Abb Schweiz Ag

Hitachi Energy Ltd

Simon Walton

Robert Turner

Sridhar Pulikanti

Nicholas James Elliott

Pietro Cairoli

Hongrae Kim

Andrew Tuckey

NIck Elliott

Parthasaradhy Kozhiparambil Kumaran

Dustin Murdock

Ian Murray Porteous

Arnoud Gerlof Van Der Wal

Nicholas James Elliot

Embodiments of the present disclosure relate to method and apparatus for detecting grid islanding in a grid supporting voltage source converter. The method includes modulating an output voltage at an output of the grid supporting voltage source converter; determining at least one grid parameter at an input to the grid supporting voltage source converter; and detecting the grid islanding for the grid supporting voltage source converter based on the at least one grid parameter.

Method and apparatus of detecting grid islanding

Embodiments of the present disclosure relate to parallel 3-level inverter without midpoint connection. The parallel 3-level inverter includes a plurality of parallel converters coupled in parallel between a common DC bus and a common AC output, wherein each of the plurality of parallel converters comprises a midpoint and the midpoints of the plurality of parallel converters are disconnected from each other.

Parallel NPC 3-level inverter without midpoint connection of the DC-links

Embodiments of present disclosure relate to apparatus and method for flux management in the ZISC based UPS system. The apparatus comprises: a first determining unit configured to determine a first offset flux on a series reactor in the ZISC based UPS system when power quality events occur in a grid connected to the ZISC based UPS system and the ZISC based UPS system operates in a grid-connected mode; and a first resetting unit configured to provide synthetic impedance damping to the series reactor to reset the first offset flux.

Apparatus and method for flux management in impedance isolation single conversion(ZISC) based UPS system

Embodiments of the present disclosure provide an electrical apparatus, a power supply system having the same and a method of manufacturing the electrical apparatus. The electrical apparatus includes a detecting circuit coupled to a generator and configured to detect a frequency of the generator. The electrical apparatus also includes a controller coupled to the detecting circuit and configured to receive a first signal indicating the detected frequency and adjust the frequency of the generator in response to determining that the detected frequency is out of a predetermined frequency range. In this way, an actively controlling of the changing rate of the power to and from generator may be achieved, if the generator frequency exceeds the configured limits.

Electrical apparatus, power supply system and method of manufacturing the electrical apparatus

A method of controlling a power converter, connected to an electrical grid, to mimic a synchronous generator, by: determining a frequency control error with respect to a setpoint and actual frequency of the grid, determining an input power to an inertia model of a synchronous generator based on the frequency control error, regulating by means of the input power a rotational frequency of the inertia model, determining a voltage control error with respect to a setpoint and actual voltage, determining an exciter parameter of a synchronous generator model based on the voltage control error, regulating by means of the exciter parameter an output voltage of the synchronous generator model, adjusting the rotational frequency or a phase angle obtained from the rotational frequency, and the output voltage based on a virtual impedance of a stator of the synchronous generator model, and controlling the power converter based on the adjusted rotational frequency or the adjusted phase angle and on the adjusted output voltage.

Method and control system for controlling a power converter

The present invention provides a method for operation of an offline uninterrupted power supplyfor providing power to a load in case of failure of a power source, the uninterrupted power supply comprising at least one disconnect switch, which is arranged between the power source and the load, at least one energy storage, at least one power converter, which is arranged between the at least one energy storage and the load at a load side of the disconnect switch, and a control device for controlling the at least one power converter to provide power from the at least one energy storage to the load in case of failure of the power source, comprising the steps of identifying a power quality event, differentiating the identified power quality events to separate load side events from power supply side quality events, and upon identification of a power supply side power quality event from an identified power quality event, providing power from the at least one energy storage to the load. The present invention also provides a offline uninterrupted power supply, in particular a medium-voltage uninterrupted power supply, to perform the above method.

UPS with source impedance compensation

One embodiment is a uninterruptable power supply (UPS) system including a utility disconnect switch (UDS) coupled with an input line and an output line and structured to selectably connect and disconnect the input line and the output line. The UDS includes a semiconductor switching device connected between the input line and the output line, a surge arrester coupled in parallel with the semiconductor switching device, a dynamic voltage balancing device and a static voltage balancing device which are coupled in parallel with the semiconductor switching device.

Growing community of inventors

Napier, New Zealand

Simon Walton