pp. 446-455, June 2008.

[4] D. P. Hohm and M. E. Ropp, “Comparative Study of Maximum Power Point Tracking Algorithms using an experimental, programmable, maximum power point tracking test bed”,P roceedings of Photovoltaic Specialists Conference ,pp. 1699 – 1702, USA,2000.

[5] Trishan Esram and Patrick 1. Chapman, “Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques”, Energy ConverSion, Issue 2, Vol. 22, pp. 439 – 449, May 2007.

Design and Performance Analysis of Three-Phase Solar PV Integrated UPQC

IEEE Transactions on Industry Applications, 2017 IEEE

ABSTRACT: This paper deals with the design and performance analysis of a three-phase single stage solar photovoltaic integrated unified power quality conditioner (PV-UPQC). The PV-UPQC consists of a shunt and series connected voltage compensators connected back to back with common DC-link.The shunt compensator performs the dual function of extracting power from PV array apart from compensating for load current harmonics. An improved synchronous reference frame control based on moving average filter is used for extraction of load active current component for improved performance of the PVUPQC. The series compensator compensates for the grid side power quality problems such as grid voltage sags/swells. The compensator injects voltage in-phase/out of phase with point of common coupling (PCC) voltage during sag and swell conditions respectively. The proposed system combines both the benefits of clean energy generation along with improving power quality. The steady state and dynamic performance of the system are evaluated by simulating in Matlab-Simulink under a nonlinear load. The system performance is then verified using a scaled down laboratory prototype under a number of disturbances such as load unbalancing, PCC voltage sags/swells and irradiation variation.

KEYWORDS:

  1. Power Quality
  2. Shunt compensator
  3. Series compensator
  4. UPQC
  5. Solar PV
  6. MPPT

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. System Configuration PV-UPQC

EXPECTED SIMULATION RESULTS:

 

Fig. 2. Performance of PV-UPQC under Voltage Sag and Swell Conditions

Fig. 3. Performance PV-UPQC during Load Unbalance Condition

Fig. 4. Performance PV-UPQC at Varying Irradiation Condition

Fig. 5. Load Current Harmonic Spectrum and THD

Fig. 6. Grid Current Harmonic Spectrum and THD

CONCLUSION:

The design and dynamic performance of three-phase PVUPQC have been analyzed under conditions of variable irradiation and grid voltage sags/swells. The performance of the system has been validated through experimentation on scaled down laboratory prototype. It is observed that PVUPQC mitigates the harmonics caused by nonlinear load and maintains the THD of grid current under limits of IEEE-519 standard. The system is found to be stable under variation of irradiation, voltage sags/swell and load unbalance. The performance of d-q control particularly in load unbalanced condition has been improved through the use of moving average filter. It can be seen that PV-UPQC is a good solution for modern distribution system by integrating distributed generation with power quality improvement.

REFERENCES:

[1] B. Mountain and P. Szuster, “Solar, solar everywhere: Opportunities and challenges for australia’s rooftop pv systems,” IEEE Power and Energy Magazine, vol. 13, no. 4, pp. 53–60, July 2015.

[2] A. R. Malekpour, A. Pahwa, A. Malekpour, and B. Natarajan, “Hierarchical architecture for integration of rooftop pv in smart distribution systems,” IEEE Transactions on Smart Grid, vol. PP, no. 99, pp. 1–1, 2017.

[3] Y. Yang, P. Enjeti, F. Blaabjerg, and H. Wang, “Wide-scale adoption of photovoltaic energy: Grid code modifications are explored in the distribution grid,” IEEE Ind. Appl. Mag., vol. 21, no. 5, pp. 21–31, Sept 2015.

[4] M. J. E. Alam, K. M. Muttaqi, and D. Sutanto, “An approach for online assessment of rooftop solar pv impacts on low-voltage distribution networks,” IEEE Transactions on Sustainable Energy, vol. 5, no. 2, pp.663–672, April 2014.

[5] J. Jayachandran and R. M. Sachithanandam, “Neural network-based control algorithm for DSTATCOM under nonideal source voltage and varying load conditions,” Canadian Journal of Electrical and Computer Engineering, vol. 38, no. 4, pp. 307–317, Fall 2015.

