Inverter technology

Inverters are an exclusively important element of electrical part of the photovoltaic power plant. Their main task is to convert DC electricity generated by photovoltaic panels into AC. The overall efficiency of a photovoltaic system depends on many functional characteristics of the inverter being used. As with the selection of photovoltaic panels, and in assessing the most suitable inverter should be taken not only its performance but also the degree of reliability. It is generally recognized that a truly cost-effective photovoltaic plant is the one that is working flawlessly.

Inverters can be classified according to several key indications:

• String Inverters and Central Inverters

  String inverters are installed near the photovoltaic panels, thus reducing losses in DC-part of the installation. Another advantage is that each string could be configured with different electrical parameters - power, voltage and current. So if part of the plant is shaded it only affects specific strings and provides less impact on the overall yield of the plant.

  On the other side central inverters are the preferred solution for systems that have no shading, all strings have the same slope and electrical characteristics. A major disadvantage of using central inverters is that in case of a fault the entire plants work is completely interrupted.

• Grid-tie and Off-grid

  Grid-tied inverters provide direct energy convert from DC to AC and send it to the grid with appropriate parameters (voltage, frequency and phase).

  Off-grid inverters are designed for autonomous systems that are not connected to the grid because of the remoteness of the site. The power received from the photovoltaic panels is stored in batteries and when needed is extracted and converted to standard network parameters (220V/50Hz), so that the electrical power can be utilized.

• Transformerless и With transformer

  This type of classification is based on inverter mode of converting DC power into AC.