Principle and Composition of Photovoltaic Power Generation
Feb 09, 2023
Photovoltaic power generation is based on the principle of photovoltaic effect, using solar panel to directly convert sunlight energy into electrical energy. Regardless of whether it is used independently or connected to the grid, the photovoltaic power generation system is mainly composed of three parts: solar panels (components), controllers and inverters. They are mainly composed of electronic components, but do not involve mechanical parts.
1. Working principle of solar photovoltaic power generation
Solar photovoltaic power generation relies on solar cell components and utilizes the electronic properties of semiconductor materials. When sunlight shines on the semiconductor PN junction, due to the strong built-in electrostatic field generated in the PN junction barrier region, it is generated on the potential barrier. The unbalanced electrons and holes in the region or the unbalanced electrons and holes generated outside the barrier region but diffused into the barrier region, under the action of the built-in electrostatic field, move in opposite directions and leave the barrier region. As a result, the potential of the P region increases, and the potential of the N region decreases, thereby generating voltage and current in the external circuit to convert light energy into electrical energy.
2. Composition of solar photovoltaic power generation system
1. Solar cell components
A solar cell can only produce a voltage of about 0.5V, which is far below the voltage required for actual use. In order to meet the needs of practical applications, solar cells need to be connected into modules. A solar module contains a certain number of solar cells connected by wires. For example, on a module, the number of solar cells is 36, which means that a solar module can generate a voltage of about 17V.
The sealed physical unit of solar cells connected by wires is called a solar cell module, which has certain anti-corrosion, windproof, hailproof, and rainproof capabilities, and is widely used in various fields and systems. When the application field requires higher voltage and current and a single component cannot meet the requirements, multiple components can be formed into a solar cell array to obtain the required voltage and current.
2. DC/AC Inverter
A device that converts direct current into alternating current. Since the solar cells emit direct current and the general load is alternating current, the inverter is indispensable. According to the operation mode, inverters can be divided into independent operation inverters and grid-connected inverters. Stand-alone inverters are used in stand-alone solar cell power generation systems to supply power to independent loads. Grid-connected inverters are used for grid-connected solar battery power generation systems to feed the generated electrical energy into the grid. Inverters can be divided into square wave inverters and sine wave inverters according to the output waveform.
3. Power distribution room design
Since the grid-connected power generation system does not have batteries, solar charge and discharge controllers and AC/DC power distribution systems, if conditions permit, the inverters of the grid-connected power generation system can be placed in the low-voltage power distribution room of the grid-connected point; A low-voltage power distribution room of 4-6m2 is enough.
IPv6 network supported 