SLLA498 October 2020
Solar string inverters are used to convert the DC power output from a string of solar panels to a usable AC power. String inverters are commonly used in residential and commercial installations. Recent improvements in semiconductor technology is allowing for string inverters with high power density (from 10s of kW to 100s of kW). Due to modularity and ease of serviceability of string inverters, they are becoming a popular alternative over central inverters.
The main limitation of solar installations is the supply and demand gap - solar energy is abundantly available during peak day hours when the demand for energy is not high. So electrical energy generated from solar power has low demand. This problem has spawned a new type of solar inverter with integrated energy storage. This application report identifies and examines the most popular power topologies used in solar string inverters as well as Power Conversion Systems (PCS) in Energy Storage Systems (ESS).