Integrated Photovoltaic and Dynamic Voltage Restorer System Configuration

ABSTRACT:  

This paper presents a new system structure for integrating a grid-connected photo voltaic (P V) system together with a self-supported dynamic voltage restorer (DVR). The proposed system termed as a “six-port converter,” consists of nine semiconductor switches in total. The proposed configuration retains all the essential features of normal P V and DVR systems while reducing the overall switch count from twelve to nine. In addition, the dual functionality feature significantly enhances the system robustness against severe symmetrical/asymmetrical grid faults and voltage dips. A detailed study on all the possible operational modes of six-port converter is presented. An appropriate control algorithm is developed and the validity of the proposed configuration is verified through extensive simulation as well as experimental studies under different operating conditions.

KEYWORDS:

  1. Bidirectional power flow
  2. Distributed power generation
  3. Photovoltaic (PV) systems
  4. Power quality
  5. Voltage control

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

 

 Fig. 1. Proposed integrated PV and DVR system configuration.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation results: operation of proposed system during health grid mode (PV-VSI: active and DVR-VSI: inactive). (a) Vpcc; (b) PQload; (c) PQgrid; (d) PQpv-VSI; and (e) PQdvr-VSI.

Fig. 3. Simulation results: operation of proposed system during fault mode (PV-VSI: inactive and DVR-VSI: active). (a) Vpcc; (b) Vdvr; (c) Vload; (d) PQload; (e) PQgrid; (f) PQpv-VSI; and (g) PQdvr-VSI.

Fig. 4. Simulation results: operation of proposed system during balance three phase sag mode (PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vdvr-VSI; (c) Vload; (d) PQgrid; (e) PQpv-VSI; and (f) PQdvr-VSI.

Fig. 5. Simulation results: operation of proposed system during unbalanced sag mode (PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vdvr-vsi; (c) Vload; (d) PQgrid; (e) PQpv-VSI; and (f) PQdvr-VSI.

Fig. 6. Simulation results: operation of proposed system during inactive PV plantmode (PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vload; (c) Vdc; (d) PQload; (e) PQdvr-VSI; and (f) PQpv-VSI.

 CONCLUSION:

 In this paper, a new system configuration for integrating a conventional grid-connected P V system and self supported DVR is proposed. The proposed configuration not only exhibits all the functionalities of existing P V and DVR system, but also enhances the DVR operating range. It allows DVR to utilize active power of P V plant and thus improves the system robustness against sever grid faults. The proposed configuration can operate in different modes based on the grid condition and P V power generation. The discussed modes are healthy grid mode, fault mode, sag mode, and P V inactive mode. The comprehensive simulation study and experimental validation demonstrate the effectiveness of the proposed configuration and its practical feasibility to perform under different operating conditions. The proposed configuration could be very useful for modern load centers where on-site P V generation and strict voltage regulation are required.

REFERENCES:

[1] R. A. Walling, R. Saint, R. C. Dugan, J. Burke, and L. A. Kojovic, “Summary of distributed resources impact on power delivery systems,” IEEE Trans. Power Del., vol. 23, no. 3, pp. 1636–1644, Jul. 2008.

[2] C. Meza, J. J. Negroni, D. Biel, and F. Guinjoan, “Energy-balance modeling and discrete control for single-phase grid-connected PV central inverters,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2734–2743, Jul.2008.

[3] T. Shimizu, O. Hashimoto, and G. Kimura, “A novel high-performance utility-interactive photovoltaic inverter system,” IEEE Trans. Power Electron., vol. 18, no. 2, pp. 704–711, Mar. 2003.

[4] S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “A review of single-phase grid-connected inverters for photovoltaic modules,” IEEE Trans. Ind.Appl., vol. 41, no. 5, pp. 1292–1306, Sep./Oct. 2005.

[5] T. Esram, J. W. Kimball, P. T. Krein, P. L. Chapman, and P. Midya, m“Dynamic maximum power point tracking of photovoltaic arrays using ripple correlation control,” IEEE Trans. Power Electron., vol. 21, no. 5, pp. 1282–1291, Sep. 2006.

Simulation and Analysis of Stand-alone Photovoltaic System with Boost Converter using MATLAB/Simulink

ABSTRACT:  

Use of renewable energy and in particular solar energy has brought significant attention over the past decades.  Many research works are carried out to analyze and validate the performance of P V modules. Implementation of experimental set up for P V based power system with DC-DC converter to validate the performance of the system is not always possible due to practical constraints. Software based simulation model helps to analyze the performance of P V and a common circuit based model which could be used for validating any commercial P V module will be more helpful.

Simulation

of mathematical model for Photo voltaic (P V) module and DC-DC boost converter is presented in this paper. The model presented in this paper can be used as a generalized P V module to analyze the performance of any commercially available P V modules. I-V characteristics and P-V characteristics of P V module under different temperature and irradiation level can be obtained using the model. The design of DC-DC boost converter is also discussed in detail. Simulation of DC-DC converter is performed and the constant DC supply fed converter and P V fed converter generates the results.

