Photovoltaic + Energy Storage + Power Grid

Work with or without DC coupled PV farm, BESS can automatically act as backup power for loads when the grid fails. But loads will shut down if battery and solar run out and the grid fails.

System Operation Logic:

Photovoltaic power supplies the load first, and the surplus power is used to charge the battery. If photovoltaic power is not enough, the battery will supply power. If photovoltaic power and battery energy storage are not enough, the main power will supplement. If the mains power is also cut off, the load will shut down.

Application Control Logic:

On-grid Operation Mode

PV power supply the loads firstly, with excess electricity used to charge the batteries. When the state of charge (SOC) of the storage exceeds a certain value, EMS will forbid all power to charge the battery, and the excess electricity will feed into the main grid.

When pv is insufficient, both the grid and the batteries supply the load together.

When there is no photovoltaic power generation, battery and grid supply the loads.

When the SOC of the storage is below a certain value, EMS will forbid the battery discharge, and then the grid will supply the loads.

Off-grid Operation Mode

When the utility power fails, the STS quickly shuts down and simultaneously triggers a switch in the PCS to islanding VF mode, achieving a seamless transfer between grid-connected and islanding modes.

When pv is enough, pv supply the loads firstly, the extra power charge the battery, If the SOC of the energy storage exceeds the threshold, EMS will limit the pv power, protect from the over charge.

When pv is insufficient, both the pv and the batteries supply the load together.

When there is no photovoltaic power generation, battery supply the loads.

When the SOC of the energy storage falls below a certain level and the utility power is lost, the load will shut down.

When the utility power is restored, the ATS automatically switches back to the utility power.