Design and Performance Analysis of Three-Phase Solar PV Integrated UPQC

2016 IEEE

ABSTRACT: In this paper, the design and performance of a threephase solar PV (photovoltaic) integrated UPQC (PV-UPQC) are presented. The proposed system combines both the benefits of distributed generation and active power filtering. The shunt compensator of the PV-UPQC compensates for the load current harmonics and reactive power. The shunt compensator is also extracting maximum power from solar PV array by operating it at its maximum power point (MPP). The series compensator compensates for the grid side power quality problems such as grid voltage sags/swells by injecting appropriate voltage in phase with the grid voltage. The dynamic performance of the proposed system is simulated in Matlab-Simulink under a nonlinear load consisting of a bridge rectifier with voltage-fed load.

KEYWORDS:

  1. Power Quality
  2. DSTATCOM
  3. DVR
  4. UPQC
  5. Solar PV
  6. MPPT

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. System Configuration PV-UPQC

EXPECTED SIMULATION RESULTS:

 Fig. 2. Performance PV-UPQC at steady state condition

Fig. 3. PCC Voltage Harmonic Spectrum and THD

Fig. 4. Load Voltage Harmonic Spectrum and THD

Fig. 5. Load Current Harmonic Spectrum and THD

Fig. 6. Grid Current Harmonic Spectrum and THD

Fig. 7. Performance PV-UPQC at varying irradiation condition

Fig. 8. Performance of PV-UPQC under voltage sag and swell conditions

CONCLUSION:

The dynamic performance of three-phase PV-UPQC has been analyzed under conditions of variable irradiation and grid voltage sags/swells. It is observed that PV-UPQC mitigates the harmonics caused by nonlinear and maintains the THD of grid voltage, load voltage and grid current under limits of IEEE-519 standard. The system is found to be stable under variation of irradiation from 1000𝑊/𝑚2 to 600𝑊/𝑚2. It can be seen that PV-UPQC is a good solution for modern distribution system by integrating distributed generation with power quality improvement.

REFERENCES:

[1] Y. Yang, P. Enjeti, F. Blaabjerg, and H. Wang, “Wide-scale adoption of photovoltaic energy: Grid code modifications are explored in the distribution grid,” IEEE Ind. Appl. Mag., vol. 21, no. 5, pp. 21–31, Sept 2015.

[2] B. Singh, A. Chandra and K. A. Haddad, Power Quality: Problems and Mitigation Techniques. London: Wiley, 2015.

[3] M. Bollen and I. Guo, Signal Processing of Power Quality Disturbances. Hoboken: Johm Wiley, 2006.

[4] P. Jayaprakash, B. Singh, D. Kothari, A. Chandra, and K. Al-Haddad, “Control of reduced-rating dynamic voltage restorer with a battery energy storage system,” IEEE Trans. Ind. Appl., vol. 50, no. 2, pp. 1295– 1303, March 2014.

[5] M. Badoni, A. Singh, and B. Singh, “Variable forgetting factor recursive least square control algorithm for DSTATCOM,” IEEE Trans. Power Del., vol. 30, no. 5, pp. 2353–2361, Oct 2015.

BLDC Motor Driven Solar PV Array Fed Water Pumping System Employing Zeta Converter

BLDC Motor Driven Solar PV Array Fed Water Pumping System Employing Zeta Converter

 ABSTRACT:

This paper proposes a simple, cost effective and efficient brushless DC (BLDC) motor drive for solar photovoltaic (SPV) array fed water pumping system. A zeta converter is utilized in order to extract the maximum available power from the SPV array. The proposed control algorithm eliminates phase current sensors and adapts a fundamental frequency switching of the voltage source inverter (VSI), thus avoiding the power losses due to high frequency switching. No additional control or circuitry is used for speed control of the BLDC motor. The speed is controlled through a variable DC link voltage of VSI. An appropriate control of zeta converter through the incremental conductance maximum power point tracking (INC-MPPT) algorithm offers soft starting of the BLDC motor. The proposed water pumping system is designed and modeled such that the performance is not affected under dynamic conditions. The suitability of proposed system at practical operating conditions is demonstrated through simulation results using MATLAB/ Simulink followed by an experimental validation.