 BLOCK DIAGRAM:

Fig. 1 Sim u link Model of proposed system

EXPECTED SIMULATION RESULTS:

Fig.2 P WM Pulse generation

Fig. 3(a) Input Voltage of DC-DC Boost Converter

Fig. 4(b) Output Voltage of Boost Converter constant DC input supply

Fig. 5 (c) Output current of Boost Converter constant DC input supply

Fig. 6 (a) Input voltage of P V fed converter

Fig. 7 (b) Output voltage and current waveform of P V fed converter

Fig. 8. Change in irradiation level of P V Module

Fig. 9. Output Voltage and Current wave forms of Boost Converter at

different irradiation level.

CONCLUSION:

A circuit based system model of P V modules helps to analyze the performance of commercial P V modules. The commonly used blocks in the form of masked subsystem block develops a general model of P V module. I-V and P-V characteristics outputs are generated for MS X 60 P V module under different irradiation and different temperature levels and the matlab/simulink simulates the module under various conditions as presented in the data sheet. The results obtained from the simulation shows excellent matching with the characteristics graphs provided in the data sheet of the selected models.

Thus,

the model can be used to analyze the performance of any commercial P V module. Matlab/Simulink simulates the DC-DC boost converter and the converter generates  the results with constant DC input supply and by interconnecting the P V module with it. The results shows close match between the output of converter with constant DC input and the P V fed converter. The P V fed DC-DC boost converter generates the output voltage and current for change of irradiation levels at constant temperature is also presented.

REFERENCES:

 [1] J. A. Go w, C.D.Manning, “ Development of photo voltaic array model for the use in power electronic simulation studies,” I E E Proceedings Electric power applications, Vol. 146, No.2, March,1999.

[2] J e e-H o o n Jung, and S. Ahmed, “Model Construction of Single Crystalline Photo voltaic Panels for Real-time Simulation,” IEEE Energy Conversion Congress & Expo, September 12-16, 2010, Atlanta, USA.

[3] T. F. E l shatter, M. T. E l ha g r y, E. M. Ab o u-E l z a  h a b, and A. A. T. Elk o u s y, “Fuzzy modeling of photo voltaic panel equivalent circuit,” in Proc. Conf. Record 28th IEEE Photo voltaic Spec. Conf., pp. 1656– 1659, 2000.

[4] M. Ba l z a n i and A. Re at ti, “Neural network based model of a P V array for the optimum performance of P V system,” in Proc. P h.D. Res. Micro electron. Electron., vol. 2, pp. 123–126, 2005.

Photovoltaic Based Dynamic Voltage Restorer with Energy Conservation Capability using Fuzzy Logic Controller

ABSTRACT:

In this paper, a Photovoltaic based Dynamic Voltage Restorer (PV-DVR) is proposed to deal with profound voltage droops, swells and blackouts on a low voltage single stage private dispersion framework. It can recoup hangs up to 10%, swells up to 190% of its ostensible esteem. Else, it will work as a Uninterruptable Power Supply (UPS) when the utility network neglects to supply. It is likewise intended to diminish the use of utility power, which is produced from atomic and warm power stations. An arrangement infusion transformer is associated in arrangement with the heap while reestablishing voltage droop and swell and it is reconfigured into parallel association utilizing semiconductor switches when it is working in UPS and power saver mode. The utilization of high advance up dc-dc converter with high-voltage gain lessens the size and required power rating of the arrangement infusion transformer. It likewise enhances the dependability of the framework. The Fuzzy Logic (FL)  controller with two data sources keeps up the heap voltage by distinguishing  the voltage varieties through d-q change strategy. Reproduction results have demonstrated the capacity of the proposed DVR  in moderating the voltage list, swell and blackout in a low voltage single stage private appropriation framework.

 

BLOCK DIAGRAM:

 

Fig. 1. Structural block diagram of the proposed system.

 EXPECTED SIMULATION RESULTS:

 

  • (a) Supply Voltage
  • (b) Injected Voltage
  • (c) Load Voltage
  • (d) Load Current

(e) Load voltage THD

Fig. 2. Supply voltage, Injected voltage, Load voltage, Load Current and

Fig. 3. Load Voltage with PI controller

  • (a) PV array output voltage without low power boost converter

(b) PV array output voltage with low power boost converter

Fig. 4. PV array output voltage without and with boost converter

Fig. 5. Output voltage of the high step up DC-DC converter

 CONCLUSION:

This paper proposed another PV based DVR to lessen the vitality utilization from the utility network. The plan of a Dynamic Voltage Restorer (DVR) which consolidates a PV exhibit module with low and high power support converters as a DC voltage source to relieve voltage hangs, swells and blackouts in low voltage single stage conveyance frameworks utilizing FL controller has been introduced. The displaying and reenactment of the proposed PV based DVR utilizing MATLAB simulink has been exhibited. The FL controller uses the blunder motion from the comparator to trigger the switches of an inverter utilizing a sinusoidal PWM conspire. The proposed DVR uses the vitality drawn from the PV cluster and the utility source to charge the battries amid typical task. The put away energies in battery are changed over to a customizable single stage air conditioning voltage for alleviation of voltage list, swell and blackout. The recreation result demonstrates that the PV based DVR with FL controller gives better unique execution in alleviating the voltage varieties. The proposed DVR is worked in:

Reserve Mode: when the PV exhibit voltage is zero and the inverter isn’t dynamic in the circuit to hold the voltage to its ostensible esteem.

