An electric power method for an electric arc furnace includes regulating the electric power frequency of a power voltage and a power current of the electrodes, independently from the mains frequency.

Techniques are described for testing whether an end effector, or component thereof, is correctly or incorrectly installed to a manipulation system. In an example, a manipulation system can include a manipulator arm configured to receive an end effector having a first moveable jaw, a transducer configured to provide first effort information of the end effector as the end effector moves, and a processor configured to provide a command signal to effect a first test move of the first moveable jaw, and to provide an installation status of the of the end effector using the first effort information of the first test move.

A device controls a power flow in an AC network and has a series converter with a DC side to connect to a DC link and an AC side to connect to the AC network via a series transformer. The device further has a bridging arrangement between the series transformer and the series converter configured to bridge the series converter. The bridging arrangement contains at least one bridging branch having a switching unit with antiparallel thyristors and a resistance in series with the switching unit. Furthermore, a method of operation operates the device.

A battery energy storage system comprises a first equipment unit comprising a first skid positionable on a surface, a first inverter and a first transformer mounted on the first skid, a second equipment unit comprising a second skid, a second inverter and a second transformer mounted on the second skid, and a support structure for positioning the second equipment unit longitudinally above and spaced apart from the first equipment unit in a laterally offset manner. A method of increasing energy storage capacity of a storage system comprises building a support structure over a first inverter and transformer unit installed at a first location, placing a second inverter and transformer unit on the support structure such that the second inverter and transformer unit is longitudinally spaced from and laterally offset from the first inverter and transformer unit and adding an additional battery container.

A method of controlling battery energy storage comprises a renewable active power source (P.sub.R), a battery energy storage system (BESS), at least one static load (P.sub.Load) and at least one high dynamic load P.sub.H.LOAD. Active power demand of the system in the point of common coupling is at quasi-constant level. The method further includes gathering constant active power limit from the external grid (P.sub.GRID) and historical data of active power profiles of: predicting the following active power profiles for day+1, calculating required active power of the battery energy storage system, setting daily peak of state of charge and minimum state of charge of the battery energy storage system, and verifying whether daily peak of state of charge and minimum state of charge ensure that instantaneous values of state of charge through the entire day of the battery energy storage system is within range of 20% to 80%.

The multi-time scale battery energy/storage system (BES) management framework proposed in the present disclosure can be used for day-ahead capacity scheduling and real-time BES operation control in the latest performance-based frequency regulation market. This multi-time scale BES management framework includes three control layers: long-term battery performance planning layer, day-ahead regulation capacity scheduling layer, real-time battery operation control layer. These three layers will coordinate with each other, and operate at different time scales.

This invention is directed to systems and methods that track a specified stored energy level profile for a BESS in a microgrid. The systems and methods including using a control algorithm that tracks the stored energy level profile for the BESS. The controller algorithm includes a Kalman Filter design for a model-based state reconstruction to overcome sensor/communication errors during real-time operation. The latter is important to guarantee the ability of the microgrid to continue its seamless operation during periods of erroneous sensor measurements or flawed communication.

A grouped consensus power allocation method for multiple energy storage units is provided, including determining a grouped coordination control strategy of multiple battery energy storage units (BESUs) of a BESS (battery energy storage system), where the multiple BESUs are communicated through a communication topology and grouped into a charging group and a discharging group, performing power coordination control power coordination control between the charging group and the discharging group based on a distributed algorithm, determining whether a switching between the charging group and the discharging group is triggered during an operation process of the BESS, and switching when it is triggered. The method can reduce the number of charging/discharging state conversions of the BESUs, prolong the service life of energy storage, ensure that the power allocation results meet the power constraints of the BESUs, reduce low-power operation times of the BESUs, and improve the efficiency of energy storage operation.

The invention provides a method and system for operating an inverter based distributed power generation source with energy storage system, as a Flexible AC Transmission System (FACTS) device—a STATCOM. The inverter based distributed power generation source can provide reactive power compensation, voltage regulation, damping enhancement, stability improvement and other benefits provided by FACTS devices. These STATCOM functions are provided when the said energy storage based distributed power generation source is doing at least one of: i) not exchanging active power with said power grid system, or ii) exchanging active power less than a maximum inverter capacity with said power grid system. The present invention thus provides a technological improvement that opens up a new set of applications and potential revenue earning opportunities for energy storage based distributed power generation sources other than simply from exchanging (injecting or absorbing) active power.

Systems and methods for supplying power (both active and reactive) at a medium voltage from a DCSTATCOM to an IT load without using a transformer are disclosed. The DCSTATCOM includes an energy storage device, a two-stage DC-DC converter, and a multi-level inverter, each of which are electrically coupled to a common negative bus. The DC-DC converter may include two stages in a bidirectional configuration. One stage of the DC-DC converter uses a flying capacitor topology. The voltages across the capacitors of the flying capacitor topology are balanced and switching losses are minimized by fixed duty cycle operation. The DC-DC converter generates a high DC voltage from a low or high voltage energy storage device such as batteries and/or ultra-capacitors. The multi-level, neutral point, diode-clamped inverter converts the high DC voltage into a medium AC voltage using a space vector pulse width modulation (SVPWM) technique.