KEYWORDS:

  1. BLDC motor
  2. SPV array
  3. Water pump
  4. Zeta converter
  5. VSI
  6. INC-MPPT

 

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1 Configuration of proposed SPV array-Zeta converter fed BLDC motor drive for water pumping system

EXPECTED SIMULATION RESULTS:

Fig.2 Performances of the proposed SPV array based Zeta converter fed BLDC motor drive for water pumping

system (a) SPV array variables, (b) Zeta converter variables, and (c) BLDC motor-pump variables.

 

CONCLUSION:

The SPV array-zeta converter fed VSI-BLDC motor-pump for water pumping has been proposed and its suitability has been demonstrated by simulated results using MATLAB/Simulink and its sim-power-system toolbox. First, the proposed system has been designed logically to fulfil the various desired objectives and then modelled and simulated to examine the various performances under starting, dynamic and steady state conditions. The performance evaluation has justified the combination of zeta converter and BLDC motor drive for SPV array based water pumping. The system under study availed the various desired functions such as MPP extraction of the SPV array, soft starting of the BLDC motor, fundamental frequency switching of the VSI resulting in a reduced switching losses, reduced stress on IGBT switch and the components of zeta converter by operating it in continuous conduction mode and stable operation. Moreover, the proposed system has operated successfully even under the minimum solar irradiance.

REFERENCES:

  • Uno and A. Kukita, “Single-Switch Voltage Equalizer Using Multi- Stacked Buck-Boost Converters for Partially-Shaded Photovoltaic Modules,” IEEE Transactions on Power Electronics, no. 99, 2014.
  • Arulmurugan and N. Suthanthiravanitha, “Model and Design of A Fuzzy-Based Hopfield NN Tracking Controller for Standalone PV Applications,” Electr. Power Syst. Res. (2014). Available: http://dx.doi.org/10.1016/j.epsr.2014.05.007
  • Satapathy, K.M. Dash and B.C. Babu, “Variable Step Size MPPT Algorithm for Photo Voltaic Array Using Zeta Converter – A Comparative Analysis,” Students Conference on Engineering and Systems (SCES), pp.1-6, 12-14 April 2013.
  • Trejos, C.A. Ramos-Paja and S. Serna, “Compensation of DC-Link Voltage Oscillations in Grid-Connected PV Systems Based on High Order DC/DC Converters,” IEEE International Symposium on Alternative Energies and Energy Quality (SIFAE), pp.1-6, 25-26 Oct. 2012.
  • K. Dubey, Fundamentals of Electrical Drives, 2nd ed. New Delhi, India: Narosa Publishing House Pvt. Ltd., 2009.

Single Stage Solar PV Fed Brushless DC Motor Driven Water Pump

 

ABSTRACT:

In order to optimize the solar photovoltaic (PV) generated power using a maximum power point tracking (MPPT) technique, a DC-DC conversion stage is usually required in solar PV fed water pumping which is driven by a brushless DC (BLDC) motor. This power conversion stage leads to an increased cost, size, complexity and reduced efficiency. As a unique solution, this work addresses a single stage solar PV energy conversion system feeding a BLDC motor-pump, which eliminates the DC-DC conversion stage. A simple control technique capable of operating the solar PV array at its peak power using a common voltage source inverter (VSI), is proposed for BLDC motor control. The proposed control eliminates the BLDC motor phase current sensors. No supplementary control is associated for the speed control of motor-pump and its soft start. The speed is controlled through the optimum power of solar PV array. The suitability of proposed system is manifested through its performance evaluation using MATLAB/Simulink based simulated results and experimental validation on a developed prototype, under the practical operating conditions.

KEYWORDS:

  1. MPPT
  2. Solar PV array
  3. BLDC motor
  4. Water pump
  5. VSI
  6. Soft starting
  7. Speed control

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig.1 Proposed water pumping based on a single stage solar PV energy conversion system.

EXPECTED SIMULATION RESULTS:

 Fig.2 Steady state and starting performance of (a) PV array and (b) motor pump, of proposed system at 1 kW/m2.