Dynamic Mode: when the DVR faculties the list, swell and blackout. DVR responds quick to infuse the required single stage pay voltages.

Sidestep Mode: when DVR is separated and skirted if there should arise an occurrence of support and fix.

Power Saver mode: when the PV cluster with low advance up dc-dc converter yield control is sufficient to deal with the heap.

Further work will incorporate a correlation with research facility investigates a low voltage DVR so as to think about recreation and trial results. The various elements of DVR require further examination.

Power management in PV-battery-hydro based standalone microgrid

ABSTRACT:

This work deals with the frequency regulation, voltage regulation, power management and load levelling of solar photovoltaic (PV)-battery-hydro based microgrid (MG). In this MG, the battery capacity is reduced as compared to a system, where the battery is directly connected to the DC bus of the voltage source converter (VSC). A bidirectional DC–DC converter connects the battery to the DC bus and it controls the charging and discharging current of the battery. It also regulates the DC bus voltage of VSC, frequency and voltage of MG. The proposed system manages the power flow of different sources like hydro and solar PV array. However, the load levelling is managed through the battery. The battery with VSC absorbs the sudden load changes, resulting in rapid regulation of DC link voltage, frequency and voltage of MG. Therefore, the system voltage and frequency regulation allows the active power balance along with the auxiliary services such as reactive power support, source current harmonics mitigation and voltage harmonics reduction at the point of common interconnection. The experimental results under various steady state and dynamic conditions, exhibit the excellent performance of the proposed system and validate the design and control of proposed MG.

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:
Fig. 1 Microgrid Topology and MPPT Control

(a) Proposed PV-battery-hydro MG

 EXPECTED SIMULATION RESULTS

 

 Fig. 2 Dynamic performance of PV-battery-hydro based MG following by solar irradiance change

(a) vsab, isc, iLc and ivscc, (b) Vdc, Ipv, Vb and Ib, (c) vsab, isa, iLa and ivsca, (d) Vdc, Ipv, Vb and Ib

 

Fig. 3 Dynamic performance of hydro-battery-PV based MG under load perturbation

(a) vsab, isc, Ipv and ivscc, (b) Vdc, Ipv, Vb and Ib, (c) vsab, isc, Ipv and ivscc, (d) Vdc, Ipv, and Vb

CONCLUSION:

In the proposed MG, an integration of hydro with the battery, compensates the intermittent nature of PV array. The proposed system uses the hydro, solar PV and battery energy to feed the voltage (Vdc), solar array current (Ipv), battery voltage (Vb) and battery current (Ib). When the load is increased, the load demand exceeds the hydro generated power, since SEIG operates in constant power mode condition. This system has the capability to adjust the dynamical power sharing among the different RES depending on the availability of renewable energy and load  demand. A bidirectional converter controller has been successful to maintain DC-link voltage and the battery charging and discharging currents. Experimental results have validated the design and  control of the proposed system and the feasibility of it for rural area electrification.

REFERENCES:

[1] Ellabban, O., Abu-Rub, H., Blaabjerg, F.: ‘Renewable energy resources: current status, future prospects and technology’, Renew. Sustain. Energy Rev.,2014, 39, pp. 748–764

[2] Bull, S.R.: ‘Renewable energy today and tomorrow’, Proc. IEEE, 2001, 89  (8), pp. 1216–1226

[3] Malik, S.M., Ai, X., Sun, Y., et al.: ‘Voltage and frequency control strategies of hybrid AC/DC microgrid: a review’, IET Renew. Power Gener., 2017, 11, (2), pp. 303–313

[4] Kusakana, K.: ‘Optimal scheduled power flow for distributed photovoltaic/ wind/diesel generators with battery storage system’, IET Renew. Power  Gener., 2015, 9, (8), pp. 916–924

[5] Askarzadeh, A.: ‘Solution for sizing a PV/diesel HPGS for isolated sites’, IET Renew. Power Gener., 2017, 11, (1), pp. 143–151

 

 

 

Single Phase Grid-Connected Photovoltaic Inverter for Residential Application with Maximum Power Point Tracking

ABSTRACT

This article proposes a topology for single-phase two stage grid connected solar photovoltaic (PV) inverter for residential applications. Our proposed grid-connected power converter consists of a switch mode DC-DC boost converter and a H-bridge inverter. The switching strategy of proposed inverter consists with a combination of sinusoidal pulse width modulation (SPWM) and square wave along with grid synchronization condition. The performance of the proposed inverter is simulated under grid connected scenario via PSIM. Furthermore, the intelligent PV module system is implemented using a simple maximum power point tracking (MPPT) method utilizing power balance is also employed in order to increase the systems efficiency.

