An energy storage power converter system (PCS) is a power electronics converter for enabling bi-directional power flow (real and/or reactive) to an AC grid.
The PCS provides the electrical interface between DC energy storage media [e.g. Li-Ion, sodium sulphur (NaS), lead acid, Ni-Cd, flow batteries, ultra caps, etc.] and the AC grid.
Why is it needed?
Power system load leveling (deferred network and generation investment)
Grid stabilization (increase use of renewables)
Grid compliance for renewable and generation systems
Power quality improvement