What is solar photovoltaic power

The basic principle of solar photovoltaic power generation is to use the photovoltaic effect of solar cells to directly convert the sun's radiant energy into electrical energy. The energy converter of solar photovoltaic power generation is the solar cell, also known as a photovoltaic cell. A photovoltaic cell is actually a large area silicon semiconductor device. The positive charge represents the silicon atom and the negative charge represents the four electrons surrounding the silicon atom. When impurities (elements) of boron or phosphorus are doped into the semiconductor silicon crystal, because there are only three electrons around the boron atom and five electrons around the phosphorus atom, a crystal structure with holes and a crystal structure with excess electrons as shown in Figure 1-2 is created, forming a P-type or N-type semiconductor.

Since P-type semiconductors contain more holes and N-type semiconductors contain more electrons, when P-type and N-type semiconductors, a special thin layer will be formed in the intersection region of the two semiconductors, and the P-type side of the thin layer is negatively charged, and when combined together, the type side is positively charged, forming a PN junction.

When the sunlight shines on the PV cell, some of the light is reflected, some is absorbed, and some passes through the cell. The absorbed light energy excites the electrons in the bound high-energy state, producing electron-hole pairs. Under the action of the built-in electric field of the PN junction, electrons and holes move with each other, with holes in the N zone moving toward the P zone and electrons in the P zone moving toward the N zone, so that a large amount of negative charge (electrons) accumulates on the light-receiving side of the solar cell, while a large amount of positive charge (holes) accumulates on the back side of the solar cell. If a load is connected to both ends of the cell, there will be current passing through the load, and when the light keeps shining, there will be a constant current flowing through the load. A single solar cell is a thin semiconductor PN junction with a rated output voltage of 0.5~0.55 V under standard lighting conditions. In order to obtain higher output voltage and larger power capacity, in practical applications, multiple solar cells are often connected together to form a cell assembly, or more cells are used to form a PV array, as shown in Figure 1-5. The output power of solar cells is random, and the output power of the same solar cell is different at different times, different locations, different light intensities, and different installation methods.