 

KEYWORDS:

  1. Photovoltaic
  2. DC-DC Boost Converter
  3. MPPT
  4. SPWM
  5. Grid Connected
  6. Power Electronics
  7. Grid Tie Inverter(GTI)

  

CIRCUIT DIAGRAM:

Figure 1. Block diagram of two-stage grid connected PV system

 

EXPECTED SIMULATION RESULTS:

Figure 2. Output voltage of the inverter without filtering

Figure 3. Output current of the inverter

Figure 4. Output voltage after connected to grid

Figure 5. Output real power

Figure 6. Output voltage’s FFT (a) before filtering and (b) after filtering

 

CONCLUSION:

The main purpose of this paper is to establish a model for the grid-connected photovoltaic system with maximum power point tracking function for residential application. A single phase two-stage grid-connected photovoltaic inverter with a combination of SPWM and square-wave switching strategy is designed using PSIM. In the proposed design, an MPPT algorithm using a boost converter is designed to operate using (P&O) method to control the PWM signals of the boost converter, which is adapted to the maximum power tracking in our PV system. Instead of using line frequency transformer at the inverter output terminals, a DC-DC boost converter is used between solar panel and inverter that efficiently amplify the 24V PV arrays output into 312V DC, which is then transformed into line frequency (50Hz) sinusoidal ac 220V rms voltage by the inverter and thereby reducing the system losses and ensures high voltage gain and higher efficiency output. The simulation results show that the proposed grid connected photovoltaic inverter trace the maximum point of solar cell array power and then converts it to a high quality ripple free sinusoidal ac power with a voltage THD below 0.1% which is very much lower than IEEE 519 standard. The simulation also confirms the proposed photovoltaic inverter can be applied as a GTI and able to supplies the AC power to utility grid line with nearly unity power factor.

 

REFERENCES

[1] W. Xiao, F. F. Edwin, G. Spagnuolo, J. Jatsvevich, “Efficient approach for modelling and simulating photovoltaic power system” IEEE Journal of photovoltaics., vol. 3, no. 1, pp. 500-508, Jan. 2013.

[2] E. Roman, R. Alonso, P. Ibanez, S. Elorduizapatarietxe, D. Goitia, “ Intelligent PV module for grid connected PV system,” IEEE Trans. Ind. Elecron., vol. 53, no. 4, pp. 1066-1072, Aug. 2006.

[3] J. A. Santiago-Gonzalez, J. Cruz-Colon, R. otero-De-leon, V. lopez- Santiago, E.I. Ortiz-Rivera, “ Thre phase induction motor drive using flyback converter and PWM inverter fed from a single photovoltaic panel,” Proc. IEEE PES General Meeting, pp. 1-6, 2011.

[4] M. D. Goudar, B. P. Patil, and V. Kumar, “ Review of topology for maximum power point tracking based photovoltaic interface,” International Journal of Research in Engineering Science & Technology, vol.2, Issue 1, pp. 35-36, Feb 2011.

[5] S. Kjaer, J. Pedersen, and F. Blaabjerg, “A review of single-phase gridconnected inverters for photovoltaic modules,” Industry Applications, IEEE Transactions, vol. 41, no. 5, pp. 1292 – 1306, Sept. – Oct. 2005.

 

Integrated Photovoltaic and Dynamic Voltage Restorer System Configuration

 

IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, 2015

ABSTRACT:

This paper presents a new system configuration for integrating a grid-connected photovoltaic (PV) system together with a self-supported dynamic voltage restorer (DVR). The proposed system termed as a “six-port converter,” consists of nine semiconductor switches in total. The proposed configuration retains all the essential features of normal PV and DVR systems while reducing the overall switch count from twelve to nine. In addition, the dual functionality feature significantly enhances the system robustness against severe symmetrical/asymmetrical grid faults and voltage dips. A detailed study on all the possible operational modes of six-port converter is presented. An appropriate control algorithm is developed and the validity of the proposed configuration is verified through extensive simulation studies under different operating conditions.

 

KEYWORDS:

  1. Bidirectional power flow
  2. Distributed power generation
  3. Photovoltaic (PV) systems
  4. Power quality
  5. Voltage control

 

SOFTWARE: MATLAB/SIMULINK

 

BLOCK DIAGRAM:

 

Fig. 1. Proposed integrated PV and DVR system configuration.

 

 EXPECTED SIMULATION RESULTS:

 

Fig. 2. Simulation results: operation of proposed system during health grid mode (PV-VSI: active and DVR-VSI: inactive). (a) Vpcc; (b) PQload; (c) PQgrid; (d) PQpv-VSI; and (e) PQdvr-VSI.

Fig. 3. Simulation results: operation of proposed system during fault mode (PV-VSI: inactive and DVR-VSI: active). (a) Vpcc; (b) Vdvr; (c) Vload; (d) PQload; (e) PQgrid; (f) PQpv-VSI; and (g) PQdvr-VSI.

Fig. 4. Simulation results: operation of proposed system during balance three phase sag mode (PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vdvr-VSI; (c) Vload; (d) PQgrid; (e) PQpv-VSI; and (f) PQdvr-VSI.

Fig. 5. Simulation results: operation of proposed system during unbalanced sag mode (PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vdvr-vsi; (c) Vload; (d) PQgrid; (e) PQpv-VSI; and (f) PQdvr-VSI.