Fig.3 Steady state and starting response of (a) PV array and (b) motor-pump, of proposed system at 200 W/m2.

Fig.4 Dynamic performance of (a) PV array and (b) BLDC motor Pump ,of Proposed  water pumping system.

Fig. 5 Responses of (a) PV array and (b) BLDC motor, under partial shading

CONCLUSION:

The proposed BLDC motor driven water pumping based on a single stage solar PV generation has been validated through a demonstration of its various steady state, starting and dynamic performances. The system has been simulated using the MATLAB toolboxes, and implemented on an experimental prototype. The topology of the proposed system has provided a DC-DC converter-less solution for PV fed brushless DC motor driven water pumping. Moreover, the motor phase current sensing elements have been eliminated, resulting in a simple and cost-effective drive. The other desired functions are the speed control without any additional circuit and a soft start of the motor-pump. A detailed comparative analysis of the proposed and the existing topologies has ultimately manifested the superiority of the proposed work.

REFERENCES:

[1] C. Jain and B. Singh, “An Adjustable DC Link Voltage Based Control of Multifunctional Grid Interfaced Solar PV System,” IEEE J. Emerg. Sel. Topics Power Electron., Early Access.

[2] A. A. A. Radwan and Y. A. R. I. Mohamed, “Power Synchronization Control for Grid-Connected Current-Source Inverter-Based Photovoltaic Systems,” IEEE Trans. Energy Convers., vol. 31, no. 3, pp. 1023-1036, Sept. 2016.

[3] P. Vithayasrichareon, G. Mills and I. F. MacGill, “Impact of Electric Vehicles and Solar PV on Future Generation Portfolio Investment,” IEEE Trans. Sustain. Energy, vol. 6, no. 3, pp. 899-908, July 2015.

[4] A. K. Mishra and B. Singh, “A single stage solar PV array based water pumping system using SRM drive,” IEEE Ind. Appl. Soc. Annu. Meeting, Portland, OR, 2016, pp. 1-8.

[5] S. Jain, A.K. Thopukara, R. Karampuri and V.T. Somasekhar, “A Single-Stage Photovoltaic System for a Dual-Inverter-Fed Open-End Winding Induction Motor Drive for Pumping Applications,” IEEE Trans. Power Electron., vol. 30, no. 9, pp. 4809 – 4818, Sept. 2015.

Analysis Of Solar Energy Embeded To Distribution Grid For Active & Reactive Power Supply To Grid

 

ABSTRACT: 

This paper presents a system of grid connected photovoltaic (PV) to the monitoring point of maximum power (MPPT). The voltage source inverter (VSI) is connected between the dc output of photovoltaic system and ac grid. The control strategy applied is based on theory of instantaneous reactive power (p-q theory). According to this proposed PV system send active power to the grid at the same time the reactive power of load and harmonics will eliminate at change in both irradiation and load condition. During no sunlight system is available only reactive power and harmonic compensation. The applicability of our system tested in simulation in Matlab / Simulink.

KEYWORDS:

  1. Grid-connected PV system
  2. Instantaneous reactive power theory
  3. MPPT
  4. Reactive power compensation
  5. Power quality

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Proposed Grid Connected PV System

EXPECTED SIMULATION RESULTS:

 

Fig. 2. Active Power of load, PV system and grid

Fig. 3. Reactive Power of load, PV system and grid

Fig. 4. Current of Load, PV Inverter and Grid

Fig. 5. Harmonic analysis with and without PV system

Fig. 6 Waveform of Grid Volatge and Current

 

CONCLUSION:

Photovoltaic power seems to be the favorable clean energy source of the future. So, to optimize its use we have proposed a direct coupling of PV system to the grid. From the results obtained, it is proven that by using the proposed system, Photovoltaic power can be efficiently extracted by solar cells and injected into the grid and compensating reactive power of the load all 24 h of the day. The proposed system also compensates the harmonics content of nonlinear load. Finally, and according to the obtained results we can consider the proposed system to be efficient solution to the growing demand of power at the present and in the future.

REFERENCES:

[1] Pandiarajan N, Ramaprabha R and RanganathMuthu. “Application of Circuit Model for Photovoltaic Energy Conversion System” INTERNATIONAL CONFERENCE’2010.

