Abstract: An energy storage system may include one or more first battery racks, one or more second battery racks, one or more DC/DC converters configured to manage the one or more second battery racks respectively, and a battery system controller configured to monitor outputs of the one or more first battery racks and outputs of the one or more DC/DC converters, and to control the outputs of the one or more DC/DC converters. Tye one or more second battery racks and the one or more DC/DC converters are additionally installed in the energy storage system after the first battery racks are installed in the energy storage system to augment the first battery racks.

Abstract: Discussed is an energy storage system that may include a plurality of first battery racks; a central DC/DC converter connected to the plurality of first battery racks and configured to perform power conversion; a plurality of second battery racks; and a plurality of DC/DC converters connected to the plurality of second battery racks respectively and configured to perform power conversion. Here, the central DC/DC converter and the plurality of DC/DC converters are connected in parallel to a DC bus connected to at least one of a power conversion device (PCS) and a power generation device.

Abstract: An energy storage system can include a plurality of first battery racks, a plurality of battery protection units configured to manage the plurality of first battery racks respectively, a plurality of second battery racks, a plurality of DC/DC converters configured to manage the plurality of second battery racks respectively, and a battery section controller configured to monitor outputs of the plurality of battery protection units and outputs of the plurality of DC/DC converters, and to control the outputs of the plurality of DC/DC converters.

Abstract: Discussed is a photovoltaic (PV) recombining apparatus configured to connect a photovoltaic (PV) system with a Direct Current (DC) bus connected to Direct Current (DC) power lines of an energy storage system (ESS) and an inverter (PCS). The PV recombination apparatus can include an inverter connection terminal connecting the photovoltaic system and the inverter, an ESS connection terminal connecting the photovoltaic system and the energy storage system, and a disconnector configured to disconnect the photovoltaic system and the DC bus according to a control command which is based on external conditions.

Abstract: An energy storage system, including a photovoltaic (PV) system and a battery system and connected with a power grid, may comprise a power conversion system (PCS) connected with the power grid and selectively connected to at least one of the photovoltaic system and the battery system; a first switch selectively connecting the photovoltaic system and a direct current (DC) link of the power conversion system; a second switch selectively connecting the battery system and a DC link of the power conversion system; and a controller for controlling a ground structure of at least one of the photovoltaic system, the battery system, and the power conversion system by controlling the first switch and the second switch based on a state of the photovoltaic system and a state of the battery system.

Abstract: Discussed is a switch control apparatus in an energy storage system connected with a power grid. The energy storage system includes a photovoltaic (PV) system, a power conversion system (PCS) selectively connected to the photovoltaic system, a first switch configured to selectively connect the photovoltaic system and a direct current (DC) link of the power conversion system, a first ground fault detector including a terminal which is connected to a ground, a second switch selectively configured to connect the photovoltaic system and another terminal of the first ground fault detector. A second switch is located between the first switch and the photovoltaic system, the switch control apparatus includes at least one processor; and a memory configured to store at least one instruction executed by the at least one processor.

Abstract: Discussed is an energy storage system connected with a power grid, and including: a photovoltaic (PV) system; a power conversion system to be connected with the power grid and selectively connected to the photovoltaic system; a first switch to selectively connect the photovoltaic system and a direct current (DC) link of the power conversion system; a first ground fault detector including a terminal connected to a ground; a second switch selectively to connect the photovoltaic system and another terminal of the first ground fault detector; and a switch controller to change a ground structure of at least one of the photovoltaic system, the power conversion system, and a battery system included in the energy storage system and to selectively connect the photovoltaic system and the DC link, by controlling the first switch and the second switch based on a power generation state of the photovoltaic system.

Abstract: A battery system management device includes at least one processor, and a memory that stores at least one command executed through the at least one processor. The at least one command includes: a command to define an equivalent model for a battery system having a predefined connecting structure including a plurality of batteries and at least one protection element; a command to calculate a short-circuit current generated in the battery system when a short circuit is generated at a location in the battery system using the equivalent model; a command to compare the calculated short-circuit current with a limiting current of the protection element; and a command to determine the number of batteries provided in the battery system based on the result of comparison.

