Capacitors on photovoltaic inverters

Capacitors play a critical role in the solar market. Among other uses, they are employed in PV inverters, which are devices that convert the DC power produced by solar cells into AC power that can be used in the electricity grid. Inverters typically make extensive use of large-sized capacitors that store electricity.

Some microinverter designs now are able to employ polyester film capacitors. One design includes a bulk capacitor from EPCOS based on polyester film, a type of plastic. The use of this device avoids the lifetime problems associated with electrolytic capacitors. Capacitors also are playing an increasing role in wind energy.

The ruggedness and small form factor of the PCC makes it suitable for space-constrained inverters in photovoltaic installations. The opportunities—and problems—for capacitors in PV inverters only increase in a new generation of products known as microinverters.

EPCOS is offering the power capacitor (PCC), which is suited for such applications. This compact power capacitor features extremely low ESR and ESL values and can be mounted directly onto the IGBT module. The ruggedness and small form factor of the PCC makes it suitable for space-constrained inverters in photovoltaic installations.

Manufacturers are offering parts specifically designed to suit the needs for solar and wind systems. With these efforts, capacitor makers are enabling the faster deployment, lower-maintenance costs and greater efficiency of renewable energy. Capacitors play a key role in renewable energy, from solar panel inverters to wind turbines.

Capacitor failure is a significant cause of malfunctions in PV inverters. These components are subjected to a variety of strains, including vibrations, mechanical stress and continuous operation at maximum voltages. Experts also note that electrolytic capacitors based on non-solid electrolytes age more quickly than those using solid electrolytes.