[2] Marcelo GradellaVillalva, Jonas Rafael Gazoli, Ernesto RuppertFilho, “Modeling And Circuit-based Simulation of Photovoltaic Arrays” 10TH Brazilian Power Electronics Conference (COBEP), pp.1244-1254, 2009.

[3] SoerenBaekhoejKjaer, John K. Pedersen FredeBlaabjerg “A Review of Single-Phase Grid-Connected Inverters for Photovoltaic Modules” IEEE Transactions On Industry Applications, 41(5), pp.1292-1306, 2005.

[4] FredeBlaabjerg, ZheChen,SoerenBaekhoejKjaer, “Power Electronics as Efficient Interface in Dispersed Power Generation Systems” IEEE Transactions On Power Electronics, 19(5)1184-1194, 2004.

[5] D. Picault, B. Raison, and S. Bacha “Guidelines for evaluating grid connected PV system topologies”. IEEE International Conference on Industrial Technology1-5, 2009.

Design of Fuzzy Logic Based Maximum Power Point Tracking Controller for Solar Array for Cloudy Weather Conditions

 

ABSTRACT:

This paper proposes Maximum Power Point Tracking (MPPT) of a photovoltaic system under variable temperature and solar radiation conditions using Fuzzy Logic Algorithm. The cost of electricity from the PV array is more expensive than the electricity from the other non-renewable sources. So, it is necessary to operate the PV system at maximum efficiency by tracking its maximum power point at any weather conditions 111. Boost converter increases output voltage of the solar panel and converter output voltage depends upon the duty cycle of the MOSFET present in the boost converter. The change in the duty cycle is done by Fuzzy logic controller by sensing the power output of the solar panel. The proposed controller is aimed at adjusting the duty cycle of the DC-DC converter switch to track the maximum power of a solar cell array. MATLABI Simulink is used to develop and design the PV array system equipped with the proposed MPPT controller using fuzzy logic 12][31. The results show that the proposed controller is able to track the MPP in a shorter time with less fluctuation. The complete hardware setup with fuzzy logic controller is implemented and the results are observed and compared with the system without MPPT (Fuzzy logic controller).

KEYWORDS:

  1. MPPT
  2. Fuzzy Logic Control
  3. DC-DC Converter,
  4. Photo voltaic systems.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Block diagram of MPPT of PV array.

EXPECTED SIMULATION RESULTS:

 Fig. 2. Power Vs output voltage

Fig. 3. Voltage Vs Current output of solar panel

Fig. 4. Output voltage of the solar panel without MPPT.

Fig. 5. Output of the solar panel with MPPT FLC under cloudy weather conditions.

Fig. 6. PWM output when driven by FLC

 CONCLUSION:

This paper presents an intelligent control method of tracking maximum power and Simulation and hardware result show that proposed MPPT controller increases the efficiency of the PV array energy conversion efficiency. Results are compared with the panel without MPPT controller.

REFERENCES:

[1] Chetan Singh Solanki,” Solar Photo Voltaics “, PHI Learning pvt. Ltd ,2009.

[2] Bor-Ren Lin,”Analysis of Fuzzy Control Method Applied to DCDC Converter controf’ , IEEE Prowe .h g APK’93, pp. 22- 28,1993.

[3] Rohin M.Hillooda, Adel M.Shard,”A rule Based Fuzzy Logic controller for a PWM inverter in Photo Voltaic Energy Conversion Scheme”, IAS’SZ, PP.762-769, 1993.

[4] Pongsakor Takum, Somyot Kaitwanidvilai and Chaiyan Jettasen ; ‘Maximum POlVer Point Tracking using jilzzy logic control for photovoltaic systems.’ Proceedings Of International Multiconference of Engineers and Computer scientists ,Vol 2,March 2011.