Abstract: Discussed is an energy storage system that may include a plurality of first battery racks; a central DC/DC converter connected to the plurality of first battery racks and configured to perform power conversion; a plurality of second battery racks; and a plurality of DC/DC converters connected to the plurality of second battery racks respectively and configured to perform power conversion. Here, the central DC/DC converter and the plurality of DC/DC converters are connected in parallel to a DC bus connected to at least one of a power conversion device (PCS) and a power generation device.

Abstract: Discussed is an energy storage system connected with a power grid, and including a photovoltaic (PV) system; a power conversion system to be connected with the power grid and selectively connected to the photovoltaic system; a first switch to selectively connect the photovoltaic system and a direct current (DC) link of the power conversion system; a first ground fault detector including a terminal connected to a ground; a second switch selectively to connect the photovoltaic system and another terminal of the first ground fault detector; and a switch controller to change a ground structure of at least one of the photovoltaic system, the power conversion system, and a battery system included in the energy storage system and to selectively connect the photovoltaic system and the DC link, by controlling the first switch and the second switch based on a power generation state of the photovoltaic system.

Abstract: Discussed is a photovoltaic (PV) recombining apparatus configured to connect a photovoltaic (PV) system with a Direct Current (DC) bus connected to Direct Current (DC) power lines of an energy storage system (ESS) and an inverter (PCS). The PV recombination apparatus can include an inverter connection terminal connecting the photovoltaic system and the inverter, an ESS connection terminal connecting the photovoltaic system and the energy storage system, and a disconnector configured to disconnect the photovoltaic system and the DC bus according to a control command which is based on external conditions.

Abstract: A battery protection apparatus including a first current sensor connected to a positive terminal of a battery to measure a first current value; a second current sensor connected to a negative terminal of the battery to measure a second current value; a contactor including a first contactor positioned between the positive terminal of the battery and the first current sensor and a second contactor positioned between the negative terminal of the battery and the second current sensor; and a controller for setting a representative current value among the first current value and the second current value, and determining whether the representative current value is an abnormal current, and thus, it is possible to measure battery current stably even when one current sensor fails by measuring and monitoring current using heterogeneous current sensors, and protecting the battery from abnormal current based on the representative current value of the battery.

Abstract: An energy storage system, including a photovoltaic (PV) system and a battery system and connected with a power grid, may comprise a power conversion system (PCS) connected with the power grid and selectively connected to at least one of the photovoltaic system and the battery system; a first switch selectively connecting the photovoltaic system and a direct current (DC) link of the power conversion system; a second switch selectively connecting the battery system and a DC link of the power conversion system; and a controller for controlling a ground structure of at least one of the photovoltaic system, the battery system, and the power conversion system by controlling the first switch and the second switch based on a state of the photovoltaic system and a state of the battery system.

Abstract: A short-circuit current prediction method includes deriving an internal equivalent circuit of a battery that reflects a short circuit condition in a direct current (DC) circuit, derive a first equivalent circuit in consideration of electrical characteristics of the battery, deriving a second equivalent circuit in consideration of electrical characteristics of a fuse, obtain a short-circuit current prediction model by reflecting the first equivalent circuit and the second equivalent circuit based on the internal equivalent circuit, and predict the short-circuit current according to a battery voltage using the short-circuit current prediction model. Thus, high-precision short-circuit current prediction is possible in units of battery modules, racks, and systems.

Abstract: Discussed is an energy storage system that can include a plurality of first battery racks, a plurality of battery protection units configured to manage the plurality of first battery racks respectively, a plurality of second battery racks, a plurality of DC/DC converters configured to manage the plurality of second battery racks respectively, and a battery section controller configured to monitor outputs of the plurality of battery protection units and outputs of the plurality of DC/DC converters, and to control the outputs of the plurality of DC/DC converters.