  

Fig. 6. Simulation results: operation of proposed system during inactive PV plant mode (PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vload; (c) Vdc; (d) PQload; (e) PQdvr-VSI; and (f) PQpv-VSI.

 

CONCLUSION:

In this paper, a new system configuration for integrating a conventional grid-connected PV system and self supported DVR is proposed. The proposed configuration not only exhibits all the functionalities of existing PV and DVR system, but also enhances the DVR operating range. It allows DVR to utilize active power of PV plant and thus improves the system robustness against sever grid faults. The proposed configuration can operate in different modes based on the grid condition and PV power generation. The discussed modes are healthy grid mode, fault mode, sag mode, and PV inactive mode. The comprehensive simulation study and experimental validation demonstrate the effectiveness of the proposed configuration and its practical feasibility to perform under different operating conditions. The proposed configuration could be very useful for modern load centers where on-site PV generation and strict voltage regulation are required.

 

REFERENCES:

  • A. Walling, R. Saint, R. C. Dugan, J. Burke, and L. A. Kojovic, “Summary of distributed resources impact on power delivery systems,” IEEE Trans. Power Del., vol. 23, no. 3, pp. 1636–1644, Jul. 2008.
  • Meza, J. J. Negroni, D. Biel, and F. Guinjoan, “Energy-balance modeling and discrete control for single-phase grid-connected PV central inverters,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2734–2743, Jul. 2008.
  • Shimizu, O. Hashimoto, and G. Kimura, “A novel high-performance utility-interactive photovoltaic inverter system,” IEEE Trans. Power Electron., vol. 18, no. 2, pp. 704–711, Mar. 2003.
  • B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “A review of single-phase grid-connected inverters for photovoltaic modules,” IEEE Trans. Ind. Appl., vol. 41, no. 5, pp. 1292–1306, Sep./Oct. 2005.

 MPPT with Single DC–DC Converter and Inverter for Grid-Connected Hybrid Wind-Driven PMSG–PV System

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, 2015

ABSTRACT: A new topology of a hybrid distributed generator based on photovoltaic and wind-driven permanent magnet synchronous generator is proposed. In this generator, the sources are connected together to the grid with the help of only a single boost converter followed by an inverter. Thus, compared to earlier schemes, the proposed scheme has fewer power converters. A model of the proposed scheme in the d − q-axis reference frame is developed. Two low-cost controllers are also proposed for the new hybrid scheme to separately trigger the dc–dc converter and the inverter for tracking the maximum power from both sources. The integrated operations of both proposed controllers for different conditions are demonstrated through simulation and experimentation. The steady-state performance of the system and the transient response of the controllers are also presented to demonstrate the successful operation of the new hybrid system. Comparisons of experimental and simulation results are given to validate the simulation model.

KEYWORDS:

  1. Grid-connected hybrid system
  2. Hybrid distributed generators (DGs)
  3. Smart grid
  4. Wind-driven PMSG–PV

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig. 1. Proposed DG system based on PMSG–PV sources.

EXPECTED SIMULATION RESULTS:

(a)

(b)

Fig. 2. DC link steady-state waveforms. (a) Experimental (voltage—50 V/div, current—10 A/div, and time—500 ms/div). (b) Simulated (voltage—20 V/div, current—5 A/div, and time—500 ms/div.

(a)

(b)

Fig. 3. Steady-state grid voltage and current waveforms. (a) Experimental (voltage—50 V/div, current—10 A/div, and time—20 ms/div). (b) Simulated (voltage—50 V/div, current—5 A/div, and time— 20 ms/div).

Experimental (Voltage 50V/div, Duty-cycle 0.6/div, Time 2s/div)

Simulated (Voltage 20V/div, Duty-cycle 0.5/div, Time 2s/div)

(a) Changes in rectifier output voltage and duty cycle of the boost converter.

Experimental (Voltage 50V/div, Current 10 A/div, Time 2s/div)

Simulated (Voltage 50V/div, Current 10/div)

(b) Changes in dc-link voltage and current

Experimental (Voltage 50V/div, Current 10A/div, Time 2s/div)

Simulated (Voltage 50V/div, Current 10A/div, Time 2s/div)

Fig.4. Transient response for a step change in PMSG shaft speed.. (c) Changes in grid current.

 CONCLUSION:

A new reliable hybrid DG system based on PV and wind driven PMSG as sources, with only a boost converter followed by an inverter stage, has been successfully implemented. The mathematical model developed for the proposed DG scheme has been used to study the system performance in MATLAB. The investigations carried out in a laboratory prototype for different irradiations and PMSG shaft speeds amply confirm the utility of the proposed hybrid generator in zero-net-energy buildings. In addition, it has been established through experimentation and simulation that the two controllers, digital MPPT controller and hysteresis current controller, which are designed specifically for the proposed system, have exactly tracked the maximum powers from both sources. Maintenance-free operation, reliability, and low cost are the features required for the DG employed in secondary distribution systems. It is for this reason that the developed controllers employ very low cost microcontrollers and analog circuitry. Furthermore, the results of the experimental investigations are found to be matching closely with the simulation results, thereby validating the developed model. The steady state waveforms captured at the grid side show that the power generated by the DG system is fed to the grid at unity power factor. The voltage THD and the current THD of the generator meet the required power quality norms recommended by IEEE. The proposed scheme easily finds application for erection at domestic consumer sites in a smart grid scenario.

