Nowadays, almost everyone can collect and get at their disposal their own independent source of electricity on solar panels (in the scientific literature they are called photovoltaic panels).
Over time, expensive equipment is compensated by the ability to receive free electricity. It is important that solar panels are an environmentally friendly source of energy. In recent years, prices for photovoltaic panels have fallen tenfold and they continue to decline, which indicates great prospects for their use.
In the classical form, such a source of electricity will consist of the following parts: directly, a solar battery (direct current generator), a battery with a charge control device and an inverter that converts direct current into alternating current.
Solar cells are made up of a collection of solar cells (photovoltaic converters) that directly convert solar energy into electrical energy.
Most solar cells are made from silicon, which is quite expensive. This fact will determine the high cost of electrical energy that is obtained using solar panels.
Photovoltaic Converter There are two types of photovoltaic converters: made of monocrystalline and polycrystalline silicon. They differ in production technology. The former have an efficiency of up to 17.5%, and the latter – 15%.
The most important technical parameter of the solar battery, which has a major impact on the efficiency of the entire installation, is its useful power. It is determined by voltage and output current. These parameters depend on the intensity of sunlight falling on the battery.
E.m.s. (electromotive force) of individual solar cells does not depend on their area and decreases when the battery is heated by the sun, by about 0.4% per 1 gram. C. The output current depends on the intensity of solar radiation and the size of the solar cells. The brighter the sunlight, the more current generated by the solar cells. The charging current and the power output are sharply reduced in cloudy weather. It does this by reducing the current delivered by the battery.
If the battery illuminated by the sun is closed to any load with resistance Rн, then an electric current I appears in the circuit, the value of which is determined by the quality of the photoelectric converter, the intensity of illumination and the load resistance. The power Pн, which is allocated in the load, is determined by the product Pн = IнUн, where Uн is the voltage at the battery terminals.
homemade solar battery The greatest power is released in the load at some optimal resistance Ropt, which corresponds to the highest efficiency (efficiency) of conversion of light energy into electrical energy. Each transducer has its own Ropt value, which depends on the quality, size of the working surface and the degree of illumination.
A solar cell consists of individual solar cells that are connected in series and in parallel in order to increase the output parameters (current, voltage and power). When the elements are connected in series, the output voltage increases, with parallel – the output current. In order to increase both current and voltage, these two connection methods are combined. In addition, with such a connection method, the failure of one of the solar cells does not lead to failure of the entire chain, i.e. increases the reliability of the entire battery.
Thus, a solar cell consists of solar cells connected in parallel in series. The value of the maximum possible current given by the battery is directly proportional to the number of parallel connected, and the emf. – solar cells connected in series. Thus, by combining the types of connection, the battery is assembled with the required parameters.
solar cells The solar cells of the battery are shunted by diodes. Usually there are 4 of them – one for each ¼ part of the battery. Diodes protect the parts of the battery from failure, which for some reason turned out to be darkened, that is, if at some point in time the light does not fall on them. The battery temporarily generates 25% less power output than under normal sun exposure of the entire battery surface.
In the absence of diodes, these solar cells will overheat and fail, since they turn into current consumers during blackout (batteries are discharged through solar cells), and when using diodes, they are shunted and no current flows through them. Diodes should be low impedance to reduce the voltage drop across them. For these purposes, Schottky diodes have recently been used.
The resulting electrical energy is accumulated in batteries, and then transferred to the load. Batteries are chemical power sources. The battery is charged when a potential is applied to it, which is greater than the battery voltage. The number of solar cells connected in series and in parallel must be such that the working