The present invention provides a power control circuit connectable to a load adapted to receive a power supply, the power control circuit adapted to absorb power from the power supply and adapted to deliver power to the power supply to stabilize at least one electrical parameter of the power supply. The present invention also provides an associated method of stabilizing at least one electrical parameter of a power supply connectable to a load, the method including absorbing power from the power supply or delivering power to the power supply. The at least one electrical parameter of the power supply includes parameters such as voltage and frequency.

A method for controlling a machine with at least one inverter-operated electric drive unit includes determining the instantaneous mains frequency of the mains supply to the machine and a deviation of the determined mains frequency over a standard frequency of the mains supply, determining a frequency correction value for adjusting the target drive frequency at which the electric motor of the machine is operated by weighting the deviation with a factor k, the factor k being specified dynamically as a function of at least one process variable of the drive load and/or of the operated drive process, and operating the machine at the adjusted target frequency.

The present disclosure provides an electrical system that includes an energy control system, a photovoltaic (PV) power generation system electrically coupled to the energy control system, an energy storage system electrically coupled to the energy control system, and a smart load panel electrically coupled to the energy control system and to a plurality of backup loads. The energy control system operates in an on-grid mode electrically connecting the PV power generation system to a utility grid and a backup mode electrically disconnecting the PV power generation system from the utility grid. The smart load panel selectively disconnects one or more of the plurality of backup loads from the energy control system when the energy control system is in the on-grid mode and when the energy control system is in the backup mode.

The system and method described herein provide grid-forming control of a power generating asset having a generator, such as a double-fed generator, connected to a power grid. Accordingly, a stator-frequency error is determined for the generator. The components of the stator frequency error are identified as a damping component corresponding to a tower damping frequency and a stator component. Based on the stator component, a power output requirement for the generator is determined. This power output requirement is combined with the damping power command to develop a consolidated power requirement for the generator. Based on the consolidated power requirement, at least one control command for the generator is determined and an operating state of the generator is altered.

The application relates to an oscillation active damping control method and system for grid-tied type-4 wind turbine generator. The method comprises: based on an interconnection model of multiple subsystems, constructing a stored energy function and a dissipated energy function of a current inner loop control subsystem, and interaction energy functions between the current inner loop control subsystem and other subsystems are constructed, then establishing an energy feedback model of Type-4 wind turbine generator; when the oscillation occurs, obtaining instantaneous angular frequency of the PLL, and then based on the energy feedback model, adjusting the current reference value of the q-axis current inner loop generated by the reactive power outer loop control subsystem, to make the stored energy function decrease with time, so as to suppress the oscillation.

A power plant-connected energy storage system maintains frequency quality of power generated and supplied by a power plant. The system includes an electric energy storage unit that includes two or more batteries of different types and is configured to be charged or discharged to improve frequency quality of power output from the power plant; and a power conditioner configured to control of the power output from the power plant and to control charge and discharge at least one of the two or more batteries in accordance with the control of the power output from the power plant. The two or more batteries include a short cycle battery having a relatively short charge/discharge cycle and a long cycle battery having a relatively long charge/discharge cycle.

Methods include, in response to a line frequency variation of a power grid, adjusting a voltage setpoint of a voltage regulator coupled to the power grid at a grid edge to maintain a voltage at the grid edge, wherein the adjusting the regulated voltage setpoint is configured to reduce the line frequency variation to stabilize the line frequency of the power grid. Apparatus include a voltage regulator configured to couple to a power grid at a grid edge and to maintain a voltage at the grid edge, wherein the voltage regulator is further configured to adjust a voltage setpoint of a voltage regulator in response to a line frequency variation of the power grid to reduce the line frequency variation and stabilize the line frequency of the power grid.

A method and a system for evaluating inertia of a power system and a storage medium. The method includes: injecting a cosine active power disturbance into the power system by small-disturbance injection, and obtaining frequency response at a node where the disturbance is injected, where the active power disturbance can be an energy storage, wind power, or photovoltaic power; acquiring an evaluation framework of inertia and frequency regulation capability of the power system according to relative characteristics of a frequency response function; and constructing a mathematical relationship between the impedance and frequency response characteristics according to a relationship among active power disturbance, frequency fluctuation and impedance.

The present disclosure provides an electrical system that includes an energy control system, a photovoltaic (PV) power generation system electrically coupled to the energy control system, an energy storage system electrically coupled to the energy control system, and a smart load panel electrically coupled to the energy control system and to a plurality of backup loads. The energy control system operates in an on-grid mode electrically connecting the PV power generation system to a utility grid and a backup mode electrically disconnecting the PV power generation system from the utility grid. The smart load panel selectively disconnects one or more of the plurality of backup loads from the energy control system when the energy control system is in the on-grid mode and when the energy control system is in the backup mode.

A system and method of a multi-channel, multi-mode electric vehicle (EV) AC to DC charger has power channels, each power channel contains an AC/DC converter and corresponding DC/DC regulator. Each channel is configured to supply DC power to a channel-connected EV. The charger also has a controllable bridging switch, connected in parallel between the power channels and disposed before or after the DC/DC regulators, and provides an intermediary path between the power channels. It also contains controllable series switches, after the DC/DC regulators to provide a break in a power channel output path. A controller controls the AC/DC converters, DC/DC regulators, bridging and series switches. The charger is multi-mode capable, enabling (a) charging an EV, (b) directing power from one channel's connected end device to another channel's connected end device, (c) injecting real or reactive power back to an AC power source, (d) active AC filtering, and (d) phase balancing.