REFERENCES:

[1] J. Byun, S. Park, B. Kang, I. Hong, and S. Park, “Design and implementation of an intelligent energy saving system based on standby power reduction for a future zero-energy home environment,” IEEE Trans. Consum. Electron., vol. 59, no. 3, pp. 507–514, Oct. 2013.

[2] J. He, Y. W. Li, and F. Blaabjerg, “Flexible microgrid power quality enhancement using adaptive hybrid voltage and current controller,” IEEE Trans. Ind. Electron., vol. 61, no. 6, pp. 2784–2794, Jun. 2014.

[3] W. Li, X. Ruan, C. Bao, D. Pan, and X. Wang, “Grid synchronization systems of three-phase grid-connected power converters: A complexvector- filter perspective,” IEEE Trans. Ind. Electron., vol. 61, no. 4, pp. 1855–1870, Apr. 2014.

[4] C. Liu, K. T. Chau, and X. Zhang, “An efficient wind-photovoltaic hybrid generation system using doubly excited permanent-magnet brushless machine,” IEEE Trans. Ind. Electron, vol. 57, no. 3, pp. 831–839, Mar. 2010.

[5] S. A. Daniel and N. A. Gounden, “A novel hybrid isolated generating system based on PV fed inverter-assisted wind-driven induction generators,” IEEE Trans. Energy Convers., vol. 19, no. 2, pp. 416–422, Jun. 2004.

Development and Comparison of an Improved Incremental Conductance Algorithm for Tracking the MPP of a Solar PV Panel

IEEE Transactions on Sustainable Energy, 2015

ABSTRACT: This paper proposes an adaptive and optimal control strategy for a solar photovoltaic (PV) system. The control strategy ensures that the solar PV panel is always perpendicular to sunlight and simultaneously operated at its maximum power point (MPP) for continuously harvesting maximum power. The proposed control strategy is the control combination between the solar tracker (ST) and MPP tracker that can greatly improve the generated electricity from solar PV systems. Regarding the ST system, the paper presents two drive approaches including open- and closed-loop drives. Additionally, the paper also proposes an improved incremental conductance algorithm for enhancing the speed of the MPP tracking of a solar PV panel under various atmospheric conditions as well as guaranteeing that the operating point always moves toward the MPP using this proposed algorithm. The simulation and experimental results obtained validate the effectiveness of the proposal under various atmospheric conditions.

KEYWORDS:

  1. Maximum power point tracker (MPPT)
  2. Solar tracker (ST)
  3. Solar PV panel

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Block diagram of the experimental setup.

EXPECTED SIMULATION RESULTS:

Fig. 2. Description of the variations of the solar irradiation and temperature.

Fig. 3. Obtained maximum output power with the P&O and improved InC algorithms under the variation of the solar irradiation.

Fig. 4. Obtained maximum output power with the InC and improved InC algorithms under the variation of the solar irradiation.

Fig. 5. Obtained maximum output power with the P&O and improved InC algorithms under both the variations of the solar irradiation and temperature.

Fig. 6. Obtained maximum output power with the InC and improved InC algorithms under both the variations of the solar irradiation and temperature.

Fig. 7. MPPs of the solar PV panel under the variation of the solar irradiation

Fig. 8. MPPs of the solar PV panel under both the variations of the solar irradiation and temperature.

Fig. 9. Experimental result of obtained maximum output power with the improved InC algorithm under the variation of the solar irradiation.

CONCLUSION:

It is obvious that the adaptive and optimal control strategy plays an important role in the development of solar PV systems. This strategy is based on the combination between the ST and MPPT in order to ensure that the solar PV panel is capable of harnessing the maximum solar energy following the sun’s trajectory from dawn until dusk and is always operated at the MPPs with the improved InC algorithm. The proposed InC algorithm improves the conventional InC algorithm with an approximation which reduces the computational burden as well as the application of the CV algorithm to limit the search space and increase the convergence speed of the InC algorithm. This improvement overcomes the existing drawbacks of the InC algorithm. The simulation and experimental results confirm the validity of the proposed adaptive and optimal control strategy in the solar PV panel through the comparisons with other strategies.

REFERENCES:

[1] R. Faranda and S. Leva, “Energy comparison of MPPT techniques for PV systems,” WSES Trans. Power Syst., vol. 3, no. 6, pp. 446–455, 2008.

[2] X. Jun-Ming, J. Ling-Yun, Z. Hai-Ming, and Z. Rui, “Design of track control system in PV,” in Proc. IEEE Int. Conf. Softw. Eng. Service Sci., 2010, pp. 547–550.

[3] Z. Bao-Jian, G. Guo-Hong, and Z. Yan-Li, “Designment of automatic tracking system of solar energy system,” in Proc. 2nd Int. Conf. Ind. Mechatronics Autom., 2010, pp. 689–691.

