In order to create a full variable shunt reactor having two magnetically controllable high-voltage throttles which is compact and at the same time can also provide capacitive reactive power, auxiliary windings are used which are inductively coupled to the high-voltage throttles. The auxiliary windings are connected to at least one capacitively acting component.

A system for stabilizing an alternating voltage grid has an inverter, which can be connected to the alternating voltage grid, and is configured to exchange reactive power with the alternating voltage grid. The system further has an inductor arrangement with variable inductor coils, which can be connected to the alternating voltage grid, and a control device, which is configured to control a reactive power in the alternating voltage grid by use of the inverter and by use of the inductor arrangement.

Provided is an arrangement for controlling a converter of a power generation system, for example, a wind turbine, the converter being connected to a connection point to a utility grid, the arrangement including: a measurement section adapted to provide measurement values indicative of values of current and voltage at the connection point, a main converter controller adapted to receive the measurement values and to generate a main converter control signal based on the measurement values, an active filter system adapted to receive the measurement values and to generate an active filter control signal based on the measurement values, an addition element adapted to add the main converter control signal and the active filter control signal and to supply the sum signal as a control signal to the converter.

A system and method to selectively pass and damp oscillations in an electric power grid via a controller of a power electronic device irrespective of the modes of the power oscillations. The system and method includes multiple limiters having dynamic limits that are openable and closeable to control the response of the controller, damping ratio dynamic gain control logic that determines a dynamic gain for a control signal based on the oscillation characteristics of one or more input signals, and pulse counter logic to selectively control at least one of the limiters based on the pulse count of the control signal.

A measurement device that performs a predetermined measurement task together with a plurality of other measurement devices is provided. This measurement device is provided with a sampling phase generator for generating a sampling phase for instructing a timing of sampling, and a communication unit for communicating with at least one of the plurality of other measurement devices. The communication unit transmits the sampling phase generated by the sampling phase generator to at least one of the plurality of other measurement devices. The sampling phase generator is configured to generate a third sampling phase, using an operation that is based on a generated first sampling phase and a second sampling phase received by the communication unit from at least one of the plurality of other measurement devices.

A system and method for controlling power flow in a hybrid power system includes a controller in communication with the hybrid power system. The controller is also in communication with at least one knowledge system to receive information related to power generation or power consumption within the hybrid power system. The controller generates a control command for each of the power converters in the hybrid power system and maintains a log of power flow to and from each device in the hybrid power system. The controller is also in communication with a provider of the utility grid and may generate the control commands for each of the power converters in response to commands provided from the provider of the utility grid.

The disclosure discloses a virtual impedance comprehensive control method for an inductive power filtering (IPF) system. According to the disclosure, harmonic damping control at grid side and zero impedance control of filters are organically combined according to a technical problem which is unsolved and process difficulty in equipment manufacturing in an existing filtering method, so that the problem of performance reduction of passive filtering equipment caused by a change in an impedance parameter of a power grid system is solved on one hand, optimization control over a quality factor of the passive filtering equipment may be implemented to reduce dependence on an equipment production process level on the other hand, a quality factor of the single-tuned filters may meet a design requirement, and an overall filtering characteristic is further improved.

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.

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.

A method can be used to control a voltage source converter of a power supporting arrangement to act as a virtual synchronous machine. The method includes obtaining a measured power level of the converter, processing the measured power level using a differential equation of an angular velocity of the virtual synchronous machine in order to obtain a control contribution, providing a phase angle of a physical quantity used to control the converter based on the control contribution, monitoring the ability of the converter to act as a virtual synchronous machine, determining that the ability of the converter to act as a virtual synchronous machine is deemed insufficient, and adjusting the control contribution by increasing the damping term and/or decreasing the moment of inertia term in response to determining that the ability of the converter to act as a virtual synchronous machine is deemed insufficient.