Inverters/converters are a key element of most renewable energy systems where the power generated is not suitable to either be used locally or to provide power directly to the electric utility. Many renewable sources such as photovoltaics generate DC power, while some renewable sources such as wind turbine systems generate AC, but not at the same voltage and/or frequency required by the utility.
As renewable energy sources have developed and the market for them has grown, the technology for power and the need for conversion has also developed. Today, inverters/converters are solid-state devices with increasingly precise control over the output power waveform, high efficiencies, and added functionality for increased safety and performance. One of the challenges facing inverter manufacturers is the ability to design for and comply with the differing regulatory requirements for safety and interconnection to the electric utility in global markets.
Two of the largest markets for inverters/converters are North America and Europe. Each market has its own regulatory framework that defines the requirements for equipment safety and for interconnection to the electric utility, as well as how compliance with these requirements must be demonstrated. Complying with these requirements affects the construction and functionality of the inverters. Factors such as the inverter output power level, input types, and the application also affect the regulatory requirements. Inverters can be part of a small system, owned and installed by homeowners, or may be part of a commercial system professionally installed and maintained. Utility interconnected systems can employ microinverters as small as a hundred watts, while commercial systems utilize inverters up to a few megawatts. All utility interconnected inverters – large, mid-range, or micro – must meet applicable local safety requirements and grid interconnection rules.