[4] W. Luo, “A solar panels automatic tracking system based on OMRON PLC,” in Proc. 7th Asian Control Conf., 2009, pp. 1611–1614.

[5] W. Chun-Sheng,W. Yi-Bo, L. Si-Yang, P. Yan-Chang, and X. Hong-Hua, “Study on automatic sun-tracking technology in PV generation,” in Proc. 3rd Int. Conf. Elect. Utility Deregulation Restruct. Power Technol., 2008, pp. 2586–2591.

High-Frequency AC-Link PV Inverter

ABSTRACT:

In this paper, a high-frequency ac-link photovoltaic (PV) inverter is proposed. The proposed inverter overcomes most of the problems associated with currently available PV inverters. In this inverter, a single-stage power-conversion unit fulfills all the system requirements, i.e., inverting dc voltage to proper ac, stepping up or down the input voltage, maximum power point tracking, generating low-harmonic ac at the output, and input/output isolation. This inverter is, in fact, a partial resonant ac-link converter in which the link is formed by a parallel inductor/capacitor (LC) pair having alternating current and voltage. Among the significant merits of the proposed inverter are the zero-voltage turn-on and soft turn-off of the switches which result in negligible switching losses and minimum voltage stress on the switches. Hence, the frequency of the link can be as high as permitted by the switches and the processor. The high frequency of operation makes the proposed inverter very compact. The other significant advantage of the proposed inverter is that no bulky electrolytic capacitor exists at the link. Electrolytic capacitors are cited as the most unreliable component in PV inverters, and they are responsible for most of the inverters’ failures, particularly at high temperature. Therefore, substituting dc electrolytic capacitors with ac LC pairs will significantly increase the reliability of PV inverters. A 30-kW prototype was fabricated and tested. The principle of operation and detailed design procedure of the proposed inverter along with the simulation and experimental results are included in this paper. To evaluate the long-term performance of the proposed inverter, three of these inverters were installed at three different commercial facilities in Texas, USA, to support the PV systems. These inverters have been working for several months now.

KEYWORDS:

  1. Inverters
  2. Photovoltaic (PV) systems
  3. Zero voltage switching

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Proposed PV inverter.

EXPECTED SIMULATION RESULTS:

Fig. 2. PV current and voltage at full power.

 

Fig. 3. AC-side current and voltage at full power.

Fig. 4. Link voltage at full power.

Fig. 5. Link current at full power.

         Fig. 6. Link current and voltage at full power, using 0.1-μF link capacitance.

Fig. 7. Link current and voltage at 15 kW.

Fig. 8. AC-side current and voltage when the irradiance drops from 850 to

650 w/m2.

Fig. 9. AC-side current and voltage when the temperature changes from

25 C to 50 C.

Fig. 10. AC-side current and voltage when the AC-side voltage drops to 10% of its nominal value (at t = 0.016 s).

Fig. 11. PV current and voltage when the AC-side voltage drops to 10% of its nominal value (at t = 0.016 s).

 CONCLUSION:

In this paper, a reliable and compact PV inverter has been proposed. This inverter is a partial resonant ac-link converter in which the link is formed by an LC pair having alternating current and voltage. The proposed converter guarantees the isolation of the input and output. However, if galvanic isolation is required, the link inductance can be replaced by a singlephase high-frequency transformer. The elimination of the dc link and low-frequency transformer makes the proposed inverter more compact and reliable compared with other types of PV inverters. In this paper, the principle of operation of the proposed converter along with the detailed design procedure has been presented. The performance of the proposed converter has been evaluated through both simulation and experimental results.

 REFERENCES:

[1] S. Chakraborty, B. Kramer, and B. Kroposki, “A review of power electronics interfaces for distributed energy systems towards achieving low-cost modular design,” Renew. Sustain. Energy Rev., vol. 13, no. 9, pp. 2323–2335, Dec. 2009.

[2] Y. Huang, F. Z. Peng, J. Wang, and D. W. Yoo, “Survey of the power conditioning system for PV power generation,” in Proc. IEEE PESC, Jun. 18–22, 2006, pp. 1–6.

[3] S. Atcitty, J. E. Granata, M. A. Quinta, and C. A. Tasca, Utility-scale gridtied PV inverter reliability workshop summary report, Sandia National Labs., Albuquerque, NM, USA, SANDIA Rep. SAND2011-4778. [Online].

Available: http://energy.sandia.gov/wp/wp-content/gallery/uploads/  Inverter_Workshop_FINAL_072811.pdf

[4] Y. C. Qin, N. Mohan, R. West, and R. Bonn, Status and needs of power electronics for photovoltaic inverters, Sandia National Labs., Albuquerque, NM, USA, SANDIA Rep. SAND2002-1535. [Online]. Available: www.prod.sandia.gov/techlib/access-control.cgi/2002/021535. pdf

[5] T. Kerekes, R. Teodorescu, P. Rodríguez, G. Vázquez, and E. Aldabas, “A new high-efficiency single-phase transformerless PV inverter topology,” IEEE Trans. Ind. Electron., vol. 58, no. 1, pp. 184–191, Jan. 2011.