[5] M.S.Cheik , Larbes, G.F Kebir and A ZerguelTas; ‘Maximum power point tracking using a jilzzy logic control scheme.’; ‘Departementd’Electronique’, Revue des Energies Renouvelables, VoI.lO,No 32 , September 2007, pp 387-395

Backstepping Control of Smart Grid-Connected Distributed Photovoltaic Power Supplies for Telecom Equipment

ABSTRACT:

Backstepping controllers are obtained for distributed hybrid photovoltaic (PV) power supplies of telecommunication equipment. Grid-connected PV-based power supply units may contain dc–dc buck–boost converters linked to single-phase inverters. This distributed energy resource operated within the self consumption concept can aid in the peak-shaving strategy of ac smart grids. New backstepping control laws are obtained for the single-phase inverter and for the buck–boost converter feeding a telecom equipment/battery while sourcing the PV excess power to the smart grid or to grid supply the telecom system. The backstepping approach is robust and able to cope with the grid nonlinearity and uncertainties providing dc input current and voltage controllers for the buck–boost converter to track the PV panel maximum power point, regulating the PV output dc voltage to extract maximum power; unity power factor sinusoidal ac smart grid inverter currents and constant dc-link voltages suited for telecom equipment; and inverter bidirectional power transfer. Experimental results are obtained from a lab setup controlled by one inexpensive dsPIC running the sampling, the backstepping and modulator algorithms. Results show the controllers guarantee maximum power transfer to the telecom equipment/ac grid, ensuring steady dc-link voltage while absorbing/injecting low harmonic distortion current into the smart grid.

KEYWORDS:

  1. Backstepping
  2. Buck–boost converter
  3. Dc/ac converter
  4. MPPT
  5. Self-consumption
  6. Smart grids

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 image001

Fig. 1. PV distributed hybrid self-consumption system and telecom load.

EXPECTED SIMULATION RESULTS:

 image002

 Fig. 2. MPPT operation.

       image003

Fig. 3. Voltage and current waveforms when there is a change from inverter to rectifier.

image004

Fig. 4. (a)Voltage and current waveforms when there is a change from inverter to rectifier. (b) Center part zoom of (a).

image005

Fig. 5. Voltage and current waveforms when the load requires 25 W.

image006

Fig. 6. Voltage and current waveforms when the load requires 62 W.

image007

Fig. 7. DC–AC converter input power.

 CONCLUSION:

This paper proposes a novel backstepping controller for a PV panel feeding a buck–boost converter, and dc linked to a telecom load and a single-phase ac–dc converter connected to a smart grid, configuring a subset of a distributed hybrid photovoltaic power supply for telecom equipments within the self-consumption concept. This setup absorbs/injects nearly sinusoidal (THD = 1.6%, lower than the 3% required by the standards) grid currents at near unity power factor and the self consumption can contribute to the smart grid peak power shaving strategy.

New nonlinear backstepping control laws were obtained for the input voltage of the buck–boost converter, thus achieving MPP operation (MPPT efficiency between 98.2% and 99.9%) and for the dc–ac converter regulating the dc telecom load voltage and controlling the ac grid current. All the control laws, fixed frequency converter modulators, voltage and current sampling, and grid synchronization have been implemented using a low-cost dsPIC30F4011 microcontroller.

Obtained experimental results show the performance of the PV self-consumption system using the backstepping control method. Results show the system dynamic behavior when the dc–ac converter changes operation from inverter to rectifier to adapt itself to the telecom load requirements. The robustness of the control laws has been tested as well. Capacitance of real capacitors can vary almost ten times around the rated value, while inductances can vary from 30% to nearly 300% of the rated value.

 REFERENCES:

[1] N. Femia, G. Petrone, G. Spagnuolo, and M. Vitelli, Power Electronics and Control Techniques for Maximum Energy Harvesting in Photovoltaic Systems. Boca Raton, FL, USA: CRC Press, 2013.

[2] A.Maki and S. Valkealahti, “Effect of photovoltaic generator components on the number of MPPs under partial shading conditions,” IEEE Trans. Energy Convers., vol. 28, no. 4, pp. 1008–1017, Dec. 2013.

