سوال ۱۶ کنکور ارشد مهندسی برق ۱۴۰۰

PASSAGE 1:

A photovoltaic panel used as an energy source is very capricious, because the power of the electric current obtained from the panel will depend on the intensity of the incident light. Additionally, the load current also remains an important factor. Users of this energy source in most cases are not able to obtain constant lighting or a constant load. Usually, the panels are fixed in one spot and they are rarely placed on revolving supports that follow the sun. As a result, sunlight falls on the panel surface at different angles. In addition, the sun can be obscured by clouds. The load is not constant, but it usually varies according to the needs of the users. Under such conditions, the voltage on the panel terminals will also undergo significant changes.

Usually, users of the power network expect stable voltage, as they do not want to worry about its fluctuations. If, for example, it is 12 V DC, then changes are expected to be rather small, 2-3% of the nominal value at the most. Freely available energy sources are rarely capable of providing such power supply conditions. Therefore, properly constructed voltage converters are used as the intermediary between these sources and the user.

Unlike "standard" DC/DC converters for power supply - and depending on the target application - converters working with renewable energy sources must offer the right parameters to match the "caprices" of the source. The most important of these are a wide range of input voltages, suitable input resistance and high breakthrough voltage between input and output, usually at least several hundred volts.

The demand for "green energy" has resulted in devices and products designed for its acquisition being produced by many competing companies. An average user of a panel will be interested mainly in ready-made plug & play modules attached to the panels, but, on the other hand, electronic engineers may be searching for converter modules designed to be integrated into user's own devices. The target applications may include illuminated traffic signs, monitoring devices or systems operating within IoT networks.

16. What does the passage mainly discuss?