A differential mode electromagnetic noise injection network includes an injection piece and a differential mode loop. The injection piece includes a semiconductor transistor or a winding differential mode inductor. The injection piece is at least provided with a first injection end, a second injection end, and a differential mode electromagnetic noise component input end. The differential mode electromagnetic noise component input end is configured to input a differential mode electromagnetic noise component. The first injection end and the second injection end are connected to any two points that are connected in series in the differential mode loop in a one-to-one correspondence, and are configured to inject the differential mode electromagnetic noise component. An active electromagnetic interference filter including the differential mode electromagnetic noise injection network mentioned above is provided.

A method operates an arrangement having a DC transmission link or a DC transmission grid to which at least two converters each having an AC voltage side and a DC voltage side are connected. A grid stabilization device is connected to the AC voltage side of one of the converters, subsequently referred to as near converter. The grid stabilization device has for the purpose of grid stabilization an energy store for the buffer storage of energy and/or an energy consumer for the consumption of electrical energy, and the grid stabilization device is isolated on the grid side from at least one other of the at least two converters, subsequently referred to as a remote converter, by way of the near converter. The grid stabilization device is actuated by at least one control signal that is produced and transmitted to the grid stabilization device by the near or the remote converter.

A method and apparatus include a primary transformer coil, a secondary transformer coil, and a center tapped inductor coupled to the secondary transformer coil. A first switch may be in electrical communication with the center tapped inductor and may be configured to affect the first output voltage. A second switch may be in electrical communication with the center tapped inductor and may be configured to affect the second output voltage. In a particular example with an analog current (AC) output voltage, the two output voltages are out of phase to each other. In a direct current (DC) implementation, the transformer may be operated to output a positive and a negative output voltage. The apparatus may function as a resonant converter, or may operate in non-resonant mode. In one implementation, an H bridge may provide reactive power support. An inductor filter may be in electrical communication with the secondary transformer coil. Where desired, a diode bridge may be in electrical communication with the primary transformer coil.

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.

A distribution feeder of an electricity grid comprises a substation and a plurality of nodes with at least one controllable reactive power resource. A method is provided for locally controlling delivery of electrical power along the distribution feeder, wherein for a feeder segment in the distribution feeder the method comprises: obtaining an actual voltage magnitude at an upstream node and at a downstream node of the feeder segment, and a real power value at the upstream node; setting a target voltage phasor at the downstream node as a value when a power flow across the feeder segment is maintained, and when equal reactive power is injected at the upstream and downstream nodes that consumes all the reactive power in the feeder segment; and adjusting operation of the at least one controllable reactive power resource so that the actual voltage magnitude at the downstream node moves towards a target voltage magnitude of the target voltage phasor.

A method of mitigating high frequency harmonics in an output current of an electrical power system connected to a power grid includes providing an active harmonic filter in a stator power path connecting a stator of the generator to the power grid. Further, the method includes controlling, via a controller, the active harmonic filter to selectively extract a high frequency harmonic component from the output current. The method also includes determining, via the controller, whether the high frequency harmonic component is a positive sequence harmonic or a negative sequence harmonic. Moreover, the method includes compensating, via the controller, for the high frequency harmonic component based on whether the high frequency harmonic component is the positive sequence harmonic or the negative sequence harmonic to mitigate the high frequency harmonics in the output current.

An energy grid network includes multiple distributed energy resources (DERs) or DER nodes. A DER node includes a local energy source and a local energy load. The DER nodes in the network generate realtime data about energy availability from local energy sources and realtime data about energy demand. The DER nodes can share the realtime data with other DER nodes in the network to provide a constant view in the network about the energy generation and energy demand within the network. The shared realtime data can be scaled at each DER node based on physical distance, time to exchange energy between nodes, or both distance and time. A DER node generates its own realtime data and receives data from one or more other DER nodes and determines the value of energy use from local or non-local sources by local and non-local loads.

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.

An arrangement has a converter with an electrical series circuit of modules each having four electronic switching elements and an electrical energy storage device. The arrangement also has a cooling device for cooling the electronic switching elements by way of a liquid coolant and a heat exchanger and a control unit for controlling the electronic switching elements. The control unit controls the electronic switching elements in such a manner that at least one current harmonic is generated in the series circuit if the temperature of the liquid coolant or the temperature of a medium, which is intended to absorb the heat at the heat exchanger, falls below a predetermined limit temperature.