What is the principle of photovoltaic power generation?
Photovoltaic power generation is a technology that converts light energy directly into electrical energy by using the photo-generated volt-effect at the semiconductor interface. The basic principle is the "photovoltaic effect", that is, the phenomenon of the potential difference between the uneven semiconductor or the different parts of the semiconductor and the metal.
The following is a detailed explanation of the principle of photovoltaic power generation, including 5 aspects:
(1) Interaction between photons and electrons:
When sunlight or another light source hits the surface of a semiconductor material, such as silicon, photons interact with electrons in the semiconductor. If the energy of the photon is large enough, it can excite electrons out of the semiconductor material to form photoelectrons.
(2) Photovoltaic effect:
The excited photoelectrons form an electric current inside the semiconductor. In the photovoltaic effect, the non-uniform semiconductor or the part of the semiconductor and the metal will produce a potential difference, and this potential difference is the photovoltaic voltage. When the photovoltaic cell is connected to a circuit, this voltage can drive the current flow, which generates electricity.
(3) Solar cell structure:
Solar cells are typically composed of two different types of semiconductor materials, such as P-type silicon and N-type silicon. When the two materials come into contact, a PN junction is formed. In a PN junction, the holes in the P-type material and the electrons in the N-type material diffuse with each other, creating an internal electric field. When sunlight strikes a solar cell, photons excite electron-hole pairs, which are separated by an internal electric field to create a photogenerated current.
(4) The working process of photovoltaic cells:
The working process of photovoltaic cells can be divided into three steps: first, the photon is absorbed and excites the electron-hole pair; Secondly, the electron-hole pair is separated by the built-in electric field to form a photogenerated current. Finally, the photogenerated current flows through the external circuit to drive the load.
(5) Composition of photovoltaic power generation system:
Photovoltaic power generation system is mainly composed of solar panels (modules), controllers and inverters. The solar panel converts light energy into direct current energy, the controller is responsible for protecting and managing the working state of the panel, and the inverter converts direct current energy into AC power to be connected to the grid.
In short, the principle of photovoltaic power generation is the process of converting light energy into electricity based on the photovoltaic effect. The light energy is converted into direct current energy through the solar panel, and then processed by the controller and inverter, and finally the electric energy is transmitted to the user. This process does not require mechanical movement or other forms of intermediate energy conversion, so it has the advantages of high efficiency, environmental protection and reliability.
