Power Conversion System (PCS) or Hybrid Inverter

BESS batteries store and deliver DC power, while most loads use AC, requiring a Power Conversion System (PCS) or hybrid inverter. 

These bidirectional devices convert DC to AC for loads or the grid and AC to DC to charge the battery, enabling charging and discharging. 

The PCS uses battery status, like SoC and DoD, to manage charge and discharge according to the BESS strategy.

The PCS can provide a fast and accurate power response by communicating with the battery. It can be driven by a pre-set strategy, 

external signals (on-site meters, etc..), or an Energy Management System (EMS). Regarding the PCS, two types of configuration are essential to know. 

AC-coupled and DC-coupled. For solar + storage applications, there is a choice between the two.

AC-coupled is when the BESS is connected external to the solar PV system on the AC side of the PV inverter. The BESS has its own dedicated inverter connected to the battery.

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