Methods and systems are described for determining value and placement of Distributed Energy Resources (DERs).

A power supply system, a converter, and a circulating current suppression method of the converter. The power supply system includes at least two converters that are coupled between a direct current power supply and an alternating current grid. Each converter obtains target output reactive power when an output current of the converter starts to increase from an initial current, obtains a reactive power compensation parameter based on the three-phase output voltages. Further, each converter obtains compensated output reactive power of the converter based on the reactive power compensation parameter and adjusts actual output reactive power of the converter based on the target output reactive power and the compensated output reactive power, so that an absolute value of a difference between common-mode output voltages of any two of the at least two adjusted converters is less than a difference threshold.

A power supply system, a converter, and a circulating current suppression method of the converter. The power supply system includes at least two converters that are coupled between a direct current power supply and an alternating current grid. Each converter obtains target output reactive power when an output current of the converter starts to increase from an initial current, obtains a reactive power compensation parameter based on the three-phase output voltages. Further, each converter obtains compensated output reactive power of the converter based on the reactive power compensation parameter and adjusts actual output reactive power of the converter based on the target output reactive power and the compensated output reactive power, so that an absolute value of a difference between common-mode output voltages of any two of the at least two adjusted converters is less than a difference threshold.

A method, apparatus, system and computer program is provided for optimizing and controlling volt-amperes reactive on an electrical control system. System-level and local-level measurements are determined and analyzed to prioritize and optimize which VAR adjusters are adjusted.

A method, apparatus, system and computer program is provided for optimizing and controlling volt-amperes reactive on an electrical control system. System-level and local-level measurements are determined and analyzed to prioritize and optimize which VAR adjusters are adjusted.

A method for providing grid-forming control of an inverter-based resource includes receiving, via a controller, one or more reference commands from an external controller. The method also includes determining, via the controller, one or more control commands for the inverter-based resource based on the one or more reference commands. Further, the method includes determining, via the controller, at least one feedforward signal as a function of the one or more control commands, one or more control signals, and one or more estimated electrical conditions of the inverter-based resource. The method also includes using the feedforward signal(s) to position at least one control angle of the inverter-based resource to an anticipated value needed to achieve the one or more reference commands, thereby enabling rapid response to the one or more reference commands received from the external controller.

Hybrid renewable energy source systems and methods are provided. A hybrid renewable energy source system can include a renewable energy source system (e.g., a photovoltaic (PV) system) in conjunction with an energy storage system (ESS), such as a battery energy storage system (BESS). The hybrid renewable energy source system can include at least one intelligent decentralized controller at the inverter/converter level, feeding a robust coordinated controller, thereby allowing the hybrid renewable energy source system to operate as a unified single power generation unit (PGU).

A method for operating a converter-based grid unit disposed electrically within an AC voltage section or adjacently to an AC voltage section of an electrical grid and electrically connected to the AC voltage section, includes using a control device to adjust infeed and drawing of active power and/or reactive power into and from the AC voltage section by actuating at least one converter of the converter-based grid unit. A multiplicity of measurement values is transmitted to the control device. The measurement values at least relate to different measurement variables and/or measurement locations within the AC voltage section or the converter-based grid unit. The control device selects a measurement value group from the multiplicity of available measurement values by selecting in accordance with a predefined selection guideline, and the at least one converter is actuated based on measurement values of the selected measurement value group.

The invention relates to controlling a power generating unit. Aspects of the invention include determining a virtual impedance value (Zvir), determining a virtual grid power (Pvsm) based on the virtual resistance value (Rvir) and the grid current (Igrid), determining a virtual synchronous machine rotational speed (ωVSM) and/or a synchronous machine angle (θVSM) of a virtual synchronous generator, and determining a voltage reference (Vabc) for controlling a line side converter to generate the desired reactive power (Qgrid) based on the virtual synchronous machine rotational speed or angle (ωVSM, θVSM), a virtual voltage (ΔVαβ, ΔVdq) and the voltage magnitude reference (Vqref).

A method for designing a battery storage at a connection point of a load to an energy supply network. In the method, at least two different load types are determined. A load profile of the load before a connection and an operation of the battery storage is recorded. The load profile is evaluated and the load is assigned to one of the load types depending on the evaluation. The battery storage is designed so that the load is assigned to a different load type after the battery storage has been connected and operated.