Grid-Connected PV-Wind-Battery-Based multi input transformer coupled bidirectional dc-dc converter for household applications

 

ABSTRACT:

 In this paper, a control strategy for power flow management of a grid-connected hybrid photovoltaic (PV)–wind battery- based system with an efficient multi-input transformer coupled bidirectional dc–dc converter is presented. The proposed system aims to satisfy the load demand, manage the power flow from different sources, inject the surplus power into the grid, and charge the battery from the grid as and when required. A transformer-coupled boost half-bridge converter is used to harness power from wind, while a bidirectional buck– boost converter is used to harness power from PV along with battery charging/discharging control. A single-phase full-bridge bidirectional converter is used for feeding ac loads and interaction with the grid. The proposed converter architecture has reduced number of power conversion stages with less component count and reduced losses compared with existing grid-connected hybrid systems. This improves the efficiency and the reliability of the system. Simulation results obtained using MATLAB/Simulink show the performance of the proposed control strategy for power flow management under various modes of operation. The effectiveness of the topology and the efficacy of the proposed control strategy are validated through detailed experimental studies to demonstrate the capability of the system operation in different modes.

 KEYWORDS:

  1. Battery charge control
  2. Bidirectional buck–boost converter
  3. Full-bridge bidirectional converter
  4. Hybrid system
  5. Maximum power-point tracking
  6. Solar photovoltaic (PV)
  7. Transformer-coupled boost dual-half-bridge bidirectional converter
  8. Wind energy

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

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Fig. 1. Grid-connected hybrid PV–wind-battery-based system for household applications.

 CIRCUIT DIAGRAM

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Fig 2. Proposed converter configuration.

 EXPECTED SIMULATION RESULTS:

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Fig. 3. Steady-state operation in the MPPT mode.

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Fig. 4. Response of the system for changes in an insolation level of source-1 (PV source) during operation in the MPPT mode.

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Fig. 5. Response of the system for changes in wind speed level of source-2 (wind source) during operation in the MPPT mode.

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Fig. 6. Response of the system in the absence of source-1 (PV source), while source-2 continues to operate at MPPT.

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Fig. 7. Response of the system in the absence of source-2 (wind source), while source-1 continues to operate at MPPT.

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Fig. 8. Response of the system in the absence of both the sources and charging the battery from the grid.

CONCLUSION:

A grid-connected hybrid PV–wind-battery-based power evacuation scheme for household application is proposed. The proposed hybrid system provides an elegant integration of PV and wind source to extract maximum energy from the two sources. It is realized by a novel multi-input transformer coupled bidirectional dc–dc converter followed by a conventional full-bridge inverter. A versatile control strategy which achieves a better utilization of PV, wind power, battery capacities without effecting life of battery, and power flow management in a grid-connected hybrid PV–wind-battery-based system feeding ac loads is presented. Detailed simulation studies are carried out to ascertain the viability of the scheme. The experimental results obtained are in close agreement with simulations and are supportive in demonstrating the capability of the system to operate either in grid feeding or in stand-alone modes. The proposed configuration is capable of supplying uninterruptible power to ac loads, and ensures the evacuation of surplus PV and wind power into the grid.

 REFERENCES:

[1] F. Valenciaga and P. F. Puleston, “Supervisor control for a stand-alone hybrid generation system using wind and photovoltaic energy,” IEEE Trans. Energy Convers., vol. 20, no. 2, pp. 398–405, Jun. 2005.

[2] 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.

[3] W. Qi, J. Liu, X. Chen, and P. D. Christofides, “Supervisory predictive control of standalone wind/solar energy generation systems,” IEEE Trans. Control Syst. Technol., vol. 19, no. 1, pp. 199–207, Jan. 2011.

[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] S.-K. Kim, J.-H. Jeon, C.-H. Cho, J.-B. Ahn, and S.-H. Kwon, “Dynamic modeling and control of a grid-connected hybrid generation system with versatile power transfer,” IEEE Trans. Ind. Electron., vol. 55, no. 4, pp. 1677–1688, Apr. 2008.

 

 

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