PCS (Power Conversion System) is the core part of an energy storage system, which is responsible for converting currents. It is a bidirectional reversible AC/DC converter that can convert the electric energy output from the grid or new energy generation through the energy storage inverter into DC power, which charges the battery. The energy released by the battery can then be converted back into AC power through the energy storage inverter and fed back to the grid or used to supply power to the load.

Energy storage converters have two working modes: grid-connected and off-grid. In grid-connected mode, the PCS bidirectionally converts the energy between the battery pack and the grid. It has features such as anti-islanding, automatic tracking of grid voltage phase and frequency, and low voltage ride-through. According to the requirements of grid dispatching or local control, the PCS charges the battery pack with AC power from the grid and can also discharge the energy storage battery. During peak grid load periods, the PCS inverts the DC power of the energy storage battery into AC power and feeds it back to the public grid; it also feeds or absorbs active power to the grid, providing reactive power compensation when necessary.

In off-grid mode, PCS is able to disconnect from the main grid and meet the set requirements, providing local partial loads with AC that meets the power quality requirements of the grid electrical energy. It can also smoothly switch between grid-connected and off-grid modes.
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Written by Mandy