Inverters and converters

The inverter or converter is the key electronic device required for almost all distributed generation (DG) sources. It provides AC power at a useable voltage and frequency for connection to the utilities' electric power grid or to provide power for off-grid loads. In general, it converts the output of photovoltaic panels, fuel cells, wind turbines, microturbines and other rotating machines to an appropriate AC voltage and frequency for direct domestic and industrial use. More complex units can also supply power with the proper characteristics to the utility grid.

A converter is a device that accepts AC or DC power and converts it to another form of AC or DC power for direct utilization by a load or accumulation in an energy storage system.

A charge controller is a device to control the charging process of energy storage products such as batteries. These devices are necessary to match the output voltage of the DG source with the rated voltage of the battery or other storage medium. They also control the level and rate of charge to prevent damage to the storage medium.

An output controller is a device external to an inverter, converter or utility interactive distributed generation source that performs utility interface functions including over- and under-voltage, over- and under-frequency, synchronization, and anti-islanding protection.