Solar PV Theory.pdf

By placing pv panels outdoors it is possible to use

Info icon This preview shows pages 10–13. Sign up to view the full content.

illuminated by a source of light. By placing PV panels outdoors, it is possible to use the sunlight (a source of renewable energy) to directly produce electrical energy. Photovoltaic panels installed outdoors that produce electrical power from sunlight are commonly referred to as solar panels. See Figure 17 . Figure 17 . Photovoltaic panels in sunlight. 3. The Solar Panel (Photovoltaic Panel) D ISCUSSION O UTLINE D ISCUSSION
Image of page 10

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

The Solar Panel (Photovoltaic Panel) Discussion 1 1 Solar Power The basic component of a PV panel is the photovoltaic (PV) cell. Each PV panel consists of a large number of PV cells which are interconnected in such a way as to obtain specific voltage and current values. A PV cell is basically a P-N junction that is usually made of silicon, just like the P-N junction in a silicon diode. However, the P-N junction in a PV cell is made of a thin slice of silicon to maximize its surface area, thereby allowing the PV cell to intercept as much light as possible. See Figure 18 . Figure 1 8 . Photovoltaic cell construction and simplified equivalent diagram. When light illuminates the N-type semiconductor surface of the P-N junction, the PV cell starts generating energy and becomes a source of current. When no electrical load is connected to the electrodes of the PV cell, the current produced is simply recirculated within the PV cell, i.e., through the P-N junction which is in fact a silicon diode. Therefore, the open-circuit voltage E OC of a PV cell (and more generally the output voltage of a PV cell) cannot exceed the value of the forward-bias voltage of a silicon diode, i.e., 0.7 V. The actual open-circuit voltage E OC of most PV cells is between 0.5 V and 0.6 V. The larger the dimensions of the P-N junction, the larger the amount of light intercepted by the PV cell and the higher the current produced. The electrical symbol of a PV cell is shown in Figure 19 . The symbol on the left-hand side of this figure is the standard symbol while the symbol on the right- hand side is an alternative symbol that is often used. Figure 19: Electrical symbols of a photovoltaic cell. Because the output voltage of a single PV cell is low (less than 0.7 V), it is common practice to connect several PV cells of the same size in series to obtain higher voltages. Figure 2 0 shows a typical arrangement used to connect PV cells in series. An arrangement of several PV cells interconnected together with its positive and negative electrodes is commonly referred to as a photovoltaic (PV) module. I I 0.7 V Negative electrode Positive electrode Light (photons) N-type semiconductor (silicon) P-type semiconductor (silicon) Standard symbol Alternative symbol
Image of page 11
– The Solar Panel (Photovoltaic Panel) Discussion Solar Power 1 2 Figure 2 0 . Typical arrangement used to connect photovoltaic cells in series.
Image of page 12

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 13
This is the end of the preview. Sign up to access the rest of the document.
  • One '14
  • Photovoltaics, Solar cell, PV cell, Photovoltaic module, pv module

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern