1. Photovoltaic Cell Fundamentals Fig 9.2 Photovoltaic cell schematic. Photovoltaic Cell Fundamentals

2. Fig 9.3 Solar irradiation and the band gap of silicon.

3. Photovoltaic Cell Fundamentals

4. Fig 9.5 Current density at a p-n junction.

5. Photovoltaic Cell Fundamentals At the p-n junction, junction current, J j is generated.

6. Photovoltaic Cell Fundamentals Fig 9.6 photovoltaic cell equivalent circuit.

7. Photovoltaic Cell Fundamentals If the cell is short-circuited, R L =0, so that J s =J L and V=0. If the circuit is open, then J L =0, output of the cell is directed through the junction with the open circuit voltage, V OC. Dividing Eq (1) by J s

8. Photovoltaic Cell Fundamentals V OC =0.6V and T=300K Fig 9.7 Current density ratio and power ratio versus voltage.

9. Photovoltaic Cell Fundamentals Fig 9.8 Effect of solar irradiation on solar cell performance. Solar irradiation increases ↑, V OC slightly increases, Current ↑. Hence, the maximum power is almost directly proportional to the solar irradiation incident on the cell.

10. Photovoltaic Cell Fundamentals Photovoltaic Components Fig 9.9 Cell modules, and arrays (NASA).

11. Photovoltaic Cell Fundamentals Fig 9.10 Typical photovoltaic cell specifications (Photowatt 125).

12. Photovoltaic Cell Fundamentals Fig 9.11 Behavior of cells in series and in parallel. (a) Two identical cells in series. (b) Two identical cells in parallel. Blocking diode : to prevent reverse current flow and other inefficiencies caused by failure of an individual cell or shading of part of a module in-series elements in arrays.

13. Photovoltaic Cell Fundamentals Fig 9.13 Specifications for the BP 3160 photovoltaic module (BP solar).

14. Photovoltaic Cell Fundamentals Photovoltaic Systems  Stand-alone vs. grid-connected.  Hierarchy of increasing complexity. 1.Direct-coupled. 2.Systems with battery storage. 3.Systems with backup power. 4.Hybrid power system. 5.System connected to the electric grid. 6.System for utility power production. Fig 9.17 Direct-coupled photovoltaic system schematic.

15. Photovoltaic Cell Fundamentals Fig 9.18 Stand-alone photovoltaic system with battery storage.

16. Photovoltaic Cell Fundamentals Fig 9.19 Photovoltaic hybrid system.

17. Photovoltaic Cell Fundamentals Fig 9.20 Schematic of a grid-connected photovoltaic system.