Control Strategy for Power Flow Management in a PV System Supplying DC Loads

ABSTRACT:

The growing concern for energy saving has increased the usage of LED-based street lights, electronic chokes, compact fluorescent lamps, and inverter-fed drives. Hence, the load profile seen by the electrical grid is undergoing a notable change as these devices have to operate from a dc source. Photovoltaics (PV) being a major energy source, the aforementioned loads can be connected directly to the dc bus. A grid-connected PV system involves a power source (PV array), a power sink (load), and two power sources/sink (utility and battery), and hence, a power

flow management system is required to balance the power flow among these sources. One such system is developed for selecting the operating mode of the bidirectional converter by sensing the battery voltage. The viability of the scheme has been ascertained by performing experimental studies on a laboratory prototype. The control strategy is digitally implemented on an Altera Cyclone II Field Programmable Gate Array (FPGA) board, and the algorithm is verified for different modes of operation by varying the load. Experimental results are presented to bring out the usefulness of the control strategy.

KEYWORDS:

  1. Bidirectional converter
  2. Dc bus
  3. Photovoltaic
  4. Power flow management system (PMS)

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1.Grid-connected PV system with ac and dc loads.

EXPECTED SIMULATION RESULTS:

 

Fig. 2. Steady-state response. (a) Rectifier mode. (b) Inverter mode.

Fig. 3. Dynamic response for step change in load: (a) AC line current control (iL—0.5 A/div; Vdc—55 V/div; Ppv—100 W/div; io—0.5 A/div). (b) AC line current control (iL—1 A/div; Vdc—55 V/div; Ppv—100 W/div; io—0.5 A/div). (c) Proposed control (iL—1 A/div; Vdc—55 V/div; Ppv—100 W/div; ib—1 A/div; io—1 A/div; Vb—5 V/div). Dynamic response for step change in insolation: (d) AC line current control (iL—0.5 A/div; Vdc—40 V/div; Ppv—100 W/div; io—1 A/div). (e) AC line current control (iL—0.5 A/div; Vdc—40 V/div; Ppv—100 W/div; io—1 A/div). (f) Proposed control (iL—0.5 A/div; Vdc—55 V/div; Ppv—200 W/div; ib—1 A/div; io—1 A/div; Vb—5 V/div). Time: 0.025 s/div.

Fig. 4. Grid failure under (a) inverting mode and (b) rectifier mode. y-axis: Iinv: 4 A/div; Vb: 80 V/div; Ib: 4 A/div; IL: 4 A/div. x-axis: time: 50 s/div.

Fig. 5. Battery voltage, battery current, and dc current waveforms for different cases under automatic power flow control. (a) Case I. (b) Case II. (c) Case III. (d) Case IV. y-axis: Vb: 10 V/div; Ibat: 2 A/div; Iinv: 4 A/div. x-axis: time: 20 s/div.

 CONCLUSION:

A versatile control strategy for power flow management in a grid-connected PV system feeding dc loads has been presented. The importance of the scheme has been brought out by performing experimental studies on a laboratory prototype. The steady-state performance of the converter for different modes of operation has been observed, and near unity power factor has been achieved in both the rectifier and inverter modes. The transient performance of the system for step changes in load and insolation have been also illustrated. The control strategy has been digitally implemented on an Altera Cyclone II FPGA board, and the algorithm has been verified for different modes of operation by varying the load, and a good correlation between the results of computer simulation and experiments has established the validity of the PMS. The significance of the proposed scheme has been demonstrated by its effectiveness in preventing undesirable shuttling of the PV operating point and also in maintaining the THD of the injected grid current within the allowable limit of 5% by setting a minimum current reference for injection. The proposed configuration has been proved to be attractive from the perspective of providing uninterruptible power to dc loads while ensuring the evacuation of excess PV power of high quality into the grid.

REFERENCES:

[1] Yazdani and P. P. Dash, “A control methodology and characterization of dynamics for a photovoltaic system interfaced with a distribution network,” IEEE Trans. Power Del., vol. 24, no. 3, pp. 1538–1551, Jul. 2009.

[2] X. Q. Guo and W. Y. Wu, “Improved current regulation of three-phase grid-connected voltage-source inverters for distributed generation systems,” IET Renew. Power Gener., vol. 4, no. 2, pp. 101–115, Mar. 2010.

[3] H. C. Chiang, T. T. Ma, Y. H. Cheng, J. M. Chang, and W. N. Chang, “Design and implementation of a hybrid regenerative power system combining grid-tie and uninterruptible power supply functions,” IET Renew. Power Gener., vol. 4, no. 1, pp. 85–99, Jan. 2010.

[4] F. Giraud and Z. M. Salameh, “Steady-state performance of a grid connected rooftop hybrid wind–photovoltaic power system with battery storage,” IEEE Trans. Energy. Convers., vol. 16, no. 1, pp. 1–7, Mar. 2001.

[5] J. M. Carrasco, L. G. Franquelo, J. T. Bialasiewicz, E. Galvàn, R. C. P. Guisado, M. A. M. Prats, J. I. León, and N. Moreno-Alfonso, “Power electronic systems for the grid integration of renewable energy sources: A survey,” IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1002– 1016, Aug. 2006.