[3] Epia Org. (2013, Jul.). Self-consumption of PV electricity—Position paper. [Online]. Available:http://www.epia.org/fileadmin/user_upload/Position_Papers/Self_and_direct_consumption_-_position_paper_-_final _version.pdf

[4] SunEdison. (2011, Nov.). Enabling the European consumer to generate power for self-consumption. [Online]. Available: http://www. sunedison.com/wps/wcm/connect/35bfb52a-ec27-4751-8670-fe6e807e8063/SunEdison_PV_Self  consumption_Study_high_resolution_%2813_ Mb%29.pdf?MOD=AJPERES

[5] A. Nourai, R. Sastry, and T.Walker, “A vision & strategy for deployment of energy storage in electric utilities,” in Proc. IEEE Power Energy Soc. Gen. Meeting, 2010, pp. 1–4.

Grid-Connected PV Array with Supercapacitor Energy Storage System for Fault Ride Through

ABSTRACT:

A fault ride through, power management and control strategy for grid integrated photovoltaic (PV) system with supercapacitor energy storage system (SCESS) is presented in this paper. During normal operation the SCESS will be used to minimize the short term fluctuation as it has high power density and during fault at the grid side it will be used to store the generated power from the PV array for later use and for fault ride through. To capture the maximum available solar power, Incremental Conductance (IC) method is used for maximum power point tracking (MPPT). An independent P-Q control is implemented to transfer the generated power to the grid using a Voltage source inverter (VSI). The SCESS is connected to the system using a bi-directional buck boost converter. The system model has been developed that consists of PV module, buck converter for MPPT, buck-boost converter to connect the SCESS to the DC link. Three independent controllers are implemented for each power electronics block. The effectiveness of the proposed controller is examined on Real Time Digital Simulator (RTDS) and the results verify the superiority of the proposed approach.

KEYWORDS:

  1. Active and reactive power control
  2. Fault ride through
  3. MPPT
  4. Photovoltaic system
  5. RTDS Supercapacitor
  6. Energy storage

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

image001

Fig.1. Grid connected PV system with energy storage

 EXPECTED SIMULATION RESULTS:

 image002

Fig.2. Grid voltage after three phase fault is applied

image003

Fig.3. PV array power PPV with SCESS and with no energy storage

image004

Fig.4. Grid active power Pg for a three phase fault with and without energy storage

image005

Fig.5.SCESS power PSC for the applied fault on the grid side

image006

Fig.6. Grid reactive power Qg during three phase fault

image007

Fig.7. DC link voltage for the applied fault

image008

Fig.8. PV array voltage VPV during three phase fault

image009

Fig.9. MPPT output voltage Vref for the applied fault

CONCLUSION:

This paper presents grid connected PV system with supercapacitor energy storage system (SCESS) for fault ride through and to minimize the power fluctuation. Incremental conductance based MPPT is implemented to track the maximum power from the PV array. The generated DC power is connected to the grid using a buck converter, VSI, buck-boost converter with SCESS. The SCESS which is connected to the DC link controls the DC link voltage by charging and discharging process. A P-Q controller is implemented to transfer the DC link power to the grid. During normal operation the SCESS minimizes the fluctuation caused by change in irradiation and temperature. During a grid fault the power generated from the PV array will be stored in the SCESS. The SCESS supplies both active and reactive power to ride through the fault. RTDS based results have shown the validity of the proposed controller.

REFERENCES:

[1] T. Esram, P.L. Chapman, “Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques,” IEEE Transaction on Energy Conversion, vol.22, no.2, pp.439-449, June 2007

[2] J. M. Enrique, E. Durán, M. Sidrach-de-Cardona, and J. M. Andújar,“Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies,” Sol. Energy, vol. 81, no. 1, pp. 31–38, Jan. 2007.

[3] W. Xiao, N. Ozog, and W. G. Dunford, “Topology study of photovoltaic interface for maximum power point tracking,” IEEE Trans. Ind. Electron., vol. 54, no. 3, pp. 1696–1704, Jun. 2007.

[4] J. L. Agorreta, L. Reinaldos, R. González, M. Borrega, J. Balda, and L. Marroyo, “Fuzzy switching technique applied to PWM boost converter operating in mixed conduction mode for PV systems,” IEEE Trans. Ind. Electron., vol. 56, no. 11, pp. 4363– 4373, Nov. 2009.

[5] A.Schneuwly, “Charge ahead [ultracapacitor technology and applications]”, IET Power Engineering Journal, vol.19, 34-37, 2005.

