As PV solar installations continue to grow rapidly over the last decade, the need for solar inverters with high efficiency, improved power density and higher power handling capabilities continue to increase. Today this is state of the art that these systems have a power conversion system (PCS) for battery storage integrated.
This application note outlines the most relevant power topology considerations for designing power stages commonly used in Solar Inverters and Energy Storage Systems (ESS).
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Solar string inverters are used to convert the DC power output from a string of solar panels to an AC power. String inverters are commonly used in residential and smaller commercial installations. Wide bandgap semiconductors like Silicon carbide (SiC) and Gallium nitride (GaN) allow to operate converters at higher switching frequencies which allows use of smaller magnetic components and in turn drive power density of these systems up. To scale power levels up very often such systems are made in modular fashion to get from 10th of kW to 100th of kWs.
To cope with the fact that Photovoltaic (PV)-systems stop generating energy when sun light goes down, these systems very often incorporate a power conversion port for a battery energy storage system (BESS). Excess energy generated during day time is stored into the battery and can be used during times the energy from the PV-string is not enough.