 

A Three-Phase Grid Tied SPV System with Adaptive dc link voltage for CPI voltage variations

 

ABSTRACT:

This paper deals with a three-phase two-stage grid tied SPV (solar photo-voltaic) system. The first stage is a boost converter, which serves the purpose of MPPT (maximum power point tracking) and feeding the extracted solar energy to the DC link of the PV inverter, whereas the second stage is a two-level VSC (voltage source converter) serving as PV inverter which feeds power from a boost converter into the grid. The proposed system uses an adaptive DC link voltage which is made adaptive by adjusting reference DC link voltage according to CPI (common point of interconnection) voltage. The adaptive DC link voltage control helps in the reduction of switching power losses. A feed forward term for solar contribution is used to improve the dynamic response. The system is tested considering realistic grid voltage variations for under voltage and over voltage. The performance improvement is verified experimentally. The proposed system is advantageous not only in cases of frequent and sustained under voltage (as in the cases of far radial ends of Indian grid) but also in case of normal voltages at CPI. The THD (total harmonics distortion) of grid current has been found well under the limit of an IEEE-519 standard.

KEYWORDS:

  1. Adaptive DC link
  2. MPPT
  3. Overvoltage
  4. Solar PV
  5. Two-stage
  6. Three phase
  7. Under voltage

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 image001

Fig. 1. System configuration.

 CONTROL SYSTEM

image002

Fig. 2. Block diagram for control approach.

 EXPECTED SIMULATION RESULTS:

 image003

 Fig. 3. Simulated performance for, (a) change in solar insolation without feedforward for PV contribution,

image004

(b) change in solar insolation with feed forward for PV contribution,

image005

(c) normal to under voltage (415 V to 350 V),

image006

(d) CPI voltage variation from normal to over voltage (415 V to 480 V).

CONCLUSION:

A two-stage system has been proposed for three-phase grid connected solar PV generation. A composite InC based MPPT algorithm is used for control of the boost converter. The performance of proposed system has been demonstrated for wide range of CPI voltage variation. A simple and novel adaptive DC link voltage control approach has been proposed for control of grid tied VSC. The DC link voltage is made adaptive with respect to CPI voltage which helps in reduction of losses in the system. Moreover, a PV array feed forward term is used which helps in fast dynamic response. An approximate linear model of DC link voltage control loop has been developed and analyzed considering feed forward compensation. The PV array feed forward term is so selected that it is to accommodate for change in PV power as well as for CPI voltage variation. A full voltage and considerable power level prototype has verified the proposed concept. The concept of adaptive DC link voltage has been proposed for grid tied VSC for PV application however, the same concept can be extended for all shunt connected grid interfaced devices such as, STATCOM, D-STATCOM etc. The proposed system yields increased energy output using the same hardware resources just by virtue of difference in DC link voltage control structure. The THDs of the grid currents and voltages are found less than 5% (within IEEE-519 standard). The simulation and experimental results have confirmed the feasibility of proposed control algorithm.

 REFERENCES:

[1] M. Pavan and V. Lughi, “Grid parity in the Italian commercial and industrial electricity market,” in Proc. Int. Conf. Clean Elect. Power (ICCEP’13), 2013, pp. 332–335.

[2] M. Delfanti, V. Olivieri, B. Erkut, and G. A. Turturro, “Reaching PV grid parity: LCOE analysis for the Italian framework,” in Proc. 22nd Int. Conf. Exhib. Elect. Distrib. (CIRED’13), 2013, pp. 1–4.

[3] H.Wang and D. Zhang, “The stand-alone PV generation system with parallel battery charger,” in Proc. Int. Conf. Elect. Control Eng. (ICECE’10), 2010, pp. 4450–4453.

[4] M. Kolhe, “Techno-economic optimum sizing of a stand-alone solar photovoltaic system,” IEEE Trans. Energy Convers., vol. 24, no. 2, pp. 511–519, Jun. 2009.

[5] D. Debnath and K. Chatterjee, “A two stage solar photovoltaic based stand alone scheme having battery as energy storage element for rural deployment,” IEEE Trans. Ind. Electron., vol. 62, no. 7, pp. 4148–4157, Jul. 2015.